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DR ANTHONY MELVIN CRASTO, Born in Mumbai in 1964 and graduated from Mumbai University, Completed his Ph.D from ICT, 1991,Matunga, Mumbai, India, in Organic Chemistry, The thesis topic was Synthesis of Novel Pyrethroid Analogues, Currently he is working with AFRICURE PHARMA, ROW2TECH, NIPER-G, Department of Pharmaceuticals, Ministry of Chemicals and Fertilizers, Govt. of India as ADVISOR, earlier assignment was
with GLENMARK LIFE SCIENCES LTD, as CONSUlTANT, Retired from GLENMARK in Jan2022 Research Centre as Principal Scientist, Process Research (bulk actives) at Mahape, Navi Mumbai, India. Total Industry exp 32 plus yrs, Prior to joining Glenmark, he has worked with major multinationals like Hoechst Marion Roussel, now Sanofi, Searle India Ltd, now RPG lifesciences, etc. He has worked with notable scientists like Dr K Nagarajan, Dr Ralph Stapel, Prof S Seshadri, etc, He did custom synthesis for major multinationals in his career like BASF, Novartis, Sanofi, etc., He has worked in Discovery, Natural products, Bulk drugs, Generics, Intermediates, Fine chemicals, Neutraceuticals, GMP, Scaleups, etc, he is now helping millions, has 9 million plus hits on Google on all Organic chemistry websites. His friends call him Open superstar worlddrugtracker. His New Drug Approvals, Green Chemistry International, All about drugs, Eurekamoments, Organic spectroscopy international,
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and implementation them on commercial scale over a 32 PLUS year tenure till date Feb 2023, Around 35 plus products in his career. He has good knowledge of IPM, GMP, Regulatory aspects, he has several International patents published worldwide . He has good proficiency in Technology transfer, Spectroscopy, Stereochemistry, Synthesis, Polymorphism etc., He suffered a paralytic stroke/ Acute Transverse mylitis in Dec 2007 and is 90 %Paralysed, He is bound to a wheelchair, this seems to have injected feul in him to help chemists all around the world, he is more active than before and is pushing boundaries, He has 100 million plus hits on Google, 2.5 lakh plus connections on all networking sites, 100 Lakh plus views on dozen plus blogs, 227 countries, 7 continents, He makes himself available to all, contact him on +91 9323115463, email amcrasto@gmail.com, Twitter, @amcrasto , He lives and will die for his family, 90% paralysis cannot kill his soul., Notably he has 38 lakh plus views on New Drug Approvals Blog in 227 countries......https://newdrugapprovals.wordpress.com/ , He appreciates the help he gets from one and all, Friends, Family, Glenmark, Readers, Wellwishers, Doctors, Drug authorities, His Contacts, Physiotherapist, etc
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Umifenovir[2] (trade names ArbidolRussian: Арбидол, Chinese: 阿比朵尔) is an antiviral treatment for influenza infection used in Russia[3] and China. The drug is manufactured by Pharmstandard (Russian: Фармстандарт). Although some Russian studies have shown it to be effective, it is not approved for use in other countries. It is not approved by FDA for the treatment or prevention of influenza.[4] Chemically, umifenovir features an indole core, functionalized at all but one positions with different substituents. The drug is claimed to inhibit viral entry into target cells and stimulate the immune response. Interest in the drug has been renewed as a result of the SARS-CoV-2 outbreak.
Umifenovir is manufactured and made available as tablets, capsules and syrup.
Testing of umifenovir’s efficacy has mainly occurred in China and Russia,[5][6] and it is well known in these two countries.[7] Some of the Russian tests showed the drug to be effective[5] and a direct comparison with Tamiflu showed similar efficiency in vitro and in a clinical setting.[8] In 2007, Arbidol (umifenovir) had the highest sales in Russia among all over-the-counter drugs.
Mode of action
Biochemistry
Umifenovir inhibits membrane fusion.[3] Umifenovir prevents contact between the virus and target host cells. Fusion between the viral envelope (surrounding the viral capsid) and the cell membrane of the target cell is inhibited. This prevents viral entry to the target cell, and therefore protects it from infection.[9]
Some evidence suggests that the drug’s actions are more effective at preventing infections from RNA viruses than infections from DNA viruses.[10]
More recent studies indicate that umifenovir also has in vitro effectiveness at preventing entry of Ebolavirus Zaïre Kikwit, Tacaribe arenavirus and human herpes virus 8 in mammalian cell cultures, while confirming umifenovir’s suppressive effect in vitro on Hepatitis B and poliovirus infection of mammalian cells when introduced either in advance of viral infection or during infection.[13][14]
Research
In February 2020, Li Lanjuan, an expert of the National Health Commission of China, proposed using Arbidol (umifenovir) together with darunavir as a potential treatment during the 2019–20 coronavirus pandemic.[15] Chinese experts claim that preliminary tests had shown that arbidol and darunavir could inhibit replication of the virus.[16][17] So far without additional effect if added on top of recombinant human interferon α2b spray.[18]
In 2007, the Russian Academy of Medical Sciences stated that the effects of Arbidol (umifenovir) are not scientifically proven.[20]
Russian media criticized lobbying attempts by Tatyana Golikova (then-Minister of Healthcare) to promote umifenovir,[21] and the unproven claim that Arbidol can speed up recovery from flu or cold by 1.3-2.3 days.[22] They also debunked claims that the efficacy of umifenovir is supported by peer-reviewed studies.[23][24]
Arbidol hydrochloride, chemical name: 6-bromo-4-(dimethylaminomethyl)-5-hydroxy-1-methyl-2-(phenylthiomethyl)-1H- Indole-3-carboxylic acid ethyl ester hydrochloride, the structural formula is as follows:
Arbidol hydrochloride is an antiviral drug developed by the Soviet Medicinal Chemistry Research Center. It was first listed in Russia in 1993. It is used as a monohydrate for medicinal purposes. This product not only has immunomodulatory and interferon-inducing effects, but also has good anti-influenza virus activity, and is clinically used for the prevention and treatment of influenza and other acute viral respiratory tract infections.
The preparation of Arbidol hydrochloride has multiple synthetic routes, Chinese patent CN1687033A and Wang Dun, Wu Xiujing, Gong Ping’s “Synthesis of Arbidol Hydrochloride” bibliographical report in Chinese Pharmaceutical Industry Magazine 2004,35(8) are Taking p-benzoquinone and 3-aminocrotonic acid ethyl ester as starting materials, through Neitzescu reaction, O-acylation, N-alkylation, bromination, thiophenol reaction, Mannich amine methylation reaction, hydrochloric acid acidification to obtain hydrochloric acid Arbidol, the total reaction yield was 22.9%.
The synthetic route is as follows:
The Nenitzescu reaction used in the synthesis of indole rings in this method, the reaction yield of this step is about 60%, resulting in a total yield of 22.9%.
U.S. Patent US5198552 and World Patent WO9008135 reported that 5-hydroxy-1,2-dimethylindole-3-ethyl carboxylate was used as raw material, and arbidol hydrochloride was prepared through bromination, condensation, Mannich reaction and salt-forming reaction you.
Although the synthesis steps of this method are short, the raw material 5-hydroxy-1,2-dimethylindole-3-carboxylic acid ethyl ester is not easy to obtain, and the large-scale application is difficult.
Song Yanling, Zhao Yanfang, Gong Pingren reported in the 3rd National Symposium on Pharmaceutical Engineering Technology and Education “Synthesis Research on Arbidol Hydrochloride” in the literature report using thiophenol as the starting material, and chloroacetoacetic acid. After the substitution reaction of the ethyl ester, the thiophenyl fragment in the molecule is introduced, which is then condensed with methylamine, followed by the Neitzescu reaction with p-benzoquinone, and the dimethylamine methyl group is introduced through the Mannich reaction. Reaction, then carry out deprotection reaction, and finally obtain the final product Arbidol hydrochloride through salification reaction
Its synthetic route is as follows:
Since the Nenitzescu reaction yield in this method is only 33.7%, the total yield is only 11.2%.
There are also bibliographical reports (Wen Yanzhen, Gao Zhiwei, Wei Wenlong, Zhi Cuimei, Wang Qi etc. in China Pharmaceutical Industry Journal 2006, “The Synthetic Route Diagram of Arbidol Hydrochloride” reported in 2006,37(12)) is based on ethyl acetoacetate. Ester and methylamine are used as starting materials, and Arbidol hydrochloride is obtained by Neitzescu reaction, acylation to protect hydroxyl group, bromination, thiophenol reaction, Mannich reaction, and acidification.
The synthetic route is as follows:
The method has relatively mild reaction conditions and relatively easy-to-obtain raw materials, but the total yield is still low, about 20%.
The above synthesis methods of Arbidol hydrochloride all use the Nenitzescu indole ring synthesis method to synthesize the indole ring of Arbidol hydrochloride, resulting in a low total reaction yield of about 10% to 20%.
SUMMARY OF THE INVENTION
In view of the above-mentioned problems, the object of the present invention is to provide a preparation method of Arbidol hydrochloride, the raw materials are easy to obtain, the reaction technical conditions are relatively simple, the reaction conditions are mild, and the total reaction yield is relatively high, reaching more than 30%. The cost is low, and it is suitable for industrial production. The method of the invention is based on the starting material of 3-iodo-4-nitrophenol, which is protected by a hydroxyl group, synthesized by indole ring, N-methylated, brominated, thiophenolated, and Mannich amine. Methylation reaction, acidification with hydrochloric acid, and purification to obtain Arbidol hydrochloride.
The reaction formula of the inventive method is as follows:
Fe stands for iron powder
CH 3 COOH stands for acetic acid
H 2 O is for water
(CH 3 ) 2 SO 4 Represents dimethyl sulfate
K 2 CO 3 stands for potassium carbonate
Example 1:
A preparation method of Arbidol hydrochloride, its steps are (preparation of compound 1):
A. Preparation of compound 1: 53 g of 3-iodo-4-nitrophenol was added to 160 g of acetone (drying over anhydrous potassium carbonate), 30.3 g of triethylamine was added, and 37.7 g of triethylamine was added dropwise at room temperature (20-25° C., the same below). g acetyl chloride, dripped in 1 hour, the reaction solution was automatically raised to reflux temperature T=56°C, reacted for 0.5h, cooled to room temperature T=25°C naturally, the reaction solution was poured into 1000g ice water, stirred, filtered, and the filter cake was washed with water , and vacuum-dried to obtain 57.4 g of compound 1 crude product with a yield of 93.6%. The next reaction was carried out directly without further purification.
B. Preparation of compound 2: 48.6 g of ethyl acetoacetate and 180 ml of freshly distilled tetrahydrofuran were added to a dry flask. Over 2 hours, 41.9 g of potassium tert-butoxide was added in portions with stirring. The temperature was raised to T=70°C (reflux), and the solution of 57.4 g of compound 1 obtained in the step and 75 mL of freshly distilled tetrahydrofuran was added dropwise, and the drop was completed in 2 hours. TLC plates monitor the reaction endpoint. After the reaction mixture was cooled to room temperature T=25°C, 93.5 ml of a 4 mol/L hydrochloric acid solution was added dropwise. The precipitated potassium chloride was removed by filtration, the solvent was evaporated under reduced pressure, and the obtained solid was washed with 45 mL of water and 60 mL of petroleum ether in turn to obtain 56.6 g of a crude product of compound 2 with a yield of 98%. The crude product can be recrystallized from the mixed solution of petroleum ether and ethyl acetate to obtain pure product.
C. Preparation of compound 3: add 56.6 g of compound 2, 160 mL of acetic acid and 160 mL of water to the flask, stir under nitrogen protection, add 30.8 g of iron powder in batches, stir vigorously, and heat the reaction mixture to T=80 °C for 4 h. End (TLC plate detection). Iron and its oxides were removed by filtration, water and acetic acid were distilled off under reduced pressure, neutralized with saturated sodium carbonate solution to weakly alkaline, extracted with ethyl acetate, dried over anhydrous magnesium sulfate, and concentrated to obtain 44.1 g of compound 3 crude product in a yield of 44.1 g. 92.3%.
D. Preparation of compound 3: add 10.0 g of compound 2, 28 mL of acetic acid and 28 mL of water to the flask, stir under nitrogen protection, add 7.2 g of iron powder in batches, stir vigorously, and simultaneously heat the reaction mixture to T=80 ° C, 4h reaction End (TLC plate detection). Iron and its oxides were removed by filtration, water and acetic acid were evaporated under reduced pressure, neutralized with saturated sodium carbonate solution to weakly alkaline, extracted with ethyl acetate, dried over anhydrous magnesium sulfate, and concentrated to obtain 7.5 g of compound 3 crude product, yield 89.4%.
E. Preparation of compound 4: 44.1 g of compound 3 prepared in step C was added to 230 ml of DMF, and after adding 35.0 g of anhydrous potassium carbonate, 31.9 g of dimethyl sulfate was slowly added dropwise at 100° C. under stirring, and the same temperature T= The reaction was carried out at 100 °C for 4 h. The reaction solution was cooled to room temperature of T=25°C, 280 ml of water was added under stirring, left to stand for crystallization, suction filtered, the filter cake was washed with water and dried to obtain 44.6 g of a crude compound 4, which was recrystallized with methanol to obtain 36.8 g of a refined compound of compound 4, Yield 79.3%
F. Preparation of compound 5: 36.8g of compound 4 was added to 200ml of carbon tetrachloride, 0.1g of benzoyl peroxide was added, heated to T=76°C and refluxed, 45.0g of bromine was added dropwise, and the reaction was completed within 2h. For 4 h, the reaction solution was cooled in an ice-water bath, filtered, and the filter cake was washed with a small amount of carbon tetrachloride, and dried to obtain 47.5 g of compound 5 crude product, with a yield of 82%.
G. Preparation of compound 6: dissolve 15.4 g of potassium hydroxide in 360 ml of methanol, stir, cool to 0-10° C. in an ice-water bath, add 12.7 g of thiophenol, react for 10 min, add 47.5 g of compound 5, and warm to room temperature, The reaction was carried out for 3 to 3.5 h, the reaction solution was poured into 1500 ml of ice water, adjusted to pH 2 with hydrochloric acid under stirring, filtered, the filter cake was washed with water, and dried in vacuo to obtain 42.9 g of crude compound 6 with a yield of 93.1%. The crude product was recrystallized with ethyl acetate, 10 g of activated carbon was decolorized, and 36.0 g of the dried compound 6 was purified, with a purification yield of 84%. The mother liquor of recrystallization is concentrated and recovered. Or to prepare compound 6, dissolve 3.3 g of potassium hydroxide in 75 ml of methanol, stir, cool to 0-10° C. in an ice-water bath, add 2.7 g of thiophenol, react for 10 min, add 10.0 g of compound 5, warm to room temperature, and react For 3-3.5 h, the reaction solution was poured into 300 ml of ice water, adjusted to pH 2 with hydrochloric acid under stirring, filtered, the filter cake was washed with water, and dried in vacuo to obtain 9.0 g of crude compound 6 with a yield of 93.1%. The crude product was recrystallized with isopropanol, 2 g of activated carbon was decolorized, and 6.3 g of the dried refined product of compound 6 was obtained, with a purification yield of 70%. The mother liquor of recrystallization is concentrated and recovered.
H. Preparation of compound 7:
In 320ml of ethanol, add, (33%) dimethylamine aqueous solution 29.2g, (37-40%) formaldehyde aqueous solution 23.8g, stir for 10min, add 36.0g compound 6, react at 60°C for 5h, the reaction is completed, 5.0g activated carbon decolorization, Filtration while hot, tetrahydrofuran was distilled off from the filtrate under reduced pressure, and dried to obtain 40.4 g of compound 7 crude product, with a yield of 99.0%. Or to prepare compound 7, under stirring and cooling conditions, 8.1 g of (33%) dimethylamine aqueous solution, 6.6 g of (37-40%) formaldehyde solution and 10 g of compound 6 were sequentially added to 100 ml of glacial acetic acid, and placed in 70 The reaction was carried out at °C for 6 hours. After the completion of the reaction, the reaction solution was concentrated under reduced pressure, 100 ml of water was added, and the pH was adjusted to 12 with trimethylamine solution. The aqueous phase was extracted three times with dichloromethane (20 ml×3), and the organic phase was dried over anhydrous sodium sulfate. Concentrate under reduced pressure and dry to obtain 9.6 g of crude compound 7, with a yield of 85.0%.
J. Preparation of compound 8:
40.4 g of the crude product of compound 7 obtained in the above step H was heated and dissolved in 150 ml of acetone, adjusted to pH=2 with hydrochloric acid while hot, a solid was precipitated, cooled to about 0°C in an ice-water bath, filtered, and the filter cake was washed with frozen acetone and dried in vacuo to obtain compound 8 Crude product 40.5g, yield 89.8%.
The above crude compound J was recrystallized from acetone-ethanol-water (3:1:1). 36.5 g of product were obtained, and the yield was 90.0%.
Research and develop a kind of method for efficient green synthesis of arbidol hydrochloride intermediate, the structural formula of arbidol hydrochloride is as follows:
Example 1: Ethyl 5-acetoxy-1,2-dimethylindole-3-carboxylate
After the device was installed, 150 mL of acetic anhydride solvent was added to the three-necked flask, and then solid ethyl 5-hydroxy-1,2-dimethylindole-3-carboxylate (23.3 g, 0.1 mol) was added while stirring. After all dissolved, heated to reflux for 4 h, after the reaction was completed, the reaction solution was cooled, and the solid was obtained by suction filtration. Wash the solid with water for 4 times (150 mL-200 mL of water each time), and slowly add 0.15 mol/L ammonia water to the solution in the third time to control the pH of the mixed system by adding water to the solid to be 8 to 9. Finally, suction filtration A solid was obtained, which was dried in an oven at 70° C. for 5 h to obtain a crude product. Recrystallization from methanol gave 18.8 g of ethyl 5-acetoxy-1,2-dimethylindole-3-carboxylate as brown crystals. Yield 65%.
Example 2: Ethyl 5-acetoxy-6-bromo-2-bromomethyl-1-methylindole-3-carboxylate
After installing the device, in a three-necked flask, ethyl 5-acetoxy-1,2-dimethylindole-3-carboxylate (17.9g, 0.065mol), catalyst (p-cymene)- Ruthenium dichloride dimer (4.0g, 0.0065moL), N-bromosuccinimide NBS (46.28g, 0.26moL) and 200mL dimethylacetamide DMA, slowly warmed to 90°C in oil bath under nitrogen protection , maintain the reaction temperature for 24h, after the reaction is over; cool the reaction solution to room temperature, add an appropriate amount of water to the reaction solution, extract 5 times with ethyl acetate, combine the organic phases, dry, spin dry the solvent to obtain a solid, use acetone After recrystallization, a white powdery solid was precipitated, which was dried in vacuo to obtain 23.3 g of ethyl 5-acetoxy-6-bromo-2-bromomethyl-1-methylindole-3-carboxylate. Yield 80%.
Example 3: Ethyl 6-bromo-5-hydroxy-1-methyl-2-phenylthiomethylindole-3-carboxylate
Install the device, add 150 mL of methanol solvent to the three-necked flask, slowly add 8.6 g of solid potassium hydroxide under stirring, cool to room temperature after all dissolved, then add thiophenol (6.2 g, 0.05 mL) under stirring, After about 15 min, ethyl 5-acetoxy-6-bromo-2-bromomethyl-1-methylindole-3-carboxylate (23.3 g, 0.05 moL) was finally added, and the reaction was stirred at room temperature for 4 h. After the reaction is completed. 10% acetic acid was added dropwise to the reaction solution until the pH of the reaction solution was 3-4. After a large amount of yellow solid was precipitated, the solid was obtained by suction filtration, washed once with water, filtered with suction, and dried at 70 °C for 5 h in a drying box. get crude products. Recrystallization from ethyl acetate gave 12.6 g of ethyl 6-bromo-5-hydroxy-1-methyl-2-phenylthiomethylindole-3-carboxylate as yellow-white crystals. Yield 60%.
Example 4: Arbidol
After installing the device, add 100 mL of glacial acetic acid solution to the three-necked flask, cool it to 0 °C, slowly add 40 mL of 40% methylamine aqueous solution, and then add 10 mL of 37% formaldehyde aqueous solution, and after the reaction is stirred for 15 min, add 6- Ethyl bromo-5-hydroxy-1-methyl-2-phenylthiomethylindole-3-carboxylate (12.6g, 0.03moL), stirred uniformly for 10 min, then began to heat up to 80°C, maintaining the reaction temperature , and react for 4 h after complete dissolution. After the reaction is over, pour the reaction solution into water, add an appropriate amount of 20% potassium hydroxide solution to neutralize it with stirring, adjust the pH of the solution to 7.0, precipitate solids, filter with suction, and wash with water once. The solid was obtained by suction filtration, and dried in an oven at 70 °C for 5 h to obtain a crude product. Recrystallize with acetonitrile, after complete dissolution, add 1 g of activated carbon to reflux for 30 min, filter hot, cool, and precipitate 8.5 g of brown solid Arbidol. Yield 60%.
Example 5: Arbidol hydrochloride
Install the device, add an appropriate amount of acetone solvent to the three-necked flask, add Arbidol (8.5g, 0.018moL) under stirring, heat to reflux, add 10mL of concentrated hydrochloric acid dropwise, reflux for 30 min, and after the reaction is over, cool the reaction The liquid was brought to room temperature, and filtered with suction to obtain crude Arbidol hydrochloride, which was dried in an oven at 50 °C for 3 h. Recrystallize with acetone:ethanol (3:2) solvent, cool at room temperature for 10 h, freeze in refrigerator for 10 h, suction filtration, wash the solid with a small amount of acetone, and obtain 7.0 g of refined Arbidol hydrochloride in a yield of 75%. MS (EI): m/z: 513.8754 ([M]+).
1,2-Dimethyl-5-hydroxyindole-3-acetic acid ethyl ester (I) is acetylated with acetic anhydride affording the O-acyl derivative (II) , which is brominated to the corresponding dibromide compound (III) . The reaction of (III) with thiophenol in KOH yields (IV) , which is then submitted to a conventional Mannich condensation with formaldehyde and dimethylamine in acetic acid, giving the free base of arbidol (V), which is treated with aqueous hydrochloric acid .
Umifenovir (Arbidol®) is an indole derivative first marketed in 1993 for the prophylactic treatment of infections caused by influenza A and B viruses [74]. Produced by Pharmstandard, it is still currently used in Russia and China to treat influenza infections [75]. Umifenovir is marketed in 50 and 100 mg capsules, being administered orally. The pharmacokinetics is limited, presenting rapid absorption and reaching the maximum concentration in 1.6–1.8 h. It is a slow elimination drug, with a half-life of 16 to 21 h, and may be administered twice a day [76].
The drug’s anti-influenza mechanism of action is related to arbidol’s ability to bind to the haemagglutinin (HA) protein [77]. The haemagglutinin (HA) protein is a homotrimeric glycoprotein found on the surface of the influenza virus, and it is essential for its infectivity. This protein is responsible for allowing the influenza virus binding to the sialic acid present on the surface of the target cells (respiratory tract cells or erythrocytes). As a result of this interaction, the virus is internalized in the host cell. Once umifenovir binds to the HA protein, this glycoprotein is prevented from binding to sialic acid, so the virus is no longer able to penetrate the host cell [78].
The structural similarity between the SARS-CoV-2 peak and the influenza virus (H3N2) HA glycoproteins justifies the fact that drugs that are capable of binding to HA can also do so to the SARS-CoV-2 spike protein. This fact was evidenced by molecular modeling studies, wherein was demonstrated that umifenovir is able to bind to the protein peak, preventing its trimerization, which would be a determining factor for the mechanism of cell adhesion (Fig. 8) [78].
Fig. 8. Umifenovir (in orange) binding region in SARS-CoV-2 spike glycoprotein. Reprinted from International Journal of Antimicrobial Agents, 56, N. Vankadari, “Arbidol: A potential antiviral drug for the treatment of SARS-CoV-2 by blocking trimerization of the spike glycoprotein”, Page 2, with permission of Elsevier. Copyright 2020. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
Recently in 2020, in vitro studies performed with Vero cells confirmed that arbidol efficiently inhibits SARS-CoV-2 infection with an EC50 of 4.11 μM. The author also determined that arbidol was able to efficiently block both viral entry and post-entry stages, and also concluded that the drug prevented the viral attachment and release of SARS-CoV-2 from the intracellular vesicles. Importantly, the EC50 of arbidol against SARS-CoV-2 led the authors to suggest that the dose of arbidol currently recommended by the Chinese Guidelines (200 mg, 3 times/day) should be elevated in order to achieve ideal therapeutic efficacy to inhibit the SARS-CoV-2 infection [79].
A clinical trial was conducted at Wuhan Jinyintan Hospital, in 2020, from February 2 to March 20 conducted to evaluate the effectiveness and safety of umifenovir in the treatment of COVID-19 patients. In this study, 81 patients were evaluated: 45 received 200 mg of umifenovir three times a day, and 36 were in the control group. The authors concluded that baseline clinical and laboratory characteristics were similar in the two groups, and patients in the umifenovir group had a longer hospital stay than those in the control [80]. Although such results may seem discouraging, further clinical trials with higher doses of umifenovir may be required in order to verify its clinical efficiency against the SARS-CoV-2 infection.
The synthesis of umifenovir was described in 2006 starting from the reaction between ethyl acetoacetate 63 and methylamine, giving enaminone 64, which next undergoes a Nentizescu condensation reaction with 1,4-benzoquinone to produce indole derivative 65 (Scheme 9). Then, an acetylation reaction is carried out to protect the hydroxyl group in 65, producing 66, which is converted to 67 after a bromination step. The reaction of intermediate 67 with thiophenol in basic medium leads to the formation of 68, which finally affords umifenovir after a Mannich reaction [81].
Drug-repurposing studies are testing a range of compounds to treat COVID-19, but manufacturers may struggle to meet demand if any of these candidates prove effective against SARS-CoV-2. The pandemic has already strained global supply chains and limited the availability of a number of products, including hand sanitizer and diagnostic test reagents. The raw materials needed to make a new antiviral drug would most likely face similar pressures. But a team led by Tim Cernak of the University of Michigan has used an AI-based retrosynthesis program called Synthia to devise alternative routes to 12 leading drug candidates under investigation. The work appears on a preprint server and has not been peer reviewed (ChemRxiv 2020, DOI: 10.26434/chemrxiv.12765410.v1). “If the world runs out of one of the drugs currently in the clinic, we are providing a backup recipe,” Cernak says. Using alternative starting materials that are readily available, the researchers aimed to find routes of similar length and cost to those of existing syntheses. For each compound, the researchers whittled down a long list of options offered by Synthia to identify the most suitable synthetic strategies. Then the team tested some of these syntheses in the lab, including four new routes to the antiviral umifenovir, currently being investigated in eight clinical trials against COVID-19. Cernak says this approach could be used more generally to rapidly identify alternative synthetic routes whenever crises cause supply chain disruptions in drug manufacturing.
Artificial intelligence finds alternative routes to COVID-19 drug candidates
If drug-repurposing studies hit pay dirt, backup recipes could help antiviral manufacturers avoid supply chain problems
The research on the disease COVID-19 is an ongoing process since its outbreak as a pandemic. The repurposing of existing approved drugs has received priority attention due to some promising results obtained regarding COVID-19. In this article, some of the important chemical methodologies adopted for the synthesis of umifenovir, (s)-cidofovir, ribavirin, and ruxolitinib have been discussed. The repurposing of these approved drugs has received priority attention due to some promising results obtained regarding COVID-19 and some drugs are under more therapeutic trials. This manuscript has highlighted the synthetic strategies of four heterocyclic-based approved drugs, umifenovir, (s)-cidofovir, ribavirin, and ruxolitinib, repurposed for the treatment of COVID-19.
Ethyl 5-acetoxy-2-methyl-1H-indole-3-carboxylate 1a: Acetic anhydride (25.9 ml, 274 mmol 20 eq.) was added to a stirred solution of ethyl 5-hydroxy-2-methyl-1H-indole- 3-carboxylate 1 (3.00 g, 13.6 mmol, 1.0 eq.) in pyridine (3.32 mL, 41.1 mmol, 3.0 eq.) and the reaction heated to reflux. After 1 h, the reaction was allowed to cool back to rt before pouring the mixture into a solution of aqueous saturated sodium bicarbonate (40 mL). The product was extracted with ethyl acetate (3 x 40 ml) and the combined organic layers were washed with water (40 mL), dried (Na 2 SO 4 ) and concentrated In vacua to yield the product as a white solid which was used without further purification (3.4g, 96%). NMR: δH ( 400 MHz, CDCl 3) 8.34 (1H, s; NH), 7.75 (1H, s, H 4 ), 7.21 (1H, d, J 8.5, H 6 ), 6.89 (1H, d, J 8.5, H 7 ), 4.38 (2H , q, J 7.1 , CO 2 CH 2 CH 3 ), 2.71 (3H, s, C 1 CH 3 ), 2.34 (3H, s, CO 2 CH 3 ), 1.43 (3H, t, J 7.1, CO 2 CH 2 CH 3 ). δ c (100 MHz, CDCl 3 ) 170.8<a name=”
0.31 (40% ethyl acetate in hexane), HRMS. (ESI-TOF): C 14 H 15 O 4 N ([M+H] + ) requires 262.1074, found 262.1074.
Ethyl 5-acetoxy-1,2-dimethyl-1H-indole-3-carboxylate 1b: Protected indole 1b (1.35 g, 5.17 mmol, 1 eq.) was dissolved in DMF (15 mL). To this solution, methyl iodide (0.965 ml, 15.5 mmol, 3.0 eq.) was added and the resulting mixture was cooled on ice. Sodium hydride (0.186 g, 7.75 mmol, 1.5 eq.) was added and the reaction was left to stir on ice for 1.5 h. After this time, a small amount of water (5.0 mL) was added to the reaction and the solvents removed in vacuo. The resultant brown oil was then purified directly by column chromatography (30% ethyl acetate in petrol) to yield the title compound as a pale yellow solid (1.50 g, 95%). NMR: δ Η (500 MHz, CDCl 3 ) 7.79 (s, 1H, H 4 ), 7.26 (m, 1H, H 6 ), 6.96 (ddd, J = 8.8, 2.4, 0.8 Hz, 1H, H7 ), 4.38 (f, J = 7.1 Hz, 2H, CO 2 CH 2 CH 3 ), 3.69 (s, 3H, NCH 3 ), 2.77 (d, J = 1.3 Hz, 3H, ΑrCΗ 3 ), 2.33 (s , 3H, CO 2 CH 3 ), 1.43 (t, J= 7.1 Hz, 3H, CO 2 CH 2 CH 3 ). δ C (150 MHz, CDCl 3 ) 170.5 (CO 2 CH 3 ), 166.0 (CO 2 Et), 146.5 (C 5 ), 146.0 (C 2 ), 134.5 (C 8 ), 127.2 (C 3 ), 116.2 ( C6 ), 114.0 (C4 ) , 109.6 (C7 ), 104.4 (C 1 ), 59.6 (CO 2 CH 2 CH 3 ), 29.9 (NCH 3 ), 21.3 (C 1 CH 3 ), 14.8 (CO 2 CH 2 CH 3 ), 12.1 (CO 2 CH 3 ) . R f : 0.4 (30% ethyl acetate in hexane). HRMS (ESI-TOF): C 15 H 17 O 4 N ,([M+H] + ) requires 276.1230, found 276.1229.
Ethyl 6-bromo-2-(bromomethyl)-5-hydroxy-1-methyl-1H-indole-3-carboxylate 2: Bromine (558 μL, 10.9 mmol, 3.0 eq.) was added to a stirred solution of protected indole ( 1b, 1.00 g, 3.63 mmol, 1.0 eq.) in carbon tetrachloride (100 mL). After refluxing for 16 h, the reaction was cooled and aqueous sodium thlosulphate (10%. w/v, 100 mL) was added and left to stir for 20 min until the orange color disappeared. After this time, the organic layer was separated, washed with water (2 x 100 mL), dried (Na 2 SO 4 and concentrated in vacuo to yield a pale yellow solid, which was used without further purification (1.40 g, 99%) NMR: δ Η (400 MHz, PDCl 3 ) 7.86 (1H, s, H 4 ), 7.54 (1H, s, H 7), 5.05 (2H, s, CH 2 Br), 4.41 (2H, q, J 7.1, CO 2 CH 2 CH 3 ), 3.69 (3H, s, NCH 3 ), 2.39 (3H, s, CO 2 CH 3 ), 1.45 (3H, t, J 7.1, CO 2 CH 2 CH 3 ), δ C (100 MHz, CDCl 3 )
1.4.5 (CO 2 CH 2 CH 3 ), R f : 0.75 (CH 2 Cl 2 ). HRMS (ESI-TOF): C 15 Η 15 O 3 ΝΒr ([M+H] + ) requires 431.9441, found 431.9441.<a name=”
Ethyl 6-bromo-5-hydroxy-1-methyl-2-((phenylthio)methyl)-1H-indole-3-carboxylate 3: Thiophenol (99.8 μL, 0.972 mmol, 1.0 eq.) was added to a solution of potassium hydroxide (164 mg, 2.92 mmol, 3.0 eq.) in methanol (2 ml) and left to stir at room temperature for 15 min. After this time, the solution was cooled on ice and bromo indole 2 (880 mg, 0.972 mmol, 10 eq.) in CH 2 Cl 2 (5 mL) was added. The reaction was left to stir for 3 h before neutralization with acetic acid. The solvent was removed in vacuo and columned directly (20% EtOAc in petrol) to yield the title product as a pale yellow solid (362 mg, 86%). NMR: δ Η (600 MHz, CDCl 3 ) 7.74 (s, 1 H, Hr), 7.43 (s, 1H, H 4 ), 7.36 (dq, J = 5.2, 3.4, 2.4 Hz, 2H, H10 ), 7.25 (dd, J = 5.2, 1.9 Hz, 3H, H 11 and 5.33 (s, 2H, SCH 2 ), 4.29 (q, J = 7.3 Hz, 2H, CO 2 CH 2 CH 3 ), 3.60 (d, J = 18.1 Hz, 3H, NCH 3 ), 1.38 (t, J = 7.3 Hz, 3H, CO 2 CH 2 CH 3 ), δ c (150 MHz, CDCl 3 ) 165.1, 147.7, 144.2, 134.1 R f : 0.35 (20% EtOAc in petrol) HRMS (ESI-TOF)-: C 19 H 18 BrNO 3 S ([M+H] + ) requires 420.0263, found 420.0260.
Arbidol [Ethyl 6-bromo-4((dimethylamino)methyl)-5-hydroxy-1-methyl-2-((phenylthio)methyl)-1H-indole-3-carboxylate] 4: 1 Indole 3 (200 mg, 0.476 mmol, 1.0 eq.) and N, N, N’, N’-tetramethylaminomethane (1-95 μL, 1.43 mmol, 3.0 eq.) were dissolved in 1,4-dioxane (2 mL). The reaction was. heated to reflux for 3.5 h before removing the solvent in vacuo. The reaction was then re-dissolved in ethyl acetate and 1 M HCl was added to the solution causing the title product to crash out as a pale yellow solid (117 mg, 51%). NMR-: δ B (500 MHz, MeOD) 7.87 (s, 1 H, H 7 ), 7.39 (dd, J = 7.4, 2.2 Hz, 2H, H 10 ), 7.35 – 7.31 (m, 3H, H 11 and H12 ) . 4.87 (s, 2H, SCH 2), 4.71 (s, 2H, CH 2 NMe 2 ), 4.33 (q, J = 7.1 Hz, 2H, CO 2 CH 2 CB 3 ), 3.63 (s, 3H, NCH 3 ), 2.97 (s, 6H, N (CH 3 ) 2 ), 1.39 (t, J = 7.1 Hz, 3H, CO 2 CH 2 CH 3 ). δ c (150 MHz, MeOD) 169.7 (CO 2 Et), 152.7 (C s ), 149.0 (C), 137.7 (C 10 ), 136.4 (C 3 ), 136.0 (C 8 ), 132.3 (C 11 ), 131.3 (CH), 129.3 (C12 ) , 119.8 (C7 ) , 113.1 (C2), 111.3 ( C6), 108.3 (C4 ) , 64.2. (CO 2 CH 2 CH 3 ), 57.4 (CH 2 NMe 2 ), 45.4 (CH 2 N(CR 3 ) 2 ); 33.7 (CH 2 SPh), 32.9 (NCH 3 ), 16.6 (CO 2 CH 2 CH 3 ). R f : 0.25 (EtOAc). HRMS (ESI-TOF): G 22 H 25 BrN 2 O 3 S ([M+H] + ) requires 477.0842, found 477.0844.
Synthesis of Arbidol Analogues
Ethyl 5-acetoxy-6-bromo-2-(((3-hydroxyhpenyl)thio)methyl)-1-methyl-1H-indole-3-carboxylate 8a: 3-hydroxythiophenol. (117 μL, 1.15 mmol, 1.0 eq.) was added to a solution of sodium carbonate (367 mg, 3.46 mmol, 3.0: eq.) and bromo indole 2 (500 mg, 1.15 mmol, 1.0 eq.) in dry ethyl acetate (10mL). The reaction was heated to 100°C and stirred for 5 h before<a name=”cooling, filtering and removing the solvent in vacuo. The compound was purified by column chromatography (40% EtOAc in Hexanes) to produce the title product as a pale yellow solid (240 mg, 44%). NMR: δ H (500 MHz,. CDCl 3 ) 7.85 (s, 1H, H 7 ), 7.56 (s, 1 H, H 4 ), 7.12 (t, J = 7.9 Ηz, 1Η, H 13 ), 6.95 – 6.90.(m, 1H, Η 14 ), 6.78 (s, 1H, H 10 ), 6.75-6.71 (m, 1H,.H 12 ), 4.69 (s, 2H, SCH 2 ), 4.30 (q, J = 7.4 Hz, 3H, CO 2 CH 2 CH 3 ), -3.66 (s, 3H, NGH 3 ), 2.4Q (s, 3H, COCH 3), 1.38 (t, J = 7.4 Hz, 3H, CO 2 CH 2 CH 3 ). Δ C (150 MHz, CDCL 3 ) 169.8, 165.0, 156.1, 144.6, 143.3, 135.6, 135.1, 130.1, 126.1, 124.8, 119.3, 113.9, 111.1, 105.8, 60.1, 30.4, 29.9, 21.0, 14. . R f : OAS (30% EtOAc in Hexane). HRMS (ESS-TOF): C 21 H 20 SrNO 5 S ([M+H] + ) requires 473.0318, found 478.0317.
Ethyl 6-bromo-5-hydroxy-24(((3-hydroxyphenyl)thio)methyl)-1-methyl-1H-indole-3-carboxylate 8: Sodium carbonate (106 mg. 1.00 mmol, 2.0 eq.) was added to a stirred solution of meta-hydroxy indole 8a (240 mg, 0.502 mmol, 1.0 eq.) in methanol (40 ml) and left to stir for 2h, The solution was then filtered and the solvent removed in vacuo, The product was re -dissolved in ethyl acetate (10 mL) and washed once with water (40 mL) before drying (Na 2 SO 4 and concentrating in vacuo to give the title product as a white solid, which could be used without further purification (160 mg, 67%), NMR-: δ H (600 MHz, MeOD) 7.60 (s, 1H, H 7 ), 7.58 (s, 1 H, H 4 ), 7.07 (dd, J = 8.2, 7.7 Hz, 1H, H 13), 6.83 – 6.81 (m, 1Η, Η 14 ), 6.79 (ddd, J = 7.7, 1.8, 0.9, 1H, H 10 ), 6.7.0 (dd, J = 8.2, 1.8, 0.9 Hz, 1H, H 12 ), 4.70 (s, 2H, SCH 2 ), 4.26 (q, J = 7.1 Hz, 2H, CO 2 CH 2 CH 3 ), 3.64 (s, 3H, NCH 3 ), 1.39 (t, J = 7.1 Hz , 3H, CO 2 CH 2 CH 3 ). δ c (150 MHz, MeOD) 166.9, 158.9, 150.6, 145.5, 136.4, 133.6, 131.0,. 130.7, 128.0, 1.24.9, 120.5, 116.0, 114.8, 107.9, 104.8, 60.8, 30.5, 30.4, 14.8. R f : 0.45 (1% MeOH in CΗ 2 Cl 2 ). HRMS (ESI-TOF): C 7 PM18 BrNO 4 S ([M+H] + ) requires 436.0213, found 436.0215.
Ethyl 2-(((3-aminophenyl)thio)methyl)-6-bromo-5-hydroxy-1-methyl-1H-indole-3-carboxyiate 9: 3-aminothiophenol (54.3 μL, 0.511 mmol, 1.0 eq.) was added to a solution of potassium hydroxide (86 mg, 1.53 mmol, 3.0 eq.) in methanol (2 ml) and left to stir at room temperature for 15 min. After this time, the solution was cooled on ice and bromo indole 2 (200 mg, 0.511 mmol, 1.0 eq.) in CH 2 Cl 2 (5 ml) was added. The reaction was left to stir for 3 h before neutralization with acetic-acid. The solvent was removed in vacuo and purified directly by preparative TLC (1% MeOH in CH 2 Cl 2 ) to yield the title product as a pale yellow solid (138 mg, 62%), NMR: δ H (500 MHz, CDCl 3) 7.74 (d, J = 1.8 Hz, 1H, H 7 ), .7.42 (d, J = 1.8 Hz., 1H, H 4 ), 7.03 (t, J = 8.1 Hz, 1 H, H 13 ), 6.75 (d, J= 7.7 Hz, 1H, H 14 ), 6.68 (s, 1H, H 10 ), 6.55 (d, J = 6.1 Hz, 1H, H 12 ), 4.68 (d, J = 1.9 Hz, 2H, SCH 2 ), 4.35 ™ 4.30 (m, 2H, COCH 2 GH 3 ),. 3.60 (d, J = 1.9 Hz, 3H, NCH 3 ), 1.40 (td, J = 7.1, 1.8 Hz, 3H, COCH 2 CH 3 ). δ c (150 MHz, CDCl 3 ) 1-66.9, 150.6, 149.6,<a name=”
146.0, 136.0, 133.5, 1 . 30.5, 128.1, 123.1, 120.2, 117.6, 115.8, 114.8, 107.9, 104.6, 68.1, 60.8, 30.4, 14.8. R f : 0.85 (1% MeOH in CH 2 Cl 2 ), HRMS (ESI-TOF): C 19 H 19 BrN 2 O 3 S ([M+H] + ) requires 435.0372, found 435.0370.
Ethyl 2-(((3-aminophenyl)thio)methyl)-6-bromo-5-hydroxy-1-methyl-1H-indole-3-carboxylate 10: 2-napthalenethiol (82.0 mg, 0.511 mmot, 1.0 eq.) was added to a solution of potassium hydroxide (86 mg, 1.53 mmol, 3.0 eq.) in methanol (2 mL) and left to stir at room temperature for 15 min. After this time, the solution was cooled on ice and bromo indole 2 (200 mg, 0.511 mmol, 1.0 eq.) in CH 2 Cl 2 (5 mL) was added. The reaction was left to stir for 3 h before neutralization with acetic acid. The solvent was removed in vacuo and purified directly by preparative TLC (1% MeOH in CH 2 Cl 2 ) to yield the title product as a pale yellow solid (118 mg, 50%). NMR: δR(600 MHz, DMSO) 9.77 (s, 1H, OH), 7.83 (d, J = 1.8 Hz, 1H, Ar), 7.81 -7.79 (m, 1H, Ar), 7.75 (d, J = 8.6 Hz, 1H , Ar), 7.72 – 7.70 (m, 1H, Ar), 7.66 (s, 1H, Hz), 7.46 (s, 1H, H 4 ), 7.45 – 7.40 (m, 2H, Ar), 7.34 (dd, J = 8.5, 1.9 Hz, 1H, Ar), 4.82 (s, 2H, CH 2 SPh), 4.04 (q, J = 7.1 Hz, 2H, CO 2 CH 2 CH 3 ), 3.63 (s, 3H, NC. %), 1.14 (t, J = 7.1 Hz, 3H, CO 2 CH 2 CH 3 ). δ c (150 MHz, DMSO) 164.3, 149.3, 143.4, 133.2, 132.0, 131.7, 131.6, 128.9, 128.4, 128.4, 127.7, 127.2, 126.8, 126.3, 1:26.0, 116.3, 116.3, 116.3 06.3, 103.3, 59.2, 30.3, 28.1, 14.3. R f : 0.75 (1% MeOH in CH2 Cl 2 ). HRMS (ESI-TOF): C 23 H 20 BrNO 3 S (fM+Hf) requires 470.0420, found 470.0420.
Ethyl 6-bromo-4-((dimethylammino)methyl)-5-hydroxy-2-(((3-hydroxyohenyl)thio)methyl)-1-methyl-1H-indole-3-carboxylate 11; Meta-hydroxy indole 8 (30.0 mg, 0.069 mmol, 1.0 eq,) and N, N,N’,N’-tetramethyldiaminomethane (47.0 μL, 0.344 mmol, 5.0 eq.) were dissolved in CH 2 Cl 2 (30 mL) . The reaction was heated to reflux for 3.5 h before removing the solvent in vacuo to, yield the title product as a pale yellow solid (34 mg. 99%). NMR; δH (500 MHz, CDCl 3 ) 7.47 (s, 1H, H 7 ), 7.12 (t, J = 7.9 Hz, 1H, H 13 ), 6.90 (d, J = 7.9 Hz, 1H, H 14 ), 6.90 ( d, J = 7.9 Hz, 1H, H 12 ), 6.66 (s, 1H, H 10 ), 4.41 (s, 2H, CH 2 NMe2 ), 4.34 (s, 2H, CH 2 SPh), 4.15 (q, J = 7.1 Hz, 2H, CO 2 CH 2 CH 3 ), 3.60 (s, 3H, NCH 3 ), 2.55 (s, 6H, CH 2N (CH 3 ) 2 ), . 1.33 – 1.21 (m, 3H, CO 2 CH 2 CH 3 ). δ c ( . 150 MHz, CDCl 3 ) 165.9, 156.7, 150.9, 142.6, 135.1, 132.2, 131.0, 130.0, 128.9, 124.6, 124.3, 119.3, 115.5, 113.4, 106.8, 106.8, 106.8, 106.8, 165.5 58.7, 44.0, 30.4, 29.9, 14.3, R f : 0.15 (10% MeOH in CH 2 Cl 2 ). HRMS (ESS-TOF): C22 H 25 BrN 2 O 4 S ([M+H] + ) requires 493.0791, found 493.0792,
0.0419 mmol, 1.0 eq.) and 1-(2-((trimethylsilyl)oxy)ethyl)piperazine (25 mg, 0.126 mmol, 3.0 eq.) were dissolved in 1,4-dioxane (2 mL) and refluxed overnight. The solvent was then removed in vacuo and the reaction columned directly to yield the title product as a yellow solid (12 mg, 51%). NMR: δ Η (400 MHz, MeOD) 7.56 (s, 1.H, H 7 ), 7.22 – 7.30 (m, 5H, SPh), 4.57 (s, 2H, CH 2 SPh), 4.14 – 4.19 (m, 4H, CH 2 NR 2 and CΟ 2 CH 2 CΗ 3 ), 3.68 (t, J = 5.9 Hz, 2H, . CH 2 OH), 3.60 (s, 3H, NCH 3 ), 2.53 – 2.70 (m, 10H, piperazine ring and CH 2 CH2 CH 2 OH), . 134 – 1.30 (rn, 3H, CO 2 CH 2 CH 3 ), δ c (150 MHz, MeOD) 167.2, 151.7, 143.9, 135.4, 134.2, 133.4, 130.1, 129.0, 125.5, 114.1, 113.6, 107.0, 108.9, 108.9, 108.9 61.5, 61.1, 59.8, 59.1, 54.3, 52.9, 30.9, 30.5, 14.7. R f : 0.15 (5% MeOH in CH 2 Cl 2 ), HRMS (ESI-TOF): C 26 H 32 BrN 3 O 4 S ([M+H] + ) requires 562.1370, found 562.1368,
Ethyl 6-bromo-5-hydroxy-2-(((2-hydroxyphenyl)thio)methyl)-1-methyl-1H-indole-3-carboxylate 16: 2-hydroxythiophenol (26.0 μL, 0.256 mmol, 1.0 eq.) was added to a solution of sodium carbonate (81.0 mg, 0.767 mmol, 3.0 eq.) and promo indole 2 (100 mg, 0.256 mmol, 1.0 eq.) in ethyl acetate (2 mL). The reaction was heated to 50°C and stirred for 2 h before cooling and removing the solvent in vacuo. The product was then re-dissolved in methanol (2 mL) and potassium hydroxide (21.5 mg, 0.384 mmol, 1.5 eq.) was added. The reaction was stirred at room temperature for 3 h before direct purification by preparative TLC (2% MeOH in CH 2 Cl 2 ) to yield the title product as. a white solid (20.5 mg, 1.8%), NMR: δ H (500 MHz, MeOD) 7.59 (s, 1H, H 7), 7.54 (s, 1H, Η 4 ), 7.17 (t, J = 7.7 Hz, 1H, H 12 ), 7.08 (d, J = 7.7 Hz, 1H, H 14 ), 6.85 (d, J =7.7 Hz , 1H, H 13 ), 6.66 (t, J = 7.7 Hz, 1H, H 15 ), 4.58 (s, 2H, SCH 2 ), 4.24 (q, J = 7.1 Hz, 2H, CO 2 CH 2 CH 3 ) , 3.59 (s, 3H, NCH 3 ), 1.40 (t, J = 7.1 Hz, 3H, CO 2 CH 2 CH 3 ). δ c (150 MHz, MeOD) 161.3, 146.4, 143.3, 134.8, 132.0, 130.4, 129.4, 123.7, 123.0, 121.8, 120.5, 114.4, 113.6, 110.0, 102.7, 60.04, 390.2, 390.2, 390.04 R f : 0.6 (2% MeOH in CH 2 Cl2 ). HRMS (ESI-TOF): C 19 H 18 BrNO 4 S ([M+H] + ) requires 436.0213, found 436.0212.
Ethyl 6-bromo-5-hydroxy-2-(((4-hydroxyphenyl)thmetihoyl)-)1-methyl-1H-indole-3-carboxylate 17: 4-hydroxythiophenol (26.0 μL, 0.256 mmol, 1.0 eq.) was added to a solution of sodium carbonate (81.0 mg, 0.767 mmol, 3.0 eq.) and bromo indole 2 (100 mg, 0.256 mmol, 1.0 eq.) in ethyl acetate (2 mL). The reaction was heated to 50°C. and stirred for 2 hours before cooling<a name=”and removing the solvent in vacuo. The product was then re-dissolved in methanol (2 mL) and potassium hydroxide (21.5 mg, 0.384 mmol, 1.5 eq.) was added. The reaction was stirred at room temperature for 3 h before direct purification by preparative TLC (2% MeOH in CH 2 Cl 2 ) to yield the title product as a white solid (2.5 mg, 2%). NMR: δ Η (600 MHz, DMSO) 7.65 (s, 1H, H 7 ), 7.49 (s, 1 H, H 4 ), 7.03 (d, J = 8.7 Hz, 2H , H 12 ), 6.58 (d, J = 8.7 Hz, 2. HH 13 ) , 4.52 (s, 2H, SCH 2 ), 4.08 (q, J = 7.2 Hz, 2H, CO 2 CH 2 CH 3 ), 3.51 (s, 3H, NCH3 ), 1.23 (t, J = 7.1 Hz, 3H, CO 2 CH 2 CH 3 ). δ c (150 MHz, DMSO) 164.2, 157.9, 149.2, 144.3, 135.7, 131.4, 126.1, 1214, 115.9, 114.1, 106.3, 102.9, 79.2, 59.0, 55.4, 30.0, R 14.3, f ; 0.5 (2% MeOH in CH 2 Cl 2 ). HRMS (ESI-TOF): C 19 H 18 BrNO 4 S ([Μ+H] + ) requires 436.0213, found 436.0213.
Ethyl 5-acetoxy-6-bromo-2-(((3-methoxyphenyl) thio)methyl)-1-methyl-1H-indole-3-carboxylate 18a: 3-methpxythiophenol (14.6 μL, 0.118 mmol, 1.0 eq.) was added to a solution of sodium carbonate (37.4 mg, 0.353 mmol, 3.0 eq.) and bromo indoles 2 (46.0 mg, 0.118 mmol, 1.0 eq.) in dry ethyl acetate (20 ml). The reaction was heated to 50°C and stirred for 2 h before addition of water. The organic layer was separated, dried (Na 2 SO 4 ) and concentrated in vacuo. The compound was purified by column chromatography (20% EtOAc in Hexanes) to produce the title product as a white solid (34 mg, 59%). UMR; δ Η (600 MHz, DMSO) 7.92 (s, 1 H, H 7 ), 7.6.6 (s, 1 H, H 4 ), 7.13 (t, J = 7.9 Hz, 1H, H 13), 6.8.7 – 6.84 (m, 1 H, H 14 , 6.79 – 6.74 (m, 2H, H 10 and H 1 2 ), 4.77 (s, 2H, SCH 2 ), 4.13 (q, J = 7.1 Hz , 2H, CO 2 CH 2 CH 3 ), 3.70 (s, 3H, NCH 3 ), 3.58 (s, 3H, SPhOCH 3 ), 2.27 (s, 3H, COCH 3 ), 1.20 (t, J = 7.1 Hz, 3H, CO 2 CH 2 CW 3 ).δ c (150 MHz, DMSO) 169.1, 163.9, 159.4, 144.9, 142.6, 135.1, 135.0, 129.9, 125.2, 123.3, 116.2, 115.1, 114.73, 110.73, 110.2 104.3, 59.5, 55.1, 30.6, 28.1, 20.7, 14.3 R f : 0.4 (20% EtOAc in Hexane) HRMS (ESI-TOF): C 22H 22 BrNO s S ([M+H] + ) requires 492.0475, found 492.0472.
Ethyl 6-bromo-5-hydroxy-2-((3(-methoxyphenyl)thio)methyl)-1-methyl-1H-indole-3-carboxylate 18: Sodium carbonate (41.3 mg, 0.390 mmol, 2.0 eq.) was added to a stirred solution of meta-methoxy indole 18a (96.0 mg, 0.195 mmot, 1.0 eq.) in methanol (10 mL) and left to stir for 2h, the solution was then filtered and the solvent removed in vacuo. The product-was re-dissolved in ethyl acetate (10 mL) and washed once with water (10 mL) before drying (Na 2 SO 4 ) and concentrating in vacuo to give the title product as a white solid, which could he used without further purification (80 mg, 91%), NMR: δ Η (600 MHz, CDCl 3 ) 7.73 (s, 1H, Η 7 ), 7.41 (s, 1H, H 4 ), 7.17 – 7.13 (m, H 13), 7.07 (m, 1H, H 14 ), 6.96 (dt, J = 7.7, 1.3, 1H, H 10 ), 6.85 (m, 1H, H 12 ),4.71 (s, 2H, SCH 2 ), 4.30 ( q, J = 7.1 Hz, 2H, CO 2 CH 2 CH 3 ), 3.63 (s, 3H, NCH 3 ), 1.41 (t, J = 7.1 Hz, 3H, CO 2 CH 2 CH 3 ). Δ C (150 MHz, CDCL 3 ) 165.2, 159.8, 147.7, 135.4, 132.6, 129.8, 12.7.2, 124.6, 119.7, 117.3, 114.1, 112.5, 107.5, 107.9, 55.4, 29.9, 29.6, 14.7 Rf :. _<a name=”0.55 (1% MeOH in CH 2 Cl 2 ). HRMS (ESl-TOF): C 20 H 20 BrNO 4 S ([M+H] + ) requires 450.0369, found 450.0367.
Ethyl 6-bromo-4-((dimethylamino)methy-5-hydroxy-2-(((2-hydroxyphenyl)thio)methyl)-1-methyl-1H-indole-3-carboxylatete 19: Ortho-hydroxy indole: 16 (13.5 mg, 0.0309 mmol, 1.0 eq.) and N, N, N’,N’-tetramethyldiaminomethane (12.7 μL, 0.0928 mmol, 3.0 eq.) were dissolved in 1,4-dioxane (2.0 mL). reaction was heated io reflux for 3.5 h before removing the solvent in vacuo to yield the title product as a white solid (13 mg, 85 %).HMR: δ H (500 MHz, MeOD) 7.53 (s, 1H, H 7 ) , 7.19 – 7.11 (m, 1H, H 4 ), 7.03 (dd, J = 7.6, 1.7 Hz, 1 H, H 12 ), 6.86 – 6.78 (m, TH, H 14 ), 6.63 (dt, J = 13.7 , 7.6 Hz, 1H, H 15 ), 4.48 (s, 2H, CH 2 Sph), 4.34 (s, 2H, CH 2NMe 2 ), 4.22 (dq, J = 10.8, 7.1, 6.3 Hz, 2H, CO 2 CH 2 CH 3 ), 3.56 (s, 3H, NCH 3 ), 2.49 (d, J = 11.4 Hz, 6H, CH 2 N(CH 3 ) 2 ), 1.42 – 1.37 (m, 3H, CO 2 CH 2 CH 3 ). Δ C (150 MHz, MEOD) 167.5, 160.4, 137.0, 136.6, 132.5, 131.6, 130.6, 126.1, 114.5, 112.6, 110.6, 106.0, 68.1, 61.4, 60.1, 43.5, 29.9, 29.9 14.6. R f : 0.4 (5% MeOH in CH 2 Cl 2 ), HRMS (ESI-TOF): C 22 H 25 BrN 2 O4 S ([M+H] + ) requires 493.0791, found 493.0793.
Ethyl 6-bromo-4-((dimethylamino)methyl-5-hydroxy-2-(((3-methoxyphenyl)thio)methyl)-1-methyl-1H-indole-3-carboxylate 21: Sodium carbonate (17.5 mg, 0165 mmol, 3.0 eq.) was added to a stirred solution of meta-methoxy indole 18 (27.0 mg, 0.055 mmol, 1 .0 eq.) in ethyl acetate (8 mL) and methanol (1 mL). to stir for 3h before filtering and removing the solvent in vacuo.The compound was then re-dissolved in 1,4-dioxane (5 mL) and N, N, N’,N’-tetramethyldiaminomethane (5.5 μL, 0.04 mmol, 3.0 eq.) as added. The reaction was heated to reflux overnight before removing the solvent in vacuo. Purification by preparative TLC (5% MeOH In CH 2 Cl 2 ) yielded the title product as a pale yellow solid (7 mg, 24%) .NMR: δ Μ (600 MHz, CDCl 3) 7.44 (s, 1H, H 7 ), 7.19 (t, J = 7.9 Hz, 1 H, H 15 ), 6.96 (rn, 1H, H 14 ), 6.82 (m, 1H, W 10 ), 6.77 (m , 1H, H 12 ), 4.52 (s, 2H, CH 2 SPh), 4.21 (qd, J = 7.2, 0.8 Hz, 2H, CO 2 CH 2 CH 3 ), 4.17 (s, 2H, CH 2 NMe 2 ), 3.66 (s, 3H, NCH 3 ), 3.58 (s, 3H, OCH 3 ), 2.38 (s, 6H, CH 2 H(CH 3 ) 2 ), 1.34 (m, 3H, CO 2 CH 2 CH 3 ). δ c (150 MHz, CDCl 3) 165.6, 159.9, 151.7, 141.7, 135.5, 131.9, 129.9, 124.7, 117.5, 114.2, 113.1, 112.6, 108.6. 106.2, 60.5, 59.9, 55.3, 44.2, 30.5, 29.9, 14.5. R f : 0.35 (5% MeOH in CH 2 Cl 2 ). HUMS (ESI-TOF): C 23 H 27 BrN 2 O 5 S ((M+H] + ) requires 523.0897, found
^ Jump up to:abLeneva IA, Russell RJ, Boriskin YS, Hay AJ (February 2009). “Characteristics of arbidol-resistant mutants of influenza virus: implications for the mechanism of anti-influenza action of arbidol”. Antiviral Research. 81 (2): 132–40. doi:10.1016/j.antiviral.2008.10.009. PMID19028526.
^Wang MZ, Cai BQ, Li LY, Lin JT, Su N, Yu HX, Gao H, Zhao JZ, Liu L (June 2004). “[Efficacy and safety of arbidol in treatment of naturally acquired influenza]”. Zhongguo Yi Xue Ke Xue Yuan Xue Bao. Acta Academiae Medicinae Sinicae. 26 (3): 289–93. PMID15266832.
^Boriskin YS, Leneva IA, Pécheur EI, Polyak SJ (2008). “Arbidol: a broad-spectrum antiviral compound that blocks viral fusion”. Current Medicinal Chemistry. 15 (10): 997–1005. doi:10.2174/092986708784049658. PMID18393857.
^Leneva IA, Burtseva EI, Yatsyshina SB, Fedyakina IT, Kirillova ES, Selkova EP, Osipova E, Maleev VV (February 2016). “Virus susceptibility and clinical effectiveness of anti-influenza drugs during the 2010-2011 influenza season in Russia”. International Journal of Infectious Diseases. 43: 77–84. doi:10.1016/j.ijid.2016.01.001. PMID26775570.
^Shi L, Xiong H, He J, Deng H, Li Q, Zhong Q, Hou W, Cheng L, Xiao H, Yang Z (2007). “Antiviral activity of arbidol against influenza A virus, respiratory syncytial virus, rhinovirus, coxsackie virus and adenovirus in vitro and in vivo”. Archives of Virology. 152 (8): 1447–55. doi:10.1007/s00705-007-0974-5. PMID17497238.
^Glushkov RG, Gus’kova TA, Krylova LIu, Nikolaeva IS (1999). “[Mechanisms of arbidole’s immunomodulating action]”. Vestnik Rossiiskoi Akademii Meditsinskikh Nauk (in Russian) (3): 36–40. PMID10222830.
^Hulseberg CE, Fénéant L, Szymańska-de Wijs KM, Kessler NP, Nelson EA, Shoemaker CJ, Schmaljohn CS, Polyak SJ, White JM. Arbidol and Other Low-Molecular-Weight Drugs That Inhibit Lassa and Ebola Viruses. J Virol. 2019 Apr 3;93(8). pii: e02185-18. doi:10.1128/JVI.02185-18PMID30700611
Umifenovir is an indole-based, hydrophobic, dual-acting direct antiviral/host-targeting agent used for the treatment and prophylaxis of influenza and other respiratory infections.13 It has been in use in Russia for approximately 25 years and in China since 2006. Its invention is credited to a collaboration between Russian scientists from several research institutes 40-50 years ago, and reports of its chemical synthesis date back to 1993.13 Umifenovir’s ability to exert antiviral effects through multiple pathways has resulted in considerable investigation into its use for a variety of enveloped and non-enveloped RNA and DNA viruses, including Flavivirus,2 Zika virus,3 foot-and-mouth disease,4 Lassa virus,6 Ebola virus,6 herpes simplex,8, hepatitis B and C viruses, chikungunya virus, reovirus, Hantaan virus, and coxsackie virus B5.13,9 This dual activity may also confer additional protection against viral resistance, as the development of resistance to umifenovir does not appear to be significant.13
Umifenovir is currently being investigated as a potential treatment and prophylactic agent for COVID-19 caused by SARS-CoV2 infections in combination with both currently available and investigational HIV therapies.1,16,17
Indication
Umifenovir is currently licensed in China and Russia for the prophylaxis and treatment of influenza and other respiratory viral infections.13 It has demonstrated activity against a number of viruses and has been investigated in the treatment of Flavivirus,2 Zika virus,3 foot-and-mouth disease,4 Lassa virus,6 Ebola virus,6 and herpes simplex.8 In addition, it has shown in vitro activity against hepatitis B and C viruses, chikungunya virus, reovirus, Hantaan virus, and coxsackie virus B5.13,9
Umifenovir is currently being investigated as a potential treatment and prophylactic agent for the prevention of COVID-19 caused by SARS-CoV-2 infections.1,16
Pharmacodynamics
Umifenovir exerts its antiviral effects via both direct-acting virucidal activity and by inhibiting one (or several) stage(s) of the viral life cycle.13 Its broad-spectrum of activity covers both enveloped and non-enveloped RNA and DNA viruses. It is relatively well-tolerated and possesses a large therapeutic window – weight-based doses up to 100-fold greater than those used in humans failed to produce any pathological changes in test animals.13
Umifenovir does not appear to result in significant viral resistance. Instances of umifenovir-resistant influenza virus demonstrated a single mutation in the HA2 subunit of influenza hemagglutinin, suggesting resistance is conferred by prevention of umifenovir’s activity related to membrane fusion. The mechanism through which other viruses may become resistant to umifenovir requires further study.13
Mechanism of action
Umifenovir is considered both a direct-acting antiviral (DAA) due to direct virucidal effects and a host-targeting agent (HTA) due to effects on one or multiple stages of viral life cycle (e.g. attachment, internalization), and its broad-spectrum antiviral activity is thought to be due to this dual activity.13 It is a hydrophobic molecule capable of forming aromatic stacking interactions with certain amino acid residues (e.g. tyrosine, tryptophan), which contributes to its ability to directly act against viruses. Antiviral activity may also be due to interactions with aromatic residues within the viral glycoproteins involved in fusion and cellular recognition,5,7 with the plasma membrane to interfere with clathrin-mediated exocytosis and intracellular trafficking,10 or directly with the viral lipid envelope itself (in enveloped viruses).13,12 Interactions at the plasma membrane may also serve to stabilize it and prevent viral entry (e.g. stabilizing influenza hemagglutinin inhibits the fusion step necessary for viral entry).13
Due to umifenovir’s ability to interact with both viral proteins and lipids, it may also interfere with later stages of the viral life cycle. Some virus families, such as Flaviviridae, replicate in a subcellular compartment called the membranous web – this web requires lipid-protein interactions that may be hindered by umifenovir. Similarly, viral assembly of hepatitis C viruses is contingent upon the assembly of lipoproteins, presenting another potential target.13
Absorption
Umifenovir is rapidly absorbed following oral administration, with an estimated Tmax between 0.65-1.8 hours.14,15,13 The Cmax has been estimated as 415 – 467 ng/mL and appears to increase linearly with dose,14,15 and the AUC0-inf following oral administration has been estimated to be approximately 2200 ng/mL/h.14,15
Volume of distribution
Data regarding the volume of distribution of umifenovir are currently unavailable.
Protein binding
Data regarding protein-binding of umifenovir are currently unavailable.
Metabolism
Umifenovir is highly metabolized in the body, primarily in hepatic and intestinal microsomess, with approximately 33 metabolites having been observed in human plasma, urine, and feces.14 The principal phase I metabolic pathways include sulfoxidation, N-demethylation, and hydroxylation, followed by phase II sulfate and glucuronide conjugation. In the urine, the major metabolites were sulfate and glucuronide conjugates, while the major species in the feces was unchanged parent drug (~40%) and the M10 metabolite (~3.0%). In the plasma, the principal metabolites are M6-1, M5, and M8 – of these, M6-1 appears of most importance given its high plasma exposure and long elimination half-life (~25h), making it a potentially important player in the safety and efficacy of umifenovir.14
Enzymes involved in the metabolism of umifenovir include members of the cytochrome P450 family (primarily CYP3A4), flavin-containing monooxygenase (FMO) family, and UDP-glucuronosyltransferase (UGT) family (specifically UGT1A9 and UGT2B7).14,11
Lu H: Drug treatment options for the 2019-new coronavirus (2019-nCoV). Biosci Trends. 2020 Jan 28. doi: 10.5582/bst.2020.01020. [PubMed:31996494]
Haviernik J, Stefanik M, Fojtikova M, Kali S, Tordo N, Rudolf I, Hubalek Z, Eyer L, Ruzek D: Arbidol (Umifenovir): A Broad-Spectrum Antiviral Drug That Inhibits Medically Important Arthropod-Borne Flaviviruses. Viruses. 2018 Apr 10;10(4). pii: v10040184. doi: 10.3390/v10040184. [PubMed:29642580]
Fink SL, Vojtech L, Wagoner J, Slivinski NSJ, Jackson KJ, Wang R, Khadka S, Luthra P, Basler CF, Polyak SJ: The Antiviral Drug Arbidol Inhibits Zika Virus. Sci Rep. 2018 Jun 12;8(1):8989. doi: 10.1038/s41598-018-27224-4. [PubMed:29895962]
Herod MR, Adeyemi OO, Ward J, Bentley K, Harris M, Stonehouse NJ, Polyak SJ: The broad-spectrum antiviral drug arbidol inhibits foot-and-mouth disease virus genome replication. J Gen Virol. 2019 Sep;100(9):1293-1302. doi: 10.1099/jgv.0.001283. Epub 2019 Jun 4. [PubMed:31162013]
Kadam RU, Wilson IA: Structural basis of influenza virus fusion inhibition by the antiviral drug Arbidol. Proc Natl Acad Sci U S A. 2017 Jan 10;114(2):206-214. doi: 10.1073/pnas.1617020114. Epub 2016 Dec 21. [PubMed:28003465]
Hulseberg CE, Feneant L, Szymanska-de Wijs KM, Kessler NP, Nelson EA, Shoemaker CJ, Schmaljohn CS, Polyak SJ, White JM: Arbidol and Other Low-Molecular-Weight Drugs That Inhibit Lassa and Ebola Viruses. J Virol. 2019 Apr 3;93(8). pii: JVI.02185-18. doi: 10.1128/JVI.02185-18. Print 2019 Apr 15. [PubMed:30700611]
Zeng LY, Yang J, Liu S: Investigational hemagglutinin-targeted influenza virus inhibitors. Expert Opin Investig Drugs. 2017 Jan;26(1):63-73. doi: 10.1080/13543784.2017.1269170. Epub 2016 Dec 14. [PubMed:27918208]
Li MK, Liu YY, Wei F, Shen MX, Zhong Y, Li S, Chen LJ, Ma N, Liu BY, Mao YD, Li N, Hou W, Xiong HR, Yang ZQ: Antiviral activity of arbidol hydrochloride against herpes simplex virus I in vitro and in vivo. Int J Antimicrob Agents. 2018 Jan;51(1):98-106. doi: 10.1016/j.ijantimicag.2017.09.001. Epub 2017 Sep 7. [PubMed:28890393]
Pecheur EI, Borisevich V, Halfmann P, Morrey JD, Smee DF, Prichard M, Mire CE, Kawaoka Y, Geisbert TW, Polyak SJ: The Synthetic Antiviral Drug Arbidol Inhibits Globally Prevalent Pathogenic Viruses. J Virol. 2016 Jan 6;90(6):3086-92. doi: 10.1128/JVI.02077-15. [PubMed:26739045]
Blaising J, Levy PL, Polyak SJ, Stanifer M, Boulant S, Pecheur EI: Arbidol inhibits viral entry by interfering with clathrin-dependent trafficking. Antiviral Res. 2013 Oct;100(1):215-9. doi: 10.1016/j.antiviral.2013.08.008. Epub 2013 Aug 25. [PubMed:23981392]
Song JH, Fang ZZ, Zhu LL, Cao YF, Hu CM, Ge GB, Zhao DW: Glucuronidation of the broad-spectrum antiviral drug arbidol by UGT isoforms. J Pharm Pharmacol. 2013 Apr;65(4):521-7. doi: 10.1111/jphp.12014. Epub 2012 Dec 24. [PubMed:23488780]
Teissier E, Zandomeneghi G, Loquet A, Lavillette D, Lavergne JP, Montserret R, Cosset FL, Bockmann A, Meier BH, Penin F, Pecheur EI: Mechanism of inhibition of enveloped virus membrane fusion by the antiviral drug arbidol. PLoS One. 2011 Jan 25;6(1):e15874. doi: 10.1371/journal.pone.0015874. [PubMed:21283579]
Blaising J, Polyak SJ, Pecheur EI: Arbidol as a broad-spectrum antiviral: an update. Antiviral Res. 2014 Jul;107:84-94. doi: 10.1016/j.antiviral.2014.04.006. Epub 2014 Apr 24. [PubMed:24769245]
Deng P, Zhong D, Yu K, Zhang Y, Wang T, Chen X: Pharmacokinetics, metabolism, and excretion of the antiviral drug arbidol in humans. Antimicrob Agents Chemother. 2013 Apr;57(4):1743-55. doi: 10.1128/AAC.02282-12. Epub 2013 Jan 28. [PubMed:23357765]
Liu MY, Wang S, Yao WF, Wu HZ, Meng SN, Wei MJ: Pharmacokinetic properties and bioequivalence of two formulations of arbidol: an open-label, single-dose, randomized-sequence, two-period crossover study in healthy Chinese male volunteers. Clin Ther. 2009 Apr;31(4):784-92. doi: 10.1016/j.clinthera.2009.04.016. [PubMed:19446151]
Wang Z, Chen X, Lu Y, Chen F, Zhang W: Clinical characteristics and therapeutic procedure for four cases with 2019 novel coronavirus pneumonia receiving combined Chinese and Western medicine treatment. Biosci Trends. 2020 Feb 9. doi: 10.5582/bst.2020.01030. [PubMed:32037389]
Nature Biotechnology: Coronavirus puts drug repurposing on the fast track [Link]
Lanraplenib (GS-9876) is a highly selective and orally active SYK inhibitor (IC50=9.5 nM) in development for the treatment of inflammatory diseases. Lanraplenib (GS-9876) inhibits SYK activity in platelets via the glycoprotein VI (GPVI) receptor without prolonging bleeding time (BT) in monkeys or humans.
Description
Lanraplenib (GS-9876) is a highly selective and orally active SYK inhibitor (IC50=9.5 nM) in development for the treatment of inflammatory diseases. Lanraplenib (GS-9876) inhibits SYK activity in platelets via the glycoprotein VI (GPVI) receptor without prolonging bleeding time (BT) in monkeys or humans[1][2][3].
Lanraplenib (GS-9876) inhibits anti-IgM stimulated phosphorylation of AKT, BLNK, BTK, ERK, MEK, and PKCδ in human B cells with EC50 values of 24-51 nM. Lanraplenib (GS-9876) inhibits anti-IgM mediated CD69 and CD86 expression on B-cells (EC50=112±10 nM and 164±15 nM, respectively) and anti-IgM /anti-CD40 co-stimulated B cell proliferation (EC50=108±55 nM). In human macrophages, Lanraplenib (GS-9876) inhibits IC-stimulated TNFα and IL-1β release (EC50=121±77 nM and 9±17 nM, respectively)[1].
Lanraplenib (GS-9876) inhibits glycoprotein VI (GPVI)-induced phosphorylation of linker for activation of T cells and phospholipase Cγ2, platelet activation and aggregation in human whole blood, and platelet binding to collagen under arterial flow[2].
Spleen tyrosine kinase (SYK) is a critical regulator of signaling in a variety of immune cell types such as B-cells, monocytes, and macrophages. Accordingly, there have been numerous efforts to identify compounds that selectively inhibit SYK as a means to treat autoimmune and inflammatory diseases. We previously disclosed GS-9973 (entospletinib) as a selective SYK inhibitor that is under clinical evaluation in hematological malignancies. However, a BID dosing regimen and drug interaction with proton pump inhibitors (PPI) prevented development of entospletinib in inflammatory diseases. Herein, we report the discovery of a second-generation SYK inhibitor, GS–9876 (lanraplenib), which has human pharmacokinetic properties suitable for once-daily administration and is devoid of any interactions with PPI. Lanraplenib is currently under clinical evaluation in multiple autoimmune indications.
Step 6. 6-(6-Aminopyrazin-2-yl)-N-(4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)imidazo|1,2-a]pyrazin-8-amine (39). To a solution of tert-butyl(6-(6-(bis(tert-butoxycarbonyl)amino)pyrazm-2-yl)imidazo[1,2-a]pyrazin-8-yl)(4-(4-(oxetan-3-yl)piperazin1yl)phenyl)carbamate 45 (200 mg, 0.269 mmol) in DCM (2 ml) was added TFA (0.5 ml, 6.578 mmol). The reaction was stirred at room temperature for 16h, treated with saturated sodium bicarbonate, extracted with EtOAc, and purified on silica gel, eluting with 5%MeOH / EtOAc to 20%MeOH / EtOAc. The desired fractions were combined and concentrated to provide 100 mg (83% yield) of the title compound 39. m/z calcd for C23H25N9O [M+H] + 444.23, found LCMS-ESI+ (m/z): [M+H] + 444.20. 1H NMR (300 MHz d6-DMSO) δ: 9.5 (s,lH), 8.588 (s, 1H), 8.47 (s, 1H), 8.12 (d, 1H), 7.95-7.92 (d5 2H), 7.88 (s, 1H), 7.62 (s, 1H), 6.99-6.96 (d, 2H), 6.46 (s, 2H), 4.57- 4.53 (m, 2H), 4.48-4.44 (m, 2H), 3.43 (m, 1H), 3.15-3.12 (m, 4H), 2.41- 2.38 (m, 4H).
Protein kinases, the largest family of human enzymes, encompass well over 500 human proteins. Spleen Tyrosine Kinase (Syk) is a member of the Syk family of tyrosine kinases, and is a regulator of early B-cell development as well as mature B-cell activation, signaling, and survival.
Acute Graft Versus Host Disease (aGVHD), also known as fulminant Graft Versus Host Disease, generally presents symptoms within the first 100 days following allogenic hematopoietic stem cell transplantation and is generally characterized by selective damage to the skin, liver, mucosa, and gastrointestinal tract. Chronic Graft Versus Host Disease (cGVHD) occurs in recipients of allogeneic hematopoietic stem cell transplant (HSCT). GVHD is considered chronic when it occurs >100 days post-transplant, though aspects of cGVHD may manifest themselves prior to the 100 day point and overlap with elements of aGVHD. The disease has a cumulative incidence of 35-70% of transplanted patients, and has an annual incidence of approximately 3,000-5,000 and a prevalence of approximately 10,000 in the US. cGVHD is difficult to treat and is associated with worse outcomes compared to those without cGVHD. Current standard of care includes a variety of approaches including systemic corticosteroids often combined with calcineurin inhibitors, mTOR inhibitors, mycophenylate mofetil, or rituximab. Despite treatment, response rates are poor (40-50%) and cGVHD is associated with significant morbidity such as serious infection and impaired quality of life; the 5-year mortality is 30-50% (Blazar et al., Nature Reviews Immunology 12, 443-458, June 2012).
Human and animal models have demonstrated that aberrant B-lymphocyte signaling and survival is important in the pathogenesis of cGVHD. B-cell targeted drugs, including SYK inhibitors (fostamatinib – Sarantopoulos et al, Biology of Blood and Marrow Transplantation, 21(2015) S 11 -S 18) and BTK inhibitors (ibrutinib – Nakasone et al, Int. J. HematoL- 27 March 2015), have been shown to selectively reduce the function and frequency of aberrant GVHD B-cell populations ex vivo.
There remains a need for new methods, pharmaceutical compositions, and regimens for the treatment of GVHD, including aGVHD and cGVHD.
Example 2. Preparation of 6-(6-aminopyrazin-2-yl)-N-(4-(4-(oxetan-3-yl)piperazin-l- yl)phenyl)imid azo [ 1,2-a] pyrazin-8-amine (2)
2-Bis(tert-butoxycarbonyl)amino-6-bromopyrazine XIV: To a mixture of 6-bromopyrazin-2-amine (5 g, 28.7 mmol) and di-tert-butyl dicarbonate (25.09 g, 1 14.94 mmol) was added DCM (10 ml) followed by DMAP (0.351 g, 29 mmol). The reaction was heated to 55 °C for lh, cooled to RT, the reaction was partitioned between water and DCM, purified on silica gel and concentrated to provide of 2-bis(tert-butoxycarbonyl)amino-6-bromopyrazine XIV. LCMS-ESI+ (m/z): [M+H]+: 374.14. XH NMR (DMSO) δ: 8.84(d, 2H), 1.39 (s, 18H).
tert-Butyl (6-(6-(bis(tert-butoxycarbonyl)amino)pyrazin-2-yl)imidazo[l,2-a]pyrazin-8-yl)(4-(4-(oxetan-3-yl)piperazin-l-yl)phenyl)carbamate XVI – CHEMISTRY A route: tert-Butyl 4-(4-(oxetan-3-yl)piperazin-l-yl)phenyl(6-(tributylstannyl)imidazo[l,2-a]pyrazin-8-yl)carbamate V (215 mg, 0.291 mmol), was combined with 2-bis(tert-butoxycarbonyl)amino-6-bromopyrazine XIV (217.58 mg, 0.581 mmol),
bis(triphenylphosphine)palladium(II) dichloride(30.61 mg, 0.044 mmol) and 1,4-dioxane (5ml). The reaction mixture was stirred in a microwave reactor at 120 °C for 30 min. The reaction mixture was quenched with saturated KF, extracted with EtOAc, purified on silica gel, eluted with EtOAc. The desired fractions were combined and concentrated to provide 100 mg (46% yield) of tert-butyl (6-(6-(bis(tert-butoxycarbonyl)amino)pyrazin-2-yl)imidazo[l,2-a]pyrazin-8-yl)(4-(4-(oxetan-3-yl)piperazin-l-yl)phenyl)carbamate XVI. LCMS-ESI+ (m/z): [M+H]+: 744.4. lH NMR (300 MHz d6-DMSO) δ: 9.37 (s, 1H), 9.18 (s, 1H), 8.77 (s, 1H), 8.33 (d, 1H), 7.87 (d, 1H), 7.28-7.25 (d, 2H), 6.92-6.89 (d, 2H), 4.55-4.41 (m, 4H), 3.4 (m, lH), 3.14-3. 11 (m,4H), 2,37-2.34 (m, 4H), 1.37 (s, 18H), 1.3 (s, 9H).
tert-Butyl (6-(6-(bis(tert-butoxycarbonyl)amino)pyrazin-2-yl)imidazo[l,2-a]pyrazin-8-yl)(4-(4-(oxetan-3-yl)piperazin-l-yl)phenyl)carbamate XVI – CHEMISTRY B route: Step 1 : To a dry 250 mL round-bottomed flask was added 2-bis(tert-butoxycarbonyl)amino-6-bromopyrazine XIV (l .Og, l .Oequiv, 2.67mmol), KOAc (790mg, 8.02mmol, 3.0equiv), 4,4,4′,4′,5,5,5′,5′-octamethyl-2,2′-bi(l ,3,2-dioxaborolane) (750mg, 2.94mmol, l . l equiv), Pd(dba) (171mg, 0.187mmol, 0.07equiv) and X-phos (128mg, 0.267mmol, O. lequiv) followed by 1,4-dioxane (25mL) and the solution was sonicated for 5 min and then purged with N2 gas for 5 min. The flask with contents was then placed under N2 atmosphere and heated at 1 10 °C for 90 min. Once full conversion to the pinacolboronate was achieved by LCMS, the reaction was removed from heat and allowed to cool to RT. Once cool, the reaction contents were filtered through Celite and the filter cake was washed 3 x 20 mL EtOAc. The resultant solution was then concentrated down to a deep red-orange
syrup providing N, N-BisBoc 6-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)pyrazin-2-amine XV, which was used directly in the next step.
Step 2: The freshly formed N, N-BisBoc 6-(4,4,5,5-tetramethyl-l ,3,2-dioxaborolan-2-yl)pyrazin-2-amine XV (2.67 mmol based on 100% conversion, 2.0 equiv based on bromide) was dissolved in 20 Ml of 1,2-dimethoxy ethane and to that solution was added tert-butyl (6-bromoimidazo[l,2-a]pyrazin-8-yl)(4-(4-(oxetan-3-yl)piperazin-l-yl)phenyl)carbamate IV (707mg, 1.34mmol, l .Oequiv), Na2CC>3 (283mg, 2.67mmol, 2.0equiv), Pd(PPh3)4 (155mg, 0.134mmol, 0.1 equiv) and water (l OmL) and the solution was degassed for 5 min using N2 gas. The reaction was then placed under N2 atmosphere and heated at 110 °C for 90 min. LCMS showed complete consumption of the bromide starting material and the reaction was removed from heat and allowed to cool to RT. The reaction was diluted with 100 mL water and 100 mL 20% MeOH/DCM and the organic layer was recovered, extracted 1 x sat. NaHCCb, 1 x sat brine and then dried over Na2SC>4. The solution was then filtered and concentrated down to an orange-red solid. The sample was then slurried in warm MeOH, sonicated then filtered, washing 2 x 20 mL with cold MeOH and then the cream-colored solid was dried on hi-vacuum overnight to yield 905 mg of tert-butyl (6-(6-(bis(tert-butoxycarbonyl)amino)pyrazin-2-yl)imidazo[l,2-a]pyrazin-8-yl)(4-(4-(oxetan-3-yl)piperazin- 1 -yl)phenyl)carbamate XVI.
6-(6-Aminopyrazin-2-yl)-N-(4-(4-(oxetan-3-yl)piperazin-l-yl)phenyl)imidazo[l,2-a]pyrazin-8-amine (2): To a solution of tert-butyl (6-(6-(bis(tert-butoxycarbonyl)amino)pyrazin-2-yl)imidazo[l,2-a]pyrazin-8-yl)(4-(4-(oxetan-3-yl)piperazin-l -yl)phenyl)carbamate XVI (200 mg, 0.269 mmol) in DCM (2 ml) was added TFA (0.5 ml, 6.578 mmol). The reaction was stirred at rt for 16h, saturated sodium bicarbonate was added, extracted with EtOAC and purified on silica gel, eluted with 5%MeOH / EtOAc, 20%MeOH / EtOAc. The desired fractions were combined and concentrated to provide the title compound 2. LCMS-ESI+(m/z): [M+H]+: 444.2. lH NMR (300 MHz d6-DMSO) δ: 9.5 (s, lH), 8.588 (s, IH), 8.47 (s, IH), 8. 12 (d, IH), 7.95-7.92 (d, 2H), 7.88 (s, IH), 7.62 (s, IH), 6.99-6.96 (d, 2H), 6.46 (s, 2H), 4.57-4.53 (m, 2H), 4.48-4.44 (m, 2H), 3.43 (m, IH), 3.15-3.12 (m, 4H), 2.41 -2.38 (m, 4H).
To a 720 L reactor, was added di-fer/-butyl (6-bromopyrazin-2-yl)imidodicarbonate (18.5 kg, 1.41 equiv, 49 mol), bis(pinacolato)diboron (13.8 kg, 1.56 equiv, 54 mol), potassium propionate (11.9 kg, 3.02 equiv, 106 mol), and bis(di-fer/-butyl(4-dimethylaminophenyl) phosphine)dichloropalladium (1.07 kg, 0.0043 equiv, 1.5 mol), followed by degassed toluene (173 L). The mixture was degassed then heated at 65 °C until the reaction was deemed complete (0% tert-butyl 2-((6-bromopyrazin-2-yl)(tert-butoxycarbonyl)amino)-2-oxoacetate) by UPLC. Upon completion, the reaction was cooled to 23 °C. Once cooled, 6-bromo-N-(4-(4-(oxetan-3-yl)piperazin-l -yl)phenyl)imidazo[l ,2-a]pyrazin-8-amine (15.0 kg, 1.00 equiv, 35 mol) was added and the mixture was degassed. A degassed aqueous potassium carbonate solution prepared using water (54 L) and potassium carbonate (20.6 g, 4.26 equiv, 149 mol) was then added to the reaction mixture and the reactor contents was degassed. The reactor contents was heated at 65 °C until reaction was deemed complete (1% 6-bromo-N-(4-(4-(oxetan-3-yl)piperazin-l-yl)phenyl)imidazo[l,2-a]pyrazin-8-amine) by UPLC. Upon completion, the reaction was cooled to 24 °C.
The cooled mixture was concentrated and then diluted with dichloromethane (300 L), transferred to a 1900 L reactor and rinsed forward with dichloromethane (57 L). N-acetyl-L-cysteine (3.8 kg) was charged and the mixture was agitated for 15 h. Water (135 L) was then added and the mixture was filtered and rinsed forward with dichloromethane (68 L). The organic layer was recovered and washed with a brine solution prepared using water (68 L) and sodium chloride (7.5 kg).
The resultant organic layer was polish filtered then concentrated and fert-butyl methyl ether (89.9 kg) was slowly charged keeping the temperature at 31 °C. The contents was cooled to 0 °C and aged, then filtered and rinsed with tert-butyl methyl ether (32.7 kg) and dried at 40 °C to give 17.2 kg of di-tert-butyl {6-[8-({4-[4-(oxetan-3-yl)piperazin-l-yl]phenyl} amino)imidazo[l,2-a]pyrazin-6-yl]pyrazin-2-yl}imidodicarbonate.
To a slurry of di-tert-butyl {6-[8-({4-[4-(oxetan-3-yl)piperazin-l -yl]phenyl} amino)imidazo[l,2-a]pyrazin-6-yl]pyrazin-2-yl}imidodicarbonate (225 g, 0.35 mol, 1 mol eq.) in water (12 parts) was added a solution of sulfuric acid (3.1 parts, 6.99 mol, 20 mol eq.) in water (5 parts). The reaction was heated to ca. 40 °C and stirred at this temperature for ca. 4 h at which point the reaction is deemed complete. The reaction mixture was cooled to ca. 22 °C, acetone (3 parts) was charged and a solution of sodium carbonate (4.1 parts, 8.75 mol, 25.0 mol eq.) in water (15 parts) was added. The resulting slurry was filtered and the wet cake was washed with water in portions (4 x 1 parts), then with fert-butyl methyl ether (4 parts). The wet cake (Example 2 free base) was dried at ca. 60 °C. To the slurry of dry Example 2 free base in 2-propanol (2.3 parts) was added a solution of succinic acid (Based on the isolated Example 2 free base: 0.43 parts, 1.6 mol eq.) in 2-propanol (15 parts). The resulting slurry was heated to ca. 40 °C and stirred at this temperature for ca. 2 h and then cooled to ca. 22 °C, followed by a stir period of ca. 16 h. The slurry was filtered at ca. 22 °C and the wet cake was washed with 2-propanol (5 parts) and dried at ca. 60 °C to afford the product.
Tranilast (INN, brand name Rizaben) is an antiallergic drug. It was developed by Kissei Pharmaceuticals and was approved in 1982 for use in Japan and South Korea for bronchial asthma. Indications for keloid and hypertrophic scar were added in the 1980s.
Kissei has developed and launched tranilast in Japan and South Korea for the treatment of allergic rhinitis, asthma and atopic dermatitis. Kissei, in collaboration with GlaxoSmithKline was additionally developing tranilast for the prevention of restenosis following percutaneous transluminal coronary angioplasty.
It should not be taken women who are or might become pregnant, and it is secreted in breast milk.[1]
Interactions
People who are taking warfarin should not also take tranilast, as they interact.[1] It appears to inhibit UGT1A1 so will interfere with metabolism of drugs that are affected by that enzyme.[1]
Adverse effects
When given systemically, tranilast appears to cause liver damage; in a large well-conducted clinical trial it caused elevated transaminases three times the upper limit of normal in 11 percent of patients, as well as anemia, kidney failure, rash, and problems urinating.[1]
As of March 2018 it was marketed in Japan, China, and South Korea under the brand names Ao Te Min, Arenist, Brecrus, Garesirol, Hustigen, Krix, Lumios, Rizaben, Tramelas, Tranilast and it was marketed as a combination drug with salbutamol under the brand name Shun Qi.[2]
In 2016 the FDA proposed that tranilast be excluded from the list of active pharmaceutical ingredients that compounding pharmacies in the US could formulate with a prescription.[1]
Pharmacology
It appears to work by inhibiting the release of histamine from mast cells; it has been found to inhibit proliferation of fibroblasts but its biological target is not known.[3] It has been shown to inhibit the release of many cytokines in various cell types, in in vitro studies.[3] It has also been shown to inhibit NALP3 inflammasome activation and is being studied as a treatment for NALP3-driven inflammatory diseases.[4]
Chemistry
Tranilast is an analog of a metabolite of tryptophan, and its chemical name is 3′,4′-dimethoxycinnamoyl) anthranilic acid (N-5′).[3]
It is almost insoluble in water, easily soluble in dimethylsulfoxide, soluble in dioxane, and very slightly soluble in ether. It is photochemically unstable in solution.[3]
Orally active anti-allergic agent. Prepn: K. Harita et al., DE 2402398; idem, US 3940422 (1974, 1976 both to Kissei).
Y. Kamijo, M. Kobayashi, and A. Ajisawa, Jpn. Kokai, 77/83,428 (1977) via Chem. Abstr.,
As of 2016, Altacor was developing a formulation of tranilast to prevent of scarring following glaucoma surgery and had obtained an orphan designation from the EMA for this use.[7][8]
History
It was developed by Kissei and first approved in Japan and South Korea for asthma in 1982, and approved uses for keloid and hypertrophic scars were added later in the 1980s.[3]
PATENT
tranilast product case US03940422 , expired in all the regional territories.
PATENT
WO2013144916 claiming tranilast complexes and cocrystals with nicotinamide, saccharin, gentisic acid, salicylic acid, urea, 4-aminobenzoic acid and 2,4-dihydroxybenzoic acid
Novel crystalline forms of tranilast or its salts as histamine H1 receptor antagonist useful for treating allergy, allergic rhinitis and atopic dermatitis.
Tranilast, (2-[[3-(3,4-dimethoxyphenyl)-l-oxo-2-propenyl]amino] benzoic acid, shown below), was originally developed as an anti-allergy drug due to its ability to inhibit the release of inflammatory mediators, such as histamine, from mast cells and basophils (P. Zampini. IntJ Immunopharmacol. 1983;
Tranilast
Tranilast has been marketed in Japan, China and South Korea by Kissei Pharmaceutical Co. Ltd, for allergic conditions such as allergic conjunctivitis, bronchial asthma, allergic rhinitis and atopic dermatitis, under the Rizaben® brand name for more than thirty years. More recently tranilast has also been shown to have anti-proliferative properties. Tranilast was shown to inhibit the proliferation of fibroblasts and suppress collagen synthesis (M. Isaji. Biochem Pharmacol. 1987; 36: 469-474) and also to inhibit the transformation of fibroblasts to myofibroblasts and their subsequent contraction (M. Isaji. Life Sci. 1994; 55: 287-292). This additional behaviour led to tranilast gaining additional approval for the treatment of keloids and hypertrophic scars.
[004] Over recent years many researchers have explored the anti-proliferative effects of tranilast to assess its potential in fibrotic and cancerous conditions. Its anti-proliferative action is believed to be due to its ability to inhibit transforming growth factor beta (TGF-b) (H. Suzawa. Jpn J Pharmacol. 1992 Oct; 60(2): 91-96). Fibrosis is a condition that can affect most organs of the body and fibroblast proliferation, differentiation and collagen synthesis are known to be key factors in the progression of most types of fibrosis. Tranilast has been shown in-vivo to have potential beneficial effects in
numerous fibrotic conditions. Tranilast has been shown in-vivo to have potential in lung fibrosis (M. Kato. Eur RespirJ. 2013; 42(57): 2330), kidney fibrosis (DJ Kelly, J Am Soc Nephrol. 2004; 15(10): 2619-29), cardiac fibrosis (J Martin, Cardiovasc Res. 2005; 65(3): 694-701), ocular fibrosis (M J Moon, BMC Opthalmol. 2016; 16: 166) and liver fibrosis (M Uno, Hepatology. 2008; 48(1): 109-18.
[005] Tranilast’s anti-tumor action has also recently been demonstrated, in-vitro and in-vivo. Tranilast has been shown to inhibit the proliferation, apoptosis and migration of several cell lines including breast cancer (R. Chakrabarti. Anticancer Drugs. 2009 Jun; 20(5): 334-45) and prostate cancer (S. Sato. Prostate. 2010 Feb; 70(3): 229-38) cell lines. In a study of mammary carcinoma in mice tranilast was found to produce a significant reduction in metastasis (R. Chakrabarti. Anticancer Drugs. 2009 Jun; 20(5): 334-45). In a pilot study in humans, tranilast was shown to have the potential to improve the prognosis of patients with advanced castration-resistant prostate cancer (K. Izumi. Anticancer Research. 2010 Jul; 30: 73077-81). In-vitro studies also showed the therapeutic potential of tranilast in glioma (M Platten. IntJ Cancer. 2001; 93:53-61), pancreatic cancer (M Hiroi, J Nippon Med Sch. 2002; 69: 224-234) and gastric carcinoma (M Yashiro, Anticancer Res. 2003; 23: 3899-3904).
[006] Given the wide range of fibrotic conditions and cancers for which tranilast could have a potential therapeutic benefit, as well as the different patient types and specific areas of the body requiring treatment, it is anticipated that patients would benefit from having multiple delivery methods for the administration of tranilast so as to best suit the patient’s needs. The pharmaceutical compositions could include, for example, a solid oral dosage, a liquid oral dosage, an injectable composition, an inhalable composition, a topical composition or a transdermal composition.
[007] Kissei Pharmaceutical Co. Ltd explored the anti-proliferative effect of tranilast in the prevention of restenosis associated with coronary intervention. In a Phase II clinical study Kissei found that the current approved dose of tranilast (300 mg/day) was insufficient to prevent restenosis and that a higher dose of 600 mg/day was needed to achieve a decrease in restenosis rates (H. Tamai, Am Heart J.1999; 138(5): 968-75). However, it was found that a 600 mg daily dosage can result in a ten-fold inter-patient variation in plasma concentrations of the drug (30-300 pmol/L) (H Kusa ma. Atherosclerosis. 1999; 143: 307-313) and in the Phase III study of tranilast for the prevention of restenosis the dose was further increased to 900mg daily (D Holmes, Circulation. 2002; 106(10): 1243-1250).
[008] The marketed oral form of tranilast (Rizaben®) contains tranilast in its pure crystalline form. Crystalline tranilast has extremely low aqueous solubility (solubility of 14.5 pg/ml in water and 0.7 pg/ml in pH 1.2 buffer solution (Society of Japanese Pharmacopoeia. 2002)). Whilst, high energy amorphous forms are often used as a means of improving the solubility of poorly soluble drug
compounds, literature shows that an amorphous form of tranilast is not completely photostable in the solid state and that it undergoes photodegradation on storage when exposed to light (S. Onoue. EurJ Pharm Sci. 2010; 39: 256-262).
[009] It is expected that the very low solubility of tranilast is a limiting factor in the oral bioavailability of the drug. Given the limited time any drug has to firstly dissolve in the
gastrointestinal tract and then be absorbed into the bloodstream, this issue will become even more limiting as the oral dose of tranilast is increased. The poor solubility of tranilast is also possibly a key factor in the high inter-patient variability reported for higher dose tranilast pharmacokinetics. As a BCS class II drug (low solubility/high permeability) it is expected that absorption from the gastrointestinal tract is hampered by the dissolution rate of the drug in gastrointestinal media as well as its overall solubility. For treatment of chronic proliferative diseases such as fibrosis and cancer it is vital for the delivery method of a drug to produce consistent, predictable plasma levels that are maintained above the minimum effective concentration. To achieve efficacious oral delivery of tranilast at higher doses there is a need for new solid forms of the drug with both high solubility and rapid dissolution rates.
[010] Given the severity of conditions involving cancer or fibrosis there is also a need for systemic treatment options by which tranilast can be delivered by healthcare specialists that do not require the patient to swallow solid oral dosage forms. Alternative dosage forms suitable for these needs could include, for example, injectable compositions, liquid oral formulations or nebulized inhaled formulations. These would require a liquid formulation of tranilast suitable for systemic delivery. [Oil] Given the potential of tranilast to treat ocular diseases, such as allergic conjunctivitis, Kissei Pharmaceutical Co. Ltd recognised the need to develop an eye drop formulation of tranilast for localised treatment. However, as well as having very low aqueous solubility, tranilast is also photochemically unstable when stored in solution, resulting in significant degradation (N Hori, Chem. Pharm. Bull. 1999; 47(12): 1713-1716). Therefore, the only way Kissei were able to achieve an eye drop liquid composition of tranilast was to use both solubilising and stabilising agents in the formulation (US Patent 5356620). The resulting 0.5% (w/v) eye drop formulation is currently also marketed under the Rizaben® brand name. However, the focus of this formulation and of the subsequent research that has attempted to produce alternative solution formulations of tranilast has always been solely on external delivery of tranilast using compositions such as eye drops and skin ointments etc. None of the liquid formulations of tranilast previously described have been produced for systemic delivery such as for oral or IV delivery. Excipients used in the previously reported external preparations are not suitable for systemic delivery. Also, despite the successful
development of an eye drop formulation of tranilast, the package insert of the marketed Rizaben® eye drops states that the product should not be stored in a refrigerator as crystals may precipitate.
[012] Thus, there remains a need for aqueous pharmaceutical compositions of tranilast suitable for systemic delivery. Given the potential photochemical degradation issue of long term storage of tranilast in solution and also the disadvantage of the larger storage facilities needed to store bulkier solution based formulations it would also be advantageous to develop a stable highly soluble solid form of tranilast that can be quickly dissolved at the time of treatment by the patient or healthcare provider to produce the required liquid formulation.
[013] Following efforts to make a liquid formulation of tranilast, Kissei made the statement that tranilast and pharmaceutically acceptable salts thereof are too insoluble in water to prepare an aqueous solution (US Patent 5356620). Since that US patent the only crystalline pharmaceutically acceptable salt to have been published is the sodium salt (N Geng, Cryst. Growth Des. 2013; 13: 3546-3553). In line with the findings of Kissei the authors of this paper stated that the apparent solubility of the crystalline tranilast sodium salt is even less than that of pure tranilast. Also, when they performed a dissolution study of tranilast in a sodium containing media they found that as the tranilast dissolved it gradually precipitated out of solution as its sodium salt indicating that the sodium salt has a lower thermodynamic solubility than the pure drug. The authors of this paper also successfully prepared the non-pharmaceutically acceptable crystalline cytosine salt of tranilast. Despite this crystalline cytosine salt showing approximately a two-fold solubility improvement over pure crystalline tranilast, not only would this crystalline cytosine salt not be suitable for systemic delivery to a patient due to cytosine not having FDA acceptability but this improvement in solubility would not be great enough to produce high dose tranilast liquid formulations such as an injectable formulation.
[014] Patent application EP1946753 discloses an attempt to prepare an external preparation of tranilast and claims the preparation of ionic liquid salts of tranilast with organic amines. The inventors claim that blending tranilast with the organic amine results in a liquid form. This application does not disclose the formation of any solid state, crystalline tranilast salts with organic amines. They demonstrate that these ionic liquid forms of tranilast have higher solubility in solvents suitable for external application to the skin and that these preparations have higher photostability than pure tranilast in the same formulation. However, this improved photostability still results in a significant proportion of the tranilast being photo-degraded and would not be suitable for long term storage. Also, the solvents used for preparation of these ionic liquid salt formulations are not suitable for internal delivery of tranilast. Moreover, there is no mention in EP1946753 of improved solubility in aqueous or bio-relevant media.
Tranilast, (2-[[3-(3,4-dimethoxyphenyl)-1-oxo-2-propenyl]amino]benzoic acid), shown below, is a therapeutic agent that exhibits an anti-allergic effect. It has been shown to inhibit the release of inflammatory mediators, such as histamine, from mast cells and basophils (P. Zampini. Int J Immunopharmacol. 1983; 5(5): 431-5). Tranilast has been used as an anti-allergic treatment, for several years in Japan and South Korea, for conditions such as allergic conjunctivitis, bronchial asthma, allergic rhinitis and atopic dermatitis.
[0004]
Tranilast is currently marketed in Japan and South Korea by Kissei Pharmaceutical Co. Ltd under the Rizaben® brand name. As well as displaying an anti-allergic effect tranilast has been shown to possess anti-proliferative properties. Tranilast was found to inhibit the proliferation of fibroblasts and suppress collagen synthesis (M. Isaji. Biochem Pharmacol. 1987; 36: 469-474) and also to inhibit the transformation of fibroblasts to myofibroblasts and their subsequent contraction (M. Isaji. Life Sci. 1994; 55: 287-292). On the basis of these effects tranilast is now also indicated for the treatment of keloids and hypertrophic scars. Its anti-fibrotic action is believed to be due to its ability to inhibit transforming growth factor beta (TGF-β) (H. Suzawa. Jpn J Pharmacol. 1992 October; 60(2): 91-96). TGF-β induced fibroblast proliferation, differentiation and collagen synthesis are known to be key factors in the progression of idiopathic pulmonary fibrosis and tranilast has been shown in-viva to have potential in the treatment of this chronic lung disease (T. Jiang. Afr J Pharm Pharmaco. 2011; 5(10): 1315-1320). Tranilast has also been shown in-vivo to be have potential beneficial effects in the treatment of airway remodelling associated with chronic asthma (S. C. Kim. J Asthma 2009; 46(9): 884-894.
[0005]
It has been reported that tranilast also has activity as an angiogenesis inhibitor (M. Isaji. Br. J Pharmacol. 1997; 122(6): 1061-1066). The results of this study suggested that tranilast may be beneficial for the treatment of angiogenic diseases such as diabetic retinopathy and age related macular degeneration. As well as showing inhibitory effects on mast cells and fibroblasts, tranilast has also demonstrated an ability to diminish tumor necrosis factor-alpha (TNF-α) from cultured macrophages (H. O. Pae. Biochem Biophys Res Commun. 371: 361-365) and T-cells (M. Platten. Science. 310: 850-855), and inhibited NF-kB-dependent transcriptional activation in endothelial cells (M. Spieker. Mol Pharmacol. 62: 856-863). Recent studies have revealed that tranilast attenuates inflammation and inhibits bone destruction in collagen induced arthritis in mice suggesting the possible usefulness of tranilast in the treatment of inflammatory conditions such as arthritis (N. Shiota. Br. Pharmacol. 2010; 159 (3): 626-635).
[0006]
As has recently been demonstrated, in-vitro and in-vivo, tranilast also possesses an anti-tumor action. Tranilast has been shown to inhibit the proliferation, apoptosis and migration of several cell lines including breast cancer (R. Chakrabarti. Anticancer Drugs. 2009 June; 20(5): 334-45) and prostate cancer (S. Sato. Prostate. 2010 February; 70(3): 229-38) cell lines. In a study of mammary carcinoma in mice tranilast was found to produce a significant reduction in metastasis (R. Chakrabarti. Anticancer Drugs. 2009 June; 20(5): 334-45). In a pilot study in humans, tranilast was shown to have the potential to improve the prognosis of patients with advanced castration-resistant prostate cancer (K. Izurni. Anticancer Research. 2010 July; 30: 73077-81).
[0007]
It has been reported that tranilast has the ability to induce or enhance neurogenesis and, therefore, could be used as an agent to treat neuronal conditions such as cerebral ischernia, glaucoma, multiple sclerosis, amyotrophic lateral sclerosis, Alzheimer’s disease, neurodegenerative trinucleotide repeat disorders, neurodegenerative lyosomal storage diseases, spinal cord injury and trauma, dementia, schizophrenia and peripheral neuropathy (A. Schneider. EP2030617).
[0008]
Tranilast’s beneficial properties have been reported to have utility in several ocular conditions. Tranilast is currently approved in Japan and Korea far the treatment of allergic conjunctivitis. WO2010137681 claims the use of tranilast as a prophylactic or therapeutic agent for the treatment of retinal diseases. The anti-fibrotic properties of tranilast have been reported to be of benefit in maintaining the filtering blob during glaucoma surgery and this has been demonstrated in a pilot study in humans (E. Chihara.J Glaucoma. 1999; 11(2): 127-133). There have also been several reported cases of the beneficial use of tranilast in the prevention of postoperative recurrence of pterygium (C. Fukui. Jap J Opthalmol. 1999; 12: 547-549). Tsuji recently reported that tranilast may be beneficial not only in the prevention of ptergium recurrence, but also for the inhibition of symblepharon and granuloma formation (A. Tsuji. Tokai J Exp Clin Med. 2011; 36(4): 120-123). Collectively it has been demonstrated that tranilast possesses anti-allergic, anti-fibrotic, anti-inflammatory, anti-tumor, neurogenesis enhancing end angiogenesis inhibitory properties and as such may be useful for the treatment of diseases associated with such properties.
[0009]
Tranilast occurs as a yellow crystalline powder that is identified by CAS Registry Number: 53902-12-8. As is typical of cinnamic acid derivatives (G. M. J. Schmidt J Chem. Soc. 1964: 2000) tranilast is photochemically unstable when in solution, tranforming into cis-isomer and dimer forms on exposure to light (N. Hori. Cehm Pharm Bull. 1999; 47: 1713-1716). Although pure crystalline tranilast is photochemically stable in the solid state it is practically insoluble in water (14.5 μg/ml) and acidic media (0.7 μg/ml in pH 1.2 buffer solution) (Society of Japanese Pharmacopoeia. 2002). Although tranilast has shown activity in various indications, it is possible that the therapeutic potential of the drug is currently limited by its poor solubility and photostability. High energy amorphous forms are often used as a means of improving the solubility of poorly soluble APIs, however, literature shows that amorphous solid dispersions of tranilast are not completely photostable in the solid state and that they undergo photodegradation on storage when exposed to light (S. Onoue. Eur J Pharm Sci. 2010; 39: 256-262). US20110136835 describes a combination of tranilast and allopurinol and its use in the treatment of hyperuricemia associated with gout and has one mention of a “co-crystal form”, but lacks any further description or characterization.
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JP2011093849A *2009-10-302011-05-12Kissei Pharmaceutical Co LtdEasily dissolvable powder inhalant composed of tranilast
^Holmes, D. R; Savage, M; Lablanche, J. M; Grip, L; Serruys, P. W; Fitzgerald, P; Fischman, D; Goldberg, S; Brinker, J. A; Zeiher, A. M; Shapiro, L. M; Willerson, J; Davis, B. R; Ferguson, J. J; Popma, J; King Sb, 3rd; Lincoff, A. M; Tcheng, J. E; Chan, R; Granett, J. R; Poland, M (2002). “Results of Prevention of REStenosis with Tranilast and its Outcomes (PRESTO) Trial”. Circulation. 106 (10): 1243–50. doi:10.1161/01.CIR.0000028335.31300.DA. PMID12208800.
Encorafenib, also known as BRAFTOVI, is a kinase inhibitor. Encorafenib inhibits BRAF gene, which encodes for B-raf protein, which is a proto-oncogene involved in various genetic mutations Label. This protein plays a role in regulating the MAP kinase/ERK signaling pathway, which impacts cell division, differentiation, and secretion. Mutations in this gene, most frequently the V600E mutation, are the most commonly identified cancer-causing mutations in melanoma, and have been isolated in various other cancers as well, including non-Hodgkin lymphoma, colorectal cancer, thyroid carcinoma, non-small cell lung carcinoma, hairy cell leukemia and adenocarcinoma of the lung 6.
On June 27, 2018, the Food and Drug Administration approved encorafenib and Binimetinib(BRAFTOVI and MEKTOVI, Array BioPharma Inc.) in combination for patients with unresectable or metastatic melanoma with a BRAF V600E or V600K mutation, as detected by an FDA-approved test Label.
Array Biopharma (a wholly owned subsidiary of Pfizer ), under license from Novartis , and licensees Pierre Fabre and Ono Pharmaceutical have developed and launched the B-Raf kinase inhibitor encorafenib . In January 2020, the US FDA’s Orange Book was seen to list encorafenib patents such as US8946250 , US8501758 , US9314464 and US9763941 , expiring in the range of 2029-2032. At that time Orange Book also reported that encorafenib as having NCE exclusivity expiring on July 27, 2023.
Encorafenib (trade name Braftovi) is a drug for the treatment of certain melanomas. It is a small molecule BRAF inhibitor [1] that targets key enzymes in the MAPK signaling pathway. This pathway occurs in many different cancers including melanoma and colorectal cancers.[2] The substance was being developed by Novartis and then by Array BioPharma. In June 2018, it was approved by the FDA in combination with binimetinib for the treatment of patients with unresectable or metastatic BRAF V600E or V600K mutation-positive melanoma.[3][4]
The most common (≥25%) adverse reactions in patients receiving the drug combination were fatigue, nausea, diarrhea, vomiting, abdominal pain, and arthralgia.[3]
Indication
Used in combination with Binimetinib in metastatic melanoma with a BRAF V600E or V600K mutation, as detected by an FDA-approved test 5.
Encorafenib has shown improved efficacy in the treatment of metastatic melanoma 3.
Encorafenib, a selective BRAF inhibitor (BRAFi), has a pharmacologic profile that is distinct from that of other clinically active BRAFis 7.
Once-daily dosing of single-agent encorafenib has a distinct tolerability profile and shows varying antitumor activity across BRAFi-pretreated and BRAFi-naïve patients with advanced/metastatic stage melanoma 7.
Mechanism of action
Encorafenib is a kinase inhibitor that specifically targets BRAF V600E, as well as wild-type BRAF and CRAF while tested with in vitro cell-free assays with IC50 values of 0.35, 0.47, and 0.3 nM, respectively. Mutations in the BRAF gene, including BRAF V600E, result in activated BRAF kinases that mahy stimulate tumor cell growth. Encorafenib is able to bind to other kinases in vitro including JNK1, JNK2, JNK3, LIMK1, LIMK2, MEK4, and STK36 and significantly reduce ligand binding to these kinases at clinically achievable concentrations (≤ 0.9 μM) Label.
In efficacy studies, encorafenib inhibited the in vitro cell growth of tumor cell lines that express BRAF V600 E, D, and K mutations. In mice implanted with tumor cells expressing the BRAF V600E mutation, encorafenib induced tumor regressions associated with RAF/MEK/ERK pathway suppression Label.
Encorafenib and binimetinib target two different kinases in the RAS/RAF/MEK/ERK pathway. Compared with either drug alone, co-administration of encorafenib and binimetinib result in greater anti-proliferative activity in vitro in BRAF mutation-positive cell lines and greater anti-tumor activity with respect to tumor growth inhibition in BRAF V600E mutant human melanoma xenograft studies in mice. In addition to the above, the combination of encorafenib and binimetinib acted to delay the emergence of resistance in BRAF V600E mutant human melanoma xenografts in mice compared with the administration of either drug alone Label.
Pharmacology
Encorafenib acts as an ATP-competitive RAF kinase inhibitor, decreasing ERK phosphorylation and down-regulation of CyclinD1.[5]This arrests the cell cycle in G1 phase, inducing senescence without apoptosis.[5] Therefore it is only effective in melanomas with a BRAF mutation, which make up 50% of all melanomas.[6] The plasma elimination half-life of encorafenib is approximately 6 hours, occurring mainly through metabolism via cytochrome P450 enzymes.[7]
Clinical trials
Several clinical trials of LGX818, either alone or in combinations with the MEK inhibitor MEK162,[8] are being run. As a result of a successful Phase Ib/II trials, Phase III trials are currently being initiated.[9]
History
Approval of encorafenib in the United States was based on a randomized, active-controlled, open-label, multicenter trial (COLUMBUS; NCT01909453) in 577 patients with BRAF V600E or V600K mutation-positive unresectable or metastatic melanoma.[3] Patients were randomized (1:1:1) to receive binimetinib 45 mg twice daily plus encorafenib 450 mg once daily, encorafenib 300 mg once daily, or vemurafenib 960 mg twice daily.[3] Treatment continued until disease progression or unacceptable toxicity.[3]
The major efficacy measure was progression-free survival (PFS) using RECIST 1.1 response criteria and assessed by blinded independent central review.[3] The median PFS was 14.9 months for patients receiving binimetinib plus encorafenib, and 7.3 months for the vemurafenib monotherapy arm (hazard ratio 0.54, 95% CI: 0.41, 0.71, p<0.0001).[3] The trial was conducted at 162 sites in Europe, North America and various countries around the world.[4]
SYN
PATENT
WO2010010154 , expiry , EU states, 2029, US in 2030 with US154 extension.
Novel deuterated analogs of diarylpyrazole compounds, particularly encorafenib are B-RAF and C-RAF kinase inhibitors, useful for treating proliferative diseases such as melanoma and colorectal cancer. Family members of the product case, WO2010010154 , expire in most of the EU states until 2029 and will expire in the US in 2030 with US154 extension. In January 2020, the US FDA’s Orange Book was seen to list encorafenib patents such as US8946250 , US8501758 , US9314464 and US9763941 , expiring in the range of 2029-2032. At that time Orange Book also reported that encorafenib as having NCE exclusivity expiring on July 27, 2023.
The mitogen-activated protein kinase (MAPK) pathway mediates the activity of many effector molecules that coordinately control cell proliferation, survival, differentiation, and migration. Cells are bound by plasma factors such as growth factors, cytokines, or hormones to plasma membrane-associated Ras and GTP and thereby activated to recruit Raf. This interaction induces Raf’s kinase activity, resulting in direct phosphorylation of MAPK / ERK (MEK), which in turn phosphorylates extracellular signal-related kinase (ERK). Activated ERK phosphorylates a range of effector molecules, such as kinases, phosphatases, transcription factors, and cytoskeleton proteins. Therefore, the Ras-Raf-MEK-ERK signaling pathway transmits signals from cell surface receptors to the nucleus and is essential for cell proliferation and survival.
[0003]
According to Raf’s ability to interact with upstream regulator Ras, Raf has three different isoforms, namely A-Raf, B-Raf, and C-Raf. An activating mutation of one of the Ras genes can be observed in about 20% of all tumors, and the Ras-Raf-MEK-ERK pathway is activated in about 30% of all tumors. Activation mutations in the B-Raf kinase domain occur in approximately 70% of melanoma, 40% of papillary cancer, 30% of low-grade ovarian cancer, and 10% of colorectal cancer. Most B-Raf mutations are found in the kinase domain, with a single substitution (V600E) accounting for 80%. The mutated B-Raf protein activates the Raf-MEK-ERK pathway by increasing kinase activity against MEK or by activating C-Raf. B-Raf inhibitors inhibit cells involved in B-Raf kinase by blocking the signal cascade in these cancer cells and eventually inducing cell arrest and / or death.
[0004]
Encorafenib (aka LGX-818, chemical name is (S)-(1-((4- (3- (5-chloro-2-fluoro-3- (methylsulfonylamino) phenyl) -1-iso Propyl-1H-pyrazol-4-yl) pyrimidin-2-yl) amino) prop-2-yl) methyl carbamate, which has the following structural formula) is a new oral BRAF jointly developed by Novartis and Array Pharmaceuticals Inhibitors can inhibit the activation of the MAPK pathway caused by B-Raf kinase mutations (such as V600 mutations, that is, glutamate mutations at amino acid 600). Encorafenib alone or in combination with MEK inhibitor Binimetinib is used to treat patients with advanced BRAF v600 mutant melanoma. On June 27, 2018, the FDA approved Encorafenib (commercial name BRAFTOVI) capsules in combination with Binimetinib (commercial name: MEKTOVI) tablets for treating melanoma patients with BRAF V600E or BRAFV 600K mutations.
It is known that poor absorption, distribution, metabolism, and / or excretion (ADME) properties are the main cause of the failure of many candidate drug clinical trials. Many drugs currently on the market also limit their scope of application due to poor ADME properties. The rapid metabolism of drugs will cause many drugs that could be highly effective in treating diseases to be difficult to make because they are metabolized from the body too quickly. Although frequent or high-dose medication may solve the problem of rapid drug removal, this method will bring problems such as poor patient compliance, side effects caused by high-dose medication, and rising treatment costs. In addition, rapidly metabolizing drugs may also expose patients to adverse toxic or reactive metabolites.
[0007]
Although Encoratenib as a BRAF inhibitor can effectively treat BRAF V600 mutant melanoma, there are still serious clinical unmet needs in this field, and the Encoratenib compound is a class II BCS with poor water solubility at weakly acidic and neutral pH Compounds have poor oral availability, so finding new compounds that have a therapeutic effect on BRAF kinase mutations, have good oral bioavailability, and have pharmaceutical properties is still a challenging task. Therefore, there remains a need in the art to develop compounds that have selective inhibitory activity and / or better pharmacodynamics / pharmacokinetics for use as BRAF inhibitors, and the present invention provides such compounds.
PAPER
European journal of cancer (Oxford, England : 1990) (2018), 88, 67-76.
^ Jump up to:abLi Z, Jiang K, Zhu X, Lin G, Song F, Zhao Y, Piao Y, Liu J, Cheng W, Bi X, Gong P, Song Z, Meng S (January 2016). “Encorafenib (LGX818), a potent BRAF inhibitor, induces senescence accompanied by autophagy in BRAFV600E melanoma cells”. Cancer Letters. 370 (2): 332–44. doi:10.1016/j.canlet.2015.11.015. PMID26586345.
^Clinical trial number NCT01909453 for “Study Comparing Combination of LGX818 Plus MEK162 and LGX818 Monotherapy Versus Vemurafenib in BRAF Mutant Melanoma (COLUMBUS)” at ClinicalTrials.gov
External links
“Encorafenib”. Drug Information Portal. U.S. National Library of Medicine.
Li Z, Jiang K, Zhu X, Lin G, Song F, Zhao Y, Piao Y, Liu J, Cheng W, Bi X, Gong P, Song Z, Meng S: Encorafenib (LGX818), a potent BRAF inhibitor, induces senescence accompanied by autophagy in BRAFV600E melanoma cells. Cancer Lett. 2016 Jan 28;370(2):332-44. doi: 10.1016/j.canlet.2015.11.015. Epub 2015 Nov 14. [PubMed:26586345]
Koelblinger P, Thuerigen O, Dummer R: Development of encorafenib for BRAF-mutated advanced melanoma. Curr Opin Oncol. 2018 Mar;30(2):125-133. doi: 10.1097/CCO.0000000000000426. [PubMed:29356698]
Moschos SJ, Pinnamaneni R: Targeted therapies in melanoma. Surg Oncol Clin N Am. 2015 Apr;24(2):347-58. doi: 10.1016/j.soc.2014.12.011. Epub 2015 Jan 24. [PubMed:25769717]
Dummer R, Ascierto PA, Gogas HJ, Arance A, Mandala M, Liszkay G, Garbe C, Schadendorf D, Krajsova I, Gutzmer R, Chiarion-Sileni V, Dutriaux C, de Groot JWB, Yamazaki N, Loquai C, Moutouh-de Parseval LA, Pickard MD, Sandor V, Robert C, Flaherty KT: Encorafenib plus binimetinib versus vemurafenib or encorafenib in patients with BRAF-mutant melanoma (COLUMBUS): a multicentre, open-label, randomised phase 3 trial. Lancet Oncol. 2018 May;19(5):603-615. doi: 10.1016/S1470-2045(18)30142-6. Epub 2018 Mar 21. [PubMed:29573941]
FDA approves encorafenib and binimetinib in combination for unresectable or metastatic melanoma with BRAF mutations [Link]
The compounds of the invention, including their salts, can be prepared using known organic synthesis techniques, and can be synthesized according to any of a number of possible synthetic routes, such as those in the schemes below. The reaction for preparing the compound of the present invention can be performed in a suitable solvent, and a person skilled in the art of organic synthesis can easily select a solvent. Suitable solvents may be substantially non-reactive with the starting materials (reactants), intermediates, or products at the temperature at which the reaction is performed (e.g., a temperature ranging from the solvent freezing temperature to the solvent boiling point temperature). A given reaction may be performed in one solvent or a mixture of more than one solvent. The skilled person can select a solvent for a specific reaction step depending on the specific reaction step.
[0166]
The preparation of the compounds of the invention may involve the protection and removal of different chemical groups. Those skilled in the art can easily determine whether protection and removal of protection are needed and the choice of an appropriate protecting group. The chemical nature of the protecting group can be found, for example, in Wuts and Greene, Protective Groups in Organic Synthesis, 4th Edition, John Wiley & Sons: New Jersey, (2006), which is incorporated herein by reference in its entirety.
[0167]
The compound of the present invention can be prepared into a single stereo by reacting a racemic mixture of the compound with an optically active resolving agent to form a pair of diastereomeric compounds, separating the diastereomers, and recovering the optically pure enantiomer isomer. Enantiomeric resolution can be performed using diastereomeric derivatives of the compounds of the present invention, with preferentially dissociable complexes (e.g., crystalline diastereomeric salts). Diastereomers have significantly different physical properties (eg, melting points, boiling points, solubility, reactivity, etc.) and can be easily separated by the advantages of these dissimilarities. Diastereomers can be separated by chromatography, preferably by separation / resolution techniques based on differences in solubility. The optically pure enantiomer is then recovered, along with the resolving reagent, by any practical means that does not allow racemization. A more detailed description of techniques suitable for resolution of stereoisomers of compounds starting from racemic mixtures can be found in Jean Jacques, Andre Collet, Samue1H. Wilen, “Enantiomers, Racemates and Resolution” (“Enantiomers, Racemates and Resolutions “), John Wiley And Sons, Inc., 1981.
[0168]
The reaction can be monitored according to any suitable method known in the art. For example, it may be by spectroscopic means such as nuclear magnetic resonance (NMR) spectroscopy (e.g. 1 H or 13 C), infrared (IR) spectroscopy, spectrophotometry (e.g. UV-visible light), mass spectrometry (MS)) or by chromatography Methods such as high performance liquid chromatography (HPLC) or thin layer chromatography (TLC) to monitor product formation.
[0169]
The compound of formula (I) of the present invention can be prepared by the following reaction scheme 1:
Wherein Y 1 , Y 2 , Y 3 , Y 4 , Y 5 , R 1 , R 2 , R 3 , R 4 , X 1 , X 2 , X 3 , X 4 and X 5 are as defined in the present invention. The compound of formula (I) can be obtained by using a compound of formula (I-1) and a sulfonating agent X 5 SO 2 Cl at a suitable base (for example, pyridine, triethylamine, 4- (N, N-dimethylamino) pyridine, etc.) Reaction with a suitable solvent (e.g., dichloromethane, THF, etc.). The reaction is performed at a temperature ranging from about 0 ° C to about 1000 ° C, and may take up to about 20 hours to complete. The reaction mixture is optionally further reacted to remove any protecting groups.
[0173]
The compound of formula (I-1) can be prepared by the following reaction scheme 2:
Wherein Y 1 , Y 2 , Y 3 , Y 4 , Y 5 , R 1 , R 2 , R 3 , R 4 , X 1 , X 2 , X 3 , X 4 and X 5 are as defined in the present invention, M is a leaving group (for example, iodine, bromine, chlorine, trifluoromethanesulfonyloxy, etc.), each Z may be, for example, hydrogen, methyl, etc., or two Z groups may be connected to form a boric acid ester. Both P groups can be H, or two P groups taken together represent a suitable nitrogen protecting group (eg, one P can be hydrogen and the other can be Boc). The compound of formula (I-2) can be obtained by using a compound of formula (I-4) and a compound of formula (I-3) in a suitable transition metal catalyst (for example, Pd (PPh 3 ) 4 or PdCl 2(dppf)), a suitable solvent (for example, DME, dioxane, toluene, ethanol, etc.) and a suitable base (for example, anhydrous potassium carbonate or sodium carbonate, etc.) are reacted. The reaction is carried out at a temperature ranging from about 20 ° C to 120 ° C, and may take about 2 hours to complete. Compounds of formula (I) can be synthesized by leaving the protecting group P from compounds of formula (I-2) (eg, by treatment with a strong acid such as hydrogen chloride in the presence of DME and dioxane).
[0177]
Compounds of formula (I-4) can be prepared by the following reaction scheme 3:
Wherein Y 1 , Y 2 , R 1 , R 2 , R 3 , R 4 , X 1 , X 2 , X 3 and X 4 are as defined in the present invention, and M is a leaving group (for example, iodine, Bromine, chlorine, trifluoromethanesulfonyloxy, etc.), and V is a leaving group (eg, iodine, bromine, chlorine, trifluoromethanesulfonyloxy, etc.). Compounds of formula (I-4) can be prepared by reacting an amine compound of formula (I-5) and a compound of formula (I-6). The reaction is performed in a suitable solvent (for example, DMSO, NMP, dioxane, or isopropanol) in the presence of a suitable base (for example, sodium carbonate or potassium carbonate, etc.) at a temperature ranging from about 25 ° C to about 120 ° C.
[0181]
Examples
[0182]
The present invention will be further described below with reference to specific embodiments. It should be understood that these examples are only used to illustrate the present invention and not to limit the scope of the present invention. The experimental methods without specific conditions in the following examples are generally based on conventional conditions or conditions recommended by the manufacturer. Unless stated otherwise, parts and percentages are parts by weight and percent by weight.
[0183]
The abbreviations used in this article have the following meanings:
Compound 1 (5.0 g, 73.4 mmol) was added to a 47% solution of hydrobromic acid (20 ml). The reaction solution was reacted at 80 ° C for 3 hours, and distilled under normal pressure. The 60-70 ° C fraction was collected to obtain a colorless liquid. 6.2g, yield 65%.
[0192]
Step 2 Synthesis of Compound A-4
[0193]
Compound A-3 (3.0 g, 27.8 mmol) was added to a DMF (20 ml) solution, the solution was lowered to 0 ° C, K 2 CO 3 (4.6 g, 33.3 mmol, 10 ml) was added, and the mixture was stirred at low temperature for 0.5 h. Then compound A-2 (4.3g, 33.3mmol) was slowly added dropwise. After the dropwise addition, the temperature was raised to 90 ° C for 10 hours. The reaction solution was extracted with DCM (50ml × 3). The organic phases were combined and dried over anhydrous sodium sulfate. The concentrated solution was subjected to column separation (eluent: petroleum ether / ethyl acetate (v / v) = 1: 1) to obtain 3.1 g of a white solid in a yield of 72%. LC-MS (APCI): m / z = 158.21.06 (M + 1) + .
[0194]
Step 3 Synthesis of Compound A-5
[0195]
Under nitrogen protection, compound A-4 (3.0 g, 19.1 mmol) was added to a solution of anhydrous THF (40 ml), and the temperature was lowered to -5 ° C, and CH 3 MgBr (19.1 ml, 57.3 mmol, 3 ml / L) was added dropwise . Anhydrous THF solution. After the dropwise addition was completed, the temperature was gradually raised to reflux for 4 h. The reaction was quenched with saturated ammonium chloride, then the pH was adjusted to neutral with dilute hydrochloric acid, and the mixture was extracted with ethyl acetate (50 ml × 3). The phases were dried over anhydrous sodium sulfate, and the concentrated solution was subjected to column separation (eluent: petroleum ether / ethyl acetate (v / v) = 2: 3) to obtain 2.0 g of a yellow solid with a yield of 61%. LC-MS (APCI): m / z = 175.21.06 (M + 1) + .
[0196]
Step 4 Synthesis of Compound A-6
[0197]
Compound A-5 (2.0g, 11.5mmol), PTSA (4.2g, 23.0mmol) were added to the acetonitrile (15ml) solution, and after dropping to 0 ° C, sodium nitrite (1.43g, 20.7mmol) and Aqueous solution (5 ml) of potassium iodide (3.82 g, 23.0 mmol). The reaction solution was reacted at room temperature for 3 hours, and extracted with ethyl acetate (30 ml × 3). The organic phases were combined, dried over anhydrous sodium sulfate, and spin-dried to obtain 2.5 g of an orange solid with a yield of 75%.
[0198]
Step 5 Synthesis of Compound A-8
[0199]
Under nitrogen protection, compound A-6 (2.0 g, 7.01 mmol) was added to a DMF (15 ml) solution, and the temperature was raised to 120 ° C. Then compound A-7 (1.9 g, 10.5 mmol, 10 ml) was added at 120 ° C. The reaction was stirred for 0.5h. Dichloromethane (30ml × 3) was extracted. The organic phases were combined, dried over anhydrous sodium sulfate, and the concentrated solution was separated by column. ) To obtain 1.9 g of the product in a yield of 80%. LC-MS (APCI): m / z = 341.06 (M + 1) + .
[0200]
Step 6 Synthesis of Compound A-9
[0201]
Under nitrogen protection, compound A-8 (1.9 g, 5.6 mmol) and guanidine carbonate (1.6 g, 12.8 mmol) were sequentially added to the NMP (20 ml) solution. At the same time, a water separation device was set up to raise the solution to 130 ° C. The reaction was stirred at 130 ° C for 10 hours. After the reaction was completed, dichloromethane (30ml × 3) was extracted, the organic phases were combined, dried over anhydrous sodium sulfate, and the concentrated solution was separated by column (eluent: petroleum ether / ethyl acetate (v / v) = 2: 3), 1.5 g of product was obtained with a yield of 81%. LC-MS (APCI): m / z = 336.86 (M + 1) + .
[0202]
Step 7 Synthesis of Compound A-10
[0203]
Compound A-9 (1.5 g, 4.5 mmol) was added to the TFA (15 ml) solution. After reducing to 0 ° C, sodium nitrite (0.93 g, 13.4 mmol) was added as a solid. The reaction solution was reacted at room temperature for 1 h. Extract with ethyl acetate (30ml × 3), combine the organic phases, dry over anhydrous sodium sulfate, spin dry the oil with MTBE (10ml), and filter to obtain 1.3g of white solid, 87% yield, LC-MS (APCI) : m / z = 338.15 (M + 1) + .
[0204]
Step 8 Synthesis of intermediate compound A
[0205]
Compound A-10 (1.3 g, 3.86 mmol) was added to a solution of POCl 3 (15 ml), and the temperature was raised to 110 ° C., and the reaction was refluxed at this temperature for 10 h. After the reaction was completed, the reaction solution was spin-dried and dichloromethane (30 ml × 2) Extraction, combined organic phases, dried over anhydrous sodium sulfate, and column separation of the concentrated solution (eluent: petroleum ether / ethyl acetate (v / v) = 4: 1), 1.0 g of product was obtained, yield 73% . LC-MS (APCI): m / z = 356.32 (M + 1) + .
[0206]
Preparation of intermediate B (S)-(methyl-d 3) (1-aminoprop-2-yl) aminocarbonate.
Compound B-1 (1.3 g, 4.5 mmol) was dissolved in a toluene (15 ml) solution, the temperature was lowered to 0 ° C, and CD 3 OD (0.5 g, 15 mmol) and triethylamine (1.7 g, 17 mmol) in toluene were added dropwise . (10ml) solution, reacted at room temperature for 2h after the dropwise addition, washed three times with ice water, dried over anhydrous sodium sulfate, filtered to obtain a toluene solution of compound B-2, and directly used in the next step.
[0212]
Step 2 Synthesis of Compound B-4
[0213]
At 0 ° C, the hydrochloride (0.5 g, 2.4 mmol) and triethylamine (0.73 g, 7.2 mmol) of compound B-3 were added to a solution of dichloromethane (10 ml) in this order, and one step of compound B was added dropwise. -2 toluene solution, reacted for 5 hours at room temperature after the addition, quenched by adding water (10ml), extracted with dichloromethane (20ml × 3), combined organic phases, dried over anhydrous sodium sulfate, and concentrated the column for separation (elution Agent: petroleum ether / ethyl acetate (v / v) = 4: 1), 0.45 g of white solid product was obtained with a yield of 80%.
[0214]
Step 3 Synthesis of intermediate compound B
[0215]
At 0 ° C, a solution of 4M hydrochloric acid in dioxane (4ml) was slowly added to a solution of compound B-4 (0.45g, 1.9mmol) in dichloromethane (10ml), and the reaction was continued at room temperature for 6h. After the reaction was completed, the solution was spin-dried, petroleum ether (10 ml) was slurried, and 0.2 g of the product was obtained by suction filtration with a yield of 77%.
[0216]
Preparation of intermediate C (1-aminoprop-2-yl-1,1,3,3,3-d 5) carbamate.
A mixture of compound C-2 (4.6 g, 61.8 mmol), compound C-1 (11.5 g, 67.6 mmol) and sodium hydroxide (7.16 g, 67.7 mmol) in water (60 ml) was stirred and reacted at 0 ° C for 3 h. After the reaction was completed, water (60 ml) was added, and the mixture was extracted with ethyl acetate (60 ml x 3). The organic phases were combined, dried over anhydrous sodium sulfate, and the concentrated solution was subjected to column separation (eluent: petroleum ether / ethyl acetate (v / v) = 10: 1), 11.2 g of an oily substance was obtained, and the yield was 88%.
[0222]
Step 2 Synthesis of Compound C-4
[0223]
Under a nitrogen atmosphere, DMSO (4.8 g, 61.5 mmol) was slowly added to a solution of oxalyl chloride (6.0 g, 47.2 mmol) in DCM (60 ml) at -78 ° C, and the mixture was stirred at -78 ° C for half an hour. Then, a solution of compound C-3 (8.0 g, 38.2 mmol) in DCM (20 ml) was added to the mixture, and the mixture was further stirred at -78 ° C for 1 h, and then triethylamine (16 ml) was added to the mixture, and the mixture was raised to At room temperature, it was washed with 1N hydrochloric acid (50ml) and sodium bicarbonate aqueous solution (50ml) successively. The organic phase was dried over anhydrous sodium sulfate, heat-shrinked, and then slurried with a volume ratio of PE: EA = 8: 1 to obtain 5.3g of a white solid product. The rate is 87%.
[0224]
Step 3 Synthesis of Compound C-5
[0225]
1,5,7-Triazabicyclo [4.4.0] dec-5-ene (0.27 g, 1.9 mmol) was added to a solution of compound C-4 (4.0 g, 19.3 mmol) in deuterated chloroform (30 ml) After the reaction solution was stirred at room temperature for 30 hours, water (10 ml) was added to quench the reaction, and the organic phase was separated and washed with saturated sodium chloride. The organic phase was dried and spin-dried to obtain 3.9 g of an oil with a yield of 98%.
[0226]
Step 4 Synthesis of compound C-6
[0227]
Under a nitrogen atmosphere, compound C-5 (4.0 g, 18.9 mmol) and tert-butylsulfinamide (2.7 g, 22.6 mmol) were added to the THF (60 ml) solution, and tetraisopropyl titanate was added at room temperature. Ester (11.8 g, 41.5 mmol), and then heated to 60 ° C for 3 h. The reaction solution was cooled to room temperature, quenched by adding water, and extracted with ethyl acetate (60 ml × 3). The organic phases were combined, dried over anhydrous sodium sulfate, and the concentrated solution was subjected to column separation (eluent: petroleum ether / ethyl acetate ( v / v) = 4: 1), 3.5 g of product was obtained with a yield of 58%. LC-MS (APCI): m / z = 315.80 (M + 1) + .
[0228]
Step 5 Synthesis of compound C-7
[0229]
At -50 ° C, NaBH 4 (0.73 g, 19.1 mmol) was added to a solution of compound C-6 (2.0 g, 6.3 mmol) in methanol (20 ml), and then the reaction was continued at low temperature for 1 h. 1M hydrochloric acid was added to quench the reaction, and the mixture was extracted with dichloromethane (30 ml × 2). The organic phases were combined, dried over anhydrous sodium sulfate, filtered and spin-dried to obtain 2.1 g of an oily product.
[0230]
Step 6 Synthesis of compound C-8
[0231]
A solution of 4M hydrochloric acid in dioxane (10 ml) was slowly added to a solution of compound C-7 (2.0 g, 6.3 mmol) in dichloromethane (20 ml) at 0 ° C, and the reaction was continued at 0 ° C for 6 h. After the reaction is completed, the solvent is spin-dried and directly used in the next step without further processing.
[0232]
Step 7 Synthesis of compound C-9
[0233]
Triethylamine (1.43 g, 14.1 mmol) was added to a solution of compound C-8 (1.5 g, 7.0 mmol) in dichloromethane (20 ml) at 0 ° C, and methyl chloroformate was added dropwise to the mixture. (0.8g, 8.5mmol), and react at room temperature for 5 hours after the addition. After the reaction is complete, water (10ml) is added to quench the reaction. The reaction solution is extracted with dichloromethane (20ml × 2). Sodium was dried, and the concentrated solution was subjected to column separation (eluent: petroleum ether / ethyl acetate (v / v) = 4: 1) to obtain 1.1 g of a white solid product with a yield of 58%.
[0234]
Step 8 Synthesis of intermediate compound C
[0235]
Under a hydrogen atmosphere, Pd-C (0.2g, 10%) was added to the compound C-9 (1.0g, 3.7mmol) in ethanol (5ml) and a 1N hydrochloric acid solution (5ml), and the reaction was stirred for 5h. After the reaction was completed, It was filtered and the filtrate was directly concentrated to obtain 0.4 g of the product.
[0236]
Example 1 (S) -methyl- (1-((4- (3- (5-chloro-2-fluoro-3- (methylsulfonylamino) phenyl) -1- (propan-2-yl -d 7) Preparation of 1H-pyrazol-4-yl) pyrimidin-2-yl) amino) propan-2-yl) carbamate (compound L-1).
Under nitrogen protection, intermediate compound A (1.0 g, 2.8 mmol), compound 1 (0.52 g, 3.1 mmol), and sodium carbonate (1.2 g, 11.2 mmol) were sequentially added to the DMSO (20 ml) solution, and the temperature was raised to 90 ° C. The reaction was stirred at this temperature for 16h. After the reaction was completed, DCM (30ml × 3) was extracted, the organic phases were combined, dried over anhydrous sodium sulfate, and the concentrated solution was separated by column (eluent: petroleum ether / ethyl acetate (v / v) = 1: 2), 0.8 g of product was obtained with a yield of 63%. LC-MS (APCI): m / z = 452.33 (M + 1) + .
[0242]
Step 2 Synthesis of Compound 4
[0243]
Under nitrogen protection, compound 2 (0.5 g, 1.11 mmol), compound 3 (0.5 g, 1.33 mmol), sodium carbonate (0.47 g, 4.43 mmol), and Pd (dppf) Cl2 (0.09 g, 0.11 mmol) were added in this order. Into a mixed solution of toluene (20 ml) and water (4 ml), heated to 80 ° C. for 2 h. The reaction solution was cooled to room temperature, extracted with ethyl acetate (30 ml × 3), the organic phases were combined, dried over anhydrous sodium sulfate, and the concentrated solution was subjected to column separation (eluent: petroleum ether / ethyl acetate (v / v) = 1: 1) 0.2 g of product was obtained with a yield of 31%. LC-MS (APCI): m / z = 569.09 (M + 1) + .
[0244]
Step 3 Synthesis of Compound 5
[0245]
At 0 ° C, a solution of 4M hydrochloric acid in dioxane (4ml) was slowly added to a solution of compound 4 (0.2g, 0.35mmol) in DCM (10ml), and the reaction mixture was warmed to room temperature for 6h. After the reaction is complete, the solution is spin-dried and directly sent to the next step without further processing. LC-MS (APCI): m / z = 469.27 (M + 1) + .
[0246]
Step 4 Synthesis of Compound L-1
[0247]
Compound 5 (0.15 g, 0.32 mmol) and triethylamine (0.16 g, 1.6 mmol) were sequentially added to the DCM (10 ml) solution. After the temperature was lowered to 0 ° C, MsCl (0.11 g, 1.0 mmol) was slowly added dropwise. After the addition was completed, the reaction temperature was raised to room temperature for 5 hours. After the reaction was completed, the reaction solution was spin-dried to obtain a residue. Toluene (9 ml), methanol (1 ml), water (10 ml), and sodium carbonate (2 g) were sequentially added to the residue. The reaction temperature was raised to 85 ° C for 10 hours, cooled to room temperature, and extracted with ethyl acetate (20ml × 3). The organic phases were combined, dried over anhydrous sodium sulfate, and the concentrated solution was subjected to column separation (eluent: dichloromethane / methanol (v / v) = 20: 1), 50 mg of product was obtained with a yield of 35%. LC-MS (APCI): m / z = 547.31 (M + 1) + . 1 H NMR (400MHz, CDCl 3 ) δ 8.08 (d, J = 11.4 Hz, 2H), 7.61 (d, J = 6.3 Hz, 1H), 7.42 (d, J = 5.6 Hz, 1H), 6.48 (d , J = 5.1 Hz, 1H), 5.32 (d, J = 18.8 Hz, 1H), 5.17 (s, 1H), 4.59 (d, J = 13.2 Hz, 1H), 3.79 (s, 1H), 3.61 (s , 3H), 3.24 (s, 1H), 2.98 (d, J = 16.6Hz, 3H), 2.01 (s, 1H), 1.31 (s, 3H).
[0248]
Example 2 (S)-(methyl-d 3)-(1-((4- (3- (5-chloro-2-fluoro-3- (methylsulfonylamino) phenyl) -1-iso Preparation of propyl-1H-pyrazol-4-yl) pyrimidin-2-yl) amino) propan-2-yl) carbamate (compound L-2).
Under nitrogen protection, compound 6 (0.5 g, 1.5 mmol), intermediate compound B (0.2 g, 1.5 mmol), and sodium carbonate (0.63 g, 6.0 mmol) were sequentially added to the DMSO (20 ml) solution, and the temperature was raised to 90 ° C. The reaction was stirred at this temperature for 16h. After the reaction was completed, DCM (30ml × 3) was extracted, the organic phases were combined, dried over anhydrous sodium sulfate, and the concentrated solution was separated by column (eluent: petroleum ether / ethyl acetate (v / v) = 1: 2), 0.42 g of product was obtained in a yield of 65%. LC-MS (APCI): m / z = 447.80 (M + 1) + .
[0254]
Step 2 Synthesis of Compound 8
[0255]
Under nitrogen protection, compound 7 (0.4 g, 0.90 mmol), compound 3 (0.4 g, 1.07 mmol), sodium carbonate (0.38 g, 3.6 mmol), and Pd (dppf) Cl2 (0.07 g, 0.09 mmol) were added in this order. Into a mixed solution of toluene (20 ml) and water (4 ml), the mixture was heated to 80 ° C. and reacted for 2 h. The reaction solution was cooled to room temperature, extracted with ethyl acetate (30 ml × 3), the organic phases were combined, dried over anhydrous sodium sulfate, and the concentrated solution was subjected to column separation (eluent: petroleum ether / ethyl acetate (v / v) = 1: 1) 0.2 g of product was obtained with a yield of 40%. LC-MS (APCI): m / z = 565.03 (M + 1) + .
[0256]
Step 3 Synthesis of Compound 9
[0257]
At 0 ° C, a solution of 4M hydrochloric acid in dioxane (4 ml) was slowly added to a solution of compound 8 (0.2 g, 0.35 mmol) in DCM (10 ml), and the reaction mixture was warmed to room temperature and continued to react for 6 h. After the reaction is complete, the solution is spin-dried and directly sent to the next step without further processing. LC-MS (APCI): m / z = 465.27 (M + 1) + .
[0258]
Step 4 Synthesis of Compound L-2
[0259]
Compound 9 (0.2 g, 0.43 mmol) and triethylamine (0.22 g, 2.1 mmol) were sequentially added to the DCM (10 ml) solution. After lowering to 0 ° C, MsCl (0.15 g, 1.3 mmol) was slowly added dropwise. After the addition was completed, the reaction temperature was raised to room temperature for 5 hours. After the reaction was completed, the reaction solution was spin-dried to obtain a residue. Toluene (9 ml), methanol (1 ml), water (10 ml), and sodium carbonate (2 g) were sequentially added to the residue. The reaction temperature was raised to 85 ° C for 10 hours, cooled to room temperature, and extracted with ethyl acetate (20ml × 3). The organic phases were combined, dried over anhydrous sodium sulfate, and the concentrated solution was subjected to column separation (eluent: dichloromethane / methanol (v / v) = 20: 1), 70 mg of product was obtained with a yield of 30%. LC-MS (APCI): m / z = 543.21 (M + 1) + . 1 H NMR (400MHz, CDCl 3 ) δ 8.01 (d, J = 11.4 Hz, 2H), 7.63 (d, J = 6.3 Hz, 1H), 7.40 (d, J = 5.8 Hz, 1H), 6.58 (d , J = 6.1 Hz, 1H), 5.47 (d, J = 18.8 Hz, 1H), 5.17 (s, 1H), 4.59 (d, J = 12.2, Hz, 1H), 3.80 (s, 1H), 3.61 ( s, 1H) 3.24 (s, 1H), 3.10 (d, J = 16.6 Hz, 3H), 2.21 (s, 1H), 1.35 (s, 3H), 1.27 (d, 6H).
Under nitrogen protection, intermediate compound A (0.6 g, 1.7 mmol), intermediate compound B (0.23 g, 1.7 mmol), and sodium carbonate (0.71 g, 6.8 mmol) were added to the DMSO (20 ml) solution in this order, and the temperature was raised to The reaction was stirred at 90 ° C for 16h at this temperature. After the reaction was completed, DCM (30ml × 3) was extracted, the organic phases were combined, dried over anhydrous sodium sulfate, and the concentrated solution was subjected to column separation (eluent: petroleum ether / ethyl acetate ( v / v) = 1: 2), 0.65 g of product was obtained with a yield of 84%. LC-MS (APCI): m / z = 454.92 (M + 1) + .
[0266]
Step 2 Synthesis of Compound 11
[0267]
Under nitrogen protection, compound 10 (0.6 g, 1.3 mmol), compound 3 (0.59 g, 1.6 mmol), sodium carbonate (0.56 g, 5.3 mmol), and Pd (dppf) Cl2 (0.10 g, 0.13 mmol) were added in this order. Into a mixed solution of toluene (20 ml) and water (4 ml), heated to 80 ° C. for 2 h. The reaction solution was cooled to room temperature, extracted with ethyl acetate (30 ml × 3), the organic phases were combined, dried over anhydrous sodium sulfate, and the concentrated solution was subjected to column separation (eluent: petroleum ether / ethyl acetate (v / v) = 1: 1) 0.32 g of the product was obtained with a yield of 43%. LC-MS (APCI): m / z = 572.10 (M + 1) + .
[0268]
Step 3 Synthesis of Compound 12
[0269]
At 0 ° C, a solution of 4M hydrochloric acid in dioxane (4 ml) was slowly added to a solution of compound 11 (0.3 g, 0.52 mmol) in DCM (10 ml), and the reaction mixture was warmed to room temperature and continued to react for 6 h. After the reaction is complete, the solution is spin-dried and directly sent to the next step without further processing. LC-MS (APCI): m / z = 472.09 (M + 1) + .
[0270]
Step 4 Synthesis of Compound L-3
[0271]
Compound 12 (0.25 g, 0.53 mmol) and triethylamine (0.27 g, 2.6 mmol) were sequentially added to the DCM (10 ml) solution. After dropping to 0 ° C, MsCl (0.18 g, 1.6 mmol) was slowly added dropwise. After the addition was completed, the reaction temperature was raised to room temperature for 5 hours. After the reaction was completed, the reaction solution was spin-dried to obtain a residue. Toluene (9 ml), methanol (1 ml), water (10 ml), and sodium carbonate (2 g) were sequentially added to the residue. The reaction temperature was raised to 85 ° C for 10 hours, cooled to room temperature, and extracted with ethyl acetate (20ml × 3). The organic phases were combined, dried over anhydrous sodium sulfate, and the concentrated solution was subjected to column separation (eluent: dichloromethane / methanol (v / v) = 20: 1), 75 mg of product was obtained with a yield of 26%. LC-MS (APCI): m / z = 550.29 (M + 1) + . 1 H NMR (400 MHz, CDCl 3 ) δ 8.13 (d, J = 11.4 Hz, 2 H), 7.63 (d, J = 6.3 Hz, 1 H), 7.40 (d, J = 5.8 Hz, 1 H), 6.65 (d , J = 6.1 Hz, 1H), 5.47 (d, J = 18.8 Hz, 1H), 5.17 (s, 1H), 4.63 (d, J = 12.2, Hz, 1H), 3.70 (s, 1H), 3.54 ( s, 1H), 3.16 (d, J = 16.6 Hz, 3H), 2.11 (s, 1H), 1.38 (s, 3H).
Under nitrogen protection, compound 6 (0.4 g, 1.1 mmol), intermediate compound C (0.16 g, 1.1 mmol), and sodium carbonate (0.50 g, 4.6 mmol) were sequentially added to the DMSO (15 ml) solution, and the solution was raised to The reaction was stirred at 90 ° C at this temperature for 16 hours. After the reaction was completed, the reaction solution was extracted with dichloromethane (30 ml × 3). The organic phases were combined, dried over anhydrous sodium sulfate, and the concentrated solution was subjected to column separation (eluent: petroleum ether). / Ethyl acetate (v / v) = 1: 2) to obtain 0.40 g of the product in a yield of 75%. LC-MS (APCI): m / z = 449.53 (M + 1) + .
[0280]
Step 2 Synthesis of Compound 14
[0281]
Under a nitrogen atmosphere, compound 13 (0.4 g, 0.9 mmol), compound 3 (0.5 g, 1.4 mmol), sodium carbonate (0.40 g, 3.56 mmol), and Pd (dppf) Cl 2 (0.08 g, 0.1 mmol) were added in this order. Into a mixed solution of toluene (20 ml) and water (4 ml), heated to 80 ° C. for 2 h. The reaction solution was cooled to room temperature, and then extracted with ethyl acetate (30 ml × 3). The organic phases were combined, dried over anhydrous sodium sulfate, and the concentrated solution was subjected to column separation (eluent: petroleum ether / ethyl acetate (v / v) = 1: 1), 0.28 g of product was obtained with a yield of 55%. LC-MS (APCI): m / z = 567.12 (M + 1) + .
[0282]
Step 3 Synthesis of Compound 15
[0283]
At 0 ° C, a solution of 4M hydrochloric acid in dioxane (2ml) was slowly added to a solution of compound 14 (0.28g, 0.50mmol) in dichloromethane (10ml), and the reaction was continued at room temperature for 6h. After the reaction is completed, the solution is directly spin-dried and directly sent to the next step without further processing. LC-MS (APCI): m / z = 467.29 (M + 1) + .
[0284]
Step 4 Synthesis of compound L-4
[0285]
Triethylamine (0.13 g, 1.28 mmol) was added to a solution of compound 15 (0.2 g, 0.43 mmol) in dichloromethane (10 ml). After the solution was lowered to 0 ° C, methanesulfonyl chloride (0.15 g, 1.3 mmol) was slowly added dropwise to the upper solution. The reaction solution was reacted at room temperature for 5 hours. After the reaction was completed, the reaction solution was spin-dried. To the residue were added toluene (9 ml), methanol (1 ml), and water (10 ml). Sodium carbonate (2g), the solution was reacted at 85 ° C for 10h, the reaction solution was cooled to room temperature, and then extracted with ethyl acetate (20ml × 3). The organic phases were combined, dried over anhydrous sodium sulfate, and the concentrated solution was subjected to column separation ( Eluent: dichloromethane / methanol (v / v) = 20: 1) to obtain 65 mg of the product with a yield of 27%. LC-MS (APCI): m / z = 545.08 (M + 1) + . 1 H NMR (400MHz, CDCl 3 ) δ8.05 (d, 2H), 7.61 (d, 1H), 7.45 (d, 1H), 6.40 (d, 1H), 5.29 (d, 1H), 5.18 (s, 1H), 4.62 (d, 1H), 3.89 (d, 1H), 3.58 (s, 3H), 3.10 (d, 3H), 2.05 (s, 1H), 1.29 (d, 6H).
[0286]
Step 5 Synthesis of compounds L-4-S and L-4-R
[0287]
The racemic compound L-4 was separated using a chiral preparative column to obtain compounds L-4-S and L-4-R.
Under nitrogen protection, intermediate compound A (0.5 g, 1.5 mmol), intermediate compound C (0.2 g, 1.5 mmol), and sodium carbonate (0.63 g, 6.0 mmol) were added to the DMSO (20 ml) solution in this order. The temperature was raised to 90 ° C, and the reaction was stirred at this temperature for 16 hours. After the reaction was completed, the reaction solution was extracted with dichloromethane (30ml × 3). The organic phases were combined, dried over anhydrous sodium sulfate, and the concentrated solution was subjected to column separation (eluent: Petroleum ether / ethyl acetate (v / v) = 1: 2) to obtain 0.45 g of the product with a yield of 68%. LC-MS (APCI): m / z = 456.68 (M + 1) + .
[0297]
Step 2 Synthesis of Compound 17
[0298]
Under a nitrogen atmosphere, compound 16 (0.45 g, 0.98 mmol), compound 3 (0.55 g, 1.54 mmol), sodium carbonate (0.42 g, 3.95 mmol), and Pd (dppf) Cl 2 (0.08 g, 0.1 mmol) were sequentially added Into a mixed solution of toluene (20 ml) and water (4 ml), heated to 80 ° C. for 2 h. The reaction solution was cooled to room temperature, and then extracted with ethyl acetate (30 ml × 3). The organic phases were combined, dried over anhydrous sodium sulfate, and the concentrated solution was subjected to column separation (eluent: petroleum ether / ethyl acetate (v / v) = 1: 1), 0.40 g of the product was obtained in a yield of 70%. LC-MS (APCI): m / z = 574.16 (M + 1) + .
[0299]
Step 3 Synthesis of Compound 18
[0300]
A solution of 4M hydrochloric acid in dioxane (2 ml) was slowly added to a solution of compound 17 (0.40 g, 0.70 mmol) in dichloromethane (10 ml) at 0 ° C, and the reaction was allowed to proceed to room temperature for 6 h. After the reaction is completed, the solution is directly spin-dried and directly sent to the next step without further processing. LC-MS (APCI): m / z = 474.21 (M + 1) + .
[0301]
Step 4 Synthesis of Compound L-5
[0302]
Triethylamine (0.23 g, 2.21 mmol) was added to a solution of compound 18 (0.35 g, 0.74 mmol) in dichloromethane (10 ml). After the solution was lowered to 0 ° C, methanesulfonyl chloride (0.25 g, 2.2 mmol) was slowly added dropwise to the upper solution. The reaction solution was reacted at room temperature for 5 hours. After the reaction was completed, the reaction solution was spin-dried. To the residue were added toluene (9 ml), methanol (1 ml), and water (10 ml). Sodium carbonate (2g), the solution was reacted at 85 ° C for 10h, the reaction solution was cooled to room temperature, and then extracted with ethyl acetate (20ml x 3), the organic phases were combined, dried over anhydrous sodium sulfate, and the concentrated solution was subjected to column separation Eluent: dichloromethane / methanol (v / v) = 20: 1) to obtain 120 mg of the product in a yield of 30%. LC-MS (APCI): m / z = 552.33 (M + 1) + . 1 H NMR (400MHz, CDCl 3 ) δ 8.02 (d, 2H), 7.61 (d, 1H), 7.45 (d, 1H), 6.40 (d, 1H), 5.22 (d, 1H), 5.18 (s, 1H), 4.59 (d, 1H), 3.58 (s, 3H), 2.98 (d, 3H), 2.05 (s, 1H).
[0303]
Step 5 Synthesis of compounds L-5-S and L-5-R
[0304]
The racemic compound L-4 was separated using a chiral preparative column to obtain compounds L-5-S and L-5-R.
Fluorodopa, also known as FDOPA, is a fluorinated form of L-DOPA primarily synthesized as its fluorine-18isotopologue for use as a radiotracer in positron emission tomography (PET).[1] Fluorodopa PET scanning is a valid method for assessing the functional state of the nigrostriatal dopaminergic pathway. It is particularly useful for studies requiring repeated measures such as examinations of the course of a disease and the effect of treatment
In October 2019, Fluorodopa was approved in the United States for the visual detection of certain nerve cells in adult patients with suspected Parkinsonian Syndromes (PS).[2][3]
The U.S. Food and Drug Administration (FDA) approved Fluorodopa F 18 based on evidence from one clinical trial of 56 patients with suspected PS.[2] The trial was conducted at one clinical site in the United States.[2]
A one-pot two-step synthesis of 6-[18F]fluoro-L-DOPA ([18F]FDOPA) has been developed involving Cu-mediated radiofluorination of a pinacol boronate ester precursor. The method is fully automated, provides [18F]FDOPA in good activity yield (104 ± 16 mCi, 6 ± 1%), excellent radiochemical purity (>99%) and high molar activity (3799 ± 2087 Ci mmol−1), n = 3, and has been validated to produce the radiotracer for human use.
Radiosynthesis of [ 18F]6F-l-DOPA The synthesis of [ 18F]6F-l-DOPA was fully-automated using a General Electric (GE) TRACERLab FXFN synthesis module (Figure S1) loaded as follows: V1: 500 µL 15mg/mL TBAOTf + 0.2 mg/mL Cs2CO3 in water; V2: 1000 µL acetonitrile; V3: 4 µmol Bpin precursor, 20 µmol Cu2+ , 500 µmol pyridine in 1 mL DMF; V4: 0.2 mL 0.25 M ascorbic acid + 0.6 mL 12.1 N HCl; V6: 3 mL acetonitrile; V7: 10 mL 0.9% saline, USP; V8: 2 mL ethanol, USP; Dilution flask: 100 mL acetonitrile ; F18 separation port: QMA cartridge ; C18 port: Strata cartridge.
PATENT
KR 2019061368
The present invention relates to an L-dopa precursor compd., a method for producing the same, and a method for producing 18F-labeled L-dopa using the same. The method of prepg. 18F-labeled L-dopa I using the L-dopa precursor II [A = halogen-(un)substituted alkyl; W, X, Y = independently protecting group] can improve the labeling efficiency of 18F. After the labeling reaction, sepn. and purifn. steps of the product can be carried out continuously and it can be performed with on-column labeling (a method of labeling through the column). The final product I, 18 F-labeled L-dopa, can be obtained at a high yield relative to conventional methods. Further, it has an advantage that it is easy to apply various methods such as bead labeling.
PAPER
Science (Washington, DC, United States) (2019), 364(6446), 1170-1174.
PAPER
European Journal of Organic Chemistry (2018), 2018(48), 7058-7065.
PATENT
WO 2018115353
CN 107311877
References
^Deng WP, Wong KA, Kirk KL (June 2002). “Convenient syntheses of 2-, 5- and 6-fluoro- and 2,6-difluoro-L-DOPA”. Tetrahedron: Asymmetry. 13 (11): 1135–1140. doi:10.1016/S0957-4166(02)00321-X.
Synthesis Reference, Daniel Kadzimirzs, Gerhard Jas, Volker Autze, “Solution-Phase Synthesis of Leuprolide and Its Intermediates.” U.S. Patent US20090005535, issued January 01, 2009.US20090005535
Leuprolide
CAS Registry Number: 53714-56-0
CAS Name: 6-D-Leucine-9-(N-ethyl-L-prolinamide)-10-deglycinamideluteinizing hormone-releasing factor (pig)
Percent Composition: C 58.59%, H 7.00%, N 18.53%, O 15.88%
Literature References: Synthetic nonapeptide agonist analog of LH-RH, q.v. Prepn: M. Fujino et al.,DE2446005 (1975 to Takeda), C.A.83, 10895y (1975); R. L. Gendrich et al.,US4005063 (1977 to Abbott). Synthesis: J. A. Vilchez-Martinez et al.,Biochem. Biophys. Res. Commun.59, 1226 (1974); M. Fujino et al.,ibid.60, 406 (1974). Comparison of biological activity with natural LH-RH: D. H. Coy et al.,ibid.67, 576 (1975). Pharmacokinetics: L. T. Sennello et al.,J. Pharm. Sci.75, 158 (1986). Clinical efficacy in prostatic carcinoma: M. B. Garnick et al.,N. Engl. J. Med.311, 1281 (1984); in benign prostatic hypertrophy: L. M. Eri, K. J. Tveter, J. Urol.150, 359 (1993). Clinical trial in endometriosis: J. M. Wheeler et al.,Am. J. Obstet. Gynecol.167, 1367 (1992).
Leuprolide belongs to the general class of drugs known as hormones or hormone antagonists. It is a synthetic 9 residue peptide analog of gonadotropin releasing hormone. Leuprolide is used to treat advanced prostate cancer. It is also used to treat uterine fibroids and endometriosis. Leuprolide is also under investigation for possible use in the treatment of mild to moderate Alzheimer’s disease.
Jitsubo , a subsidiary of Sosei , was investigating JIT-1007 , presumed to be a biosimilar version of an undisclosed peptide therapeutic, generated using its proprietary Molecular Hiving, for the treatment of an unidentified indication, however no development has been reported for some time, this program is assumed to be discontinued.
Leuprorelin was patented in 1973 and approved for medical use in the United States in 1985.[1][3] It is on the World Health Organization’s List of Essential Medicines, the most effective and safe medicines needed in a health system.[4] In the United Kingdom a monthly dose costs the NHS about GB£75.24.[5] In the United States the equivalent dose has a wholesale cost of US$1,011.93.[6] It is sold under the brand name Lupron among others.[1]
It may be used for precocious puberty in both males and females,[8] and to prevent premature ovulation in cycles of controlled ovarian stimulation for in vitro fertilization (IVF).
Along with triptorelin and goserelin, it is has been used to delay puberty in transgender youth until they are old enough to begin hormone replacement therapy.[10] Researchers have recommended puberty blockers after age 12, when the person has developed to Tanner stages 2-3, and then cross-sex hormones treatment at age 16. This use of the drug is off-label, however, not having been approved by the Food and Drug Administration and without data on long-term effects of this use.[11]
It is considered a possible treatment for paraphilias.[12] Leuprorelin has been tested as a treatment for reducing sexual urges in pedophiles and other cases of paraphilia.[13][14]
Side effects
Common side effects of Lupron Injection include redness/burning/stinging/pain/bruising at the injection site, hot flashes (flushing), increased sweating, night sweats, tiredness, headache, upset stomach, nausea, diarrhea, constipation, stomach pain, breast swelling or tenderness, acne, joint/muscle aches or pain, trouble sleeping (insomnia), reduced sexual interest, vaginal discomfort/dryness/itching/discharge, vaginal bleeding, swelling of the ankles/feet, increased urination at night, dizziness, breakthrough bleeding in a female child during the first 2 months of leuprorelin treatment, weakness, chills, clammy skin, skin redness, itching, or scaling, testicle pain, impotence, depression, or memory problems.[15] The rates of gynecomastia with leuprorelin have been found to range from 3 to 16%.[16]
Mechanism of action
Leuprorelin is a gonadotropin-releasing hormone (GnRH) analogue acting as an agonist at pituitaryGnRH receptors. Agonism of GnRH receptors initially results in the stimulation of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secretion by the anterior pituitary ultimately leading to increased serum estradiol and testosterone levels via the normal physiology of the hypothalamic–pituitary–gonadal axis (HPG axis); however, because propagation of the HPG axis is incumbent upon pulsatile hypothalamic GnRH secretion, pituitary GnRH receptors become desensitised after several weeks of continuous leuprorelin therapy. This protracted downregulation of GnRH receptor activity is the targeted objective of leuprorelin therapy and ultimately results in decreased LH and FSH secretion, leading to hypogonadism and thus a dramatic reduction in estradiol and testosterone levels regardless of sex.[17][18]
In the treatment of prostate cancer, the initial increase in testosterone levels associated with the initiation of leuprorelin therapy is counterproductive to treatment goals. This effect is avoided with concurrent utilisation of 5α-reductase inhibitors, such as finasteride, which function to block the downstream effects of testosterone.
Leuprorelin was discovered and first patented in 1973 and was introduced for medical use in 1985.[19][20] It was initially marketed only for daily injection, but a depot injectionformulation was introduced in 1989.[20]
Society and culture
Names
Leuprorelin is the generic name of the drug and its INN and BAN, while leuprorelin acetate is its BANM and JAN, leuprolide acetate is its USAN and USP, leuprorelina is its DCIT, and leuproréline is its DCF.[21][22][23][24] It is also known by its developmental code names A-43818, Abbott-43818, DC-2-269, and TAP-144.[21][22][23][24]
Leuprorelin is marketed by Bayer AG under the brand name Viadur, by Tolmar under the brand name Eligard, and by TAP Pharmaceuticals (1985–2008), by Varian Darou Pajooh under the brand name Leupromer and Abbott Laboratories (2008–present) under the brand name Lupron. It is available as a slow-release implant or subcutaneous/intramuscular injection.
In the UK and Ireland, leuprorelin is marketed by Takeda UK as Prostap SR (one-month injection) and Prostap 3 (three-month injection).
Approvals
Available formsLupron injection was first approved by the FDA for treatment of advanced prostate cancer on April 9, 1985.
Lupron depot for monthly intramuscular injection was first approved by the FDA for palliative treatment of advanced prostate cancer on January 26, 1989, and subsequently in 22.5 mg/vial and 30 mg/vial for intramuscular depot injection every 3 and 4 months, respectively. 3.75 mg/vial and 11.25 mg/vial dosage forms were subsequently approved for subcutaneous depot injection every month and every 3 months, respectively for treatment of endometriosis or fibroids. 7.5 mg/vial, 11.25 mg/vial, and 15 mg/vial dosage forms were subsequently approved for subcutaneous depot injection for treatment of children with central precocious puberty.
Viadur (72 mg yearly subcutaneous implant) was first approved by the FDA for palliative treatment of advanced prostate cancer on March 6, 2000. Bayer will fulfill orders until current supplies are depleted, expected by the end of April 2008
Eligard (7.5 mg for monthly subcutaneous depot injection) was first approved by the FDA for palliative treatment of advanced prostate cancer on January 24, 2002, and subsequently in 22.5 mg, 30 mg, and 45 mg doses for subcutaneous depot injection every 3, 4, and 6 months, respectively.
Leupromer 7.5 (7.5 mg, one month depot for subcutaneous injection) is the second in situ-forming injectable drug in the world. It is used for palliative treatment of advanced prostate cancer, endometriosis, and uterine fibroids. It was approved by The Ministry of Health and Medical Education Of Iran.
Leuprorelin is available in the following forms, among others:[25][26][27]
Short-acting daily intramuscular injection (Lupron): 5 mg/mL (2.8 mL) used as 1 mg every day.
Long-acting depot intramuscular injection (Lupron Depot): 7.5 mg once a month, 22.5 mg every 3 months, or 30 mg every 4 months.
Long-acting depot subcutaneous injection (Eligard): 7.5 mg once a month, 22.5 mg every 3 months, 30 mg every 4 months, or 45 mg every 6 months.
Long-acting subcutaneous implant (Viadur): 65 mg pellet once every 12 months.
“Lupron protocol”
A 2005 paper in the controversial and non-peer reviewed journal Medical Hypotheses suggested leuprorelin as a possible treatment for autism,[28] the hypothetical method of action being the now defunct hypothesis that autism is caused by mercury, with the additional unfounded assumption that mercury binds irreversibly to testosterone and therefore leuprorelin can help cure autism by lowering the testosterone levels and thereby mercury levels.[29] However, there is no scientifically valid or reliable research to show its effectiveness in treating autism.[30] This use has been termed the “Lupron protocol”[31] and Mark Geier, the proponent of the hypothesis, has frequently been barred from testifying in vaccine-autism related cases on the grounds of not being sufficiently expert in that particular issue[32][33][34] and has had his medical license revoked.[31] Medical experts have referred to Geier’s claims as “junk science”.[35]
Veterinary use
Leuprorelin is frequently used in ferrets for the treatment of adrenal disease. Its use has been reported in a ferret with concurrent primary hyperaldosteronism,[36] and one with concurrent diabetes mellitus.[37]
Research
As of 2006 leuprorelin was under investigation for possible use in the treatment of mild to moderate Alzheimer’s disease.[38]
Process for producing leuprorelin as LH-RH (GnRH) agonist useful for treating endometriosis, uterine fibroids, premenopausal breast cancer and prostate cancer.
^Crosignani PG, Luciano A, Ray A, Bergqvist A (January 2006). “Subcutaneous depot medroxyprogesterone acetate versus leuprolide acetate in the treatment of endometriosis-associated pain”. Human Reproduction. 21 (1): 248–56. doi:10.1093/humrep/dei290. PMID16176939.
^Badaru A, Wilson DM, Bachrach LK, et al. (May 2006). “Sequential comparisons of one-month and three-month depot leuprolide regimens in central precocious puberty”. The Journal of Clinical Endocrinology and Metabolism. 91 (5): 1862–7. doi:10.1210/jc.2005-1500. PMID16449344.
^Dreger, A. (2009, Jan.-Feb.). Gender Identity Disorder in childhood: Inconclusive advice to parents. Hastings Center Report, pp. 26-29.
^Saleh FM, Niel T, Fishman MJ (2004). “Treatment of paraphilia in young adults with leuprolide acetate: a preliminary case report series”. Journal of Forensic Sciences. 49 (6): 1343–8. doi:10.1520/JFS2003035. PMID15568711.
^Schober JM, Byrne PM, Kuhn PJ (2006). “Leuprolide acetate is a familiar drug that may modify sex-offender behaviour: the urologist’s role”. BJU International. 97 (4): 684–6. doi:10.1111/j.1464-410X.2006.05975.x. PMID16536753.
^Schober JM, Kuhn PJ, Kovacs PG, Earle JH, Byrne PM, Fries RA (2005). “Leuprolide acetate suppresses pedophilic urges and arousability”. Archives of Sexual Behavior. 34 (6): 691–705. doi:10.1007/s10508-005-7929-2. PMID16362253.
^Di Lorenzo G, Autorino R, Perdonà S, De Placido S (December 2005). “Management of gynaecomastia in patients with prostate cancer: a systematic review”. Lancet Oncol. 6 (12): 972–9. doi:10.1016/S1470-2045(05)70464-2. PMID16321765.
^Mutschler E, Schäfer-Korting M (2001). Arzneimittelwirkungen (in German) (8 ed.). Stuttgart: Wissenschaftliche Verlagsgesellschaft. pp. 372–3. ISBN978-3-8047-1763-3.
^Geier M, Geier D (2005). “The potential importance of steroids in the treatment of autistic spectrum disorders and other disorders involving mercury toxicity”. Med Hypotheses. 64 (5): 946–54. doi:10.1016/j.mehy.2004.11.018. PMID15780490.
^Desmarchelier M, Lair S, Dunn M, Langlois I (2008). “Primary hyperaldosteronism in a domestic ferret with an adrenocortical adenoma”. Journal of the American Veterinary Medical Association. 233 (8): 1297–301. doi:10.2460/javma.233.8.1297. PMID19180717.
^Boari A, Papa V, Di Silverio F, Aste G, Olivero D, Rocconi F (2010). “Type 1 diabetes mellitus and hyperadrenocorticism in a ferret”. Veterinary Research Communications. 34(Suppl 1): S107–10. doi:10.1007/s11259-010-9369-2. PMID20446034.
^Doraiswamy PM, Xiong GL (2006). “Pharmacological strategies for the prevention of Alzheimer’s disease”. Expert Opinion on Pharmacotherapy. 7 (1): 1–10. doi:10.1517/14656566.7.1.S1. PMID16370917.
Percent Composition: C 64.18%, H 5.19%, Cl 6.77%, F 18.13%, N 2.67%, O 3.05%
Literature References: Prepn: H. K. F. Hermans, C. J. E. Niemegeers, DE2040231; eidem,US3575990 (both 1971 to Janssen); Sindelár et al.,Collect. Czech. Chem. Commun.38, 3879 (1973). Pharmacology and toxicology: Janssen et al.,Eur. J. Pharmacol.11, 139 (1970). Crystal structure: Koch, Acta Crystallogr.29B, 1538 (1973).
Properties: White, microcrystals, mp 105-107°. Slightly sol in water, dil HCl (<0.5 mg/ml). LD50 orally in mice (day 7): 86.8 mg/kg (Janssen).
Penfluridol (Semap, Micefal, Longoperidol) is a highly potent, first generation diphenylbutylpiperidineantipsychotic.[1] It was discovered at Janssen Pharmaceutica in 1968.[2] Related to other diphenylbutylpiperidine antipsychotics, pimozide and fluspirilene, penfluridol has an extremely long elimination half-life and its effects last for many days after single oral dose. Its antipsychotic potency, in terms of dose needed to produce comparable effects, is similar to both haloperidol and pimozide. It is only slightly sedative, but often causes extrapyramidal side-effects, such as akathisia, dyskinesiae and pseudo-Parkinsonism. Penfluridol is indicated for antipsychotic treatment of chronic schizophrenia and similar psychotic disorders, it is, however, like most typical antipsychotics, being increasingly replaced by the atypical antipsychotics. Due to its extremely long-lasting effects, it is often prescribed to be taken orally as tablets only once a week (q 7 days). The once-weekly dose is usually 10–60 mg. A 2006 systematic review examined the use of penfluridol for people with schizophrenia:
Penfluridol compared to typical antipsychotics (oral) for schizophrenia[3]
Summary
Although there are shortcomings and gaps in the data, there appears to be enough overall consistency for different outcomes. The effectiveness and adverse effects profile of penfluridol are similar to other typical antipsychotics; both oral and depot. Furthermore, penfluridol is shown to be an adequate treatment option for people with schizophrenia, especially those who do not respond to oral medication on a daily basis and do not adapt well to depot drugs. One of the results favouring penfluridol was a lower drop out rate in medium term when compared to depot medications. It is also an option for people with long-term schizophrenia with residual psychotic symptoms who nevertheless need continuous use of antipsychotic medication. An additional benefit of penfluridol is that it is a low-cost intervention.[3]
Penfluridol
ATC:N05AG03
Use:neuroleptic
Chemical name:1-[4,4-bis(4-fluorophenyl)butyl]-4-[4-chloro-3-(trifluoromethyl)phenyl]-4-piperidinol
Formula:C28H27ClF5NO
MW:523.97 g/mol
CAS-RN:26864-56-2
EINECS:248-074-5
LD50:87 mg/kg (M, p.o.);
160 mg/kg (R, p.o.)
Synthesis
PAPER
Late stage functionalization of secondary amines via a cobalt-catalyzed electrophilic amination of organozinc reagents
Org Lett 2019, 21(2): 494
Although Penfluridol listed for many years, but its chemical preparation technology abroad little studied in the earlier literature, there are several prepared as follows:
[0013] Process (a): 1971 Document Ger.0ffen [P], 2040231, (1971) Hermans.HKF first reported Penfluridol chemical synthesis, which process is as follows:
[0014]
[0015] The process of cyclopropyl methanol (ΙΠ) by 4,4, _-difluorophenyl-one ([pi) as a starting material, the reaction of cyclopropyl magnesium bromide-bis 4- (fluorophenyl), then the reaction with thionyl chloride to give 1,1_-bis (4-fluorophenyl) -4-chloro-butene (IV), obtained by catalytic hydrogenation 1,1_-bis (4-phenyl gas) burning chlorobutanol _4_ (V), and finally with 4-chloro-3-methylphenyl gas-4-piperidinol (X VH) in methyl isobutyl ketone was refluxed for three days the reaction to produce Penfluridol (the I), Document: Sindelar.K.et al, Collect Czech.Chem.Commun [J], 38 (12): 3879-3901, (1973).
[0016] In the above process, starting material and documentation of cyclopropyl magnesium bromide hardly prepared each reaction were not reported preparation yield, and therefore Document Sindelar · K · et al, Collect Czech · Chem · Commun [ J], 38 (12):. 3879-3901, (1973) that this technology is not very good.
[0017] Process (b): 1973, Sindelar.K successful research and the following other technology, which process is as follows:
[0018]
[0019] The process consists of 4,4_-bis (4-fluorophenyl) butoxy alkyl iodide as a starting material, 4,4_ ethylenedioxythiophene condensing piperidone removal of generated hydrogen iodide in N-pentanone – [4,4-bis (4-fluorophenyl) butoxy group] -4,4-dioxo-condensing vinyl piperidone, N-then obtained by acid hydrolysis [4,4-bis (4-fluorophenyl ) azetidinyl] -4-piperidone (W), the compound with 4-chloro-3-trifluoromethyl phenyl magnesium bromide reacted Penfluridol (I).
[0020] This process route may seem simple, but there are more desired to prepare intermediates, the process is more complex, with low yields reported in the literature.
[0021] Process (c): as follows:
[0022]
[0023] In this process, 4-chloro – (4-fluorophenyl) butyryl-one (Shan) starts, 4-fluorophenyl magnesium bromide reacts with 4-chloro – bis (4-fluorophenyl) butanol ( IX), and then boiling the reaction hydroiodic acid to give 4-iodo-in, red phosphorus catalyst – bis (4-fluorophenyl) butoxy left foot and finally burning ^^ – ^ – methyl ^ two gas – chlorophenyl Bu ‘piperidinol prepared products San ^ top five gas profitable ⑴.
[0024] This synthesis has the characteristics of high yield, but the intermediate (IX), (X) quality is not purified, many by-products, difficult to control the quality of products, and hydroiodic acid to be used, the source of raw material is difficult, therefore, not ideal technology.
[0025] Process (d), as follows:
[0026]
[0027] The process begins by Stobber reaction with 4,4 – fluorophenyl ketone reaction product diethyl succinate and compound (XI), and then generates bis (4-fluorophenyl) methine acid or base hydrolysis after succinic acid (M), by catalytic hydrogenation to give 4,4_-bis (4-fluorophenyl) butanoic acid after, the reaction with thionyl chloride without isolating the compound (XIV) with the compound directly (XW), by reduction after obtain the final product – Penfluridol.The disadvantage of this process is that, in the above reaction step, Stobber the reaction yield is low; hydrogenation catalyst manufacturing operation more difficult and unsafe; reaction with thionyl chloride, large air pollution, and other refractory.
[0028] The various preparation techniques Penfluridol other drug earlier British Patent Brit. 1141664 and German patent Ger. Off en. 2040231 has been reported, but no other foreign patent reports.In neither country has patent coverage, and no magazine reported.
The reaction formula is as follows:
[0058]
[0059] Step (5), the preparation of compounds of formula (XW) as shown, may be employed a method reported in the literature, or prepared using a method specifically includes the following steps:
[0060]
0124] (6) Penfluridol drug (I) were prepared:
[0125]
[0126] In three 500ml reaction flask equipped with a mechanical stirrer, a condenser, a thermometer, a calcium chloride tube, was added 250ml of anhydrous diethyl ether, 2 · 4g (0 · 0631mol) tetrahydro lithium aluminum hydride, stirring was started, was added 20g (0 · 0372mol) amide (6), the addition was completed, 38 ° C for 6 hours.
[0127] completion of the reaction, water was added 4.2ml decomposition for 25 minutes, followed by addition of 5.4ml of 20% by weight concentration of sodium hydroxide solution decomposition for 20 minutes, 14.2ml decomposed with water for 15 minutes;
[0128] The decomposition was filtered, the filtrate (ethyl ether) and dried over anhydrous potassium carbonate.Filtered, the filter cake was washed with a little ether.The filtrate and the washings added to a distillation flask, recovery ether atmospheric distillation, vacuum drained, was added a mixed solvent l〇〇ml [chloroform: petroleum ether (60-90 ° C) = 1: 4, weight ratio, stirred and heated to reflux dissolution, filtered while hot, the filtrate was allowed to stand for crystallization at about 10 ° C, to be naturally deposited crystal after freezing -5 ° C overnight, filtered, the cake was washed with a mixed solvent, drain, ventilation pressure at 70 ° C dried to constant weight to give white crystalline product Penfluridol drug (I), mp 105-107 ° C, yield 81.5%.
[0132] equipped with a mechanical stirrer, a condenser, a thermometer 2000ml three reaction bottle, were added ammonium bicarbonate 240g (3.04mol), aqueous ammonia at a concentration of 20 wt %% of 15148 (17.812111〇1,
[0133] 1640ml), benzyl chloride 80g (0.632mol), reaction was stirred for 6 hours.Reaction to complete rested stratification.Aqueous layer was separated, and aqueous ammonia recovery bicarbonate atmospheric heating to 100 ° c, the water was distilled off under reduced pressure, with 50% sodium hydroxide PH12 above, extraction with benzene and dried solid sodium hydroxide.Recovery of benzene atmospheric distillation, vacuum distillation, collecting 33.4 g of the product obtained, yield 50.7%, content 99%,
[0134]
[0135] (3) N_ benzyl – bis ([beta] methoxycarbonyl-ethyl) amine (C) (referred to as diester thereof):
[0136]
[0137] The reaction flask equipped with a mechanical stirrer, a condenser, a thermometer three 250ml, 43g methyl acrylate (0.5111〇1) methanol 328 (401111), was added with stirring 21.48 benzylamine (0.2111〇1), The reaction was stirred for 7 hours.Completion of the reaction, recovery of excess methyl acrylate and methanol, water chestnut vacuum distillation until the internal temperature l〇〇-ll〇 ° C, to give the crude product as a yellow oil (C) 54g, yield 97%, content 94.3%.
[0138] (3) 1 – benzyl-4-piperidone (E) (referred to as the hydrolyzate) is prepared:
[0139]
[0140] In a reaction flask equipped with a 500ml three mechanical stirrer, thermometer, fractional distillation apparatus, was added 27% sodium methoxide 27g, crude diester was 33.4g (0.12mol), toluene 300ml, stirred and heated, the temperature reached 90 when ° C or more, additional 50ml toluene was reacted for 3 hours.Cooled to room temperature, and neutralized with acetic acid to PH6, standing layer.The toluene layer was separated and extracted with 150ml of 22% hydrochloric acid three times.Hydrochloric acid extracts were combined, heated with stirring for 4 hours.Recovered by distillation under reduced pressure and hydrochloric acid (about 120ml distilled dilute hydrochloric acid) was cooled to distillation l〇 ° C below, with 40% sodium hydroxide PH12 above.With 80ml ethyl acetate 3 times extracted with ethyl acetate extracts were combined, sub-net water, dried over anhydrous sodium sulfate.Sodium sulfate was removed by filtration, recovering ethyl acetate atmospheric distillation, vacuum drained hydrolyzed to give (E) and the crude product 19g, yield 84%.
[0141] (4) 1-ethoxycarbonyl-4-piperidone (F) (referred to as a carbonyl group-piperidone) Preparation:
[0142]
[0143] equipped with a mechanical stirrer, a condenser, 250ml three reaction flask thermometer, was added ethyl chloroformate 23.9g (0 · 22mo 1), benzene 100ml, stirring slowly added dropwise [The crude hydrolyzate (E ) 37 · 8g (0 · 2mo 1) + 20ml phenyl] solution dropwise, the reaction was heated with stirring for 5 hours.Water chestnut evaporated under reduced pressure and ethyl benzene chlorine, Li mechanical change stream distilled off under reduced pressure, low boiling point evaporated to give the product 268 was collected, yield 76%.
[0144] (5) 1 – ethoxycarbonyl-4- (3-trifluoromethyl-4-chlorophenyl) -4-piperidinol (G) (referred to as a carbonyl group-piperidinol) is:
[0145]
[0146] In three 500ml reaction flask equipped with a mechanical stirrer, a condenser, a thermometer, a dropping funnel and a calcium chloride drying tube over anhydrous anhydrous absolute, at room temperature was added magnesium metal shoulder 2.5g (0.103mol) 20ml of anhydrous ethyl ether and slowly stirring was started.
[0147] 2-chloro-5-bromo – trifluorotoluene (referred bromide) was dissolved under 27g (0.104mol) at room temperature in 130ml anhydrous diethyl ether and stirred to obtain a uniform liquid mass (W is);
[0148] When the liquid material taken 15ml was added to the above reaction, a solution of iodine 0.13g, 1,2- dibromoethane 0.2g, initiated Grignard reaction was heated until the iodine color disappeared, the reaction slowed down, slow slow dropping liquid material (W).The addition was completed, refluxing was continued for 1 hour.Completion of the reaction, cooled to room temperature, slowly added dropwise at room temperature carbonyl piperidone (F) water solution was cooled at normal [carbonyl-piperidone 13.6g (0.0795mol) + 40ml dry ether], dropwise, the reaction was heated with stirring 1.5 hour.L〇〇ml ammonium chloride solution concentration of 20% by weight was added, refluxed for 15 minutes and allowed to stand 30 minutes at room temperature stratification.Discharged aqueous layer (lower layer), the residual liquid was distilled (upper layer) at an external temperature of 55 ° C atmospheric distillation recovery ether, discharge hot, refrigerated overnight, the precipitated solid.Filtered, washed with a small amount of time, drained, and dried to give the product (G) 24.1g, yield 85.7%, mp 118-126Γ.
[0151] equipped with a mechanical stirrer, a condenser, 250ml three reaction flask thermometer, were added ethanol 40ml, 158 of sodium hydroxide (0.375111〇1), carbonyl piperidinol (6) 2 (^ (0.0569111〇1 ), heated to reflux, and the reaction stirred for 3.5 hours. the reaction was completed, 50ml of water was added, the reaction was refluxed for 10 minutes, the hot reaction solution was placed in 300g of crushed ice, stirred well, and the precipitated solid, -5 ° C frozen standing for 2 hours the above.
[0152] filtered, washed with water to pH 8-9, drained, and dried to give piperidinol (XVH) 15g, yield 94%, mp 137-144 ° C, ash content <5%.
[0153] Example 2
[0154] (a) 3- (4-fluorobenzoyl) propionic acid (2) (the acid) is prepared:
[0155]
[0156] The reaction flask equipped with a mechanical stirrer, a condenser, a thermometer three 500ml, was added 17.1g (0.171mol) of succinic anhydride, l〇5g (1 · 09mol) fluorobenzene, stirred and dissolved.Added in one portion 60g (0 · 306mol) in dry wrong trichloride, stirring, the reaction was stirred at 100 ° C for 2 hours, at a concentration of 10% by weight hydrochloric acid 165ml exploded 30 minutes;
[0157] Other embodiments with Example 1, the product, 111.? 105-107 ° (:, this step a yield of 81.5%, 46.7% overall yield.
References
^van Praag HM, Schut T, Dols L, van Schilfgaarden R., Controlled trial of penfluridol in acute psychosis, Br Med J. 1971 December 18;4(5789):710-3
^Janssen PA, Niemegeers CJ, Schellekens KH, Lenaerts FM, Verbruggen FJ, Van Nueten JM, Schaper WK., The pharmacology of penfluridol (R 16341) a new potent and orally long-acting neuroleptic drug, Eur J Pharmacol. 1970 July 15;11(2):139-54
R Bhattacharyya, R Bhadra U Roy, S Bhattacharyya, J Pal S Sh Saha – Resurgence of Penfluridol:Merits and Demerits, Eastern Journal of Psychiatry, January-June 2015 vol 18, Issue 1 p 23 –29
GlaxoSmithKline (previously Glaxo Wellcome ) was developing elacridar, an inhibitor of the multidrug resistance transporter BCRP (breast cancer resistant protein), as an oral bioenhancer for the treatment of solid tumors.
Elacridar is an oral bioenhancer which had been in early clinical trials at GlaxoSmithKline for the treatment of cancer, however, no recent development has been reported. It is a very potent inhibitor of P-glycoprotein, an ABC-transporter protein that has been implicated in conferring multidrug resistance to tumor cells.
SYN
The condensation of 2-(4-nitrophenyl)ethyl bromide with 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline by means of K2CO3 and KI in DMF at 100 C gives 6,7-dimethoxy-2-[2-(4-nitrophenyl)ethyl]-1,2,3,4-tetrahydroisoquinoline,
Which is reduced with H2 over Pd/C in ethanol to yield the corresponding amine . Finally, this compound is condensed with 5-methoxy-9-oxo-9,10-dihydroacridine-4-carboxylic acid by means of DCC and HOBt in DMF to afford the target carboxamide.
The intermediate 5-methoxy-9-oxo-9,10-dihydroacridine-4-carboxylic acidhas been obtained as follows: The condensation of 2-amino-3-methoxybenzoic acid with 2-bromobenzoic acid by means of K2CO3 and copper dust give the diphenylamine , which is cyclized to the target acridine Elacridar by means of POCl3 in refluxing acetonitrile.
Deuterated analogs of elacridar as P-gp/BCRP inhibitor by preventing efflux useful for treating cancer.
Elacridar, previously referred to as GF120918, is a compound with the structure of 9,10-dihydro-5-methoxy-9-oxo-N-[4-[2-(1 ,2,3,4-tetrahydro- 6,7-dimethoxy-2-isoquinolinyl)ethyl] phenyl]-4-acridine-carboxamide or, as sometimes written, N-4-[2-(1 ,2,3,4-tetrahydro-6,7-dimethoxy-2-isoquinolinyl)ethyl]-phenyl)-9,10-dihydro-5-methoxy- 9-oxo-4-acridine carboxamide. Elacridar was originally described as a P-gp selective inhibitor but is now recognized as a dual P-gp/BCRP inhibitor. (Matsson P, Pedersen JM, Norinder U, Bergstrom CA, and Artursson P 2009 Identification of novel specific and general inhibitors of the three major human ATP-binding cassette transporters P-gp, BCRP and MRP2 among registered drugs. Pharm Res 26:1816-1831 ).
003 Elacridar has been examined with some success both in vitro and in vivo as a P-gp and BCRP inhibitor. By way of example, in cancer patients, coadministration of elacridar with therapeutic agents such as paclitaxel (P-gp substrate) and topotecan (BCRP substrate) improved their oral absorption – presumably by preventing efflux into the intestinal lumen by P-gp/BCRP pumps located in the Gl tract. Similarly, in rodents, elacridar has been coadministered with some success with pump substrates such as morphine, amprenavir, imatinib, dasatinib, gefitinib, sorafenib, and sunitinib to increase drug levels in the brain (by blocking efflux mediated by P-gp and BCRP at the blood brain barrier). A summary of some of these studies can be found in a study report by Sane et al. (Drug Metabolism And Disposition 40:1612-1619, 2012).
004 Administration of elacridar has several limitations. By way of example, elacridar has unfavorable physicochemical properties; it is practically insoluble in water, making it difficult to formulate as, for example, either an injectable or oral dosage form. Elacridar’s poor solubility and high lipophilicity result in dissolution rate-limited absorption from the gut lumen.
005 A variety of approaches have been pursued in order to increase efficacy of elacridar. For example, United States Patent Application Publication 20140235631 discloses a nanoparticle formulation in order to increase oral bioavailability.
006 Sane et al. (Journal of Pharmaceutical Sciences, Vol. 102, 1343-1354 (2013)) report a micro-emulsion formulation of elacridar to try and overcome its dissolution-rate-limited bioavailability.
007 Sawicki et al. (Drug Development and Industrial Pharmacy, 2017 VOL. 43, NO. 4, 584-594) described an amorphous solid dispersion formulation of freeze dried elacridar hydrochloride-povidone K30-sodium dodecyl sulfate. However, when tested in healthy human volunteers, extremely high doses (e.g. 1000 mg) were required to achieve a Cmax of 326 ng/ml. (Sawicki et al. Drug Deliv. and Transl.
Res. Published online 18 Nov 2016).
008 Montesinos et al. (Mol Pharm. 2015 Nov 2; 12(11 ):3829-38) attempted several PEGylated liposome formulations of elacridar which resulted in a partial increase in half life, but without an increase in efficacy when co-administered with a therapeutic agent.
009 Because of the great unpredictability in the art and poor correlations in many cases between animal and human data, the value of such formulation attempts await clinical trial.
0010 Studies of the whole body distribution of a microdose of 11C elacridar after intravenous injection showed high level accumulation in the liver (Bauer et al. J Nucl Med. 2016;57:1265-1268). This has led some to suggest that systemic levels of elacridar are also substantially limited by clearance in the liver.
0011 A potentially attractive strategy for improving metabolic stability of some drugs is deuterium modification. In this approach, one attempts to slow the CYP-mediated metabolism of a drug or to reduce the rate of formation of inactive metabolites by replacing one or more hydrogen atoms with deuterium atoms.
Deuterium is a safe, stable, non-radioactive isotope of hydrogen. Compared to hydrogen, deuterium forms stronger bonds with carbon. In select cases, the increased bond strength imparted by deuterium can positively impact the absorption, distribution, metabolism, excretion and/or toxicity (‘ADMET’) properties of a drug, creating the potential for improved drug efficacy, safety, and/or tolerability. At the same time, because the size and shape of deuterium are essentially identical to those of hydrogen, replacement of hydrogen by deuterium would not be expected to affect the biochemical potency and selectivity of the drug as compared to the original chemical entity that contains only hydrogen.
0012 Over the past 35 years, the effects of deuterium substitution on the rate of metabolism have been reported for a very small percentage of approved drugs (see, e.g., Blake, M I et al, J Pharm Sci, 1975, 64:367-91 ; Foster, A B, Adv Drug Res 1985, 14:1 -40 (“Foster”); Kushner, D J et al, Can J Physiol Pharmacol 1999, 79-88; Fisher, M B et al, Curr Opin Drug Discov Devel, 2006, 9:101 -09 (“Fisher”)). The results have been variable and unpredictable. For some compounds, deuteration indeed caused decreased metabolic clearance in vivo. For others, no change in metabolism was observed. Still others demonstrated increased metabolic clearance. The great unpredictability and variability in deuterium effects has led experts to question or dismiss deuterium modification as a viable drug design strategy for inhibiting metabolism (see Foster at p. 35 and Fisher at p. 101 ).
0013 The effects of deuterium modification on a drug’s metabolic properties are not predictable even when deuterium atoms are incorporated at known sites of metabolism. Only by actually preparing and testing a deuterated drug can one determine if and how the rate of metabolism will differ from that of its non-deuterated counterpart. See, for example, Fukuto et al. (J. Med. Chem. 1991 , 34, 2871 -76). Many drugs have multiple sites where metabolism is possible. The site(s) where deuterium substitution is required and the extent of deuteration necessary to see an effect on metabolism, if any, will be different for each drug.
0014 Considering elacridar’s challenging physicochemical and ADMET properties in humans, in spite of recent formulation advancements, there remains a need in the art for elacridar analogs that can achieve higher, less variable levels in the systemic circulation, at the blood-brain barrier, and elsewhere to optimize efflux inhibition.
Example 1 : Synthesis of Instant Analogs and Compositions
00179 This example demonstrates a synthetic method for making elacridar analogs, deuterium substitutions based upon the deuteration of the starting compounds. The synthesis and the analog numbers refer to Figure 4.
00180 Step 1
00181 A 12L three-neck flask was charged with compound 1 (270.5 g, 1.618 mol), compound 2 (357.8 g, 1.78 mol, 1.1 eq.), K2C03 (447 g, 3.236 mol, 2.0 eq), Cu (20.6 g, 0.324 mol, 0.2 eq.) and ethanol (2.7 L) and the resulting mixture was heated to reflux under nitrogen for 1 hour. The reaction mixture was cooled to room
temperature after the reaction progress was checked with LC-MS. Water (2.7 L) was added and the mixture was filtered through a pad of Celite. The Celite was washed with water (1.35L) and the combined filtrate was adjusted to pH~2 by addition of concentrated HCI (~410 mL) over 15 min. The resulting suspension was stirred at 10°C for 1.5 hours and the solid was filtered, washed with water (2.7 L) and dried at 45°C using a vacuum oven for 2 days to give compound 3 (465 g, ~100%) as a yellow solid.
00182 Step 2
00183 A suspension of compound 3 (498 g, 1.734 mol) in acetonitrile (4.0 L) was heated to reflux under stirring. To the suspension was added POCb (355.5 mL,
3.814 mol, 2.2 eq.) drop-wise over 2h. The mixture was heated at reflux for 2.5h and then cooled to 30 °C. To the mixture was slowly added water (3.0 L) and the resultant thick slurry was heated to reflux for 1 5h. The slurry was cooled to 10 °C and filtered. The solid was washed with water (2 X 1.0 L), acetonitrile (2 X 1.0 L) and dried using a vacuum oven overnight at 45 °C to afford compound 4 (426 g, 91.3%) as a yellow solid.
00184 Step 3:
00185 A 12L three-neck flask was charged with compound 5 (475g, 2.065 mol), compound 6 (474.8g, 2.065 mol), K2C03 (314g, 2.273 mol), Kl (68.6g, 0.413 moL) and DMF (2.5L) and the resulting mixture was heated to 70 °C and stirred for 2.5 hours. After LC-MS showed that the reaction was complete, the mixture was cooled to 50 °C and methanol (620 ml_) was added. Then the mixture was cooled to 30 °C and water (4.75 L) was added. The resulting suspension was cooled to 10 °C and for 1 hour. The solid was filtered, washed with water (2 X 2.5 L) and air dried for 2 days to afford the compound 7 (630 g, 89.1 %) as a yellow solid.
00186 Step 4
00187 To a solution of compound 7 (630 g, 1.84 mol) in THF/ethanol (8 L at 1 :1 ) was added Pd/C (10%, 50% wet, 30 g). The mixture was stirred under an
atmosphere of hydrogen (1 atm, balloon) at 15-20 °C for 4h. The reaction mixture was filtered through a pad of Celite and the pad was washed with TFIF (1.0 L). The filtrate was concentrated to 3 volumes under vacuum and hexanes (4.0 L) was added. The resulting slurry was cooled to 0 °C and stirred for 1 h. The solid was filtered and washed with hexanes (2 X 500 ml_) and air dried overnight to afford the compound 8 (522 g, 90.8%) as an off -white solid.
00188 Step 5
00189 A 5L three-neck flask was charged with compound 4 (250 g, 0.929 mol, 1 eq.), compound 8 (290 g, 0.929mol, 1 eq.) and DMF (2.5 L) and the resulting mixture was stirred at room temperature until it became a clear solution. To the solution was added TBTU (328 g, 1.021 mol, 1.1 eq.), followed by triethylamine (272 ml_, 1.95 mol, 2.1 eq.) and the resulting mixture was stirred at room temperature under nitrogen overnight. The mixture was poured slowly into water (7.5 L) with stirring and the resulting suspension was stirred for 1 hour at room temperature. The solid was filtered and washed with water (2 X 7 L). The solid thus obtained was dried using a vacuum oven at 50 °C for two days and 509.0 g (97.3%) of compound 9 was obtained as yellow solid.
00190 Step 6
00191 300.0 g (0.532 mol) of compound 9 was suspended in acetic acid (1.2 L) and heated to 70 °C. The resultant solution was hot filtered and heated to 70°C again. Preheated ethanol (70 °C, 3.6 L) was then added. To this solution was added concentrated HCI (66.0 ml_, 0.792 mol, 1.5 eq.) dropwise over 30 min. The resulting solution was stirred at 70°C until crystallization commenced (~about 20 min). The suspension was cooled to room temperature over 3h, filtered, washed with ethanol (2 X 1.8 L) and dried using a vacuum oven at 60°C over the weekend to afford compound 10 (253.0 g, 79.2%) as a brown solid.
Example 2 Manufacture of a Deuterated Elacridar analog EE60.
00192 EE60 is synthesized by the procedure shown in Figure 4 and as continued in Figure 5.
00193 The structure of EE60 is confirmed as follows: Samples of 5 pi are measured using an LC system comprising an UltiMate 3000 LC Systems (Dionex, Sunnyvale, CA) and an 2996 UV diode array detector (Waters). Samples are injected on to a 100 x 2mm (ID) 3.5 pm ZORBAX Extend-C18 column (Agilent, Santa Clara, CA). Elution is done at a flow rate of 0.4 mL/min using a 5 minute gradient from 20% to 95% B (mobile phase A was 0.1 % FICOOFI in water (v/v) and mobile phase B was methanol). 95% B is maintained for 1 min followed by re-equilibration at 20% B. Chromeleon (v6.8) is used for data acquisition and peak processing.
Example 3: Manufacture of a Deuterated Elacridar analog EE59
00194 EE59 was synthesized by the procedure shown in Figure 6.
00195 The resulting yellowish brown precipitate was removed by filtration and the filter cake was dried overnight (72 mg). Analysis of the filter cake by LCMS indicated the presence of a single peak at multiple wavelengths (215 nm, 220 nm, 254 nm,
280 nm); each peak confirmed the presence of the desired product (LC retention time, 5.3 min; m/z = 575 [(M+FI)+]).
Example 4: Demonstration of superior properties of instant analogs and compositions: in vivo ADMET.
00197 Pharmacologic studies are performed according to Ward KW et al (2001 Xenobiotica 317783-797) and Ward and Azzarano (JPET 310:703-709, 2004).
Briefly, instant analogs are administered solutions in 10% aqueous polyethylene glycol-300 (PEG-300) or 6% Cavitron with 1 % dimethyl sulfoxide, or as well triturated suspensions in 0.5% aqueous HPMC containing 1 % Tween 80. Blood samples are collected at various times up to 48 h after drug administration; plasma samples are prepared and at “70°C until analysis.
00198 Mice. Instant analogs are administered to four groups of animals by oral gavage (10 ml/kg dose volume). Three groups receive instant analogs as a suspension at 3, 30, or 300 mg/kg, and the fourth group receive instant analogs as a solution in Cavitron at 3 mg/kg. Blood sampling in mice is performed via a tail vein at 0.5, 1 , 2, 4, 8, 24, and 32 h postdose.
00199 Rats. A total of seven groups of animals receive instant analogs by oral gavage (10 ml/kg). Three groups receive instant analogs as a suspension at 3, 30, or 300 mg/kg, and a fourth and fifth group each receive instant analogs as a solution in Cavitron or PEG-300, respectively, at 3 mg/kg. A sixth and seventh group of rats with indwelling hepatic portal vein catheters receive instant analogs by oral gavage (10 ml/kg) as a suspension at 3 or 30 mg/kg, respectively. Blood sampling in rats are performed via a lateral tail vein; samples are also obtained from the hepatic portal vein catheter. Blood samples are obtained before dosing and at 5, 15, 30, and 45 min, and 1 ,1.5, 2, 3, 4, 6, 8, 10, 24, and 32 h postdose.
00200 Dogs. Dogs receive instant analogs by lavage (4 ml/kg) on three separate occasions with dosages at 3 and 30 mg/kg as a suspension and 3 mg/kg as a solution in Cavitron. Blood samples are obtained from a cephalic vein and from the hepatic portal vein catheter before dosing and at 5, 15, 30, and 45 min and 1 , 1.5, 2, 3, 4, 6, 8, 10, 24, 32, and 48 h postdose.
00201 Monkeys. Monkeys receive instant analogs by oral gavage (8 ml/kg dose volume) on three separate occasions at dosages of 3 and 30 mg/kg as a suspension and 3 mg/kg as a solution in Cavitron. Blood samples are obtained from a femoral vein via an indwelling catheter and from the hepatic portal vascular access port
before dosing and at 5, 15, and 30 min and 1 , 1.5, 2, 4, 6, 8, 10, 24, 32, and 48 h postdose.
00202 Humans. Healthy volunteers receive instant analogs orally at doses ranging from 25 mg to 1000 mg. Blood samples are obtained and analyzed for analog concentrations at 0, 15 min, 30 min, 45 min, 60 min, 90 min, 120 min, 180 min, 2 hr, 4 hr, 6hr, 8 hr, 12 hr, 24 hr, and 48 h after administration .
Analytical Methods
00203 Instant analogs are isolated from samples by precipitation with acetonitrile and quantified by LC/MS/MS coupled with an atmospheric pressure chemical ionization interface (475°C). Internal standards [in acetonitrile/10 mM ammonium formate, pH 3.0; 95:5 (v/v)] are added to 50 pi samples and vortexed and centrifuged for 30 min at 4000 rpm. The supernatants are injected onto the LC/MS/MS system using an HTS PAL autosampler (CTC Analytics, Zwingen, Switzerland) coupled to an Aria TX2 high-throughput liquid chromatographic system using turbulent flow technology (Cohesive Technologies, Franklin, MA) in focus mode. The mobile phase consists of a mixture of 0.1 % formic acid in water and 0.1 % formic acid in
acetonitrile. The turbulent flow column is a 0.5 X 50-mm Cyclone P column
(Cohesive Technologies) in series to a 2 X 20 mm, 4 pm Polar RP (Phenomenex, Torrance, CA) analytical column. Positive-ion multiple reaction monitoring is used for the detection of instant analogs and internal standard and the selected precursor and product ions are mlz 564 and 252, respectively. Using a (1/x) weighted linear regression analysis of the calibration curve, linear responses in analyte/internal standard peak area ratios are observed for instant analog concentrations ranging from 2 to 10,000 ng/ml.
00204 Alternatively, useful analytical methods to demonstrate the surprising and superior properties of the instant elacridar analogs are the methods as described by Stokvis et al, J Mass Spectr 2004: 39: 1122-1130.
CAS Name: L-Valine 2-[(2-amino-1,6-dihydro-6-oxo-9H-purin-9-yl)methoxy]ethyl ester
Additional Names: L-valine ester with 9-[(2-hydroxyethoxy)methyl]guanine; valaciclovir; ValACV
Molecular Formula: C13H20N6O4
Molecular Weight: 324.34
Percent Composition: C 48.14%, H 6.22%, N 25.91%, O 19.73%
Literature References: L-Valine ester prodrug of acyclovir, q.v. Prepn: T. A. Krenitsky et al.,EP308065; L. M. Beauchamp, US4957924 (1989, 1990 both to Wellcome). Evaluation as prodrug: L. M. Beauchamp et al.,Antiviral Chem. Chemother.3, 157 (1992). Clinical pharmacokinetics: S. Weller et al.,Clin. Pharmacol. Ther.54, 595 (1993). Review of pharmacology and clinical efficacy in herpes virus infections: C. M. Perry, D. Faulds, Drugs52, 754-772 (1996). Clinical trial to prevent cytomegalovirus disease in renal transplantation: D. Lowance et al.,N. Engl. J. Med.340, 1462 (1999); to prevent transmission of genital herpes: L. Corey et al.,ibid.350, 11 (2004).
Derivative Type: Hydrochloride
CAS Registry Number: 124832-27-5
Manufacturers’ Codes: 256U; BW-256U87; BW-256
Trademarks: Valtrex (GSK)
Properties: Crystalline solid, occurs as hydrate. uv max (water): 252.8 nm (e 8530). Soly in water: 174 mg/ml.
Absorption maximum: uv max (water): 252.8 nm (e 8530)
Therap-Cat: Antiviral.
Keywords: Antiviral; Purines/Pyrimidinones
Valaciclovir is the hydrochloride salt of L-valyl ester of the antiviral drug aciclovir (Zovirax[R]). It was first launched in 1995 by GlaxoSmithKline (GSK) for the oral treatment of recurrent genital herpes, varicella zoster virus (VZV) and herpes simplex virus (HSV) infection in immunocompetent adults.
Valaciclovir was originally developed by GSK and was subsequently licensed to Sigma-Tau and Sanofi (formerly known as sanofi-aventis). In March 2003, GSK and Shionogi signed a letter of intent to copromote both aciclovir and valaciclovir in Japan, where it has been marketed by GSK since 2000.
Valaciclovir was patented in 1987 and came into medical use in 1995.[2][3] It is available as a generic medication.[4] A month supply in the United Kingdom costs the NHS about £3 as of 2019.[4] In the United States the wholesale cost of this amount is about US$2.80.[5]In 2016 it was the 168th most prescribed medication in the United States with more than 3 million prescriptions.[6]
Medical uses
Valtrex brand valaciclovir 500mg tablets
Valaciclovir is used for the treatment of HSV and VZV infections, including:[7]
It has shown promise as a treatment for infectious mononucleosis[11][12][13] and is preventively administered in suspected cases of herpes B virus exposure.[14]
Valaciclovir is not recommended in Bell’s palsy due to lack of benefit.[15]
Valaciclovir belongs to a family of molecules. Valaciclovir is a prodrug, an esterified version of aciclovir that has greater oral bioavailability (about 55%) than aciclovir.[10] It is converted by esterases to the active drug, aciclovir, and the amino acid, valine, via hepaticfirst-pass metabolism. Aciclovir is selectively converted into a monophosphate form by viral thymidine kinase, which is more effective (3000 times) in phosphorylation of aciclovir than cellular thymidine kinase. Subsequently, the monophosphate form is further phosphorylated into a disphosphate by cellular guanylate kinase and then into the active triphosphate form, aciclo-GTP, by cellular kinases.[10]
Mechanism of action
Aciclo-GTP, the active triphosphate metabolite of aciclovir, is a very potent inhibitor of viralDNA replication. Aciclo-GTP competitively inhibits and inactivates the viralDNA polymerase.[10] Its monophosphate form also incorporates into the viral DNA, resulting in chain termination. It has also been shown that the viral enzymes cannot remove aciclo-GMP from the chain, which results in inhibition of further activity of DNA polymerase. Aciclo-GTP is fairly rapidly metabolized within the cell, possibly by cellular phosphatases.[16]
Aciclovir is active against most species in the herpesvirus family. In descending order of activity:[17]
The drug is predominantly active against HSV and, to a lesser extent, VZV. It is only of limited efficacy against EBV and CMV. However, valacyclovir has recently been shown to lower or eliminate the presence of the Epstein–Barr virus in subjects afflicted with acute mononucleosis, leading to a significant decrease in the severity of symptoms.[11][12][13] Although it can prevent the establishment of viral latency, acyclovir therapy has not proven effective at eradicating latent viruses in nerve ganglia.[17]
As of 2005, resistance to valaciclovir has not been significant. Mechanisms of resistance in HSV include deficient viral thymidine kinase and mutations to viral thymidine kinase and/or DNA polymerase that alter substrate sensitivity.[18]
Valaciclovir was patented in 1987 and came into medical use in 1995.[2][3] It is available as a generic medication.[4] A month supply in the United Kingdom costs the NHS about £3 as of 2019.[4] In the United States the wholesale cost of this amount is about US$2.80.[5] In 2019, it was the 168th most prescribed medication in the United States with more than 3 million prescriptions.[6]
Formulations
It is marketed by GlaxoSmithKline under the trade names Valtrex and Zelitrex. Valaciclovir has been available as a generic drug in the U.S. since November 25, 2009.[19]
Acyclovir (I) was coupled with N-Cbz-L-valine (II) in the presence of DCC and DMAP to afford the Cbz-protected valyl ester (III). The N-benzyloxycarbonyl group of (III) was then removed by either hydrogenation over Pd/C or by transfer hydrogenation in the presence of formic acid. AU 8820978; EP 0308065; EP 0596542; JP 1989068373; JP 1991115284; US 4957924; US 5061708
SYN 2
In an alternative procedure, condensation of L-valine (IV) with methyl acetoacetate (V) in the presence of NaOH produced the enamine-protected valine sodium salt (VI). Condensation of (VI) with the tosylate (VII), (prepared from acyclovir (I) and tosyl chloride) afforded ester (VIII). Then, acidic hydrolysis of the enaminoester moiety of (VIII) furnished the target valine ester. Similar procedures were also reported using omega-mesyl and omega-chloro acyclovir.
SYN3
The esterification of acyclovir (I) with N-(tert-butoxycarbonyl)-L-valine (II) by means of EDC, TEA and DMAP in DMF gives the corresponding ester (III) which is finally deprotected by means of HCl in water to afford the target valacyclovir.
Valaciclovir
Synonyms:Valacyclovir, BW-256U, 256 U 87
ATC:J05AB11
Use:antiviral, prodrug of aciclovir
Chemical name:l-valine 2-[(2-amino-1,6-dihydro-6-oxo-9H-purin-9-yl)methoxy]ethyl ester
^ Jump up to:ab“NADAC as of 2019-02-27”. Centers for Medicare and Medicaid Services. Retrieved 3 March 2019. Cite error: The named reference “NADAC2019” was defined multiple times with different content (see the help page).
^ Jump up to:ab“The Top 300 of 2019”. clincalc.com. Retrieved 22 December 2018. Cite error: The named reference “:1” was defined multiple times with different content (see the help page).
^Elad S, Zadik Y, Hewson I, et al. (August 2010). “A systematic review of viral infections associated with oral involvement in cancer patients: a spotlight on Herpesviridea”. Support Care Cancer. 18 (8): 993–1006. doi:10.1007/s00520-010-0900-3. PMID20544224.
^ Jump up to:abBalfour et al. (December 2005) A controlled trial of valacyclovir in infectious mononucleosis. Presented at the 45th Interscience Conference on Antimicrobial Agents and Chemotherapy, Washington, DC., December 18, 2005. Abstract V1392
^ Jump up to:abBalfour HH, Hokanson KM, Schacherer RM, et al. (May 2007). “A virologic pilot study of valacyclovir in infectious mononucleosis”. Journal of Clinical Virology. 39 (1): 16–21. doi:10.1016/j.jcv.2007.02.002. PMID17369082.
^Baugh, Reginald F.; Basura, Gregory J.; Ishii, Lisa E.; Schwartz, Seth R.; Drumheller, Caitlin Murray; Burkholder, Rebecca; Deckard, Nathan A.; Dawson, Cindy; Driscoll, Colin (November 2013). “Clinical Practice Guideline: Bell’s Palsy”. Otolaryngology–Head and Neck Surgery. 149 (3_suppl): S1–S27. doi:10.1177/0194599813505967. ISSN0194-5998. In summary, antiviral therapy alone (acyclovir or valacyclovir) is not recommended in the treatment of Bell’s palsy due to lack of effectiveness of currently available drugs, unnecessary cost, and the potential for drug-related complications.
CAS Name:N-(2-Piperidinylmethyl)-2,5-bis(2,2,2-trifluoroethoxy)benzamide
Molecular Formula: C17H20F6N2O3
Molecular Weight: 414.34
Percent Composition: C 49.28%, H 4.87%, F 27.51%, N 6.76%, O 11.58%
Literature References: Prepn: E. H. Banitt, W. R. Brown, US3900481 (1975 to Riker); of the acetate: eidem,US4005209 (1977 to Riker); E. H. Banitt et al.,J. Med. Chem.20, 821 (1977). Preliminary pharmacological study: J. R. Schmid et al.,Fed. Proc.34,775 (1975). In vitro electrophysiological study: A. B. Hodess et al.,J. Cardiovasc. Pharmacol.1, 427 (1979). Antiarrhythmic effects: P. Somani, Clin. Pharmacol. Ther.27, 464 (1980). Use in acute exptl myocardial infarction: H. Gülker et al.,Z. Cardiol.70, 124 (1981). Clinical study in ventricular arrhythmias: J. L. Anderson et al.,N. Engl. J. Med.305, 473 (1981). Determn of acetate in human plasma by spectrophotofluorometry: S. F. Chang et al.,Arzneim.-Forsch.33, 251 (1983). Review of pharmacology and clinical efficacy: D. M. Roden, R. L. Woosley, N. Engl. J. Med.315, 36-41 (1986). Symposium on clinical experience: Am. J. Cardiol.62, Suppl., 1D-67D (1988). Comprehensive description: S. Alessi-Severini et al.,Anal. Profiles Drug Subs. Excip.21, 169-195 (1992).
Percent Composition: C 48.10%, H 5.10%, F 24.03%, N 5.91%, O 16.86%
Properties: White granular solid from isopropyl alcohol/isopropyl ether, mp 145-147°. Soly at 37° (mg/ml): water 48.4, alcohol 300.
Melting point: mp 145-147°
Therap-Cat: Antiarrhythmic (class IC).
Keywords: Antiarrhythmic.
Flecainide acetate is an antiarrhythmic that was first launched by 3M Pharmaceuticals in 1985 for the oral treatment of ventricular arrhythmias and supraventricular tachyarrhythmias
In 2007, the product was approved in Japan for the treatment of atrial fibrillation.
The compound was originally developed at 3M Pharmaceuticals. In January 1984, 3M signed a development and marketing agreement with Eisai for the Japanese market.
3M’s pharmaceutical operations as well as regional marketing and intellectual property rights were acquired by Graceway in the U.S., Canada and Latin America, by Meda in Europe, and by Ironbridge Capital and Archer Capital in the Asia Pacific region, including Australia and South Africa. In 2011, Graceway’s active compounds were acquired by Medicis. In 2012, Medicis was acquired by Valeant (now Bausch Health).
Flecainide was approved for medical use in the United States in 1985.[1] It is available as a generic medication.[2] A month supply in the United Kingdom costs the NHS about £7.68 as of 2019.[2] In the United States the wholesale cost of this amount is about 18.60 USD.[4]In 2016 it was the 273rd most prescribed medication in the United States with more than a million prescriptions.[5]
It also has limited use in the treatment of certain forms of ventricular tachycardia (VT). In particular, flecainide has been useful in the treatment of ventricular tachycardias that are not in the setting of an acute ischemic event. It has use in the treatment of right ventricular outflow tract (RVOT) tachycardia[6] and in the suppression of arrhythmias in arrhythmogenic right ventricular dysplasia (ARVD).[7]Studies (notably the Cardiac Arrhythmia Suppression Trial) have shown an increased mortality when flecainide is used to suppress ventricular extrasystoles in the setting of acute myocardial infarction.[8][9]
In individuals suspected of having the Brugada syndrome, the administration of flecainide may help reveal the ECG findings that are characteristic of the disease process. This may help make the diagnosis of the disease in equivocal cases.[10]
Flecainide has been introduced into the treatment of arrhythmias in children.
Results of a medical study known as the Cardiac Arrhythmia Suppression Trial (CAST) demonstrated that patients with structural heart disease (such as a history of MI (heart attack), or left ventricular dysfunction) and also patients with ventricular arrhythmias, should not take this drug. The results were so significant that the trial was stopped early and preliminary results were published.[12]
The dose may need to be adjusted in certain clinical scenarios. As with all other antiarrhythmic agents, there is a risk of proarrhythmiaassociated with the use of flecainide. This risk is probably increased when flecainide is co-administered with other class Ic antiarrhythmics, such as encainide. The risk of proarrhythmia may also be increased by hypokalemia.[13] The risk of proarrhythmia is not necessarily associated with the length of time an individual is taking flecainide, and cases of late proarrhythmia have been reported.[14] Because of the role of both the liver and the kidneys in the elimination of flecainide, the dosing of flecainide may need to be adjusted in individuals who develop either liver failure or renal failure.
Because of the negative inotropic effects of flecainide, it should be used with caution in individuals with depressed ejection fraction, and may worsen congestive heart failure in these individuals. It should be avoided in people with ischaemic heart disease and the elderly.[15]
Due to the narrow therapeutic index of flecainide, physicians should be alert for signs of toxicity before life-threatening arrhythmias occur like torsades de pointes. While the toxic effects of flecainide are closely related to the plasma levels of the drug,[17] it is unfeasible to check the plasma concentration in an individual on a regular basis.
Signs of flecainide toxicity include marked prolongation of the PR interval and widening of the QRS duration on the surface ECG. There may be signs and symptoms attributable to overt heart failure secondary to sudden decreased myocardial contractility.
Treatment
Treatment of flecainide cardiac toxicity involves increasing the excretion of flecainide, blocking its effects in the heart, and (rarely) institution of cardiovascular support to avoid impending lethal arrhythmias. Modalities that have had success include administration of a beta-sympathomimetic agent,[17] and administration of a sodium load[17](often in the form of hypertonicsodium bicarbonate). Placing the individual on cardiopulmonary bypass support may be necessary in order to temporarily remove the need for a beating heart and to increase blood flow to the liver.[18][19]
Flecainide has high bioavailability after an oral dose,[26] meaning that most of the drug that is ingested will enter the systemic blood stream. Peak serum concentrations can be seen 1 to 6 hours after ingestion of an oral dose. While the plasma half-life is about 20 hours, it is quite variable, and can range from 12 to 27 hours.[27] During oral loading with flecainide, a steady state equilibrium is typically achieved in 3 to 5 days.
The majority of flecainide is eliminated by the kidneys, with the remainder metabolized by the cytochrome P450 2D6 isoenzyme in the liver.[28] Therefore, alterations in renal function or urine pH will greatly affect the elimination of flecainide, as more is eliminated by the kidney than by the hepatic route.
Because of the dual elimination routes of flecainide and its tendency to decrease myocardial contractility,[15] flecainide interacts with numerous pharmaceuticals and can potentiate the effects of other myocardial depressants and AV node blocking agents. In addition, flecainide can decrease the metabolism or elimination of many (but not all) agents that use the cytochrome P450 enzyme system.
A full list of drug interactions with flecainide can be obtained from the manufacturer. Some important drug interactions with flecainide include:[citation needed]
Alcohol – may further depress normal heart function
Flecainide intoxication is rare but serious due to the cardiogenic shock that it provokes. Its diagnosis can be difficult in the lack of contributing anamnestic elements. Clinical and paraclinical signs are not specific. Treatment is primarily symptomatic, which gives good results thanks to the hypertonic solution of sodium salts. Organ donation is possible in the case of braindead patients who suffered a flecainide intoxication.[29]
Mechanism of action
Flecainide works by blocking the Nav1.5sodium channel in the heart, slowing the upstroke of the cardiac action potential.[30] This thereby slows conduction of the electrical impulse within the heart, i.e. it “reduces excitability”. The greatest effect is on the His-Purkinje system and ventricular myocardium. The effect of flecainide on the ventricular myocardium causes decreased contractility of the muscle, which leads to a decrease in the ejection fraction.
The effect of flecainide on the sodium channels of the heart increases as the heart rate increases; This is known as use-dependence and is why that flecainide is useful to break a tachyarrhythmia.[31]
Flecainide also inhibits ryanodine receptor 2 (RyR2),[32] a major regulator of sarcoplasmic release of stored calcium ions. It can reduce calcium sparks and thus arrhythmogenic calcium waves in the heart.[33] While Flecainide therapy has been shown to suppress ventricular arrhythmias in patients with catecholaminergic polymorphic ventricular tachycardia(CPVT) and mouse models of this disease, the relative contribution from the inhibition of sodium channels and of RyR2 in this effect on CPVT is unclear.[34]
Brand names
Flecainide is sold under the trade name Tambocor (manufactured by 3M pharmaceuticals). Flecainide went off-patent on February10, 2004. In addition to being marketed as Tambocor, it is also available in generic version and under the trade names Almarytm, Apocard, Ecrinal, and Flécaine.
Following is one of the synthesis routes: 2-Aminomethylpyridine (II) is condensed with 2,2,2-trifluoroethyl-2,5-bis(2,2,2-trifluoroethoxy)benzoate (I) in refluxing glyme to produce 2,5-bis(2,2,2-trifluoroethoxy)-N-(2-pyridylmethyl)benzamide (III), and the yielding product is then hydrogenated with H2 over Pd/C in acetic acid.
Flecainide acetate, 2,5-bis(2,2,2-trifluoroethoxy)-N-(2-piperidylmethyl)benzamide acetate (I), is a drug for the treatment of arrhythmia. It and its neutral base are described in U.S. Pat. No. 3,900,481.
A key intermediate for the synthesis of Flecainide and its pharmaceutically acceptable salts is 2,5-bis(2,2,2-trifluoroethoxy)benzoic acid (II). One prior method for the preparation of this intermediate, disclosed in British patent No. GB 2045760, is a multistep process which comprises the preparation of 1,4-bis(2,2,2-trifluoroethoxy)benzene from hydroquinone using the very expensive reagent trifluoroethyltriflate (CF3CH2OSO2CF3). 1,4-bis(2,2,2-trifluoroethoxy)benzene is then converted to 2,5-bis(2,2,2-trifluoroethoxy)benzoic acid (II) through a multistep process. An alternative method described in the same patent begins from 1,4-dibromobenzene, which is then condensed with more than 8 equivalents of 2,2,2-trifluoroethanol, to furnish the 1,4-bis(2,2,2-trifluoroethoxy)benzene intermediate. 2,5-bis(2,2,2-trifluoroethoxy)benzoic acid (II) is also be prepared starting from 1-bromo-4-fluorobenzene (PCT WO 02/066413) or from 2-bromo-5-chlorobenzoic acid (PCT WO 99/02498). All these approaches have limited commercial utility due to the cost of the reagents and the necessity for specialized equipment.
The method disclosed in British patent No. GB 2045760 for the preparation of the Flecainide base starts from 2,5-bis(2,2,2-trifluoroethoxy)benzoic acid which is converted to its acid chloride and reacts either with 2-(aminomethyl)piperidine to form Flecainide in one step or with 2-(aminomethyl)pyridine, followed by catalytic hydrogenation of the pyridine ring, to form Flecainide base in two steps. The disadvantage of the one step process is that the acid chloride reacts non-selectively with both nitrogen atoms of the 2-(aminomethyl)piperidine, resulting in a mixture of the two acylated isomers.
Other preparations of Flecainide base are disclosed in WO 99/02498 and US2003/0032835. The process disclosed in WO 99/02498 starts from the cyanomethyl ester of 2,5-bis(2,2,2-trifluoroethoxy)benzoic acid, which selectively reacts with the primary amino group of 2-(aminomethyl)piperidine to furnish Flecainide. US 2003/032835 discloses a procedure which involves converting 2,5-bis(2,2,2-trifluoroethoxy)benzoic acid to its activated 2,2,2-trifluoroethyl ester which then selectively reacts with the primary amino group of 2-(aminomethyl)piperidine to furnish Flecainide. Although activated esters of this type can be used for the formation of Flecainide, the reagents required to prepare them are expensive on the industrial scale. Moreover, the resulting cyanomethanol and 2,2,2-trifluoroethanol by-products are highly toxic. Esters from less expensive, non-toxic and readily available alcohols are still desired for commercial purposes. Based on the above deficiencies, a new process overcoming these deficiencies was required.
EXAMPLE 1
Preparation of 2-(2,2,2-trifluoroethoxy)benzoic acid
To a solution of 2,2,2-trifluoroethanol (40.0 g) and DMF (100 ml) was added sodium tert-butoxide (23.0 g) at 0° C. The solution was stirred at 20 to 25° C. for 1 hour at which point 2-chlorobenzoic acid (25.0 g) was added followed by cupric bromide (2.0 g). The mixture was stirred at 120° C. for 5 hours, cooled to 10° C., and water (30 ml) was added followed by 20% HCl solution (90 ml). The solution was extracted with dichloromethane (3×50 ml). The combined organic layers were washed with water (3×50 ml) and the volume was concentrated to 90 ml. Hexane (150 ml) was added to the residues, and the mixture was concentrated to volume of 120 ml and a further portion of hexane (30 ml) was added. The mixture was heated at 50° C. for 30 minutes and then stirred at room temperature for 1 hour. The solids were filtered to yield the crude product. This material was dissolved in ethyl acetate (50 ml), charcoal (1.7 g) was added and the mixture was stirred at room temperature a further 2 hours. The solution was filtered through Celite™ and crystallized from ethyl acetate/hexane to yield the pure product (30.9 g, yield 88.0%) as a white solid, m.p. 85–86° C.
EXAMPLE 2
Preparation of 5-bromo-2-(2,2,2-trifluoroethoxy)benzoic acid
To a solution of 2-(2,2,2-trifluoroethoxy)benzoic acid (22 g) in methylene chloride (100 ml), was added AlCl3 (13.3 g) at 0° C.followed by bromine (16.0 g, 0.1 mol). The reaction mixture was stirred at 0° C. for 1 hour and then at reflux for 2 hours. The solids were filtered and water (50 ml) and ethyl acetate (50 ml) were added to the filtrate. The aqueous layer was separated and extracted with ethyl acetate (2×60 ml) and the combined organic layers were washed with water (2×60 ml). The organic layer was concentrated under vacuum to dryness and hexane (100 ml) was added and the resulting suspension was stirred at 20 to 25° C. for 1 hour. The mixture was filtered and the cake was rinsed with heptanes (2×20 ml). The damp solids were dried in vacuum at 45° C. for 5–6 hours to give a white solid (28.3 g, yield 94.6%), m.p. 126–128° C.
EXAMPLE 3
Preparation of 2,5-bis(2,2,2-trifluoroethoxy)benzoic acid.
To a solution of 2,2,2-trifluoroethanol (14.7 g) and DMF (125 ml) was added sodium tert-butoxide (12.8 g) at 0° C. The solution was stirred at 20 to 25° C. for 1 hour at which point 5-bromo-2-(2,2,2-trifluoroethoxy)benzoic acid (20 g) was added followed by cupric bromide (2.0 g). The mixture was stirred at 100° C. for 10 hours, cooled to 10° C., and water (30 ml) was added followed by 20% HCl solution (90 ml). The solution was extracted with dichloromethane (3×80 ml), and the combined organic layers were washed with water (3×60 ml). The solution was concentrated to one-third of the original volume and hexane (200 ml) was added. The resulting suspension was stirred at room temperature for 2 hours, filtered and the damp cake was rinsed with hexane (2×40 ml). The damp cake was dried in vacuo at 40° C. for 5 hours to give the product as a white solid (16.02 g, yield 75.3%).
EXAMPLE 4
Preparation of methyl 2,5-bis(2,2,2-trifluoroethoxy)benzoate
A solution of 2,5-bis(2,2,2-trifluoroethoxy)benzoic acid (20 g) and thionyl chloride (15.0 g) in methanol (100 ml) was stirred at 80° C. for 2 hours. The solvents were evaporated under vacuum to give an oil residue. Toluene (100 ml) was added to the residue and the solution was washed with saturated NaHCO3 (30 ml) solution followed by water (3×30 ml). The organic layer was concentrated under reduced pressure to give the product as a white solid (20.5 g, yield 98.0%).
EXAMPLE 5
Preparation of Flecainide
A mixture of methyl 2,5-bis(2,2,2-trifluoroethoxy)benzoate (1.5 g), 2-(aminomethyl)piperidine (0.62 g) in toluene (3 ml) was stirred at reflux for 10 hours. After cooling to room temperature, water (10 ml) was added and two layers solution were separated. The aqueous layer was extracted with toluene (2×10 ml) and the combined organic layers were washed with water (3×10 ml). The organic layer was concentrated under reduced pressure to give Flecainide free base as a white solid (1.63 g, 85%).
EXAMPLE 6
Preparation of Flecainide acetate
To a solution of Flecainide free base (1.5 g) in isopropanol (7.5 ml) was added glacial acetic acid (0.3 g) and the solution was stirred under reflux for 2 hours. The solution was cooled to room temperature and hexane (15 ml) was added and solids began to precipitate. The resulting suspension was stirred at 20–25° C. for 2 hours and the solids were filtered and then rinsed with hexane (2×10 ml). The damp cake was dried in vacuum for 4 hours to give Flecainide acetate as a white solid (1.54 g, Yield 89%).
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Flecainide
ATC:C01BC04
Use:antiarrhythmic
Chemical name:N-(2-piperidinylmethyl)-2,5-bis(2,2,2-trifluoroethoxy)benzamide
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DRUG APPROVALS BY DR ANTHONY MELVIN CRASTO
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New Drug Approvals 