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DR ANTHONY MELVIN CRASTO Ph.D

DR ANTHONY MELVIN CRASTO Ph.D

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 GLENMARK PHARMACEUTICALS LTD, Research Centre as Principal Scientist, Process Research (bulk actives) at Mahape, Navi Mumbai, India. Total Industry exp 30 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, Dr T.V. Radhakrishnan and Dr B. K. Kulkarni, 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, etc in organic chemistry are some most read blogs He has hands on experience in initiation and developing novel routes for drug molecules and implementation them on commercial scale over a 30 year tenure till date Dec 2017, 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 9 million plus hits on Google, 2.5 lakh plus connections on all networking sites, 50 Lakh plus views on dozen plus blogs, 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 19 lakh plus views on New Drug Approvals Blog in 216 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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Riamilovir, Triazavirin


Image result for riamilovirChemSpider 2D Image | Triazavirin | C5H4N6O3S[1,2,4]Triazolo[5,1-c][1,2,4]triazin-4(1H)-one, 7-(methylthio)-3-nitro-.png

Riamilovir, Triazavirin

Riamilovir sodium dihydrate, CAS 928659-17-0,
Riamilovir CAS: 123606-06-4
Chemical Formula: C5H4N6O3S
Molecular Weight: 228.19

[1,2,4]Triazolo[5,1-c][1,2,4]triazin-4(1H)-one, 7-(methylthio)-3-nitro- (9CI)

7-(Methylthio)-3-nitro[1,2,4]triazolo[5,1-c][1,2,4]triazin-4(6H)-one

1,2,4]Triazolo[5,1-c][1,2,4]triazin-4(6H)-one, 7-(methylthio)-3-nitro-

7-(methylsulfanyl)-3-nitro[1,2,4]triazolo[5,1-c][1,2,4]triazin- 4(1H)-one

7-thio-substituted-3-nitro-1,2,4-triazolo[5,1-c]-1,2,4-triazin-4(1H)-one

Riamilovir sodium CAS 116061-59-7

Riamilovir sodium dihydrate, CAS 928659-17-0, Triazavirin

Flavivirus infection; Zika virus infection

Image result for Zika virus

Zika virus

Image result for Flavivirus

Flavivirus

Anti-viral drug

http://apps.who.int/medicinedocs/documents/s23256en/s23256en.pdf

Image result for Ural Federal University

Triazavirin (TZV) is a broad-spectrum antiviral drug developed in Russia through a joint effort of Ural Federal UniversityRussian Academy of Sciences, Ural Center for Biopharma Technologies and Medsintez Pharmaceutical.

Image result for Medsintez Pharmaceutical

It has an azoloazine base structure, which represents a new structural class of non-nucleoside antiviral drugs.[1]

It was originally developed as a potential treatment for pandemic influenza strains such as H5N1, and most of the testing that has been done has focused on its anti-influenza activity.[2][3][4]

However triazavirin has also been found to have antiviral activity against a number of other viruses including tick-borne encephalitis,[5]and is also being investigated for potential application against Lassa fever and Ebola virus disease.[6][7][8][9][10]

Image result for Ebola virus

Ebola virus

Yunona Holdings, was investigating riamilovir sodium dihydrate (triazavirin), a novel nucleoside inhibitor of human influenza virus A and B replication, for the potential oral treatment of influenza virus infection.

In November 2009, the company was seeking to outlicense the drug for development in the EU, presumed to be for use as a prescription medicine .

The Ural Branch of the Russian Academy of Sciences had previously developed, and Yunona Holdings registered and launched, triazavirinin in Russia as an OTC product .

Negative-sense, single-stranded RNA viruses (ssRNA), such as ssRNA viruses belonging to the Order Mononegavirales such as viruses in the Rhabdoviridae family, in particular the Rabies virus, the Filoviridae family, in particular the Ebolavirus, and the Paramyxoviridae family, in particular the Measles virus, other ssRNA viruses belonging to unassigned families such as notably the

Arenaviridae family, the Bunyaviridae family and the Orthomyxoviridae family and other unassigned ssRNA viruses such as notably the Deltavirus, cause many diseases in wildlife, domestic animals and humans. These ssRNA viruses belonging to different families are genetically and antigenically diverse, exhibiting broad tissue tropisms and a wide pathogenic potential.

For example, the Filoviridae viruses belonging to the Order

Mononegavirales, in particular the Ebolaviruses and Marburgviruses, are among the most lethal and most destructive viruses in the world. Filoviridae viruses are of particular concern as possible biological weapons since they have the potential for aerosol dissemination and weaponization.

The Ebolavirus includes five species: the Zaire, Sudan, Reston, Tai Forest and Bundibugyo Ebolaviruses. In particular the Zaire, Sudan and Bundibugyo Ebolavirus cause severe, often fatal, viral hemorraghic fevers in humans and nonhuman primates.

For more than 30 years, the Ebolavirus has been associated with periodic episodes of hemorrhagic fever in Central Africa that produce severe disease in

infected patients. Mortality rates in outbreaks have ranged from 50% for the Sudan species of the Ebolavirus to up to 90% for the Zaire species of the Ebolavirus ((Sanchez et al., Filoviridae: Marburg and Ebola Viruses, in Fields Virology, pages 1409-1448 (Lippincott Williams & Wilkins, Philadelphia)). In November 2007, during an outbreak in the Bundibugyo district of Uganda, near the border with the Democratic Republic of the Congo the fifth species of the Ebolavirus was discovered, the Bundibugyo species. Said outbreak resulted in a fatality rate of about 25% (Towner et al., PLoS Pathog., 4(11 ) :e1000212 (2008)). The Zaire species of the Ebolavirus has also decimated populations of wild apes in this same region of Africa (Walsh et al., Nature, 422:611-614 (2003)).

When infected with the Ebolavirus, the onset of illness is abrupt and is characterized by high fever, headaches, joint and muscle aches, sore throat, fatigue, diarrhea, vomiting, and stomach pain. A rash, red eyes, hiccups and internal and external bleeding may be seen in some patients. Within one week of becoming infected with the virus, most patients experience chest pains and multiple organ failure, go into shock, and die. Some patients also experience blindness and extensive bleeding before dying.

Another example of a negative sense single-stranded RNA envelope virus is the Morbilllivirus such as the Measles virus which is associated with Measles and the Lyssavirus such as the Rabies virus.

The Lyssavirus, belonging to the family Rhabdoviridae, includes eleven recognized species, in particular the Rabies virus which is known to cause Rabies. Rabies is an ancient disease with the earliest reports possibly dated to the Old World before 2300 B.C and remains a world health threat due to remaining lack of effective control measures in animal reservoir populations and a widespread lack of human access to vaccination. The Rabies virus is distributed worldwide among mammalian reservoirs including carnivores and bats. Each year there are many reported cases of transmission of the Rabies virus from animals to humans (e.g. by an animal bite). More than 50,000 people annually die of Rabies, particularly in Asia and Africa.

Thus, there remains a need for antiviral compounds which are effective for use in the treatment of the ssRNA virus infections different from the Influenza A and Influenza B virus infections

SYNTHESIS CONTRUCTED WITH 3 ARTICLES AS BELOW

RU 2340614 C2 20081210,

e-EROS Encyclopedia of Reagents for Organic Synthesis, 1-7; 2009,

European Journal of Medicinal Chemistry, 113, 11-27; 2016

Khimiya Geterotsiklicheskikh Soedinenii (1989), (2), 253-7.

Khimiya Geterotsiklicheskikh Soedinenii (1992), (11), 1555-9.

Zhurnal Organicheskoi Khimii (1996), 32(5), 770-776

PAPER

Russian Journal of Organic Chemistry (Translation of Zhurnal Organicheskoi Khimii) (2002), 38(2), 272-280.

https://link.springer.com/article/10.1023%2FA%3A1015538322029

Russian Journal of Organic Chemistry

Volume 38, Issue 2pp 272–280

Adamantylation of 3-Nitro- and 3-Ethoxycarbonyl-1,2,4-triazolo[5,1-c]-1,2,4-triazin-4-ones

Abstract

Reaction of 3-nitro- and 3-ethoxycarbonyl-1,2,4-triazolo[5,1-c]-1,2,4-triazin-4-ones with 1-adamantanol (or 1-adamantyl nitrate) in concentrated sulfuric acid or with 1-bromoadamantane in sulfolane affords N-adamantyl derivatives. The adamantylation of 3-nitro-1,4-dihydro-7H-1,2,4-triazolo[5,1-c]-1,2,4-triazin-4-one yields a mixture of N8– and N1-isomers that undergo interconversion in concentrated sulfuric acid along intermolecular mechanism.

PATENT

RU 2340614 C2 20081210,

PAPER

Russian Chemical Bulletin (2010), 59(1), 136-143.

Synthesis and antiviral activity of nucleoside analogs based on 1,2,4-triazolo[3,2-c][1,2,4]triazin-7-ones

Abstract

Nucleoside analogs containing hydroxybutyl, hydroxyethoxymethyl, allyloxymethyl, and propargyloxymethyl fragments were synthesized based on 1,2,4-triazolo[3,2-c][1,2,4]triazin-7-ones isosteric to purine bases. Some of the compounds obtained inhibit in vitro reproduction of influenza and respiratory syncytial virus infection.

PATENT

WO 2015117016

https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2015117016&recNum=1&maxRec=&office=&prevFilter=&sortOption=&queryString=&tab=PCTDescription

PAPER

Chemistry of Heterocyclic Compounds (New York, NY, United States) (2015), 51(3), 275-280.

https://link.springer.com/article/10.1007%2Fs10593-015-1695-4

The nucleophilic susbstitution of nitro group in [1,2,4]triazolo[5,1-c][1,2,4]triazinones upon treatment with cysteine and glutathione was studied as a model for the interaction with thiol groups of virus proteins, which mimics the metabolic transformations of antiviral drug Triazavirin® and its derivatives.

Chemistry of Heterocyclic Compounds

Volume 51, Issue 3pp 275–280

Nucleophilic substitution of nitro group in nitrotriazolotriazines as a model of potential interaction with cysteine-containing proteins

  1. 1.Ural Federal University named after the First President of Russia Boris YeltsinYekaterinburgRussia
  2. 2.Institute of Organic SynthesisUral Branch of the Russian Academy of SciencesYekaterinburgRussia
  3. 3.Research Institute of InfluenzaMinistry of Healthcare of the Russian FederationSaint-PetersburgRussia

PATENT

WO 2017144709

Example 1 : One pot synthesis of the sodium salt of 7-methylthio-3-nitro [1 ,

2, 4] triazolo [5,1 -c] [1, 2, 4] triazin -4 (1H)-one

Step 1 : Diazotization of compound (B): A solution (solution [1], herein after) was prepared of 5.8 g (0.05 ) of 5-amino-3-mercapto-1 ,2,4-triazole in 6.7 ml of nitric acid (15 M) and 12 ml of water. Said solution [1] was refrigerated to -7°C . Then a 40% sodium nitrite solution was added to the solution [1] in portions of 0.5 mL to obtain a total amount of sodium nitrite equal to 3.8 g in the mixture.

Step 2: Condensation of diazonium compound with an a-nitroester:

To the resulting diazonium salt of step 1 , 8.54 ml of diethyl nitromaionate was added. After holding for five minutes, a cooled solution of sodium hydroxide was slowly added dropwise to the reaction mixture until the pH was between pH 9 and pH 10 (solution [2], herein after). The resulting solution [2] was stirred at 0°C for 1 hour and at room temperature for 2 hours.

Step 3: alkylation: To the solution [2] of step 2, 6.23 ml (0.1 moi) of methyl iodide was added. The mixture was stirred for 1 hour at room temperature and filtered. The resulting precipitate was successively crystallized from water and dried in air. The reaction scheme is depicted below in Scheme 1.

SCHEME 1

The yield was 9.87 g (69%).

Physical and chemical characteristics of the sodium salt of 7-methylthio-3-nitro

[1, 2, 4] triazolo [5,1-c] [1, 2, 4] triazin -4 (1H)-one sodium salt: yellow crystalline powder, soluble in water, acetone, dimethylsulfoxide, dimethylformamide. insoluble in chloroform; Tmelt = 300°C, H NMR spectrum, δ, ppm, solvent DMSO-d6: 2.62 (3H, s, SCH3); IR spectrum, n, cm“1: 3535 (OH), 1649 (C=0), 1505 (N02), 1367 (N02); found.. %: C – 20.86, H 2.51 , N 29.28;

C5H;N6Na05S; Calculated, %: C – 20.98, H 2.47, N 29.36.

Example 2: Synthesis of the sodium salt of 7-methylthio-3-nitro [1, 2, 4] triazolo [5,1-c] [1, 2, 4] triazin -4 (1H)-one sodium salt

In this example the synthesis comprises 3 steps: in the first step 5-amino-3-mercapto-1.2,4-triazole (i.e. compound (B)) was prepared by condensation of aminoguanidine with a thio-derivative (thio ester) of formic acid, HC(=0)S-R, wherein -R was: methyl. In the second step 5-amino-3-mercapto-1 , 2,4-triazole was converted to the corresponding diazonium salt. In the third step this diazonium salt was reacted with an a-nitroester, 2-nitroacetoacetic ester, to form the 7-methylthio-3-nitro [1, 2, 4] triazolo [5,1-c] [1, 2, 4] triazin -4 (1H)-one. The different steps are explained in more detail below.

Step 1 : Synthesis of compound (B): In a reaction flask equipped with a stirrer, reflux condenser, under inert gas (nitrogen, argon), 20 g (0.1 mol) of aminoguanidine and 7.6 g (0.1 mol) methylthio-formate was added to 400 ml of absolute pyridine. The reaction mixture was boiled for 4 hours at 115°C.

Subsequently the reaction mixture was transferred into distilled water and washed several times with water. The washed mixture was dried over a Nutsche filter under vacuum. Recrystallization was carried out from ethanol. The reaction scheme is depicted below in Scheme 2.

SCHEME 2

The yield was 19.3 g (70%)

Step 2: Diazotation of compound (B): A solution (solution [3], herein after) was prepared of 26 g (0.1 mol) of 5-amino-3-mercapto-1 ,2,4-triazole (as obtained in step 1) in 32 ml of nitric acid (0.1 mol) and 200 ml of water. The solution was mixed and cooled to -5°C. In a separate recipient, a 0.1 M solution of sodium nitrite was prepared by dissolving 16 g of sodium nitrite in 100 ml of water. The sodium nitrite solution was put in the freezer until there was ice formation and subsequently the ice was crushed. Thereafter, the solution [3] and the sodium nitrite crushed ice were transferred into a 1 L reactor and stirred for 1 hour while the reactor temperature was kept at 0°C. The low temperature and the fact that the two reaction components are in different phases (i.e. liquid and solid) ensured a slow gradual progress of diazotization reaction at the phase interface. The end of the diazotization process was controlled by a iodine starch test (proof of the absence of sodium nitrite in a free state).

The rea

SCHEME 3

Step 3: Condensation of the diazonium compound with an α-nitroester: A solution (solution [4], herein after) was prepared by mixing 17.5 g of methyl 2- nitro-acetoacetate in 300 mL of isopropanoi. The solution [4] was mixed with the diazonium salt of step 2. The mixture was cooled to 0°C. At 0°C, a 10% sodium hydroxide solution was added to the reaction mixture (to neutralize residual nitrite and acetate) until there was a marked alkaline reaction (pH between 8 and 9). The temperature was controlled and was kept below +5°C. The resulting mixture was stirred for 1 hour. The precipitate was filtered off and dried in air. The yield was 78%.

The reaction scheme is depicted in Scheme 4

SCHEME 4

Example 3: Synthesis of the sodium salt of 7-methylthio-3-nitro [1, 2, 4] triazolo [5,1-c] [1, 2, 4] triazin -4 (1H)-one

The synthesis of the sodium salt of 7-methylthio-3-nitro-1 ,2,4-triazolo [5,1-c]-1 ,2,4-triazin-7-one may be carried out as in Example 2, only in step 2 the aqueous alcohol solution is replaced by an alcohol with alkali (such as sodium hydroxide). The yield of the antiviral compound (A) (sodium salt of 7-methylthio-3-nitro [1 2, 4] triazolo [5,1-c] [1 , 2. 4] triazin -4 (1 H)-one) may increase to 83%. The reaction scheme is depicted below in Scheme 5:

SCHEME 5

PATENT

WO2017144708

Process for the preparation of 7-thio-substituted-3-nitro-1,2,4-triazolo[5,1-c]-1,2,4-triazin-4(1H)-one i.e. riamilovir sodium dihydrate is claimed. Also claimed are use of triazolo compounds for the treatment of ssRNA virus infections such as Zika virus and flavivirus, ssRNA viruses different from the Influenza A and Influenza B viruses and compositions comprising them. Along with concurrently published WO2017144709 claiming similar derivatives. Represents new area of interest from Doring International Gmbh and the inventors on this moiety.

Example 1 : One pot synthesis of the sodium salt of 7-methylthio-3-nitro [1, 2, 4] triazolo [5,1 -cj [1, 2, 4] triazin -4 (1H)-one

Step 1: Diazotization of compound (B): A solution (solution [1], herein after) was prepared of 5.8 g (0.05 M) of 5-amino-3-mercapto-1 ,2,4-triazole in 6.7 ml of nitric acid (15 M) and 12 ml of water. Said solution [1] was refrigerated to -7°C . Then a 40% sodium nitrite solution was added to the solution [1] in portions of 0.5 mL to obtain a total amount of sodium nitrite equal to 3.8 g in the mixture.

Step 2: Condensation of diazonium compound with an a-nitroester: To the resulting diazonium salt of step 1 , 8.54 ml of diethyl nitromalonate was added. After holding for five minutes, a cooled solution of sodium hydroxide was slowly added dropwise to the reaction mixture until the pH was between pH 9 and pH 10 (solution [2], herein after). The resulting solution [2] was stirred at 0°C for 1 hour and at room temperature for 2 hours.

Step 3: alkylation: To the solution [2] of step 2, 6.23 ml (0.1 mol) of methyl iodide was added. The mixture was stirred for 1 hour at room temperature and

filtered. The resulting precipitate was successively crystallized from water and dried in air. The reaction scheme is depicted below in Scheme 1.

SCHEME 1

The yield was 9.87 g (69%).

Physical and chemical characteristics of the sodium salt of 7-methylthio-3-nitro

[1, 2, 4] triazolo [5,1-c] [1, 2, 4] triazin -4 (1H)-one sodium salt: yellow crystalline powder, soluble in water, acetone, dimethylsulfoxide, dimethylformamide, insoluble in chloroform; Tmei, = 300°C, 1H NMR spectrum, δ, ppm, solvent DMSO-d6: 2.62 (3H, s, SCH3); IR spectrum, n, cm“1: 3535 (OH), 1649 (CO), 1505 (N02), 1367 (N02); found, %: C – 20.86, H 2.51 , N 29.28; C5H7N6Na05S; Calculated, %: C – 20.98, H 2.47, N 29.36.

Example 2: Synthesis of the sodium salt of 7-methylthio-3-nitro [1, 2,

4] triazolo [5,1-c] [1, 2, 4] triazin -4 (1H)-one sodium salt

In this example the synthesis comprises 3 steps: in the first step 5-amino-3-mercapto-1 ,2,4-triazole (i.e. compound (B)) was prepared by condensation of aminoguanidine with a thio-derivative (thio ester) of formic acid, HC(=0)S-R, wherein -R was: methyl. In the second step 5-amino-3-mercapto-1 ,2,4-triazole was converted to the corresponding diazonium salt. In the third step this diazonium salt was reacted with an a-nitroester, 2-nitroacetoacetic ester, to form the 7-methylthio-3-nitro [1, 2, 4] triazolo [5,1-c] [1, 2, 4] triazin -4 (1H)-one. The different steps are explained in more detail below.

Step 1 : Synthesis of compound (B): In a reaction flask equipped with a stirrer, reflux condenser, under inert gas (nitrogen, argon), 20 g (0.1 mo!) of

aminoguanidine and 7.6 g (0.1 mol) methylthio-formate was added to 400 ml of absolute pyridine. The reaction mixture was boiled for 4 hours at 115°C. Subsequently the reaction mixture was transferred into distilled water and washed several times with water. The washed mixture was dried over a Nutsche filter under vacuum. Recrystallization was carried out from ethanol. The reaction scheme is depicted below in Scheme 2.

SCHEME 2

The yield was 19.3 g (70%)

Step 2: Diazotation of compound (B): A solution (solution [3], herein after) was prepared of 26 g (0.1 mol) of 5-amino-3-mercapto-1 ,2,4-triazole (as obtained in step 1 ) in 32 ml of nitric acid (0.1 mol) and 200 ml of water. The solution was mixed and cooled to -5°C. In a separate recipient, a 0.1 M solution of sodium nitrite was prepared by dissolving 16 g of sodium nitrite in 100 ml of water. The sodium nitrite solution was put in the freezer until there was ice formation and subsequently the ice was crushed. Thereafter, the solution [3] and the sodium nitrite crushed ice were transferred into a 1 L reactor and stirred for 1 hour while the reactor temperature was kept at 0°C. The low temperature and the fact that the two reaction components are in different phases (i.e. liquid and solid) ensured a slow gradual progress of diazotization reaction at the phase interface. The end of the diazotization process was controlled by a iodine starch test (proof of the absence of sodium nitrite in a free state).

The rea

SCHEME 3

Step 3: Condensation of the diazonium compound with an a-nitroester: A solution (solution [4], herein after) was prepared by mixing 17.5 g of methyl 2-nitro-acetoacetate in 300 mL of isopropanol. The solution [4] was mixed with the diazonium salt of step 2. The mixture was cooled to 0°C. At 0°C, a 10% sodium hydroxide solution was added to the reaction mixture (to neutralize residual nitrite and acetate) until there was a marked alkaline reaction (pH between 8 and 9). The temperature was controlled and was kept below +5°C. The resulting mixture was stirred for 1 hour. The precipitate was filtered off and dried in air. The yield was 78%.

The reaction scheme is depicted in Scheme 4

SCHEME 4

Example 3: Synthesis of the sodium salt of 7-methylthio-3-nitro [1, 2, 4] triazolo [5,1-c] [1, 2, 4] triazin -4 (1H)-one

The synthesis of the sodium salt of 7-methy I th io-3-nitro- 1 ,2, 4-triazolo [5,1-c]-1 ,2,4-triazin-7-one may be carried out as in Example 2, only in step 2 the aqueous alcohol solution is replaced by an alcohol with alkali (such as sodium hydroxide). The yield of the antiviral compound (A) (sodium salt of 7-methylthio-3-nitro [1 2, 4] triazolo [5,1-c] [1 , 2, 4] triazin -4 (1 H)-one) may increase to 83%.

The reaction scheme is depicted below in Scheme 5:

SCHEME 5

References

  1. Jump up^ Rusinov VL, Sapozhnikova IM, Ulomskii EN, Medvedeva NR, Egorov VV, Kiselev OI, Deeva EG, Vasin AV, Chupakhin ON. Nucleophilic substitution of nitro group in nitrotriazolotriazines as a model of potential interaction with cysteine-containing proteins. Chemistry of Heterocyclic Compounds 2015;51(3):275-280. doi 10.1007/s10593-015-1695-4
  2. Jump up^ Loginova SIa, Borisevich SV, Maksimov VA, Bondarev VP, Kotovskaia SK, Rusinov VL, Charushin VN. Investigation of triazavirin antiviral activity against influenza A virus (H5N1) in cell culture. (Russian) Antibiotiki i Khimioterapiia. 2007;52(11-12):18-20. PMID 19275052
  3. Jump up^ Karpenko I, Deev S, Kiselev O, Charushin V, Rusinov V, Ulomsky E, Deeva E, Yanvarev D, Ivanov A, Smirnova O, Kochetkov S, Chupakhin O, Kukhanova M. Antiviral properties, metabolism, and pharmacokinetics of a novel azolo-1,2,4-triazine-derived inhibitor of influenza A and B virus replication. Antimicrobial Agents and Chemotherapy. 2010 May;54(5):2017-22. doi: 10.1128/AAC.01186-09 PMID 20194696
  4. Jump up^ Kiselev OI, Deeva EG, Mel’nikova TI, Kozeletskaia KN, Kiselev AS, Rusinov VL, Charushin VN, Chupakhin ON. A new antiviral drug Triazavirin: results of phase II clinical trial. (Russian). Voprosy Virusologii. 2012 Nov-Dec;57(6):9-12. PMID 23477247
  5. Jump up^ Loginova SIa, Borisevich SV, Rusinov VL, Ulomskiĭ UN, Charushin VN, Chupakhin ON. Investigation of Triazavirin antiviral activity against tick-borne encephalitis pathogen in cell culture. (Russian). Antibiotiki i Khimioterapiia. 2014;59(1-2):3-5. PMID 25051708
  6. Jump up^ “Target: Ebola”. Pravda. Retrieved 18 January 2015.
  7. Jump up^ “Yekaterinburg pharmacies to sell domestic antiviral drug”. Retrieved 18 January 2015.
  8. Jump up^ “Ebola crisis: Vaccine ‘too late’ for outbreak. BBC News, 17 October 2014”BBC News.
  9. Jump up^ Kukil Bora. Russia Will Begin Testing Triazavirin, Used For Lassa Fever, And Other Drugs On Ebola: Health Ministry. International Business Times, 12 November 2014
  10. Jump up^ Darya Kezina. New antiviral drug from Urals will help fight Ebola and other viruses. Russia Beyond the Headlines, 12 November 2014
Triazavirin
Triazavirin.svg
Legal status
Legal status
Identifiers
CAS Number
PubChem CID
ChemSpider
ECHA InfoCard 100.217.074
Chemical and physical data
Formula C5H4N6O3S
Molar mass 228.189
3D model (JSmol)

///////////riamilovir sodium dihydrate, Riamilovir , ANTIVIRAL, Triazavirin, Flavivirus infection,  Zika virus infection

O=C1N2C(NN=C1[N+]([O-])=O)=NC(SC)=N2

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Doravirine, MK-1439


Doravirine.svg

Image for unlabelled figure

Doravirine.png

Doravirine, MK-1439……….. AN ANTIVIRAL

3-Chloro-5-({1-[(4-methyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-3-yl)methyl]-2-oxo-4-(trifluoromethyl)-1,2-dihydro-3-pyridinyl}oxy)benzonitrile

Benzonitrile, 3-chloro-5-[[1-[(4,5-dihydro-4-methyl-5-oxo-1H-1,2,4-triazol-3-yl)methyl]-1,2-dihydro-2-oxo-4-(trifluoromethyl)-3-pyridinyl]oxy]-

3-chloro-5-({1-[(4-methyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-3-yl)methyl]-2-oxo-4-(trifluoromethyl)-1,2-dihydropyridin-3-yl}oxy)benzonitrile

(3-Chloro-5-((1-((4-methyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-3-yl)methyl)-2-oxo-4-(trifluoromethyl)-1,2-dihydropyridin-3-yl)oxy)benzonitrile)

1338225-97-0 CAS

MF  C17H11ClF3N5O3
MW 425.7  Merck Sharp & Dohme Corp

Merck Frosst Canada Ltd. INNOVATOR

Jason Burch, Bernard Cote, Natalie Nguyen,Chun Sing Li, Miguel St-Onge, Danny Gauvreau,

Reverse transcriptase inhibitor

UNII:913P6LK81M

  • Originator Merck & Co
  • Class Antiretrovirals; Nitriles; Pyridones; Small molecules; Triazoles
  • Mechanism of Action Non-nucleoside reverse transcriptase inhibitors
  • Phase III HIV-1 infections

Most Recent Events

  • 16 Jul 2016 No recent reports of development identified for phase-I development in HIV-1-infections(Monotherapy, Treatment-naive) in Germany (PO, Tablet)
  • 01 Jun 2016 Merck Sharp & Dohme completes a phase I pharmacokinetics trial in subjects requiring methadone maintenance therapy in USA (PO, Tablet) (NCT02715700)
  • 01 May 2016 Merck completes a phase I trial in severe renal impairment in USA (NCT02641067)

SYNTHESIS COMING………

WO  2015084763

STR1

CONTD………………………

STR1

img_pgene01.jpg

SPECTRAL DATA

19F DMSOD6
STR1

13C NMR DMSOD6

STR1

1H NMR DMSOD6

STR1

3-chloro-5-((2-oxo-1-((5-oxo-4,5-dihydro-1H-1,2,4-triazol-3-yl)methyl)-4-(trifluoromethyl)-1,2-dihydropyridin-3-yl)oxy)benzonitrile.

1H NMR (400 MHz, DMSO-d6) δ 11.47 (br. s., 1H), 11.40 (s, 1H), 7.93 (d, J = 7.3 Hz, 1H), 7.75 (t, J =1.5 Hz, 1H), 7.58 (dd, J = 1.2, 2.3 Hz, 1H), 7.51 (t, J = 2.1 Hz, 1H), 6.66 (d, J = 7.3 Hz, 1H), 5.02 (s, 2H)

13C NMR (101 MHz, DMSO-d6) δ 157.25, 156.20, 155.97, 142.52, 140.09 (q, JC-F = 2.0 Hz), 137.74,134.97, 130.17 (q, JC-F = 31.2 Hz), 126.53, 121.70 (q, JC-F = 274.7 Hz), 121.16, 118.37, 116.96, 113.70,99.96 (q, JC-F = 4.0 Hz), 44.90

19F NMR (376 MHz, DMSO-d6) δ -62.24 (s, 1F)
HRMS [M + H]+ for C16H10ClF3N5O3 calcd, 412.0419; found, 412.0415.
mp 148.46-156.11 °C

REF Org. Process Res. Dev., Article ASAP, DOI: 10.1021/acs.oprd.6b00163

http://pubs.acs.org/doi/suppl/10.1021/acs.oprd.6b00163

STR1

str2

Doravirine (MK-1439) is a non-nucleoside reverse transcriptase inhibitor under development by Merck & Co. for use in the treatment of HIV/AIDS. Doravirine demonstrated robust antiviral activity and good tolerability in a small clinical study of 7-day monotherapy reported at the 20th Conference on Retroviruses and Opportunistic Infections in March 2013. Doravirine appeared safe and generally well-tolerated with most adverse events being mild-to-moderate.[2][3]

Highly active antiretroviral therapy (HAART) is the standard of care for the treatment of HIV infection. Typically, this protocol recommends the combination of two nucleoside reverse-transcriptase inhibitors (NRTIs) with either a non-nucleoside reverse-transcriptase inhibitor (NNRTI), a ritonavir-boosted protease inhibitor or an integrase inhibitor. 

NNRTI-based combinations have become first-line therapy mainly because of their demonstrated efficacies, convenient dosing regimen and relatively low toxicities. These inhibitors block the polymerase activity of the HIV reverse transcriptase by binding to an allosteric hydrophobic pocket adjacent to the active site. Efavirenz (1, ) is a first generation NNRTI that has been conveniently co-formulated with NRTIs tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) as a once-a-day fixed-dose combination (Atripla®). Although recommended for the therapy of treatment-naïve patients, efavirenz suffers from neurocognitive side effects, teratogenicity and exacerbation of hyperlipidemia. Moreover, the low barrier to genetic resistance of first generation NNRTIs led to the emergence of resistant viruses bearing mutations K103N and Y181C in patients failing therapy.

Structures of marketed and lead NNRTIs.

Figure .

Structures of marketed and lead NNRTIs.

Second generation NNRTIs etravirine (2) and rilpivirine (3) efficiently suppress the replication of the K103N resistant mutants as shown by an improved activity in cell culture assays . Etravirine (200 mg, bid) is approved for use in treatment-experienced adult patients with multi-drug resistance. With an improved pharmacokinetic profile, the close analog rilpivirine (25 mg, qd) was recently approved for use in treatment-naïve patients. Phase III data reveal that at the 96-week point, a rilpivirine/truvada®  combination was better tolerated than efavirenz/truvada®. However, the virologic failure rate was twice as high for rilpivirine (14%) than it was for efavirenz (8%). For patients with viral load greater than 500,000 copies/mL, the response rate is 62% (rilpivirine) versus 81% (efavirenz). As a result, rilpivirine is not recommended for treating HIV patients with viral load >500,000 copies/mL. This difference in treatment durability could be explained by the much higher ratio of trough concentration over the antiviral activity for efavirenz versus rilpivirine.

Investigational next-generation, non-nucleoside reverse transcriptase inhibitor (NNRTI), at the 21st Conference on Retroviruses and Opportunistic Infections (CROI). Interim data demonstrating potent antiretroviral (ARV) activity for four doses (25, 50, 100 and 200 mg) of once-daily, oral doravirine in combination with tenofovir/emtricitabine in treatment-naïve, HIV-1 infected adults after 24 weeks of treatment were presented during a late-breaker oral session. Based on these findings as well as other data from the doravirine clinical program, Merck plans to initiate a Phase 3 clinical trial program for doravirine in combination with ARV therapy in the second half of 2014.

“Building on our long-standing commitment to the HIV community, Merck continues to evaluate new candidates we believe have the potential to make a meaningful difference in the lives of HIV patients,” said Daria Hazuda, Ph.D., vice president, Infectious Diseases, Merck Research Laboratories. “We look forward to advancing doravirine into Phase 3 clinical trials in the second half of 2014.”

Doravirine Clinical Data

This randomized, double-blind clinical trial examined the safety, tolerability and efficacy of once-daily doravirine (25, 50, 100 and 200 mg) in combination with once-daily tenofovir/emtricitabine versus efavirenz (600 mg), in treatment-naïve, HIV-1 infected patients. The primary efficacy analysis was percentage of patients achieving virologic response (< 40 copies/mL).

At 24 weeks, doravirine doses of 25, 50, 100, and 200 mg showed virologic response rates consistent with those observed for efavirenz at a dose of 600 mg. All treatment groups showed increased CD4 cell counts.

Proportion of Patients with Virologic
Response at 24 weeks (95% CI)

Mean CD4 Change
from Baseline (95% CI)

Treatment* Dose (mg) n/N

% <40
copies/mL

cells/μL

Doravirine 25 32/40 80.0 (64.6, 90.9) 158 (119, 197)
50 32/42 76.2 (60.5, 87.9) 116 (77, 155)
100 30/42 71.4 (55.4, 84.3) 134 (100, 167)
200 32/41 78.0 (62.4, 89.4) 141 (96, 186)
Efavirenz 600 27/42 64.3 (48.0, 78.4) 121 (73, 169)
Missing data approach: Non-completer = Failure Observed Failure

*In combination with tenofovir/emtricitabine

The incidence of drug-related adverse events was comparable among the doravirine-treated groups. The overall incidence of drug-related adverse events was lower in the doravirine-treated groups (n=166) than the efavirenz-treated group (n=42), 35 percent and 57 percent, respectively. The most common central nervous system (CNS) adverse events at week 8, the primary time point for evaluation of CNS adverse experiences, were dizziness [3.0% doravirine (overall) and 23.8% efavirenz], nightmare [1.2% doravirine (overall) and 9.5% efavirenz], abnormal dreams [9.0% doravirine (overall) and 7.1% efavirenz], and insomnia [5.4% doravirine (overall) and 7.1% efavirenz].

Based on the 24-week data from this dose-finding study, a single dose of 100 mg doravirine was chosen to be studied for the remainder of this study, up to 96 weeks.

About Doravirine

DORAVIRINE

Doravirine, also known as MK-1439, is an investigational next-generation, NNRTI being evaluated by Merck for the treatment of HIV-1 infection. In preclinical studies, doravirine demonstrated potent antiviral activity against HIV-1 with a characteristic profile of resistance mutations selected in vitro compared with currently available NNRTIs. In early clinical studies, doravirine demonstrated a pharmacokinetic profile supportive of once-daily dosing and did not show a significant food effect.

Merck’s Commitment to HIV

For more than 25 years, Merck has been at the forefront of the response to the HIV epidemic, and has helped to make a difference through our proud legacy of commitment to innovation, collaborating with the community, and expanding global access to medicines. Merck is dedicated to applying our scientific expertise, resources and global reach to deliver healthcare solutions that support people living with HIV worldwide.

About Merck

Today’s Merck is a global healthcare leader working to help the world be well. Merck is known as MSD outside the United States and Canada. Through our prescription medicines, vaccines, biologic therapies, and consumer care and animal health products, we work with customers and operate in more than 140 countries to deliver innovative health solutions. We also demonstrate our commitment to increasing access to healthcare through far-reaching policies, programs and partnerships. For more information, visit www.merck.com and connect with us on TwitterFacebook and YouTube.

PATENT

WO 2014089140

The compound 3 -chloro-5-( { 1 – [(4-methyl-5 -oxo-4,5 -dihydro- 1 H- 1 ,2,4-triazol-3 – yl)methyl]-2-oxo-4-(trifluoromethyl)-l,2-dihydropyridin-3-yl}oxy)benzonitrile has the following chemical structure.

Figure imgf000017_0001

Anhydrous 3 -chloro-5-( { 1 – [(4-methyl-5 -oxo-4,5 -dihydro- 1 H- 1 ,2,4-triazol-3 -yl)methyl] -2-oxo-4- (trifluoromethyl)-l,2-dihydropyridin-3-yl}oxy)benzonitrile is known to exist in three crystalline forms – Form I, Form II and Form III. The differential scanning calorimetry (DSC) curve for crystalline anhydrous Form II shows an endotherm with an onset at 230.8° C, a peak maximum at 245.2°C, and an enthalpy change of 3.7 J/g, which is due to polymorphic conversion of anhydrous Form II to anhydrous Form I, and a second melting endotherm with an onset at 283.1°C, a peak maximum at 284.8°C, and an enthalpy change of 135.9 J/g, due to melting of Anhydrous Form I. Alternative production and the ability of this compound to inhibit HIV reverse transcriptase is illustrated in WO 201 1/120133 Al, published on October 6, 201 1, and US 201 1/0245296 Al, published on October 6, 201 1, both of which are hereby incorporated by reference in their entirety.

The process of the present invention offers greater efficiency, reduced waste, and lower cost of goods relative to the methods for making the subject compounds existing at the time of the invention. Particularly, the late stage cyanation and methylation steps are not required.

The following examples illustrate the invention. Unless specifically indicated otherwise, all reactants were either commercially available or can be made following procedures known in the art. The following abbreviations are used:

EXAMPLE 1

Figure imgf000018_0001
Figure imgf000018_0002

Step 1

Figure imgf000018_0003

1 2

3-(Chloromethyl)-l-(2-methoxypropan-2-yl)-4-methyl-lH-l,2,4-triazol-5(4H)-one (2): A

100 ml round bottom flask equipped with stir bar and a nitrogen inlet was charged with 1 (5 g, 33.9 mmol) and (lS)-(+)-10-camphorsulfonic acid (0.39 g, 1.694 mmol) at ambient temperature. After 2,2-dimethoxy propane (36.0 g, 339 mmol) was charged at ambient temperature, the resulting mixture was heated to 45°C. The resulting mixture was stirred under nitrogen at 45°C for 18 hours and monitored by HPLC for conversion of the starting material (< 5% by HPLC). After the reaction was completed, the batch was taken on to the next step without further workup or isolation. ‘H NMR (CDCI3, 500 MHz): 4.45 (s, 2H), 3.35 (s, 3H), 3.21 (s, 3H), 1.83 (s, 6H).

Step 2

Figure imgf000019_0001

3-Fluoro-l-((l-(2-methoxypropan-2-yl)-4-methyl-5-oxo-4,5-dihydro-lH-l,2,4-triazol-3- yl)methyl)-4-(trifluoromethyl)pyridin-2(lH)-one (3): A mixture of 2 (100 mg, 93.1% purity, 0.49 mmol), pyridone (1 17 mg, 97.6% purity, 0.49 mmol) and K2CO3 (82 mg, 0.59 mmol) in DMF (0.5 ml) was aged with stirring at ambient temperature for 3h. After the reaction was completed, the batch was taken on to the next step without further work up or isolation.

Step 3

Figure imgf000019_0002

3-Chloro-5-((l-((l-(2-methoxypropan-2-yl)-4-methyl-5-oxo-4,5-dihydro-lH-l,2,4-triazol-3- yl)methyl)-2-oxo-4-(trifluoromethyl)-l,2-dihydropyridin-3-yl)oxy)benzonitrile (4): To a mixture of compound 3 in DMF (reaction mixture from the previous step) was added 3-chloro-5- hydroxybenzonitrile (1.77 g, 1 1.5 mmol) at ambient temperature. The resulting mixture was then heated to 95-100°C and held for 20 hours.

Upon completion (typically 18-20 hours), the reaction was cooled to room temperature, diluted with ethyl acetate and washed with water. The aqueous cut was back extracted with ethyl acetate. The organic layers were combined and then concentrated to an oil. MeOH (80 ml) was added and the resulting slurry was taken on to the next step. XH NMR (CDC13, 500 MHz): 7.60 (d, IH), 7.42 (s, IH), 7.23 (s, IH), 7.12 (s, IH), 6.56 (d, IH), 5.14 (s, 2H), 3.30 (s, 3H), 3.22 (s, 3H), 1.82 (s, 6H).

Step 4

Figure imgf000020_0001

4 5

3-Chloro-5-((l-((4-methyl-5-oxo-4,5-dihydro-lH-l,2,4-triazol-3-yl)methyl)-2-oxo-4- (trifluoromethyl)-l,2-dihydropyridin-3-yl)oxy)benzonitrile (5): To a solution of 4 (5.74 g., 1 1.53 mmol) in MeOH (from previous step) was added concentrated hydrochloric acid (lml, 12.18 mmol) at ambient temperature. The resulting mixture was agitated for 1 hour at room temperature.

The resulting solids were collected by filtration and dried under a nitrogen sweep, providing 5 as a white solid (2.63 g, 46% yield): XH NMR (DMSO, 400 MHz): 1 1.74 (S, IH), 7.92 (d, IH), 7.76 (s, IH), 7.61 (s, IH), 7.54 (s, IH), 6.69 (d, IH), 5.15 (s, 2H), 3.10 (s, 3H)

EXAMPLE 2

Figure imgf000021_0001

Step 1

Figure imgf000021_0002

Phenyl methylcarbamate: 40% Aqueous methylamine (500 g, 6.44 mol) was charged to a 2 L vessel equipped with heat/cool jacket, overhead stirrer, temperature probe and nitrogen inlet. The solution was cooled to -5 °C. Phenyl chloroformate (500.0 g, 3.16 mol) was added over 2.5 h maintaining the reaction temperature between -5 and 0 °C. On complete addition the white slurry was stirred for lh at ~0 °C.

The slurry was filtered, washed with water (500 mL) and dried under 2 sweep overnight to afford 465g (96%> yield) of the desired product as a white crystalline solid; 1H NMR (CDCI3, 500 MHz): δ 7.35 (t, J = 8.0 Hz, 2H), 7.19 (t, J = 8.0 Hz, 1H), 7.12 (d, J = 8.0 Hz, 2H), 4.95 (br s, 1H), 2.90 (d, J = 5 Hz, 3H).

Step 2

Figure imgf000022_0001

2-(2-Hydroxyacetyl)-N-methylhydrazinecarboxamide: Part A: Phenyl methylcarbamate (300 g, 1.95 mol) was charged to a 2 L vessel with cooling jacket, overhead stirrer, temperature probe, reflux condenser and nitrogen inlet. IPA (390 mL) was added at 23 °C. Hydrazine hydrate (119 g, 2.33 mol) was added and the slurry heated to 75 °C for 6 h.

Part B: On complete reaction (>99% conversion by HPLC), IPA (810 mL) and glycolic acid (222 g, 2.92 mol) were added and the mixture stirred at 83-85 °C for 10-12 h. The reaction mixture is initially a clear colorless solution. The mixture is seeded with product (0.5 g) after 4h at 83-85 °C. The slurry was slowly cooled to 20 °C over 2h and aged for lh.

The slurry was filtered and washed with IPA (600 mL). The cake was dried under 2 sweep to afford 241.8g (81% yield) of the desired product as a white crystalline solid: XH NMR (D20, 500 MHz): δ 4.11 (s, 2H), 2.60 (s, 3H).

Step 3

Figure imgf000022_0002

3-(Hydroxymethyl)-4-methyl-lH-l,2,4-triazol-5(4H)-one: 2-(2-Hydroxyacetyl)-N- methylhydrazinecarboxamide (130 g @ ~95wt%, 0.84 mol), w-propanol (130 mL) and water (130 mL) were charged to a 1 L vessel with jacket, overhead stirrer, temperature probe, reflux condenser and nitrogen inlet. Sodium hydroxide (pellets, 16.8 g, 0.42 mol) was added and the slurry warmed to reflux for 3h. The reaction mixture was cooled to 20 °C and the pH adjusted to 6.5 (+/- 0.5) using cone hydrochloric acid (28.3 mL, 0.34 mol). Water was azeotropically removed under vacuum at 40-50 °C by reducing the volume to -400 mL and maintaining that volume by the slow addition of n-propanol (780 mL). The final water content should be <3000 ug/mL. The resultant slurry (~ 400 mL) was cooled to 23 °C and heptane (390 ml) was added. The slurry was aged lh at 23 °C, cooled to 0 °C and aged 2h. The slurry was filtered, the cake washed with 1 :2 n-PrOH/heptane (100 mL) and dried to provide 125g (85% yield) of an off- white crystalline solid. The solid is ~73 wt% due to residual inorganics (NaCl): ‘H NMR (CD3OD, 500 MHz): δ 3.30 (s, 3H), 4.46 (s, 2H).

Step 4

Figure imgf000023_0001

3-(Chloromethyl)-4-methyl-lH-l,2,4-triazol-5(4H)-one (1): A mixture of 3- (Hydroxymethyl)-4-methyl-lH-l,2,4-triazol-5(4H)-one (54 g, at 73wt%, 307 mmol) in ethyl acetate (540 mL) was stirred at 45 °C. SOCI2 (26.9 mL, 369 mmol) was added over 30-45 min and aged at 50 °C for 2h. Monitor reaction progress by HPLC. On complete reaction (>99.5% by area at 210nm.), the warm suspension was filtered and the filter cake (mainly NaCl) was washed with ethyl acetate (108 mL). The combined filtrate and wash were concentrated at 50-60 °C under reduced pressure to approximately 150 mL. The resulting slurry was cooled to -10 °C and aged lh. The slurry was filtered and the filter cake washed with ethyl acetate (50 mL). The cake was dried under 2 sweep to afford 40. lg (86% yield) of the desired product as a bright yellow solid: ‘H NMR (CD3OD, 500 MHz): δ 3.30 (s, 3H), 4.58 (s, 2H).

EXAMPLE 3

Figure imgf000023_0002

3-fluoro-4-(trifluoromethyl)pyridin-2(lH)-one (2): To a 250 ml round bottom flask equipped with overhead stirring and a nitrogen inlet was added a mixture of sulfuric acid (24.31 ml, 437 mmol) and water (20.00 ml). To this was added 2,3-difluoro-4-(trifluoromethyl)pyridine (6.83 ml, 54.6 mmol) and the mixture was heated to 65 °C and stirred for 4 h. By this time the reaction was complete, and the mixture was cooled to room temperature. To the flask was slowly added 5M sodium hydroxide (43.7 ml, 218 mmol), maintaining room temperature with an ice bath. The title compound precipitates as a white solid during addition. Stirring was maintained for an additional lh after addition. At this time, the mixture was filtered, the filter cake washed with 20 mL water, and the resulting white solids dried under nitrogen. 3-fluoro-4- (trifluoromethyl)pyridin-2(lH)-one (2) was obtained as a white crystalline solid (9.4g, 51.9 mmol, 95 % yield): ¾ NMR (CDC13, 400 MHz): 12.97 (br s, 1H), 7.36 (d, 1H), 6.44 (m, 1H).

EXAMPLE 4

Step 1 – Ethyl Ester Synthesis Experimental Procedure;

Figure imgf000024_0001

Ethyl 2-(3-chloro-5-cyanophenoxy)acetate (A): A 1L round bottom flask equipped with overhead stirring was charged with 3-chloro-5-hydroxybenzonitrile (50.0 g, 98 wt% purity, 319 mmol) and 15% aqueous DMF (200 mL DMF + 35.5 mL FLO). To the resulting solution was added diisopropylethylamine (61.3 mL, 99.0% purity, 1.1 equiv) and ethyl 2-bromoacetate (35.7 g, 98% purity, 1.15 equiv) at ambient temperature. The resulting solution was warmed to 50°C under nitrogen and aged for 12 h. Upon completion of the reaction the batch was cooled to 0- 5°C. To the clear to slightly cloudy solution was added 5% seed (3.8g, 16.0 mmol). H20 (64.5mL) was added to the thin suspension via syringe pump over 3h while maintaining the temp at 0-5 °C. Additional FLO (200mL) was added over lh while maintaining the temp at 0-5 °C. The final DMF/FLO ratio is 1 : 1.5 (10 vol). The resulting slurry was typically aged lh at 0-5 °C. The batch was filtered and the cake slurry washed with 2: 1 DMF/water (150 mL, 3 vol), followed by water (200 mL, 4 vol). The wet cake was dried on the frit with suction under a nitrogen stream at 20-25 °C; note: heat must not be applied during drying as product mp is 42 °C. The cake is considered dry when H20 is <0.2%. Obtained 73.4 g ethyl ester as a light tan solid, 96% yield (corrected), 99.5 LCAP: XH NMR (CDC13, 400 MHz) δ = 7.29 (s, 1H), 7.15 (s, 1H), 7.06 (s, 1H), 4.67 (s, 2H), 4.32 (q, 2H), 1.35 (t, 3H) ppm. Step 2 – Pyridone Synthesis

Synthetic Scheme; batch

TEA, TFAA, 10 °C;

then MeOH, rt

Figure imgf000025_0001

[isolated solid, A] [PhMe exit stream, B]

Figure imgf000025_0002

[PhMe/MeOH solution, C] [PhMe/MeOH/NH3 solution, D] [isolated solid, E]

Experimental Procedures;

Aldol Condensation, Ester A to Diene C

(2E/Z,4E)-Ethyl 2-(3-chloro-5-cyanophenoxy)-5-ethoxy-3-(trifluoromethyl)penta-2,4- dienoate (C): Ester A (25.01 g, 104.4 mmol, 1.00 equiv) was charged to toluene (113.43 g, 131 mL, 5.24 vol) and 4-ethoxy-l, l, l-trifluoro-3-buten-2-one (26.43 g, 157.2 mmol, 1.51 equiv) was added.

The flow reactor consisted of two feed solution inlets and an outlet to a receiving vessel. The flow reactor schematic is shown in Figure 1.

The ester solution was pumped to one flow reactor inlet. Potassium tert-pentoxide solution was pumped to the second reactor inlet. Trifluoroacetic anhydride was added continuously to the receiver vessel. Triethylamine was added continuously to the receiver vessel. The flow rates were: 13 mL/min ester solution, 7.8 mL/min potassium tert-pentoxide solution, 3.3 mL/min trifluoroacetic anhydride and 4.35 mL/min triethylamine.

Charged toluene (50 mL, 2 vol) and potassium trifluoroacetate (0.64 g, 4.21 mmol, 0.04 equiv) to the receiver vessel. The flow reactor was submerged in a -10 °C bath and the pumps were turned on. The batch temperature in the receiver vessel was maintained at 5 to 10 °C throughout the run using a dry ice/acetone bath. After 13.5 min the ester solution was consumed, the reactor was flushed with toluene (10 mL) and the pumps were turned off.

The resulting yellow slurry was warmed to room temperature and aged for 4.5 h. Charged methanol (160 mL) to afford a homogeneous solution which contained 81.20 area percent diene C by HPLC analysis.

The solution of diene C (573 mL) was used without purification in the subsequent reaction. Cyclization, Diene C to E

3-Chloro-5-((2-oxo-4-(trifluoromethyl)-l,2-dihydropyridin-3-yl)oxy)benzonitrile (E): To a solution of diene C in PhMe/MeOH (573 mL; 40.69 g, 104.4 mmol theoretical C) was charged methanol (25 mL, 0.61 vol). Ammonia (32 g, 1.88 mol, 18 equiv based on theoretical C) was added and the solution was warmed to 60 °C. The reaction was aged at 60 °C for 18 h. The temperature was adjusted to 35-45 °C and the pressure was decreased maintain a productive distillation rate. The batch volume was reduced to -300 mL and methanol (325 mL, 8 vol) was charged in portions to maintain a batch volume between 250 and 350 mL. The heating was stopped and the system vented. The resulting slurry was cooled to room temperature and aged overnight.

The batch was filtered and the cake washed with methanol (3x, 45 mL). The wet cake was dried on the frit with suction under a nitrogen stream to afford 18.54 g of a white solid: XH NMR (DMSO-i/6, 500 MHz): δ 12.7 (br s, 1H), 7.73 (t, 1H, J= 1.5 Hz), 7.61-7.59 (m, 2H), 7.53 (t, 1H, J= 2.0 Hz), 6.48 (d, 1H, J= 7.0 Hz) ppm.

Step 3 – Chlorination, Alkylation and Isolation of 3-Chloro-5-({l-[(4-methyl-5-oxo-4,5-dihydro- lH-l,2,4-triazol-3-yl)methyl]-2-oxo-4-(trifluoromethyl)-l,2-dihydropyridin-3-yl}oxy)benzonitrile

Figure imgf000027_0001

3-(Chloromethyl)-4-methyl-lH-l,2,4-triazol-5(4H)-one: 3-(Hydroxymethyl)-4-methyl-lH- l,2,4-triazol-5(4H)-one (1.638 kg of 68wt%, 8.625 mol) and N-methylpyrrolidinone (8.9 L) was charged into a 30 L vessel. The suspension was aged for lOh at ambient temperature. The slurry was filtered through a 4L sintered glass funnel under 2 and the filter cake (mainly NaCl) was washed with NMP (2.23 L). The combined filtrate and wash had a water content of 5750 μg/mL. The solution was charged to a 75L flask equipped with a 2N NaOH scrubber to capture off-gasing vapors. Thionyl chloride (0.795 L, 10.89 mol) was added over lh and the temperature rose to 35 °C. HPLC analysis indicated that the reaction required an additional thionyl chloride charge (0.064 L, 0.878 mol) to bring to full conversion. The solution was warmed to 50 °C, placed under vacuum at 60 Torr (vented to a 2N NaOH scrubber), and gently sparged with subsurface N2 (4 L/min). The degassing continued for lOh until the sulfur dioxide content in the solution was <5 mg/mL as determined by quantitative GC/MS. The tan solution of 3-(chloromethyl)-4-methyl-lH-l,2,4-triazol-5(4H)-one in NMP weighed 13.0 kg and was assayed at 9.63 wt% providing 1.256 kg (97% yield).

3-chloro-5-((l-((4-methyl-5-oxo-4,5-dihydro-lH-l,2,4-triazol-3-yl)methyl)-2-oxo-4- (trifluoromethyl)-l,2-dihydropyridin-3-yl)oxy)benzonitrile: To a 75L flask was charged a 9.63wt% solution of 3-(chloromethyl)-4-methyl-lH-l,2,4-triazol-5(4H)-one in NMP (1 1.6 kg, 7.55 mol), 3 -chloro-5 -((2-oxo-4-(trifluoromethyl)- 1 ,2-dihydropyridin-3 -yl)oxy)benzonitrile (2.00 kg, 6.29 mol), NMP (3.8 L) and 2-methyl-2-butanol (6.0 L). To the resulting suspension was slowly added N,N-diisopropylethylamine (4.38 L, 25.2 mol) over 4h. The reaction was aged 18h at ambient temperature. The reaction is considered complete when HPLC indicates <1% 3 -chloro-5 -((2-oxo-4-(trifluoromethyl)-l,2-dihydropyridin-3-yl)oxy)benzonitrile remaining. The tan solution was quenched with acetic acid (1.26 L, 22.0 mol) and aged at ambient temperature overnight. The tan solution was warmed to 70 °C. Water (2.52 L) was added and the batch was seed with anhydrate Form II (134 g). The thin suspension was aged lh at 70 °C. Additional water (14.3 L) was added evenly over 7 h. The slurry was aged 2h at 70 °C and then slowly cooled to 20 °C over 5 h. The slurry was filtered and washed with 2 : 1 NMP/water (6 L), followed by water washes (6 L x 2). The filter cake was dried over a 2 sweep to give 2.53 kg (85% yield – corrected) of a white solid that was confirmed to be crystalline Form II by X-ray powder detraction analysis.

PATENT

WO 2015084763

The following scheme is an example of Step 3A.

EXAMPLE 1

1

Step 1

c| 0. h CH3NH3 Me.NA0.Ph

H

Phenyl methylcarbamate: 40% Aqueous methylamine (500 g, 6.44 mol) was charged to a 2 L vessel equipped with heat/cool jacket, overhead stirrer, temperature probe and nitrogen inlet. The solution was cooled to -5 °C. Phenyl chloroformate (500.0 g, 3.16 mol) was added over 2.5 h maintaining the reaction temperature between -5 and 0 °C. On complete addition the white slurry was stirred for lh at ~0 °C.

The slurry was filtered, washed with water (500 mL) and dried under a nitrogen sweep overnight to afford 465g (96% yield) of the desired product as a white crystalline solid; XH NMR (CDCI3, 500 MHz): δ 7.35 (t, J = 8.0 Hz, 2H), 7.19 (t, J = 8.0 Hz, 1H), 7.12 (d, J = 8.0 Hz, 2H), 4.95 (br s, 1H), 2.90 (d, J = 5 Hz, 3H).

Step 2

2-(2-Hydroxyacetyl)-N-methylhydrazinecarboxamide: Part A: Phenyl methylcarbamate (300 g, 1.95 mol) was charged to a 2 L vessel with cooling jacket, overhead stirrer, temperature probe, reflux condenser and nitrogen inlet. IPA (390 mL) was added at 23 °C. Hydrazine hydrate (119 g, 2.33 mol) was added and the slurry heated to 75 °C for 6 h.

Part B: On complete reaction (>99% conversion by HPLC), IPA (810 mL) and glycolic acid (222 g, 2.92 mol) were added and the mixture stirred at 83-85 °C for 10-12 h. The reaction mixture was initially a clear colorless solution. The mixture was seeded with product (0.5 g) after 4h at 83-85 °C. The slurry was slowly cooled to 20 °C over 2h and aged for lh. Seed was used to advance the crystallization, but the crystalline product can be precipitated and isolated without seed by allowing the solution to age at 83-85 °C for 4 hours.

The slurry was filtered and washed with IPA (600 mL). The cake was dried under a nitrogen sweep to afford 241.8g (81% yield) of the desired product as a white crystalline solid: XH NMR (D20, 500 MHz): δ 4.11 (s, 2H), 2.60 (s, 3H).

Step 3

3-(Hydroxymethyl)-4-methyl-lH-l,2,4-triazol-5(4H)-one: 2-(2-Hydroxyacetyl)-N-methylhydrazinecarboxamide (130 g @ ~95wt%, 0.84 mol), w-propanol (130 mL) and water (130 mL) were charged to a 1 L vessel with jacket, overhead stirrer, temperature probe, reflux condenser and nitrogen inlet. Sodium hydroxide (pellets, 16.8 g, 0.42 mol) was added and the slurry warmed to reflux for 3h. The reaction mixture was cooled to 20 °C and the pH adjusted to 6.5 (+/- 0.5) using concentrated hydrochloric acid (28.3 mL, 0.34 mol). Water was

azeotropically removed under vacuum at 40-50 °C by reducing the volume to -400 mL and maintaining that volume by the slow addition of n-propanol (780 mL). The final water content was <3000 ug/mL. The resultant slurry (~ 400 mL) was cooled to 23 °C and heptane (390 ml) was added. The slurry was aged lh at 23 °C, cooled to 0 °C and aged 2h. The slurry was filtered, the cake washed with 1 :2 n-PrOH/heptane (100 mL) and the filter cake was dried under a nitrogen sweep to provide 125g (85% yield) of an off-white crystalline solid. The solid was -73 wt% due to residual inorganics (NaCl): ¾ NMR (CD3OD, 500 MHz): δ 3.30 (s, 3H), 4.46 (s, 2H).

Step 4

3-(Chloromethyl)-4-methyl-lH-l,2,4-triazol-5(4H)-one (1): A mixture of 3-(Hydroxymethyl)-4-methyl-lH-l,2,4-triazol-5(4H)-one (54 g, at 73wt%, 307 mmol) in ethyl acetate (540 mL) was stirred at 45 °C. SOCl2 (26.9 mL, 369 mmol) was added over 30-45 min and aged at 50 °C for 2h. The reaction progress was monitored by HPLC. On complete reaction (>99.5% by area at 210nm), the warm suspension was filtered and the filter cake (mainly NaCl) was washed with ethyl acetate (108 mL). The combined filtrate and wash were concentrated at 50-60 °C under reduced pressure to approximately 150 mL. The resulting slurry was cooled to – 10 °C and aged lh. The slurry was filtered and the filter cake washed with ethyl acetate (50 mL). The cake was dried under a nitrogen sweep to afford 40. lg (86% yield) of the desired product as a bright yellow solid: XH NMR (CD3OD, 500 MHz): δ 3.30 (s, 3H), 4.58 (s, 2H).

EXAMPLE 2

Step 1 – Ethyl Ester Synthesis

Experimental Procedure;

A

Ethyl 2-(3-chloro-5-cyanophenoxy)acetate (A): A 1L round bottom flask equipped with overhead stirring was charged with 3-chloro-5-hydroxybenzonitrile (50.0 g, 98 wt% purity, 319 mmol) and 15% aqueous DMF (200 mL DMF + 35.5 mL Η20). To the resulting solution was added diisopropylethylamine (61.3 mL, 99.0% purity, 1.1 equiv) and ethyl 2-bromoacetate (35.7 g, 98% purity, 1.15 equiv) at ambient temperature. The resulting solution was warmed to 50°C under nitrogen and aged for 12 h. Upon completion of the reaction the batch was cooled to 0-5°C. To the clear to slightly cloudy solution was added 5% seed (3.8g, 16.0 mmol). H20 (64.5mL) was added to the thin suspension via syringe pump over 3h while maintaining the temperature at 0-5 °C. Additional H20 (200mL) was added over lh while maintaining the temp at 0-5 °C. The final DMF/H20 ratio is 1 : 1.5. The resulting slurry was aged lh at 0-5 °C. The batch was filtered and the cake slurry washed with 2: 1 DMF/water (150 mL), followed by water (200 mL). The wet cake was dried on the frit with suction under a nitrogen stream at 20-25 °C. The cake is considered dry when H20 is <0.2%. Obtained 73.4 g ethyl ester as a light tan solid, 96% yield: XH NMR (CDC13, 400 MHz) δ = 7.29 (s, 1H), 7.15 (s, 1H), 7.06 (s, 1H), 4.67 (s, 2H), 4.32 (q, 2H), 1.35 (t, 3H) ppm. Seed was used to advance the crystallization, but the crystalline product can be precipitated and isolated without seed by allowing the solution to age at 0-5 °C for at least about 2 hours.

Step 2 – Pyridone Synthesis

Synthetic Scheme;

Experimental Procedures;

Aldol Condensation

(2E/Z,4E)-Ethyl 2-(3-chloro-5-cyanophenoxy)-5-ethoxy-3-(trifluoromethyl)penta-2,4-dienoate (C): Ethyl 2-(3-chloro-5-cyanophenoxy)acetate (25.01 g, 104.4 mmol, 1.00 equiv) was charged to toluene (113.43 g, 131 mL) and 4-ethoxy-l, l,l-trifluoro-3-buten-2-one (26.43 g, 157.2 mmol, 1.51 equiv) was added.

The flow reactor consisted of two feed solution inlets and an outlet to a receiving vessel. The flow reactor schematic is shown in Figure 1.

The ester solution was pumped to one flow reactor inlet. Potassium tert-amylate solution was pumped to the second reactor inlet. Trifluoroacetic anhydride was added continuously to the receiver vessel. Triethylamine was added continuously to the receiver vessel.

The flow rates were: 13 mL/min ester solution, 7.8 mL/min potassium tert-amylate solution, 3.3 mL/min trifluoroacetic anhydride and 4.35 mL/min triethylamine.

Charged toluene (50 mL) and potassium trifluoroacetate (0.64 g, 4.21 mmol, 0.04 equiv) to the receiver vessel. The flow reactor was submerged in a -10 °C bath and the pumps were turned on. The batch temperature in the receiver vessel was maintained at 5 to 10 °C throughout the run using a dry ice/acetone bath. After 13.5 min the ester solution was consumed, the reactor was flushed with toluene (10 mL) and the pumps were turned off.

The resulting yellow slurry was warmed to room temperature and aged for 4.5 h. Charged methanol (160 mL) to afford a homogeneous solution which contained 81.20 LCAP diene .

The solution of diene (573 mL) was used without purification in the subsequent reaction.

Cyclization

3-Chloro-5-((2-oxo-4-(trifluoromethyl)-l,2-dihydropyridin-3-yl)oxy)benzonitrile (E): To a solution of diene in PhMe/MeOH (573 mL; 40.69 g, 104.4 mmol theoretical) was charged methanol (25 mL). Ammonia (32 g, 1.88 mol, 18 equiv based on theoretical) was added and the solution was warmed to 60 °C. The reaction was aged at 60 °C for 18 h. The temperature was adjusted to 35-45 °C and the pressure was decreased to maintain a productive distillation rate. The batch volume was reduced to -300 mL and methanol (325 mL) was charged in portions to maintain a batch volume between 250 and 350 mL. The heating was stopped and the system vented. The resulting slurry was cooled to room temperature and aged overnight.

The batch was filtered and the cake washed with methanol (3x, 45 mL). The wet cake was dried on the frit with suction under a nitrogen stream to afford 18.54 g of a white solid: XH NMR (DMSO-ifc, 500 MHz): δ 12.7 (br s, 1H), 7.73 (t, 1H, J= 1.5 Hz), 7.61-7.59 (m, 2H), 7.53 (t, 1H, J= 2.0 Hz), 6.48 (d, 1H, J= 7.0 Hz) ppm.

Step 3 – Chlorination, Alkylation and Isolation of 3-Chloro-5-({l-[(4-methyl-5-oxo-‘ dihydro-lH-l,2,4-triazol-3-yl)methyl]-2-oxo-4-(trifluoromethyl)-l,2-dihydropyridin-3-yl}oxy)benzonitrile

3-(Chloromethyl)-4-methyl-lH-l,2,4-triazol-5(4H)-one: 3-(Hydroxymethyl)-4-methyl-lH-l,2,4-triazol-5(4H)-one (1.638 kg of 68wt%, 8.625 mol) and N-methylpyrrolidinone (8.9 L) was charged into a 30 L vessel. The suspension was aged for lOh at ambient temperature. The slurry was filtered through a 4L sintered glass funnel under 2 and the filter cake (mainly NaCl) was washed with NMP (2.23 L). The combined filtrate and wash had a water content of 5750 μg/mL. The solution was charged to a 75L flask equipped with a 2N NaOH scrubber to capture off-gasing vapors. Thionyl chloride (0.795 L, 10.89 mol) was added over lh and the temperature rose to 35 °C. HPLC analysis indicated that the reaction required an additional thionyl chloride charge (0.064 L, 0.878 mol) to bring to full conversion. The solution was warmed to 50 °C, placed under vacuum at 60 Torr (vented to a 2N NaOH scrubber), and gently sparged with subsurface nitrogen (4 L/min). The degassing continued for lOh until the sulfur dioxide content in the solution was <5 mg/mL as determined by quantitative GC/MS. The tan solution of 3-(chloromethyl)-4-methyl-lH-l,2,4-triazol-5(4H)-one in NMP weighed 13.0 kg and was assayed at 9.63 wt% providing 1.256 kg (97% yield).

3-chloro-5-((l-((4-methyl-5-oxo-4,5-dihydro-lH-l,2,4-triazol-3-yl)methyl)-2-oxo-4-(trifluoromethyl)-l,2-dihydropyridin-3-yl)oxy)benzonitrile: To a 75L flask was charged a 9.63wt% solution of 3-(chloromethyl)-4-methyl-lH-l,2,4-triazol-5(4H)-one in NMP (1 1.6 kg, 7.55 mol), 3-chloro-5-((2-oxo-4-(trifluoromethyl)-l,2-dihydropyridin-3-yl)oxy)benzonitrile (2.00 kg, 6.29 mol), NMP (3.8 L) and 2-methyl-2-butanol (6.0 L). To the resulting suspension was slowly added N,N-diisopropylethylamine (4.38 L, 25.2 mol) over 4h. The reaction was aged 18h at ambient temperature. The reaction is considered complete when HPLC indicated <1% 3-chloro-5-((2-oxo-4-(trifluoromethyl)-l,2-dihydropyridin-3-yl)oxy)benzonitrile remaining. The tan solution was quenched with acetic acid (1.26 L, 22.0 mol) and aged at ambient temperature overnight. The tan solution was warmed to 70 °C. Water (2.52 L) was added and the batch was seeded with anhydrate Form II (134 g)(procedures for making anhydrate Form II are described in WO2014/052171). The thin suspension was aged lh at 70 °C. Additional water (14.3 L) was added evenly over 7 h. The slurry was aged 2h at 70 °C and then slowly cooled to 20 °C over 5 h. The slurry was filtered and washed with 2 : 1 NMP/water (6 L), followed by water washes (6 L x 2). The filter cake was dried under N2 to give 2.53 kg (85% yield) of a white solid that was confirmed to be crystalline Form II of the title compound by X-ray powder detraction analysis.

EXAMPLE 3

Ethyl 2-(3-chloro-5-cyanophenoxy)acetate (A):

70%

Step 3

Three step one pot sequence

Steps 1 and 2:

To an oven dried 250mL round bottom flask was added sodium 2-methylpropan-2-olate (12.85 g, 134 mmol) and BHT (0.641 g, 2.91 mmol) then added DMF (30mL). After lOmin, a light yellow solution resulted. 2-Phenylethanol (7.66 ml, 63.9 mmol) was added and the solution exothermed to 35 °C. The light yellow solution was warmed to 55 °C and then a solution of 3,5-dichlorobenzonitrile (10 g, 58.1 mmol) in DMF (15mL) was added over 2h via syringe pump. The resulting red-orange suspension was aged at 55-60 °C. After 2h, HPLC showed >98% conversion to the sodium phenolate.

Step 3:

The suspension was cooled to 10 °C, then ethyl 2-bromoacetate (8.70 ml, 78 mmol) was added over lh while maintaining the temperature <20 °C. The resulting mixture was aged at ambient temperature. After lh, HPLC showed >99% conversion to the title compound.

Work-up and isolation:

To the suspension was added MTBE (50mL) and H20 (50mL) and the layers were separated. The organic layer was washed with 20% aq brine (25mL). The organic layer was assayed at 12.5g (90% yield). The organic layer was concentrated to -38 mL, diluted with hexanes (12.5mL) and then cooled to 5 °C. The solution was seeded with 0.28g (2 wt%) of crystalline ethyl 2-(3-chloro-5-cyanophenoxy)acetate and aged 0.5h at 5 °C to give a free flowing slurry. Hexane (175mL) was added to the slurry over lh at 0-5 °C. The slurry was filtered at 0-5 °C, washed with hexane (50 mL) and dried under a nitrogen sweep to give 9.8g (70% yield) of the title compound as a white crystalline solid. Seed was used to advance the crystallization, but the crystalline product can be precipitated and isolated without seed by allowing the solution to age at 0-5 °C for at least about 2 hours.

Paper

Discovery of MK-1439, an orally bioavailable non-nucleoside reverse transcriptase inhibitor potent against a wide range of resistant mutant HIV viruses
Bioorg Med Chem Lett 2014, 24(3): 917

http://www.sciencedirect.com/science/article/pii/S0960894X13014546

The optimization of a novel series of non-nucleoside reverse transcriptase inhibitors (NNRTI) led to the identification of pyridone 36. In cell cultures, this new NNRTI shows a superior potency profile against a range of wild type and clinically relevant, resistant mutant HIV viruses. The overall favorable preclinical pharmacokinetic profile of 36 led to the prediction of a once daily low dose regimen in human. NNRTI 36, now known as MK-1439, is currently in clinical development for the treatment of HIV infection.

Full-size image (16 K)

Full-size image (10 K)

Scheme 1. 

Reagents and conditions: (a) K2CO3, NMP, 120 °C; (b) KOH, tert-BuOH, 75 °C; (c) Zn(CN)2, Pd(PPh3)4, DMF, 100 °C.

Full-size image (12 K)

Scheme 3.

Reagents and conditions: (a) K2CO3, DMF, −10 °C; (b) MeI or EtI, K2CO3, DMF.

36 IS DORAVIRINE

PATENT

WO 2011120133

http://www.google.com/patents/WO2011120133A1?cl=en

Scheme I depicts a method for preparing compounds of Formula I in which hydroxypyridine 1-1 is alkylated with chlorotriazolinone 1-2 to provide 1-3 which can be selectively alkylated with an alkyl halide (e.g., methyl iodide, ethyl iodide, etc.) to afford the desired 1-4. Scheme I

Figure imgf000039_0001

Scheme II depicts an alternative route to compounds of the present invention, wherein fluorohydroxypyridine II-l can be alkylated with chlorotriazolinone II-2 to provide the alkylated product II-3 which can be converted to the desired II-5 via nucleophilic aromatic substitution (S] fAr) using a suitable hydroxyarene II-4.

Scheme II

Figure imgf000039_0002

Hydroxypyridines of formula I-l (Scheme 1) can be prepared in accordance with Scheme III, wherein a SNAr reaction between pyridine III-l (such as commercially available 2- chloro-3-fluoro-4-(trifluoromethyl)pyridine) and hydroxyarene H-4 can provide chloropyridine III-2, which can be hydrolyzed under basic conditions to the hydroxypyridine I-l. Scheme III

Figure imgf000040_0001

Another method for preparing hydroxypyridines of formula I-l is exemplified in Scheme IV, wherein S Ar coupling of commercially available 2-chloro-3-fluoro-4- nitropyridone-N-oxide IV-1 with a suitable hydroxyarene II-4 provides N-oxide IV-2, which can first be converted to dihalides IV-3 and then hydro lyzed to hydroxypyridine IV-4. Further derivatization of hydroxypyridine IV-4 is possible through transition metal-catalyzed coupling processes, such as Stille or boronic acid couplings using a PdLn catalyst (wherein L is a ligand such as triphenylphosphine, tri-tert-butylphosphine or xantphos) to form hydroxypyridines IV-5, or amination chemistry to form hydroxypyridines IV-6 in which R2 is N(RA)RB.

Scheme IV

Figure imgf000040_0002

IV-1

Figure imgf000040_0003

– – Scheme V depicts the introduction of substitution at the five-position of the hydroxypyridines via bromination, and subsequent transition metal-catalyzed chemistries, such as Stille or boronic acid couplings using PdLn in which L is as defined in Scheme IV to form hydroxypyridines V-3, or amination chemistry to form hydroxypyridines V-4 in which R3 is N(RA)RB.

Scheme V

Figure imgf000041_0001

As shown in Scheme IV, fiuorohydroxypyridines II-l (Scheme II) are available from the commercially available 3-fluoroypridines VI- 1 through N-oxide formation and rearrangement as described in Konno et al., Heterocycles 1986, vol. 24, p. 2169.

Scheme VI

Figure imgf000041_0002

The following examples serve only to illustrate the invention and its practice. The examples are not to be construed as limitations on the scope or spirit of the invention.

The term “room temperature” in the examples refers to the ambient temperature which was typically in the range of about 20°C to about 26°C.

EXAMPLE 1

3-Chloro-5-({ l-[(4-methyl-5-oxo-4,5-dihydro-lH-l ,2,4-triazol-3-yl)methyl]-2-oxo-4- (trifluoromethyl)-l ,2-dihydropyridin-3-yl}oxy)benzonitrile (1-1)

Figure imgf000042_0001

Step 1(a):

Figure imgf000042_0002

A mixture of the 3-bromo-5-chlorophenol (3.74 g; 18.0 mmol), 2-chloro-3-fluoro- 4-(trifluoromethyl)pyridine (3.00 g; 15.0 mmol) and 2CO3 (2.49 g; 18.0 mmol) in NMP (15 mL) was heated to 120°C for one hour, then cooled to room temperature. The mixture was then diluted with 250 mL EtOAc and washed with 3 x 250 mL 1 :1 H20:brine. The organic extracts were dried (Na2S04) and concentrated in vacuo. Purification by ISCO CombiFlash (120 g column; load with toluene; 100:0 to 0:100 hexanes:CH2Cl2 over 40 minutes) provided title compound (1-2) as a white solid. Repurification of the mixed fractions provided additional title compound. lH NMR (400 MHz, CDCI3): δ 8.55 (d, J = 5.0 Hz, 1 H); 7.64 (d, J = 5.0 Hz, 1 H);

7.30 (s, 1 H); 6.88 (s, 1 H); 6.77 (s, 1 H).

3-(3-bromo-5-chlorophenoxy)-4-(trifluoromethyl)pyridin-2-ol (1-3)

Figure imgf000042_0003

To a suspension of 3-(3-bromo-5-chlorophenoxy)-2-chloro-4- (trifluoromethyl)pyridine (1-2; 3.48 g; 8.99 mmol) in lBuOH (36 mL) was added KOH (1.51 g; 27.0 mmol) and the mixture was heated to 75°C overnight, at which point a yellow oily solid had precipitated from solution, and LCMS analysis indicated complete conversion. The mixture was cooled to room temperature, and neutralized by the addition of -50 mL saturated aqueous NH4CI. The mixture was diluted with 50 mL H2O, then extracted with 2 x 100 mL EtOAc. The combined organic extracts were dried (Na2S04) and concentrated in vacuo. Purification by ISCO CombiFlash (120 g column; dry load; 100:0 to 90: 10 CH2Cl2:MeOH over 40 minutes) provided the title compound (1-3) as a fluffy white solid. lH NMR (400 MHz, DMSO): δ 12.69 (s, 1 H); 7.59 (d, J = 6.9 Hz, 1 H); 7.43 (t, J = 1.7 Hz, 1 H); 7.20 (t, J = 1.9 Hz, 1 H); 7.13 (t, J = 2.0 Hz, 1 H); 6.48 (d, J = 6.9 Hz, 1 H).

3-chloro-5-{[2-hydroxy-4-(trifluoromethyl)pyridin-3-yl]oxy}benzonitrile (1-4)

Figure imgf000043_0001

To a suspension of 3-(3-bromo-5-chlorophenoxy)-4-(trifluoromethyl)pyridin-2-ol (1-3; 3.25 g; 8.82 mmol) in NMP (29 mL) was added CuCN (7.90 g; 88 mmol) and the mixture was heated to 175°C for 5 hours, then cooled to room temperature slowly. With increased fumehood ventilation, 100 mL glacial AcOH was added, then 100 mL EtOAc and the mixture was filtered through Celite (EtOAc rinse). The filtrate was washed with 3 x 200 mL 1 : 1 H20:brine, then the organic extracts were dried (Na2S04) and concentrated in vacuo.

Purification by ISCO CombiFlash (120 g column; dry load; 100:0 to 90:10 CH2Cl2:MeOH over 40 minutes), then trituration of the derived solid with Et20 (to remove residual NMP which had co-eluted with the product) provided the title compound (1-4). lH NMR (400 MHz, DMSO): δ 12.71 (s, 1 H); 7.75 (s, 1 H); 7.63-7.57 (m, 2 H); 7.54 (s, 1 H); 6.49 (d, J = 6.9 Hz, 1 H).

Step 1(d): 5-(chloromethyl)-2,4-dihydro-3H-l,2,4-triazol-3-one (1-5)

Figure imgf000043_0002

The title compound was prepared as described in the literature: Cowden, C. J.; Wilson, R. D.; Bishop, B. C; Cottrell, I. F.; Davies, A. J.; Dolling, U.-H. Tetrahedron Lett. 2000, 47, 8661.

3 -chloro-5 -( { 2-oxo- 1 – [(5 -oxo-4,5 -dihydro- 1 H- 1 ,2,4-triazol-3 -yl)methyl] – 4- (trifiuoromethyl)- 1 ,2-dihydropyridin-3 -yl } oxy)benzonitrile (1-6)

Figure imgf000044_0001

A suspension of the 3-chloro-5-{[2-hydroxy-4-(trifluoromethyl)pyridin-3- yl]oxy}benzonitrile (1-4; 2.00 g; 6.36 mmol), 5-(chloromethyl)-2,4-dihydro-3H-l,2,4-triazol-3- one (1-5; 0.849 g; 6.36 mmol) and K2CO3 (0.878 g; 6.36 mmol) in DMF (32 mL) was stirred for 2 hours at room temperature, at which point LCMS analysis indicated complete conversion. The mixture was diluted with 200 mL Me-THF and washed with 150 mL 1 : 1 : 1 H20:brine:saturated aqueous NH4CI, then further washed with 2 x 150 mL 1 : 1 H20:brine. The aqueous fractions were further extracted with 150 mL Me-THF, then the combined organic extracts were dried (Na2S04) and concentrated in vacuo. Purification by ISCO CombiFlash (80 g column; dry load; 100:0 to 90:10 EtOAc:EtOH over 25 minutes) provided the title compound (1-6) as a white solid. lH NMR (400 MHz, DMSO): δ 1 1.46 (s, 1 H); 1 1.39 (s, 1 H); 7.93 (d, J = 7.3 Hz, 1 H); 7.76 (s, 1 H); 7.58 (s, 1 H); 7.51 (s, 1 H); 6.67 (d, J = 7.3 Hz, 1 H); 5.02 (s, 2 H).

Step 1(f): 3 -chloro-5 -( { 1 – [(4-methyl-5-oxo-4,5 -dihydro- 1 H- 1 ,2,4-triazol-3 -yl)methyl] -2- oxo-4-(trifluoromethyl)- 1 ,2-dihydropyridin-3 -yl } oxy)benzonitrile (1 -1 )

A solution of 3-chloro-5-({2-oxo-l -[(5-oxo-4,5-dihydro-lH-l,2,4-triazol-3- yl)methyl]- 4-(trifluoromethyl)-l ,2-dihydropyridin-3-yl}oxy)benzonitrile (1-6; 2.37 g; 5.76 mmol) and K2CO3 (0.796 g; 5.76 mmol) in DMF (58 mL) was cooled to 0°C, then methyl iodide (0.360 mL; 5.76 mmol) was added. The mixture was allowed to warm to room

temperature, and stirred for 90 minutes, at which point LCMS analysis indicated >95%

conversion, and the desired product of -75% LCAP purity, with the remainder being unreacted starting material and 6/s-methylation products. The mixture was diluted with 200 mL Me-THF, and washed with 3 x 200 mL 1 : 1 H20:brine. The aqueous fractions were further extracted with 200 mL Me-THF, then the combined organic extracts were dried (Na2S04) and concentrated in vacuo. The resulting white solid was first triturated with 100 mL EtOAc, then with 50 mL THF, which provided (after drying) the title compound (1-1) of >95% LCAP. Purification to >99% LCAP is possible using Prep LCMS (Max-RP, 100 x 30 mm column; 30-60% CH3CN in 0.6% aqueous HCOOH over 8.3 min; 25 mL/min). lH NMR (400 MHz, DMSO): δ 1 1.69 (s, 1 H); 7.88 (d, J = 7.3 Hz, 1 H); 7.75 (s, 1 H); 7.62 (s, 1 H); 7.54 (s, 1 H); 6.67 (d, J = 7.3 Hz, 1 H); 5.17 (s, 2 H); 3.1 1 (s, 3 H). EXAMPLE 1A

3-Chloro-5-({ l-[(4-methyl-5-oxo-4,5-dihydro-lH-l ,2,4-triazol-3-yl)methyl]-2- (trifluoromethyl)-l ,2-dihydropyridin-3-yl}oxy)benzonitrile (1-1)

Figure imgf000045_0001

Step lA(a): 2-chloro-3-(3-chloro-5-iodophenoxy)-4-(trifluoromethyl)pyridine (1A-2)

Figure imgf000045_0002

A mixture of the 3-chloro-l-iodophenol (208 g; 816.0 mmol), 2-chloro-3-fluoro-

4-(trifluoromethyl)pyridine (155 g; 777.0 mmol) and K2CO3 (161 g; 1 165.0 mmol) in NMP (1.5 L) was held at 60°C for 2.5 hours, and then left at room temperature for 2 days. The mixture was then re-heated to 60°C for 3 hours, then cooled to room temperature. The mixture was then diluted with 4 L EtOAc and washed with 2 L water + 1 L brine. The combined organics were then washed 2x with 500 mL half brine then 500 mL brine, dried over MgS04 and concentrated to afford crude 1A-2. lH NMR (500 MHz, DMSO) δ 8.67 (d, J = 5.0 Hz, 1 H), 7.98 (d, J = 5.0 Hz, 1 H), 7.63-7.62 (m, 1 H), 7.42-7.40 (m, 1 H), 7.22 (t, J = 2.1 Hz, 1 H).

Step lA(b): 2-chloro-3-(3-chloro-5-iodophenoxy)-4-(trifluoromethyl)pyridine (1A-3)

Figure imgf000045_0003

To a suspension of 3-(3-chloro-5-iodophenoxy)-2-chloro-4- (trifluoromethyl)pyridine (1A-2; 421 g, 970 mmol) in t-BuOH (1 L) was added KOH (272 g, 4850 mmol) and the mixture was heated to 75°C for 1 hour, at which point HPLC analysis indicated >95% conversion. The t-BuOH was evaporated and the mixture diluted with water (7mL/g, 2.4L) and then cooled to 0°C, after which 12N HC1 (~240mL) was added until pH 5. This mixture was then extracted with EtOAc (20mL/g, 6.5L), back extracted with EtOAc 1 x 5mL/g (1.5L), washed 1 x water:brine 1 : 1 (l OmL/g, 3.2L), 1 x brine (lOmL/g, 3.2L), dried over MgS04, filtered and concentrated to afford a crude proudct. The crude product was suspended in MTBE (2.25 L, 7mL/g), after which hexanes (1 L, 3 mL/g) was added to the suspension over ten minutes, and the mixturen was aged 30minutes at room temperature. The product was filtered on a Buchner, rinsed with MTBE hexanes 1 :2 (2 mL/g = 640 mL), then hexanes

(640mL), and dried on frit to afford 1A-3. lH NMR (400 MHz, acetone-d6): δ 11.52 (s, 1 H); 7.63 (d, J = 7.01 Hz, 1 H); 7.50-7.48 (m, 1 H); 7.34-7.32 (m, 1 H); 7.09-7.07 (m, 1 H); 6.48 (d, J = 7.01 Hz, 1 H).

Step lA(c): 3-chloro-5-{[2-hydroxy-4-(trifluoromethyl)pyridin-3-yl]oxy}benzonitrile (1-4)

Figure imgf000046_0001

A solution of 3-(3-chloro-5-iodophenoxy)-4-(trifluoromethyl)pyridin-2-ol (1A-3; 190 g; 457 mmol) in DMF (914 mL) was degassed for 20 minutes by bubbling N2, after which CuCN (73.7 g; 823 mmol) was added, and then the mixture was degassed an additional 5 minutes. The mixture was then heated to 120°C for 17 hours, then cooled to room temperature and partitioned between 6 L MeTHF and 2 L ammonium buffer (4:3: 1 = NH4CI

sat/water/NH-iOH 30%). The organic layer washed with 2 L buffer, 1 L buffer and 1 L brine then, dried over MgS04 and concentrated. The crude solid was then stirred in 2.2 L of refluxing

MeCN for 45 minutes, then cooled in a bath to room temperature over 1 hour, aged 30 minutes, then filtered and rinsed with cold MeCN (2 x 400mL). The solid was dried on frit under N2 atm for 60 hours to afford title compound 1-4. lH NMR (400 MHz, DMSO): δ 12.71 (s, 1 H); 7.75 (s, 1 H); 7.63-7.57 (m, 2 H); 7.54 (s, 1 H); 6.49 (d, J = 6.9 Hz, 1 H).

Steps lA(d) and lA(e)

The title compound 1-1 was then prepared from compound 1-4 using procedures similar to those described in Steps 1(d) and 1(e) set forth above in Example 1.

Patent

WO-2014052171

Crystalline anhydrous Form II of doravirine, useful for the treatment of HIV-1 and HIV-2 infections. The compound was originally claimed in WO2008076223. Also see WO2011120133. Merck & Co is developing doravirine (MK-1439), for the oral tablet treatment of HIV-1 infection. As of April 2014, the drug is in Phase 2 trials.

CLIPS

The next-generation non-nucleoside reverse transcriptase inhibitor (NNRTI) doravirine (formerly MK-1439) showed potent antiretroviral activity and good tolerability in combination with tenofovir/FTC (the drugs in Truvada) in a dose-finding study presented at the 21st Conference on Retroviruses and Opportunistic Infections (CROI) last week in Boston.

NNRTIs are generally well tolerated and well suited for first-line HIV treatment, but as a class they are susceptible to resistance. Pre-clinical studies showed that Merck’s doravirine has a distinct resistance profile and remains active against HIV with common NNRTI resistance mutations including K103N and Y181C.

As reported at last year’s CROI, doravirine reduced HIV viral load by about 1.3 log in a seven-day monotherapy study. Doravirine is processed by the CYP3A4 enzyme, but it is neither a CYP3A4 inducer nor inhibitor, so it is not expected to have major drug interaction concerns.

Javier Morales-Ramirez from Clinical Research Puerto Rico reported late-breaking findings from a phase 2b study evaluating the safety and efficacy of various doses of doravirine versus efavirenz (Sustiva) for initial antiretroviral therapy.

This study included 208 treatment-naive people living with HIV from North America, Europe and Asia. More than 90% were men, 74% were white, 20% were black and the median age was 35 years. At baseline, the median CD4 cell count was approximately 375 cells/mm3 and 13% had received an AIDS diagnosis. Study participants were stratified by whether their viral load was above (about 30%) or below 100,000 copies/ml; median HIV RNA was approximately 4.5 log10.

Morales-Ramirez reported 24-week results from part 1 of the study, which will continue for a total of 96 weeks. In this part, participants were randomly allocated into five equal-sized arms receiving doravirine at doses of 25, 50, 100 or 200mg once daily, or else efavirenz once daily, all in combination with tenofovir/FTC.

At 24 weeks, 76.4% of participants taking doravirine had viral load below 40 copies/ml compared with 64.3% of people taking efavirenz. Response rates were similar across doravirine doses (25mg: 80.0%; 50mg: 76.2%; 100mg: 71.4%; 200mg: 78.0%). More than 80% of participants in all treatment arms reached the less stringent virological response threshold of <200 copies/ml.

Both doravirine and efavirenz worked better for people with lower pre-treatment viral load in an ad hoc analysis. For people with <100,000 copies/ml at baseline, response rates (<40 copies/ml) ranged from 83 to 89% with doravirine compared with 74% with efavirenz. For those with >100,000 copies/ml, response rates ranged from 50 to 91% with doravirine vs 54% with efavirenz.

Median CD4 cell gains were 137 cells/mm3 for all doravirine arms combined and 121 cells/mmfor the efavirenz arm.

Doravirine was generally safe and well tolerated. People taking doravirine were less than half as likely as people taking efavirenz to experience serious adverse events (3.0% across all doravirine arms vs 7.1% with efavirenz) or to stop treatment for this reason (2.4 vs 4.8%). Four people taking doravirine and two people taking efavirenz discontinued due to adverse events considered to be drug-related.

The most common side-effects were dizziness (3.6% with doravirine vs 23.8% with efavirenz), abnormal dreams (9.0 vs 7.1%), diarrhoea (4.8 vs 9.5%), nausea (7.8 vs 2.4%) and fatigue (6.6 vs 4.8%). Other central nervous system (CNS) adverse events of interest included insomnia (5.4 vs 7.1%), nightmares (1.2 vs 9.5%) and hallucinations (0.6 vs 2.4%). Overall, 20.5% of people taking doravirine reported at least one CNS side-effect, compared with 33.3% of people taking efavirenz.

People taking doravirine had more favourable lipid profiles and less frequent liver enzyme (ALT and AST) elevations compared with people taking efavirenz.

The researchers concluded that doravirine demonstrated potent antiretroviral activity in treatment-naive patients, a favourable safety and tolerability profile, and fewer drug-related adverse events compared with efavirenz.

Based on these findings, the 100mg once-daily dose was selected for future development and will be used in part 2 of this study, a dose-confirmation analysis that will enrol an additional 120 participants.

In the discussion following the presentation, Daniel Kuritzkes from Harvard Medical School noted that sometimes it takes longer for viral load to go down in people who start with a high level, so with further follow-up past 24 weeks doravirine may no longer look less effective in such individuals.

Reference

Morales-Ramirez J et al. Safety and antiviral effect of MK-1439, a novel NNRTI (+FTC/TDF) in ART-naive HIV-infected patients. 21st Conference on Retroviruses and Opportunistic Infections, Boston, abstract 92LB, 2014.

Merck Moves Doravirine Into Phase 3 Clinical Trials

Wednesday Mar 19 | Posted by: roboblogger | Full story: EDGE

Earlier this month, at the 21st Conference on Retroviruses and Opportunistic Infections , Merck indicated plans to initiate a Phase 3 clinical trial program for doravirine in combination with ARV therapy in the second half of 2014.

PAPER

A Robust Kilo-Scale Synthesis of Doravirine

Process Research and Development, Merck Research Laboratories, 126 E. Lincoln Ave., Rahway, New Jersey 07065,United States
Process Research and Development, Merck Frosst Center for Therapeutic Research, 16711 Trans Canada Highway, Kirkland, Quebec H9H 3L1, Canada
WuXi AppTec Co., Ltd., No. 1 Building, No. 288 FuTe ZhongLu, WaiGaoQiao Free Trade Zone, Shanghai 200131, China
Org. Process Res. Dev., Article ASAP
Abstract Image

Doravirine is non-nucleoside reverse transcriptase inhibitor (NNRTI) currently in phase III clinical trials for the treatment of HIV infection. Herein we describe a robust kilo-scale synthesis for its manufacture. The structure and origin of major impurities were determined and their downstream fate-and-purge studied. This resulted in a redesign of the route to introduce the key nitrile functionality via a copper mediated cyanation which allowed all impurities to be controlled to an acceptable level. The improved synthesis was scaled to prepare ∼100 kg batches of doravirine to supply all preclinical and clinical studies up to phase III. The synthesis affords high-quality material in a longest linear sequence of six steps and 37% overall yield.

PAPER

Highly Efficient Synthesis of HIV NNRTI Doravirine

Department of Process Chemistry, Merck & Co., Inc., P.O. Box 2000, Rahway, New Jersey 07065, United States
Org. Lett., 2015, 17 (6), pp 1353–1356
DOI: 10.1021/ol503625z
Publication Date (Web): March 09, 2015
Copyright © 2015 American Chemical Society

Gauthier, D. R., Jr.; Sherry, B. D.; Cao, Y.; Journet, M.; Humphrey, G.; Itoh, T.; Mangion, I.; Tschaen, D. M.Org. Lett. 2015, 17, 1353, DOI: 10.1021/ol503625z………..http://pubs.acs.org/doi/full/10.1021/ol503625z

STR1

US20100034813 * 8 Nov 2007 11 Feb 2010 Yi Xia Substituted pyrazole and triazole compounds as ksp inhibitors
US20100256181 * 14 Nov 2008 7 Oct 2010 Tucker Thomas J Non-nucleoside reverse transcriptase inhibitors
US20110245296 * 6 Oct 2011 Jason Burch Non-nucleoside reverse transcriptase inhibitors
Reference
1 * COWDEN ET AL.: “A new synthesis of 1,2,4-triazolin-5-ones: application to the convergent synthesis of an NK1 antagonist.“, TETRAHEDRON LETTERS, vol. 41, no. 44, 2000, pages 8661 – 8664, XP004236142
Patent ID Date Patent Title
US2015329521 2015-11-19 PROCESS FOR MAKING REVERSE TRANSCRIPTASE INHIBITORS
US9150539 2015-10-06 Crystalline form of a reverse transcriptase inhibitor
US2015232447 2015-08-20 CRYSTALLINE FORM OF A REVERSE TRANSCRIPTASE INHIBITOR
US2013296382 2013-11-07 NON-NUCLEOSIDE REVERSE TRANSCRIPTASE INHIBITORS
US2011245296 2011-10-06 NON-NUCLEOSIDE REVERSE TRANSCRIPTASE INHIBITORS

References

  1.  Collins, Simon; Horn, Tim. “The Antiretroviral Pipeline.” (PDF). Pipeline Report. p. 10. Retrieved 6 December 2015.
  2. Safety and Antiviral Activity of MK-1439, a Novel NNRTI, in Treatment-naïve HIV+ Patients. Gathe, Joseph et al. 20th Conference on Retroviruses and Opportunistic Infections. 3–6 March 2013. Abstract 100.
  3.  CROI 2013: MK-1439, a Novel HIV NNRTI, Shows Promise in Early Clinical Trials. Highleyman, Liz. HIVandHepatitis.com. 6 March 2013.
Doravirine
Doravirine structure.svg
Systematic (IUPAC) name
3-Chloro-5-({1-[(4-methyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-3-yl)methyl]-2-oxo-4-(trifluoromethyl)-1,2-dihydro-3-pyridinyl}oxy)benzonitrile
Clinical data
Routes of
administration
Oral[1]
Legal status
Legal status
  • Investigational New Drug
Identifiers
CAS Number 1338225-97-0
ATC code none
PubChem CID 58460047
ChemSpider 28424197
UNII 913P6LK81M Yes
KEGG D10624
ChEMBL CHEMBL2364608
Synonyms MK-1439
PDB ligand ID 2KW (PDBe, RCSB PDB)
Chemical data
Formula C17H11ClF3N5O3
Molar mass 425.75 g/mol

//////////Doravirine, MK-1439, 1338225-97-0 , Merck Sharp & Dohme Corp, Reverse transcriptase inhibitor, ANTIVIRAL, Non-nucleoside reverse transcriptase, HIV, Triazolinone, Pyridone, Inhibitor,

Supporting Info

AND

Supporting Info

Cn1c(n[nH]c1=O)Cn2ccc(c(c2=O)Oc3cc(cc(c3)Cl)C#N)C(F)(F)F

Fosamprenavir


Fosamprenavir.svg

 

Fosamprenavir

BASE

CAS 226700-79-4
[(1S,2R)-3-[[(4-Aminophenyl)sulfonyl](2-methylpropyl)amino]-1-(phenylmethyl)-2-(phosphonooxy)propyl]carbamic acidC-[(3S)-tetrahydro-3-furanyl] ester
Additional Names: (3S)-tetrahydro-3-furyl [(aS)-a-[(1R)-1-hydroxy-2-(N1-isobutylsulfanilamido)ethyl]phenethyl]carbamate dihydrogen phosphate (ester)
Manufacturers’ Codes: VX-175
Molecular Formula: C25H36N3O9PS
Molecular Weight: 585.61
Percent Composition: C 51.27%, H 6.20%, N 7.18%, O 24.59%, P 5.29%, S 5.48%
WO 9933815 PRODUCT PATENT

Fosamprenavir ball-and-stick.png

Fosamprenavir
Systematic (IUPAC) name
{[(2R,3S)-1-[N-(2-methylpropyl)(4-aminobenzene)sulfonamido]-3-({[(3S)-oxolan-3-yloxy]carbonyl}amino)-4-phenylbutan-2-yl]oxy}phosphonic acid
Clinical data
Trade names Lexiva
AHFS/Drugs.com monograph
MedlinePlus a604012
  • C (United States)
Oral
Pharmacokinetic data
Bioavailability Unknown
Protein binding 90%
Metabolism Hydrolysed to amprenavirand phosphate in GI tractepithelium
Half-life 7.7 hours
Excretion Fecal (as metabolites of amprenavir)
Identifiers
226700-81-8 
J05AE07
PubChem CID 131536
DrugBank DB01319 Yes
ChemSpider 116245 Yes
UNII WOU1621EEG Yes
ChEMBL CHEMBL1664 Yes
NIAID ChemDB 082186
Chemical data
Formula C25H36N3O9PS
585.608 g/mol
623.700 g/mol (calciumsalt)
 Figure imgf000002_0001
Calcium salt
 CAS 226700-81-8
Manufacturers’ Codes: GW-433908G
Trademarks: Lexiva (GSK); Telzir (GSK)
Molecular Formula: C25H34CaN3O9PS
Molecular Weight: 623.67
Percent Composition: C 48.15%, H 5.49%, Ca 6.43%, N 6.74%, O 23.09%, P 4.97%, S 5.14%
Properties: White microcrystalline needles, mp 282-284°. Soly in water (25°): 0.31 mg/ml.
Melting point: mp 282-284°
Therap-Cat: Antiviral.

 

 

Fosamprenavir (marketed by ViiV Healthcare as the calcium salt), under the trade names Lexiva (U.S.) and Telzir (Europe) is apro-drug of the protease inhibitor and antiretroviral drug amprenavir. The FDA approved it October 20, 2003, while the EMEA approved it on July 12, 2004. The human body metabolizes fosamprenavir in order to form amprenavir, which is the active ingredient. That metabolization increases the duration that amprenavir is available, making fosamprenavir a slow-release version of amprenavir and thus reducing the number of pills required versus standard amprenavir.

A head-to-head study with lopinavir[1] showed the two drugs to have comparable potency, but patients on fosamprenavir tended to have a higher serum cholesterol. Fosamprenavir’s main advantage over lopinavir is that it is cheaper.

PATENT

http://www.google.com/patents/WO2012032389A2

Fosamprenavir calcium has HIV aspartyl protease inhibitory activity and is particularly well suited for inhibiting HIV-1 and HIV-2 viruses; it is chemically known as calcium (3S) tetrahydro-3-furanyl(l S,2R)-3-[[(4-aminophenyl) sulfonyl] (isobutyl) amino]- l-benzyl-2- (phosphonooxy)propyl carbamate and represented by formula la.

Figure imgf000002_0001

(la)

There are very few references available in the literature for preparation of fosamprenavir and its intermediates. Patent US 5 585 397 provides process for preparation of fosamprenavir intermediate (IV), as depicted in scheme 1 , wherein it is purified using silica gel chromatography, however it does not provide any purity data. Purification by column chromatography is not suitable on commercial scale, since it is time consuming, requires large volume of solvents and is very much laborious.

Figure imgf000003_0001

Scheme 1: Process for preparation of fosamprenavir intermediate (IV) as given in US 5

585 397 Another patent US 6 281 367, provides process for preparation of fosamprenavir intermediate (IV) as depicted in scheme 2, but it does not provide any method for purification of compound (IV).

Figure imgf000004_0001

P= amine protecting

group deprotection

Figure imgf000004_0002

Scheme 2: Process for preparation of fosamprenavir intermediate (VI) as given in US 6

281 367

The patent US 6 514 953 provides process for preparation of fosamprenvair calcium (la) utilizing compound (IV), as depicted in Scheme 3, however it does not provide purity of fosamprenavir calcium (la) or the intermediates thereof.

Figure imgf000005_0001

Aq. soln. of Ca(OAc)2

monohydrate

Figure imgf000005_0002

(la) crude (la)

Scheme 3: Process for preparation of fosamprenavir Calcium (la) as given in US 6 514

953 Another patent, US 6 436 989, which is product patent for fosamprenavir salts, provide process for preparation of fosamprenavir sodium salt (VII) from compound (IV) as depicted in Scheme 4:

Figure imgf000006_0001

(VIA)

(V)

3 eq. NaHC03

resin column,

lyophilize

Figure imgf000006_0002

Scheme 4: Process for preparation of fosamprenavir sodium (VII) as given in US 6 436989. US 6 436 989 provides compound (V) and (VIA) with an HPLC purity of 90% and 92% respectively, however purity of fosamprenavir sodium salt (VII) is not mentioned. This patent provides fosmaprenavir salt intermediates with very low HPLC purity. The prior art literature describes synthesis of fosamprenavir calcium and its intermediates and like any synthetic compound, fosmaprenavir calcium can contain number of impurities from various source like starting material, reaction by-products, degradation, isomeric impurities etc. The prior art documents for fosamprenavir calcium does not provide any information for the impurities that may have been formed from the various synthetic processes provided therein.

Fosamprenavir calcium i.e. calcium (3S) tetrahydro-3-furanyl(lS,2R)-3-[[(4-aminophenyl) sulfonyl] (isobutyl) amino]- 1 -benzyl-2-(phosphonooxy)propyl carbamate (la), is a chiral substrate containing three asymmetrical carbon centre resulting into eight stereoisomers.

Different isomers of a chiral drug molecule bind differently to target receptors, one isomer of a drug may have a desired beneficial effect while the other may cause serious and undesired side effects or sometimes even beneficial but entirely different effects, hence in the drug molecules the effective isomer is preferred in pure form, free of other undesired isomers, thus fosamprenavir calcium free of its other stereoisomer would always be preferred.

The methods described above for preparation of fosamprenavir does not describe suitable methods to minimize formation of R-isomer impurity (lb)

Figure imgf000007_0001

(lb)

One of the approach to minimize R-isomer impurity (lb) is to use highly pure intermediate (S)-3-tetrahydrofuranyl-N-succinimidyl carbonate (Ila), in the synthesis of fosamprenavir. US 5 585 397 provides process for preparation of N-succinimidlyl-(S)-3-tetrahydrofuryl carbonate (Ila), however it does not provide any method for purification neither does it provide any purity data for the same. The PCT application WO 94/18192 provides process for preparation (S)-3-tetrahydrofuranyl- N-succinimidyl carbonate (Ila) as depicted in scheme 5. The application discloses recrystallization of compound (Ila) from EtOAc/hexane. At our hands, crystallization of compound (Ila) from ethyl acetate/hexane provided compound (Ila) containing the intermediate R-isomer impurity compound (lib) upto 0.37% area percentage of HPLC, which is not suitable for its use in the synthesis of fosamprenavir substantially free of R-isomer impurity (lb).

Figure imgf000008_0001

(VIII) (IX) (II)

a= S-isomer a= S-isomer

b= R-isomer b= R-isomer

Scheme 5: process for preparation of (S)-3-tetrahydrofuranyl-N-succinimidyl carbonate

Commercially available (S)-3-tetrahydrofuranol (Villa) contains upto 5% area percentage of HPLC of (R)-3-tetrahydrofuranyl (Vlllb), which on reaction with N,N-disuccinimidyl carbonate (IX) results in (S)-3-tetrahydrofuranyl-N-succinimidyl carbonate (Ila) containing upto 2.5% area percentage of HPLC of the R-isomer impurity, (R)-3-tetrahydrofuranyl-N- succinimidyl carbonate (lib). This impure (S)-3-tetrahydrofuranyl-N-succinimidyl carbonate (Ila) when converted to fosamprenavir calcium (la) by series of reaction, results into fosamprenavir calcium containing upto 2.0 % area percentage of HPLC of (3R) tetrahydro-3- furanyl(l S,2R)-3-[[(4-aminophenyl) sulfonyl] (isobutyl) amino]- 1 -benzy 1-2- (phosphonooxy)propyl carbamate (lb), which is undesired isomer of fosamprenavir calcium. Impurities of any form are undesirable in the active pharmaceutical product since it may have adverse effect on the patient to be treated.

The purity of API produced is clearly a necessary condition for commercialization. The impurities produced in the manufacturing process must be limited to very small amount and are preferred to be substantially absent. The ICH Q7A guidance for API manufacturers requires that process impurities must be maintained below set limits utilizing various parameters. In the United States the Food and Drug Administration guidelines, would mostly limit the amount of impurities present in the API, similarly in other countries the impurity levels would be defined in their respective pharmacopeias.

The process for preparation of fosamprenavir calcium (la) of present invention is as depicted in scheme 5.

Figure imgf000012_0001

crude fosamprenavir calcium (la)

Example 2: Preparation of pure fosamprenavir calcium (I).

Mixture of 100 g (0.23 mol) (2R,3S)-N-(3-amino-2-hydroxy-4-phenylbutyl)-N-isobutyl-4- nitrobenzene sulphonamide (III), 65 g (0.28 mol) (S)-3-tetrahydrofuranyl-N-succinimidyl carbonate (Ila) (of Example 1) and 24 g (0.23) triethylamine in 800 ml dichloromethane was stirred at ambient temperature for 4 hours, extracted with 10% sodium bicarbonate solution. The organic layer was separated, washed with water and concentrated. To the concentrated mass was added 1000 ml methanol and heated to 60-65°, cooled to 25°C and solid was filtered, washed with methanol and dried. Mixture of 100 g (0.186 mol) (3S)-tetrahydro-3-furyl N-[(l S,2R)-l-benzyl-2-hydroxy-3-(N- isobutyl-4-nitrobenzene sulphonamido) propyl] carbamate (IV) and 200 ml pyridine was cooled to 0-10°C and 70.0 g (0.456 mol) of POCl3 was added and stirred at ambient temperature for 4 hours, 400 ml methyl isobutyl ketone was added, cooled and 1 : 1 cone. HC1- water was added. Mixture was heated to 50°C for 1 hour, cooled to 25-30°C. Organic layer was separated, washed with water and partially concentrated; 500 ml water and 31.5 g sodium bicarbonate was added and stirred. The organic layer was separated and 100 ml ethylacetate, 400 ml methanol and 5.0 g Pd/C was added. The reaction mass was stirred under hydrogen pressure for 4 hours at 30°C. The mixture was filtered, catalyst washed with methanol. The filtrate was heated to 50°C and 33.0 g (0.186 mol) calcium acetate monohydrate in 100 ml water was added and stirred for 30 minutes. Cooled to 30°C and stirred. Solid was filtered, washed with 1 : 1 mixture of methanol-water and dried to obtain crude fosamprenavir calcium. 65 g (0.104 mol) crude fosamprenavir calcium and 1 170 ml denatured ethanol was heated to 70-72°C, charcaolized. Water (138 ml) was added and mixture stirred for 30 minutes. Cooled to ambient temperature and stirred. Solid filtered, washed with 1 : 1 ethanol-water and dried. Methanol (315 ml) was added to the solid, stirred and filtered. The filtrate was concentrated under vacuum to obtain solid, which was dried to obtain 37.5 g pure fosamprenavir calcium. HPLC purity: fosamprenavir calcium (la): 99.85%; R-isomer impurity (lb): 0.05%; all other individual impurities less than 0.1%.

Fosamprenavir sodium, GW-433908A, 908, VX-175(free acid)

………………………………….

PAPER

Org. Biomol. Chem., 2004,2, 2061-2070

DOI: 10.1039/B404071F

http://pubs.rsc.org/en/content/articlelanding/2004/ob/b404071f#!divAbstract

Efficient and industrially applicable synthetic processes for precursors of HIV protease inhibitors(Amprenavir, Fosamprenavir) are described. These involve a novel and economical method for the preparation of a key intermediate, (3S)-hydroxytetrahydrofuran, from L-malic acid. Three new approaches to the assembly of Amprenavir are also discussed. Of these, a synthetic route in which an (S)-tetrahydrofuranyloxy carbonyl is attached to L-phenylalanine appears to be the most promising manufacturing process, in that it offers satisfactory stereoselectivity in fewer steps.

 

Graphical abstract: New approaches to the industrial synthesis of HIV protease inhibitors

…………………

EP 0659181; EP 0885887; JP 1996501299; US 5585397; WO 9405639

The reaction of the chiral epoxide (I) with isobutylamine (II) in refluxing ethanol gives the secondary amine (III), which is protected with benzyl chloroformate (IV) and TEA, yielding the dicarbamate (V). Selective deprotection of (V) with dry HCl in ethyl acetate affords the primary amine (VI), which is treated with 3(S)-tetrahydrofuryl N-succinimidinyl carbonate (VII) (prepared by condensation of tetrahydrofuran-3(S)-ol (VIII) with phosgene and N-hydroxysuccinimide (IX)) and DIEA in acetonitrile to provide the corresponding carbamate (X). The deprotection of (X) by hydrogenation with H2 over Pd/C in ethanol gives the secondary amine (XI), which is condensed with 4-nitrophenylsulfonyl chloride (XII) by means of NaHCO3 in dichloromethane/water to yield the sulfonamide (XIII). Finally, the nitro group of (XIII) is reduced with H2 over Pd/C in ethyl acetate to afford the target

………………………….

The reaction of the chiral epoxide (I) with isobutylamine (II) in refluxing ethanol gives the secondary amine (III), which is protected with benzyl chloroformate (IV) and TEA, yielding dicarbamate (V). Selective deprotection of (V) with dry HCl in ethyl acetate affords the primary amine (VI), which is treated with 3(S)-tetrahydrofuryl N-succinimidinyl carbonate (VII) — obtained by reaction of tetrahydrofuran-3(S)-ol (VIII) first with phosgene and then with N-hydroxysuccinimide (IX) — and DIEA in acetonitrile to provide the corresponding carbamate (X). Deprotection of (X) by hydrogenation with H2 over Pd/C in ethanol gives the secondary amine (XI), which is condensed with 4-nitrophenylsulfonyl chloride (XII) by means of NaHCO3 in dichloromethane/water to yield the sulfonamide intermediate (XIII).

……………………………

 

Esterification of the OH group of compound (XIII) with PO3H3 by means of DCC in hot pyridine gives the corresponding phosphite (XVII), which is oxidized with bis(trimethylsilyl)peroxide in bis(trimethylsilyl)azane to yield the expected phosphate (XVIII). Reduction of the nitro group of (XVIII) with H2 over Pd/C in ethyl acetate affords fosamprenavir (XIX). Finally, fosamprenavir (XIX) is treated with aqueous NaHCO3 or with calcium acetate in water to provide the corresponding salts. Alternatively, the phosphate (XIX) can be obtained directly by reaction of intermediate (XIII) with POCl3 in pyridine, followed by hydrolysis with 2N HCl.

………………………………………..

HIV protease inhibitor; water soluble prodrug of amprenavir, q.v. Prepn: R. D. Tung et al., WO 9933815;eidem, US 6559137 (1999, 2003 both to Vertex).

Prepn of crystalline calcium salt: I. G. Armitage et al., WO 0004033 (2000 to Glaxo); eidem, US 6514953 (2003 to SKB).

Clinical pharmacokinetics: C. Falcoz et al., J. Clin. Pharmacol. 42, 887 (2002).

Review of pharmacology and clinical experience in HIV: T. M. Chapman et al., Drugs 64, 2101-2124 (2004); C. Arvieux, O. Tribut,ibid. 65, 633-659 (2005).

References

  1.  Eron J Jr, Yeni P, Gathe J Jr et al. (2006). “The KLEAN study of fosamprenavir-ritonavir versus lopinavir-ritonavir, each in combination with abacavir-lamivudine, for initial treatment of HIV infection over 48 weeks: a randomised non-inferiority trial”. Lancet 368 (9534): 476–82.doi:10.1016/S0140-6736(06)69155-1. PMID 16890834.

 

WO1994005639A1 * Sep 7, 1993 Mar 17, 1994 Vertex Pharma Sulfonamide inhibitors of hiv-aspartyl protease
WO1994018192A1 Feb 7, 1994 Aug 18, 1994 Merck & Co Inc Piperazine derivatives as hiv protease inhibitors
INKO02772010A Title not available
US5585397 Sep 7, 1993 Dec 17, 1996 Vertex Pharmaceuticals, Incorporated Viricides
US6281367 Mar 18, 1999 Aug 28, 2001 Glaxo Wellcome Inc. Process for the synthesis of HIV protease inhibitors
US6436989 Dec 24, 1997 Aug 20, 2002 Vertex Pharmaceuticals, Incorporated Prodrugs of aspartyl protease inhibitors
US6514953 Jul 15, 1999 Feb 4, 2003 Smithkline Beecham Corporation Calcium (3S) tetrahydro-3-furanyl(1S,2R)-3-[[(4-aminophenyl)sulfonyl](isobutyl)amino]-1-benzyl-2-(phosphonooxy)propylcarbamate
Reference
1 * EKHATO I VICTOR ET AL: “Isotope labeled ‘HEA/HEE’ moiety in the synthesis of labeled HIV-protease inhibitors. Part II“, JOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, JOHN WILEY, CHICHESTER, GB, vol. 48, no. 3, 1 January 2005 (2005-01-01), pages 179-193, XP009112607, ISSN: 0362-4803
2 * MOON KIM B ET AL: “SYNTHESIS OF A CHIRAL AZIRIDINE DERIVATIVE AS A VERSATILE INTERMEDIATE FOR HIV PROTEASE INHIBITORS“, ORGANIC LETTERS, AMERICAN CHEMICAL SOCIETY, US, vol. 3, no. 15, 1 January 2001 (2001-01-01), pages 2349-2351, XP001179485, ISSN: 1523-7060, DOI: 10.1021/OL016147S
3 * SORBERA, L. A. ET AL.: “FOSAMPRENAVIR“, DRUGS OF THE FUTURE, PROUS SCIENCE, ES, vol. 26, no. 3, 1 March 2001 (2001-03-01), pages 224-231, XP009001334, ISSN: 0377-8282, DOI: 10.1358/DOF.2001.026.03.615590

 

Vertex Pharmaceuticals’ Boston Campus, United States of America

 

 

Promising Antiviral Compounds Discovered


Scientists sifted through thousands of potentially efficacy compounds and managed to identify two promising candidates for the development of drugs against human adenovirus, a cause of ailments ranging from colds to gastrointestinal disorders to pink eye

Scientists at the U.S. Department of Energy’s Brookhaven National Laboratory have identified two promising candidates for the development of drugs against human adenovirus, a cause of ailments ranging from colds to gastrointestinal disorders to pink eye. A paper published in FEBS Letters, a journal of the Federation of European Biochemical Societies, describes how the researchers sifted through thousands of compounds to determine which might block the effects of a key viral enzyme they had previously studied in atomic-level detail.

http://www.dddmag.com/news/2013/07/promising-antiviral-compounds-discovered?et_cid=3348636&et_rid=523035093&type=cta

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