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Iloperidone (Fanapt)
Iloperidone (Fanapt), ILO-522, HP-873, Zomaril, 133454-47-4, antipsychotic
1-[4-[3-[4-(6-Fluoro-1,2-benzisoxazol-3-yl)-1-piperidinyl]propoxy]-3-methoxyphenyl]ethanone; 1-[3-(4-Acetyl-2-methoxyphenoxy)propyl]-4-(6-fluoro-1,2-benzisoxazol-3-yl)piperidine; 4′-[3-[4-(6-Fluoro-1,2-benzisoxazol-3-yl)-1-piperidinyl]propoxy]-3′-methoxyacetophenone
Aventis Pharma (Originator), Novartis (Licensee), Titan (Licensee)
Vanda Pharmaceuticals (Licensee)
Iloperidone(Fanapt) is a monoamine directed towards acting upon and antagonizing specific neurotransmitters, particularly multiple dopamine and serotonin receptor subtypes.
Schizophrenia is a chronic, severe, and debilitating mental disorder that affects approximately 2.4 million Americans, around 1.1% of the population. The net cost of this disorder is staggering as estimates from 2002 reveal this disorder to cost $62.7 billion. A major issue with the treatment of schizophrenia is that patients show varying levels of response and tolerance to available therapies. Although the symptoms of the disease are very severe, estimates show that approximately 3 out of 4 patients discontinue medication prior to completing 18 months of treatment, many times due to the severe side effects of the approved medications.
Synthesis
J.T. Strupczewski, K.J. Bordeau, Y. Chiang, E.J. Glamkowski, P.G.
Conway, R. Corbett, H.B. Hartman, M.R. Szewczak, C.A. Wilmot andG.C. Helsley, J. Med. Chem., 38, 1119 (1995).
US 4355037
V. Miklos, WO Patent 031497 (2010).
J.T. Strupczewski, EP Patent 0402644 (1990)
The product is protected by the U.S. Pat. No. 5,364,866, U.S. Pat. No. RE 39198 E and EP 402644 B1.U.S. Pat. No. 5,364,866 and U.S. Pat. No. 5,663,449.EP 542136, EP 612318, EP 730452, JP 95501055, JP 97511215, US 5364866, US 5776963, WO 9309102, WO 9511680.US 4355037,EP 0542136; EP 0612318; EP 0730452; EP 0957102; EP 0959075; EP 0959076; EP 0963984; JP 1995501055; JP 1997511215; US 5364866; US 5776963; WO 9309102; WO 9511680
The first reported synthetic method for Iloperidone is described in patent EP 402644 A1.
In U.S. Patent US5776963 and patent family EP4 (^ 644, there is disclosed a method for preparing iloperidone,
The synthetic method reported(4, 5) for 1 involves two chemical steps: O-alkylation of acetovanillone (2) with 1-bromo-3-chloropropane (3) to obtain chloro derivative 4 followed byN-alkylation of piperidine intermediate 5 with 4. The reported process for 4 comprises O-alkylation of 2 with 3 in acetone in the presence of potassium carbonate for 20 h to provide 4as an oil after usual work up, which was then vacuum (0.1 mmHg) distilled to collect desired product 4 at 141–143 °C with around 85% yield (Scheme 1, Path A). Some of the drawbacks of this process are as follows: longer reaction time (around 20 h), formation of 6–7% of dimer impurity (10, Scheme 2), high-vacuum distillation to achieve the quality, which is always a cumbersome process at industrial scale, requiring special apparatus and skill set, and degradation and charring of some portion of product during high-vacuum distillation. Further, the next step comprises N-alkylation of 4 with 5 in N,N-dimethylformamide (DMF) in the presence of potassium carbonate to provide iloperidone (1) as a crude solid, which was purified by crystallization using ethanol to yield pure 1 with 58% yield (Scheme 1, Path A). Some of the lacunae observed with the above process includes the following: (a) low yields, (b) formation of carbamate impurity 13 (Scheme 2) in the range 15–20% due to the use of potassium carbonate, (c) ineffective purification by crystallization using ethanol to eliminate carbamate impurity below 0.15%, and (d) iloperidone obtained by the above synthetic process was beige in color.
The synthetic route is as follows:
The reaction of piperidine-4-carboxylic acid (I) with formic acid and acetic anhydride gives 1-formylpiperidine-4-carboxylic acid (II), which is treated with SOCl2 and acetic anhydride to yield the corresponding acyl chloride (III). The Friedel-Crafts condensation of (III) with refluxing 1,3-difluorobenzene (IV) by means of AlCl3 affords 4-(2,4-difluorobenzoyl)-1-formylpiperidine (V), which is treated with hydroxylamine in refluxing ethanol to give the corresponding oxime (VI). The cyclization of (VI) by means of NaH in hot THF/DMF yields 6-fluoro-3-(1-formylpiperidin-4-yl)-1,2-benzisoxazole (VII), which is treated with HCl in refluxing ethanol to afford 6-fluoro-3-(4-piperidyl)-1,2-benzisoxazole (VIII). Finally, this compound is condensed with 4-(3-chloropropoxy)-3-methoxyacetophenone (IX) by means of K2CO3 in hot DMF. The intermediate 4-(3-chloropropoxy)-3-methoxyacetophenone (IX) can be obtained by condensation of 4-hydroxy-3-methoxyacetophenone (IX) with 3-chcloropropyl bromide (X) by means of NaH or K2CO3 in DMF.
Iloperidone, also known as Fanapt, Fanapta, and previously known as Zomaril, is an atypical antipsychotic for the treatment ofschizophrenia.
Accordingly, 6-fluoro-3-(4-piperidyl)-1,2-benzoxazole 1 and 1-[4-(3-chloropropoxy)-3-methoxy-phenyl]ethanone 2 were heated in presence of potassium carbonate using dimethylformamide solvent to afford 1-[4-[3-[4-(6-fluoro-1,2-benzoxazol-3-yl)-1-piperidyl]propoxy]-3-methoxy-phenyl]ethanone also called Iloperidone
It was approved by the U.S. Food and Drug Administration (FDA) for use in the United States on May 6, 2009.
It’s not yet approved in India.
Hoechst Marion Roussel Inc. made initial inquiries into the drug; however, in May 1996, they discontinued research, and in June 1997 gave research rights to Titan Pharmaceuticals. Titan then handed over worldwide development, manufacturing and marketing rights to Novartis in August 1998. On June 9, 2004, Titan Pharmaceuticals announced that the Phase III development rights have been acquired by Vanda Pharmaceuticals. The original launch date was scheduled for 2002. On November 27, 2007, Vanda Pharmaceuticals announced that the U.S. Food and Drug Administration (FDA) had accepted their New Drug Application for iloperidone, confirming the application is ready for FDA review and approval. On July 28, 2008, the FDA issued a “Not Approvable” letter to Vanda Pharmaceuticals concerning the drug, stating that further trials are required before a decision can be made concerning marketed usage of iloperidone.
Chemically designated as 1-[4-[3-[4-(6-fluoro-1,2-benzisoxazol-3-yl)-1-piperidinyl]propoxy]-3-methoxyphenyl]ethanone, is a second generation atypical antipsychotic agent. Iloperidone, also known as Fanapt, Fanapta, and Zomaril, was approved by the U.S. Food and Drug Administration (FDA) for use in the United States on May 6, 2009 and is indicated for the acute treatment of schizophrenia in adults. Iloperidone has been shown to act as an antagonist at all tested receptors. It was found to block the sites of noradrenalin (α2C), dopamine (D2A and D3), and serotonin (5-HT1A and 5-HT6) receptors.(2) In addition, pharmacogenomic studies identified single nucleotide polymorphisms associated with an enhanced response to iloperidone during acute treatment of schizophrenia. It is considered an “atypical” antipsychotic because it displays serotonin receptor antagonism, similar to other atypical antipsychotics. The older typical antipsychotics are primarily dopamine antagonists.(3)
Iloperidone won FDA approval for use treating schizophrenia in the United States on May 6, 2009
Iloperidone (1-[4-[3-[4-(6-fluoro-1,2-benzisoxazole-3-yl)-1-piperidinyl]propoxy]-3-methoxyphenyl]ethanone) is an atypical new-generation antipsychotic medicament belonging to the class of piperidinyl-benzisoxazole derivatives, which is used to treat schizophrenia, bipolar disorder and other psychiatric conditions. Iloperidone acts as a serotonin/dopamine receptor antagonist (5-HT2A/D2).
Iloperidone, also known as Fanapt, Fanapta, and previously known as Zomaril, is an atypical antipsychotic drug used for the treatment of schizophrenia. The chemical name of iloperidone is l-[4-[3-[4-(6-fluoro-l,2-benzisoxazol-3-yl)-l- piperidinyl]propoxy] -3-methoxyphenyl]ethanone.
EP 0402644 patent discloses first synthetic route of synthesis of iloperidone as shown in Scheme I, which consists of alkylation reaction between l-(4-(3-chloropropoxy-3- methoxyphenyl)ethanone of the formula (II) and 6-fluoro-3-piperidin-4-yl-l ,2 benzisoxazole hydrochloride of the formula (III) in presence of potassium carbonate in N,N dimethyl formamide. The reaction has been subsequently worked up and the compound of formula (I) is extracted from water using ethyl acetate. The compound of formula (I) is purified by crystallization using ethanol. The overall yield of compound of formula (I) is 58%.
Formula (I)
SCHEME 1 Further, we have analyzed the reported synthetic route for synthesis of iloperidone; following limitations have been observed and identified in the reported synthetic route:
a) The yield obtained using said synthetic route as reported in US RE39198 is 58%. Hence, this route of synthesis is not cost efficient at commercial scale due to low yield;
b) Use of potassium carbonate as a base in reaction leads to formation of carbon dioxide as one of the side products during the reaction, which further hinders in the manufacturing process by actively participating in manufacturing process and thereby leads to the formation o
Formula (IV)
which is in the range of 15-20%, and thereby resulting in low yield of iloperidone;
c) Purification by crystallization using ethanol as a solvent is not effective in eliminating or controlling carbamate impurity below 0.15% as per the ICH guide lines for the known impurities; and
d) Iloperidone obtained by the above synthetic process is beige in colour.
CN101768154 discloses the synthesis of iloperidone by N-alkylation reaction between l-(4-(3- chloropropoxy-3-methoxyphenyl)ethanone of the formula (II) and 6-fluoro-3-piperidin-4-yl-l,2 benzisoxazole hydrochloride of the formula (III) in inorganic alkaline solution, particularly; alkali metal carbonate solution. We have analyzed the reported synthetic route for synthesis of iloperidone and have observed and identified that the use of alkaline carbonate solution leads to the formation of carbamate impurity in the range of 1 to 1.5%.
Several patents were published after, describing essentially the same synthetic way such as US5364866 and US5663449.
The synthesis of iloperidone is described in USRE39198 (corresponding to EP 0 402 644 example 3) according to the following synthesis scheme:
In agreement with said patent, the intermediate isolated, 1-[4-(3-chloropropoxy)-3-methoxyphenyl]ethanone, is reacted with 6-fluoro-3-(4-piperidinyl)-1,2-benzisoxazole hydrochloride in N,N-dimethyl formamide at 90° C. for 16 hours. When the reaction is complete, the mixture is poured into water and extracted with ethyl acetate. The crude product thus obtained is crystallised twice from ethanol to give crystallised iloperidone with a total yield of 58%.
The yield of this process is very low; moreover, the process begins with two isolated intermediates, and requires an aqueous extractive work-up step with an increase in volumes and consequent reduction in the productivity and efficiency of the process. Said process also requires a double crystallisation step to obtain a beige product. The quality levels obtained are not described in the text of the example, but a beige color does not suggest a high-quality product, as iloperidone is a white substance.
The synthesis of intermediate 1-[4-(3-chloropropoxy)-3-methoxyphenyl]ethanone is disclosed in U.S. Pat. No. 4,366,162. Example 1 describes the preparation of said intermediate by reacting acetovanillone with 1-bromo-3-chloropropane in acetone with potassium carbonate. At the end of the reaction the resulting product is purified by distillation and obtained as an oily intermediate which is left to stand in order to obtain the solid intermediate.
The synthesis of intermediate 1-[4-(3-chloropropoxy)-3-methoxyphenyl]ethanone is also disclosed in U.S. Pat. No. 4,810,713. Preparation 12 describes the synthesis of said intermediate from acetovanillone and 1-bromo-3-chloropropane in sodium hydroxide alkalinized water. At the end of the reaction the product obtained is extracted in toluene, the organic phases are washed with basic aqueous solutions and finally, the intermediate 1-[4-(3-chloropropoxy)-3-methoxyphenyl]ethanone is crystallised with the aid of diisopropyl ether. The intermediate isolated is then recrystallised twice from cyclohexane and twice from petroleum ether.
An alternative process for the synthesis of iloperidone is reported in CN 102070626.
Scheme 2 shows the synthesis procedure:
The decision to alkylate acetovanillone with 1-chloro-3-propanol requires an extra synthesis step (to convert the OH group to an OR leaving group) compared with the procedure reported by the combination of patents USRE39198 (EP402644) and U.S. Pat. No. 4,366,162/U.S. Pat. No. 4,810,713, making said process less efficient from the economic standpoint.
WO2011061750 discloses an alternative iloperidone synthesis process as reported in Scheme 3:
Said process uses reagents such as methyl magnesium chloride to effect the Grignard reaction to convert the aldehyde group to a secondary alcohol group, which are much more complicated to manage on an industrial scale than the synthesis methods previously described. Moreover, the oxidation reaction of the next step uses reagents such as chromic acid or potassium permanganate, which have a very high environmental impact and very low industrial applicability.
WO2011055188 discloses a process for the synthesis of iloperidone comparable to the one reported in USRE39198 from two isolated intermediates 1-[4-(3-chloropropoxy)-3-methoxyphenyl]ethanone and 6-fluoro-3-(4-piperidinyl)-1,2-benzisoxazole hydrochloride. The same patent application also gives preparation examples of the intermediate 1-[4-(3-chloropropoxy)-3-methoxyphenyl]ethanone isolated as crystalline solid by procedures similar to those known in the literature.
CN 101824030 reports an iloperidone synthesis method similar to that of CN 102070626 which involves the same problems of inefficiency due to the additional step of inserting the leaving group required for alkylation with 6-fluoro-3-(4-piperidinyl)-1,2-benzisoxazole hydrochloride.
CN 101781243 discloses an alternative iloperidone synthesis process as reported in Scheme 4.
Said process is not advantageous compared with the preceding processes as the intermediate with the oxime group, due to the nature of this functional group, is particularly liable to degradation due to the action of numerous factors such as the presence of metals, acid pHs and basic pHs.
CN101768154 discloses a process for the synthesis of iloperidone comparable to the one reported in USRE39198 from two isolated intermediates, 1-[4-(3-chloropropoxy)-3-methoxyphenyl]ethanone and 6-fluoro-3-(4-piperidinyl)-1,2-benzisoxazole hydrochloride.
CN 101735208 describes a process for the synthesis of iloperidone comparable to the one reported in CN 101781243, namely through the intermediate with the functional oxime group.
IN 2007MU01980 discloses a process for the synthesis of iloperidone comparable to the one reported in USRE39198 from two isolated intermediates, 1-[4-(3-chloropropoxy)-3-methoxyphenyl]ethanone and 6-fluoro-3-(4-piperidinyl)-1,2-benzisoxazole hydrochloride.
WO 2010031497 describes an alternative iloperidone synthesis process as reported in Scheme 5.
The considerable economic disadvantage of the process reported in WO2010031497 is based on the fact that by reversing the order of alkylation and performing that of intermediate 6-fluoro-3-(4-piperidinyl)-1,2-benzisoxazole hydrochloride first, a greater loss of yield is generated on this intermediate which, according to the literature, is more difficult to synthesise and consequently more expensive than the intermediate 1-[4-(3-chloropropoxy)-3-methoxyphenyl]ethanone, with a globally greater economic inefficiency of the iloperidone preparation process.
CN 102212063 discloses a process for the synthesis of iloperidone with the same arrangement of the synthesis steps as patent application WO 2010031497.
WO2011154860 describes a process for the synthesis of iloperidone wherein a phase transfer catalyst is used to prepare the intermediate 1-[4-(3-chloropropoxy)-3-methoxyphenyl]ethanone which, as in all the other preparation examples previously described, is crystallised, isolated and dried before use in the next step with 6-fluoro-3-(4-piperidinyl)-1,2-benzisoxazole hydrochloride. Scheme 6 shows the synthesis scheme of the process of WO2011154860.
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EXAMPLE 1:
Tetrabutyl ammonium bromide (2.40 gm) was added to a stirred solution of Potassium hydroxide (0.724 kg) in mixture of Heptane (2.0L). and water (10.0L), followed by addition of 1- [4-(3-chloropropoxy)-3-methoxyphenyl]ethanone (2, 1.0kg) and 6-fluoro-3-piperidin-4-yl-l,2- benzisoxazole hydrochloride^, 1.1 1kg) at 30°C. This reaction mass was stirred for 15 to 20 min. The temperature of the reaction mass was raised to 70°C and was maintained for 8 to 10 hours. After completion of reaction (by TLC, Mobile Phase: Toluene/ Acetone/Ethyl acetate = 6:2:2 mL), the mixture was cooled to 30°C, diluted with dichloromethane (2.5 L) and stirred for 30 minutes. The dichloromethane layer was separated. The aqueous layer was re-extracted with dichloromethane (1.0L). The combined dichloromethane layer was washed with water (1.5L) and decolorized with activated charcoal (0.05 kg). The solvent was distilled off completely to obtain the residue. The residue obtained was dissolved in isopropyl alcohol (5.0L) at reflux temperature to obtain the clear solution. The clear solution obtained was cooled to 30°C followed by 0°C and stirred for 60 min to precipitate out crystals. The colorless crystals of compound (I) obtained were filtered. The crystalline solid was dried under vacuum (650-700 mm/Hg) to obtain pure compound (I) as a crystalline solid. HPLC analysis was performed for the crystalline solid obtained. The purity of Iloperidone, impurity profile and yield are shown in table 1 below.
Table 1 : Analysis data of iloperidone i.e. purity, yield and impurity profile.
EXAMPLE 2:
Tetrabutyl ammonium bromide (2.40 gm) was added to a stirred solution of Potassium hydroxide (0.724 kg) in mixture of Heptane (2.0L) and water (10.0L), followed by addition of 1- [4-(3-chloropropoxy)-3-methoxyphenyl]ethanone (2, 1.0kg) and 6-fluoro-3-piperidin-4-yl-l,2- benzisoxazole hydrochloride^, 1.1 1kg) at 30°C. This reaction mass was stirred for 15 to 20 min. The temperature of the reaction mass was raised to 70°C and maintained for 8 to 10 hours. After completion of reaction (by TLC, Mobile Phase: Toluene/ Acetone/Ethyl acetate = 6:2:2 mL), the mixture was cooled to 30°C, the reaction mixture was filtered to obtain wet crude iloperidone. Further, the obtained wet crude was dried at 60-65 °C under vacuum to furnish crude iloperidone (1.72 kg). The dried crude iloperidone was dissolved in isopropyl alcohol (5.0 L) at reflux temperature and decolorized with activated charcoal (0.05 kg). Obtained filtrate was cooled to 30°C followed by 0°C and stirred for 60 min to precipitate out crystals. The colorless crystals of compound (I) obtained were filtered. The crystalline solid was dried under vacuum (650-700 mm/Hg) to obtain pure compound (I) as a crystalline solid. HPLC analysis was performed for the crystalline solid obtained. The purity of Iloperidone, impurity profile and yield are shown in table 2 below.
Table 2: Analysis data of iloperidone i.e. purity, yield and impurity profile.
EXAMPLE-3:
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UPLC-MS [M+H+]=427
1H-NMR (in DMSO) (chemical shifts expressed in ppm with respect to the TMS signal): 2.06-1.78 (6H, m); 2.13 (2H, m); 2.49 (2H, t); 2.52 (2H, m); 2.97 (2H, m); 3.11 (1H, tt); 3.83 (3H, s); 4.12 (2H, t); 7.06 (1H, d); 7.22 (1H, m); 7.46 (1H, d); 7.61-7.58 (2H, m); 7.94 (1H, dd).
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.Improved and Efficient Process for the Production of Highly Pure Iloperidone: A Psychotropic Agent
http://pubs.acs.org/doi/full/10.1021/op400335p?prevSearch=iloperidone&searchHistoryKey=
The present work describes an improved and highly efficient process for the synthesis ofiloperidone (1), an antipsychotic agent, which is free from potential impurities. The synthesis comprises N-alkylation of 1-(4-(3-chloropropoxy)-3-methoxyphenyl)ethanone (4) with 6-fluoro-3-piperidin-4-yl-1,2-benzisoxazole hydrochloride (5) in a mixture of water and heptane as solvent and sodium hydroxide as a base in the presence of tetrabutylammonium bromide as a phase transfer catalyst to yield iloperidone (1) with a yield of around 95% and a purity of 99.80% by HPLC. The present work also describes the optimization details performed to achieve the process attributes responsible for high yield and purity.
FT-IR (KBr, λmax, cm–1): 3031, 2949, 2779, 2746, 2822, 1669, 1614, 1585, 1510, 1462, 1448, 1415, 1380, 1313, 1262, 1221, 1177, 1150, 1123, 1077, 1034, 997, 985, 955, 884, 876, 853, 812, 781, 643, 610, 569, 475.
1H NMR (CDCl3): δ 2.03–2.10 (m, 6H), 2.12–2.18 (m, 2H), 2.55–2.56 (s, 3H), 2.58–2.60 (t, 2H), 3.02–3.09 (m, 3H), 3.91 (s, 3H), 4.10–4.19 (t, 2H), 6.91–6.93 (d, 1H), 7.01–7.06 (dd, 1H), 7.21–7.24 (dd, 1H), 7.51–7.52 (d, 1H), 7.53–7.56 (dd, 1H), 7.69–7.65 (dd, 1H).
13C NMR (CDCl3): 26.02, 26.40, 30.36, 34.34, 53.36, 54.90, 55.80, 67.16, 97.04, 97.31, 110.20, 111.02, 111.98, 112.23, 117.12, 122.36, 122.46, 123.06, 130.11, 149.00, 152.66, 160.91, 162.60, 163.53, 163.66, 165.09, 198.59.
MS (ESI, m/z): 427.2 [M + H].+
Anal. Calcd (%) for C24H27FN2O4(426.48): C, 67.54; H, 6.33; found (%): C, 67.24; H, 6.18.
HPLC
HPLC analysis developed at Megafine India using a Hypersil BDS C18 column (250 mm × 4.6 mm, particle size 5 μm); mobile phase A comprising a mixture of 5.0 mM ammonium dihydrogen orthophosphate buffer and 0.1% triethylamine; mobile phase B comprising a mixture of acetonitrile/methanol in the ratio 80:20 v/v; gradient elution: time (min)/A (v/v): B (v/v); T0.01/65:35, T8.0/65:35, T25.0/35:65, T35.0/35:65, T37.0/65:35, T45.0/65:35; flow rate 1.0 mL/min; column temperature 30 °C; wavelength 225 nm. The observed retention time of iloperidone under these chromatographic conditions is about 17.0 min.
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http://www.asianjournalofchemistry.co.in/User/ViewFreeArticle.aspx?ArticleID=25_10_2
N oxide impurity
m.p. 155-157 ºC;
FT-IR (KBr, νmax, cm-1):
3083, 2958, 2878, 1655, 1606, 1584, 1509, 1467, 1419, 1348,1273, 1223, 1182, 1143, 1121, 1032, 971, 957, 881, 857, 813,
802;
1H NMR (300 MHz, CDCl3)
δ 1.89-1.93 (m, 2H), 2.31-2.40 (m, 2H), 2.55 (s, 3H), 2.60-2.72 (m, 2H), 3.29-3.52 (m,
2H), 3.29-3.52 (m, 2H), 3.29-3.52 (m, 2H), 3.29-3.52 (m, 1H),3.85 (s, 3H), 4.23(t, 2H, J = 6.0 Hz), 7.11 (d, 1H, J = 8.4 Hz),7.30-7.36 (m, 1H), 7.62-7.65 (m, 1H), 7.71-7.74 (dd, J = 9.3and 2.0 Hz, 1H), 8.02-8.07 (dd, J = 8.7 and 5.4 Hz, 1H);
13CNMR (75 MHz, CDCl3)
δ 22.13, 24.70, 26.35, 31.49, 55.54,63.21, 67.07, 67.82, 97.51, 110.35, 111.86, 112.67, 123.11,
123.67, 129.95, 148.63, 152.22, 160.79, 163.10, 163.69,196.40;
MS (ESI, m/z): 443 [M + H]+.
Anal. calcd. (%) forC24H27N2O5F (442.19): C, 65.15; H, 6.15; N, 6.33; found (%):C, 65.11; H, 6.09; N, 6.29.
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INTERMEDIATES
FANAPT is a psychotropic agent belonging to the chemical class of piperidinyl-benzisoxazole derivatives. Its chemical name is 4′-[3-[4-(6-Fluoro-1,2-benzisoxazol-3-yl)piperidino]propoxy]-3′-methoxyacetophenone. Its molecular formula is C24H27FN2O4 and its molecular weight is 426.48. The structural formula is:
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Iloperidone is a white to off-white finely crystalline powder. It is practically insoluble in water, very slightly soluble in 0.1 N HCl and freely soluble in chloroform, ethanol, methanol, and acetonitrile.
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Title: Iloperidone
CAS Registry Number: 133454-47-4
CAS Name: 1-[4-[3-[4-(6-Fluoro-1,2-benzisoxazol-3-yl)-1-piperidinyl]propoxy]-3-methoxyphenyl]ethanone
Manufacturers’ Codes: HP-873; ILO-522
Trademarks: Zomaril (Novartis)
Molecular Formula: C24H27FN2O4
Molecular Weight: 426.48
Percent Composition: C 67.59%, H 6.38%, F 4.45%, N 6.57%, O 15.01%
Literature References: Combined dopamine (D2) and serotonin (5HT2) receptor antagonist. Prepn: J. T. Strupczewski et al., EP402644; eidem, US 5364866 (1990, 1994 both to Hoechst-Roussel); eidem, J. Med. Chem. 38, 1119 (1995).
Pharmacology: M. R. Szewczak et al., J. Pharmacol. Exp. Ther. 274, 1404 (1995).
Clinical pharmacokinetics: S. M. Sainati et al., J. Clin. Pharmacol.35, 713 (1995).
HPLC determn in plasma: A. E. Mutlib, J. T. Strupczewski, J. Chromatogr. B 669, 237 (1995). Receptor binding study: S. Kongsamut et al., Eur. J. Pharmacol. 317, 417 (1996).
Review of pharmacology and therapeutic potential in schizophrenia: J. M. K. Hesselink, Curr. Opin. Cent. Peripher. Nerv. Syst. Invest. Drugs 2, 71-78 (2000); K. K. Jain, Expert Opin. Invest. Drugs 9, 2935-2943 (2000).
Properties: Crystals from ethanol, mp 118-120°.
Melting point: mp 118-120°
Therap-Cat: Antipsychotic.
Keywords: Antipsychotic; Benzisoxazoles; Serotonin-Dopamine Antagonist.
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Bjork, A. K. K.; Abramo, A. L.; Kjellberg, B. E. S. US 4366162, 1982.
-
Strupczewski, J. T.; Helsley, G. C.; Chiang, Y.; Bordeau, K. J. EP 0402644A1, 1990.
-
Ansari, S. A.; Hirpara, H. M.; Yadav, A. K.; Gianchandani, J. P. WO2012164516, 2012.
-
Azad, M. A. K.; Pandey, G.; Singh, K.; Prasad, M.; Arora, S. K. WO2012/090138 A1, 2012.
-
Dwivedi, S. D.; Patel, D. J.; Shah, A. P. WO2012/063269, 2012.
-
Athalye, S. S.; Parghi, K. D.; Ranbhan, K. J.; Sarjekar, P. B. WO2012/153341, 2012.
-
Raman, J. V.; Rane, D.; Kevat, J.; Patil, D. WO2011/154860, 2011.
-
Reguri, B. R.; Arunagiri, M.; Yarroju, P. C.; Kasiyappan, G. S.; Ponnapall, K. WO2011/055188, 2011.
-
Shiwei, Z.; Feng, J. US 2012/0172699A1, 2012.
-
Bettoni, P.; Roletto, J.; Paissoni, P. EP 2644608A1, 2013.
-
Mathad, V. T.; Solanki, P. V.; Pandit, B. S.; Uppelli, S. B. WO2012/123963 A2, 2012.
-
Strupczewski, J. T.; Allen, R. C.; Gardner, B. A.; Schmid, B. L.; Stache, U.; Glamkowski, E. J.; Jones, M. C.; Ellis, D. B.; Huger, F. P.; Dunn, R. W. J. Med. Chem. 1985, 28, 761–769
[ACS Full Text
], [PubMed], [CAS]-
20 Mucke, H. A. M.; Castañer, J. Drugs Future 2000, 25(1), 29.
-
(21) Steiner, G.; Bach, A.; Bialojan, S.; Greger, G.; Hege, H.-G.;.Höger, T.; Jochims, K.; Munschauer, R.; Neumann, B.; Teschendorf, H.-J.; Traut, M.; Unger, L.; Gross, G. Drugs Future 1998 23(2), 191.
WO2003037337A1 * Oct 29, 2002 May 8, 2003 Markus Ahlheim Depot formulations of iloperidone and a star polymer WO2008027993A2 * Aug 29, 2007 Mar 6, 2008 Eurand Inc Drug delivery systems comprising solid solutions of weakly basic drugs CN101768154A Sep 19, 2009 Jul 7, 2010 浙江华海药业股份有限公司 New preparation method of iloperidone EP0402644A1 May 16, 1990 Dec 19, 1990 Hoechst-Roussel Pharmaceuticals Incorporated N-(aryloxyalkyl)heteroarylpiperidines and -heteroarylpiperazines,a process for their preparation and their use as medicaments EP0542136A1 * Nov 5, 1992 May 19, 1993 Hoechst-Roussel Pharmaceuticals Incorporated Heteroarylpiperidines, pyrrolidines and piperazines and their use as antipsychotics and analgetics US5364866 Oct 30, 1992 Nov 15, 1994 Hoechst-Roussel Pharmaceuticals, Inc. Heteroarylpiperidines, pyrrolidines and piperazines and their use as antipsychotics and analetics US5663449 Jun 6, 1995 Sep 2, 1997 Hoechst Marion Roussel, Inc. Intermediate compounds in the synthesis of heteroarylpiperidines, pyrrolidines and piperazines USRE39198 Nov 15, 2000 Jul 18, 2006 Aventis Pharmaceuticals Inc. Heteroarylpiperidines, pyrrolidines and piperazines and their use as antipsychotics and analgesics -
IRBESARTAN
IRBESARTAN, SR 47436, BMS-186295
Avapro® (Bristol-Myers Squibb) and Karvea®
(Sanofi-Winthrop)
2-butyl-3-({4-[2-(2H-1,2,3,4-tetrazol-5-yl)phenyl]phenyl}methyl)-1,3-diazaspiro[4.4]non-1-en-4-one
138402-11-6 CAS NO
U.S. Patents 5,270,317 and 5,352,788, 6,162,922
The compound prepared according to US 5270317 is polymorph A
-
Irbesartan is known by following chemical names:
- (a) 2-Butyl-3-[[2′-(1H-tetrazol-5-yl)[1,1′-biphenyl]-4-yl]methyl]-1,3-diazaspiro[4,4]non-1-en-4-one
- (b) 2-Butyl-3-[p-(o-1H-tetrazol-5-ylphenyl)benzyl]-1,3-diazaspiro[4,4]non-1-en-4-one
- (c) 2-n-butyl-4-spirocyclopentane-1-[(2′-(tetrazol-5-yl)biphenyl-4-yl) methyl]-2-imidazolin-5-one.
-
The structural formula of Irbesartan is represented below.
Irbesartan
-
The synthesis of irbesartan is first disclosed in US5270317 (equivalentEP0454511 ) and subsequently, several other patents disclose the synthesis of irbesartan by different methods. Basically the synthesis of this molecule involves two common intermediates namely spiroimidazole and substituted 4′-bromomethylbiphenyl.
-
US 5270317 describes preparation of irbesartan wherein 1-[(2′-cyanobiphenyl-4-yl)methyl]-2-n-butyl-4-spirocyclopentane-2-imidazolin -5-one which is reacted with tributyltin azide in xylene at reflux temperature for 66 hours to give a product which is isolated from the reaction mass as trityl irbesartan and then deprotected in methanol/THF mixture using 4N hydrochloric acid to get irbesartan.
-
US5629331 describes a process for the preparation of irbesartan from 1-[(2′-cyanobiphenyl)4-yl)methyl]-2-n-butyl-4-spirocyclopentane-2-imidazolin-5-one using sodium azide, TEA.HCl in N-methylpyrrolidone. The product is isolated from the alkaline reaction mass after acidification to pH 4.7 to 5.8 and the crude product is recrystallised from IPA/water to get Form A and ethanol/water to get Form B.
Irbesartan (INN) /ɜrbəˈsɑrtən/ is an angiotensin II receptor antagonist used mainly for the treatment of hypertension. Irbesartan was developed by Sanofi Research (now part ofsanofi-aventis). It is jointly marketed by sanofi-aventis and Bristol-Myers Squibb under thetrade names Aprovel, Karvea, and Avapro.
It is marketed in Brazil by Sanofi-Aventis under the trade name Aprovel .
As with all angiotensin II receptor antagonists, irbesartan is indicated for the treatment ofhypertension. Irbesartan may also delay progression of diabetic nephropathy and is also indicated for the reduction of renal disease progression in patients with type 2 diabetes,[1]hypertension and microalbuminuria (>30 mg/24 hours) or proteinuria (>900 mg/24 hours).[2]
Irbesartan is also available in a combination formulation with a low dose thiazide diuretic, invariably hydrochlorothiazide, to achieve an additive antihypertensive effect. Irbesartan/hydrochlorothiazide combination preparations are marketed under similar trade names to irbesartan preparations, including Irda, CoIrda, CoAprovel, Karvezide,Avalide and Avapro HCT.
A large randomized trial following 4100+ men and women with heart failure and normal ejection fraction (>=45%) over 4+ years found no improvement in study outcomes or survival with irbesartan as compared to placebo.[3]
BMS annual sales approx $1.3bn. Sanofi-aventis annual sales approx $2.1bn. In the United States, a generic version is available. Patent expired March 2012.
- Lewis EJ, Hunsicker LG, Clarke WR, Berl T, Pohl MA, Lewis JB, Ritz E, Atkins RC, Rohde R, Raz I; Collaborative Study Group. (2001). “Renoprotective effect of the angiotensin-receptor antagonist irbesartan in patients with nephropathy due to type 2 diabetes”. N Engl J Med 345 (12): 851–60. doi:10.1056/NEJMoa011303.PMID 11565517.
- Rossi S, editor. Australian Medicines Handbook 2006. Adelaide: Australian Medicines Handbook; 2006. ISBN 0-9757919-2-3
- Massie BM, Carson PE, McMurray JJ, Komajda M, McKelvie R, Zile MR, Anderson S, Donovan M, Iverson E, Staiger C, Ptaszynska A (December 2008). “Irbesartan in patients with heart failure and preserved ejection fraction”. N. Engl. J. Med. 359 (23): 2456–67.doi:10.1056/NEJMoa0805450. PMID 19001508.
4……….C. A. Bernhart, P. M. Perreaut, B. P. Ferrari, Y. A. Muneaux,
J.-L. A. Assens, J. Clement, F. Haudricourt, C. F. Muneaux,
J. E. Taillades, M.-A. Vignal, J. Gougat, P. R. Guiraudou, C.
A. Lacour, A. Roccon, C. F. Cazaubon, J.-C. Brelihre, G. Le
Fur, D. Nisato, J. Med. Chem. 1993, 36, 3371–3380.
5…. K. F. Croom, M. P. Curran, K. L. Goa, Drugs 2004 64,
999–1028.
6… C. Bernhard, J.-C. Breliere, J. Clement, D. Nisato, P. M. Perreaut, C. F. Muneaux, (Elf Sanofi) US 5 270 317; Chem. Abstr. 1993, 119, 95560.
7. S. Chava, M. Bandari, K. S. Mathuresh, (Matrix Laboratories) WO 2005/122699; Chem. Abstr. 2005, 144, 88292.
5. S. Zupan~i~, A. Pe~avar, R. Zupet, (Krka) WO 2006/073376;
Chem. Abstr. 2006, 145, 124576.
8. C. V. Kavitha, S. L. Gaonkar, J. N. Chandra, S. Narendra, C.
T. Sadashiva, K. S. Rangappa, Bioorg. Med. Chem. 2007, 15,
7391–7398.
9. S. Rádl, J. Stach, O. Klecán, (Zentiva) WO 2005/021535;
Chem. Abstr. 2005, 142, 298118.
10. B. Satyanarayana, Y. Anjaneyulu, P. Veerasomaiah, P. P.
Reddy, Heterocycl. Commun. 2007, 13, 223–228.
11. V. V. Korrapati, P. Rao, R. Dandala, V. K. Handa, I. V. S. Rao,
A. Rani, A. Naidu, Synth. Commun. 2007, 37, 2897–2905.
12. J. Havlí~ek, Z. Mandelová, R. Weisemann, I. Strˇelec, S.
Rádl, Collect. Czech. Chem. Commun. 2009, 77, 347.
Irbesartan of formula (I).
The chemical name of Irbesartan is 2-Butyl-3-[[2′-(lH-tetrazol-5-yl)[l,l’-biphenyl]-4- yl]methyl]-l,3-diazaspiro[4,4]non-l-en-4-one and formula is C2SH2SN6O and molecular weight is 428.53. The current pharmaceutical product containing this drug is being sold by Sanofi Synthelabo using the tradename AVAPRO, in the form of tablets. Irbesartan is useful in the treatment of diabetic neuropathy, heart failure therapy and hypertension. Irbesartan is angiotension II type I (AΙIi)-receptor antagonist. Angiotension II is the principal pressor agent of the rennin-angiotension system and also stimulates aldosterone synthesis and secretion by adrenal cortex, cardiac contraction, renal resorption of sodium, activity of the sympathetic nervous system and smooth muscle cell growth. Irbesartan blocks the vasoconstrictor and aldosterone- secreting effects of angiotension II by selectively binding to the ATi angiotension II receptor. U.S. Pat. Nos. 5,270,317 and 5,559,233 describes a process for the preparation of N- substituted heterocyclic derivatives which involves reacting a heterocyclic compound of the formula
with a (biphenyl-4-yl)methyl derivative of the formula
wherein R1, R2, R3, R4, R5, and t, z and Hal have the meanings given in said U.S. Pat. No.
5,270,317, in the presence of an inert solvent such as DMF, DMSO or THF, with a basic reagent, for example KOH, a metal alcoholate, a metal hydride, calcium carbonate or triethylamine. The products of the reaction were purified by chromatography.
U.S. Pat. Nos. 5,352,788, and 5,559,233, and WO 91/14679 also describe identical alkylation of the nitrogen atom of the heterocyclic compound with the halo-biphenyl compound using the same inert solvent and the same basic reagents.
-
US5629331 describes a process for the preparation of irbesartan from 1-[(2′-cyanobiphenyl)4-yl)methyl]-2-n-butyl-4-spirocyclopentane-2-imidazolin-5-one using sodium azide, TEA.HCl in N-methylpyrrolidone. The product is isolated from the alkaline reaction mass after acidification to pH 4.7 to 5.8 and the crude product is recrystallised from IPA/water to get Form A and ethanol/water to get Form B.
-
WO 2005/051943 A1 describes a process for the preparing irbesartan wherein 1-[(2′-cyanobiphenyl-4-yl)methyl]-2-n-butyl-4-spirocyclopentane-2-imidazolin-5-one is reacted with tributyltin chloride, sodium azide and TBAB in toluene at reflux temperature for 20 hours. Product is isolated from the reaction mass as trityl irbesartan and then deprotected in methanol and formic acid to get irbesartan.
-
WO 2006/023889 describes a method for preparing irbesartan, wherein 1-(2′-cyanobiphenyl-4-yl)methyl)-2-n-butyl-4-spirocyclopentane-2-imidazolin-5-one is reacted with sodium azide and triethylamine hydrochloride in N-methyl-2-pyrrolidone to give irbesartan.
-
WO 2005/113518 describes a process for preparing irbesartan wherein cyano irbesartan in xylene, is reacted with tributyltin chloride and sodium azide at reflux temperature till reaction is completed followed by aqueous work-up and recrystallization to give irbesartaN
-
The process involving use of zinc salt for the transformation of nitrile to tetrazole is a safe and efficient process as reported in JOC (2001) 66, 7945-50. The use of zinc salt for transforming nitrile to tetrazole has also been published in WO9637481 and US5502191
Also Canadian Patent No. 2050769 describes the alkylation of the nitrogen atom of the heterocycle of the formula
with a compound of the formula
wherein X, R1, Z1 and Z6 have the meanings given therein, in the presence of N,N- dimethylformamide and a basic reagent, such as alkali metal hydrides for example sodium or potassium hydride.
All of the above identified patents describe alkylation in solvents, such as N5N- dimethylformamide or DMSO, etc. in the presence of a basic reagent, for example, a metal hydride or a metal alcoholate etc. The strong bases, such as metal hydride or a metal alcoholate require anhydrous reaction conditions. Since N,N-dimethylformamide is used as a solvent, its removal requires high temperature concentration by distillation, which can result in degradation of the final product. The product intermediate is also purified by chromatography which is commercially not feasible and cumbersome on large scale. Another process given in Canadian Patent No. 2050769 provides synthetic scheme as herein given below.
This process comprises the steps of protecting carboxylic group present on cyclopentane ring which is deprotected in consecutive step by vigourous hydrogenation condition in autoclave which is operationally difficult at a large scale.
US Patent No. 2004242894 also discloses the process of preparation of lrbesartan from 4- bromomethyl biphenyl 2′-(lH-tetrazol (2-triphenylmethyl) 5-yl) and Ethyl ester of 1- Valeramido cyclopentanecarboxylic acid in toluene in presence of base and PTC, and then hydrolyzing the protecting group. However this requires chromatographic purification.
This patent also discloses the process of preparation of tetrazolyl protected lrbesartan using 2,6 lutidine and oxalylchloride in toluene. However in this process the yield is as low as 30%.
US Patent No. 2004192713 discloses the process of preparation of lrbesartan by condensing the two intermediates via Suzuki coupling reaction. The reaction scheme is as given herein below.
However, this process has several disadvantages such as use of the reagents like butyl lithium and triisobutyl borate at low temp such as -20 to -30°C under Argon atmosphere condition which is difficult to maintain at commercial scale.
WO2005113518 discloses the process of preparation of Irbesartan by condensing n- pentanoyl cycloleucine (V) with 2-(4-aminomethyl phenyl) benzonitrile (VI) using dicyclocarbodiimide (DCC) and 1 -hydroxy benzotriazole as catalyst to give an open chain intermediate of formula (VIII) which is then cyclized in the presence of an acid, preferably trifluoro acetic acid to give cyano derivative of formula (VII) and which in turn is converted to Irbesartan by treating it with tributyl tin chloride and sodium azide.
In this application further describes another process comprising the steps of reacting 2- butyl-l,3-diazasρiro[4,4]non-l-en-4-one monohydrochloride (A) with 4-bromobenzyl bromide (B) in presence of base and solvent to give 3-[4-bromobenzyl]-2-butyl-l,3- diazaspiro[4,4]non-l-en-4-one (C) which is condensed with 2-[2′-(triphenylmethyl-2’H- tetrazol-5′-yl)phenyl boronic acid in the presence of tetrakis triphenyl phosphine palladium and base to give lrbesartan (I). However these processes suffer with several disadvantages such as it uses trifluoroacetic acid for the cyclization step which is highly corrosive material. The process requires an additional step of activation by DCC. This step not only increases number of steps but also create problem in handling DCC at an industrial scale as it is highly prone to hazard which makes the process least preferred on a large scale production of lrbesartan. Further it uses phenyl boronic acid derivative and triphenyl phosphine complex which are harmful for the skin and eye tissue and also harmful for respiratory system. Tetrakis triphenyl phosphine palladium is also a costly material which increases overall cost for the production of lrbesartan. Moreover the yield is as low as 22%. All the above patents/applications are incorporated herein as reference. In summary, prior art relating to the process for the preparation of lrbesartan suffers with several drawbacks such as i) It requires chromatographic purification of intermediates at various stages. ii) It requires specific autoclave conditions for a deprotection of protecting group. iii) It requires maintaining low temperature conditions such as -300C and requires special handling care and air and moisture tight condition with the reagents such as butyl lithium and triisobutyl borate. iv) It uses hazardous and highly corrosive reagents, v) It suffers low yield problem. vi) All the process is having more number of reaction steps.
- Irbesartan is described in Bernhart et al., U.S. Patent No. 5,270,317
-
Irbesartan, is a potent, long-acting angiotensin II receptor antagonist which is particularly useful in the treatment of cardiovascular ailments such as hypertension and heart failure. Its chemical name is2-n-butyl-4-spirocyclopentane-1-[(2′-(tetrazol-5-yl)biphenyl-4-yl)methyl]-2-imidazolin-5-one.
Irbesartan is an antihypertensive agent known from EP 454511. From EP 708103, which discloses their X-ray spectra, two polymorphs are known where form A can be produced form a solvent system containing less than 10% of water, while Form B from a system with more than 10% of water. The specific morphological variant of form A can be prepared having properties as disclosed in EP 1089994. Additional form has been disclosed in WO 04089938. Amorphous irbesartan is known from WO 03050110. It is said that Irbesartan produced as taught in EP 454511 is a fluffy material with relatively low bulk and tap densities and undesirable flow characteristics, which consequently has unadvantageous electrostatic properties, among them a high chargeability as measured by tribugeneration between -30 and -40 nanocoulomb/g (10‘9As/g). Alternativelyirbesartan could be prepared by complex process using sonifications and/or temperature oscillations according to EP 1089994 to exhibit a chargeability as measured by tribugeneration between -0 and -10 nanocoulomb/g.
According to EP 454511 a solid composition in form of tablets is prepared by mixing the active ingredient with a vehicle such as gelatine, starch, lactose, magnesium stearate, talc, gum Arabic or the like and can be optionally coated. The compositions containing from 20% to 70% by weight of irbesartan are known from EP 747050.
WO 04/007482 teaches the acidification to pH 2 – 3,5 of trityl irbesartan, which is sufficient to remove the protecting group, but not to convert into an acid addition salt; WO 04/065383 is likewise silent on hydrohalide acid addition salts. WO
06/011859 relates to the preparation of a hydrochloride salt of irbesartan in order to incorporate it into a pharmaceutical formulation. W099/38847 mentions optional conversion of irbesartan into hydrochloride, hydrobromide or hydrogen sulfate salts
……………………………………………
…………………
Example 1Preparation of Compounds of formula IVa and IVb:
-
-
A jacketed 1,000 mL 3-neck flask was charged with 4′-methylbiphenyl-2-carbonitrile (Compound 1, 100.0 g) and CH2CI2 (500 mL) under nitrogen. To a 500 mL Erlenmeyer flask with magnetic stirrer, sodium bromate (NaBrO3; 31.2 g) was dissolved in water (170 mL). The NaBrO3 solution was transferred to the 1,000 mL flask and the reaction mixture was cooled to about 5 °C or less. Aqueous HBr solution (48 %, 105.0 g) was added to the 1,000 mL flask and the resulting reaction mixture was recycled though a UV lamp reactor. The reaction mixture was kept at 0-20 °C and the recycling was continued until the reaction was deemed complete by HPLC. Optionally, additional sodium bromate and hydrogen bromide may be added. The relative amounts of Compound 2 and Compound 3 were about 80-90% and about 10-20% respectively. Aqueous sodium metabisulfite solution (2.0 g of in 10 mL water) was added to the reaction mixture. Allow the phases to settle and the methylene chloride phase was washed with water and used in the next step without further purification.
Example 2Preparation of Compound II:
-
-
A 1L 3-neck flask was charged with Compound V (134.0 g), MTBAC (5.0 g) and CH2Cl2 (170 mL) and cool to -5 to 5 °C. An aqueous solution of KOH (182.6 g in 212 mL water) was added slowly to the 1L flask and the reaction temperature was kept at ≤ 5 °C. The methylene chloride solution of Compound IVa and Compound IVb from Example 1 was added to the reaction mixture slowly, while maintaining the temperature at 0-10 °C. Diethyl phosphite (39.66g) was added drop wise at 0-10 °C. Check the reaction mixture for completion of the reduction reaction, and additional diethyl phosphite may be added.
-
The reaction mixture was allowed to warm to ambient (20-30 °C) and agitated until the reaction was deemed complete by HPLC. Water (150 mL) was added and the phases were separated. The organic layer was extracted with water (230 mL) and polish filtered.
-
The methylene chloride (which contained the crude Compound II) was distilled off and exchanged with about 400 mL of methyl tert-butyl ether (MTBE) (optionally, the MTBE recycled from washing below can be used here). Upon cooling, crystallization occurred (optionally seeds were added) and after further cooling to below 25°C, crystals of Compound II were isolated, washed with MTBE and dried in vacuum at a temperature of less than 60°C. HPLC retention time: 18.126 min. Typically, the yield was about 85 to about 88%. Alternatively, IPA could be used as the crystallization and washing solvent
-
Optionally, the solvent (i.e., MTBE or IPA) used to wash the crystals of Compound II above can be recycled and used to crystallize the crude Compound II in the next batch. Since the washed solvent contains Compound II as well as impurities, it was surprisingly found that the washed solvent can be recovered and used again in crystallizing the crude compound of formula II in the next batch without sacrificing its purity while increasing its yield.
Example 3Preparation of Compound I:
-
-
A reactor was charged with Compound II (1 kg), triethylamine chlorhydrate (0.713 kg), sodium azide (0.337 kg) and N-methyl pyrrolidinone (2.07 kg), and the reaction mixture was heated to about 122°C under stirring. After completion of the reaction as determined by HPLC, the reaction mixture was cooled to about 45°C, and an aqueous solution of sodium hydroxide (35%, 5.99 kg) and water (3.0 kg) were added, the resulting mixture was stirred at a temperature between about 20 and about 40°C for about 0.5 hours. The aqueous phase was discarded and the organic phase was treated with toluene (1.73 kg) and water (5.0 kg), and stirred for about 0.5 hours at about 20 – about 30°C. The toluene phase was discarded and the aqueous phase was washed with ethyl acetate (1.8 kg) and treated with aqueous HCl until pH was adjusted to about 4.8 – about 5.2. Precipitation occurred and the resulting suspension was stirred for about 1 hour at about 20 – about 25°C. The precipitation was collected and washed with water three times (1.0 kg x 3). The crude wet product was recrystallized using a mixture of iso-propanol (0.393 kg) and water (4.5 kg). HPLC retention time: 11.725 min. The yield for Compound I was about 87%.
…………………………………………….
SPECTRAL DATA
The ESI mass spectrum of irbesartan showed a protonated molecular ion peak at m/z 429.3 confirming the molecular weight 428. The fragmentation pattern of parent ion 429.3 showed the fragment ions at m/z 385.9, 235.1, 207, 195.4, 192.1, 180.2 and 84
The FT-IR spectrum exhibited a characteristic stretching absorption band at 1732 cm-1 for the carbonyl group of amide functionality. The presence of this band at higher frequency was due to the ring stretching due to five member ring system. Another band at 1614cm-1 was due to C=N stretching vibrations
1H and 13C- NMR were recorded using DMSO-d6 as a solvent. In 1H-NMR the signal due to tetrazole NH proton was not detected may probably due to the tautomerism.
SEE
http://orgspectroscopyint.blogspot.in/2013/12/irbesartan-spectral-data.html
DP 1 IS IMPURITY
………………………………………….
NMR
1H-NMR (DMSO d6): δppm 0.78 (t, 3H); 1.17-1.30 (sex, 2H); 1.40-1.50 (quent, 2H); 1.64-1.66 (m, 2H); 1.80-1.82 (m, 6H); 2.22-2.29 (t, 2H); 4.67 (s, 2H); 7.07 (s, 4H); 7.50- 7.68 (m, 4H) M+: 429.6
,…………………..
m.p:181-182oC,
IR (KBr, cm-1) 1732 (C=O), 1616 (C=N); 1H NMR (DMSO-d6): δ 7.95–7.32 (m, 8 H), 4.80 –4.60 (s, 2 H), 3.60– 3.00 (br s, 1 H), 2.40– 2.20 (t, 2 H , J = 6.04 Hz), 2.00– 1.60 (m, 8 H),1.60–1.45 (quint, 2 H), 1.40– 1.20 (sext, 2 H), 0.91–0.70 (t, 3H, J = 7.41 Hz);
13C-NMR (DMSOd6): δ 186.5, 162.0,155.9, 141.9, 139.2, 137.2. 131.9, 131.4, 130.1, 128.7, 127.1, 124.3, 76.7, 43.1,
37.7, 28.3, 27.4, 26.3, 22.4, 14.5;
MS: m/z= 429 [M+1];
Anal. Calcd for C25H28N6O : C, 70.07; H,
6.59; N, 19.61. Found: C, 70.04; H, 6.57; N, 19.58.
http://www.acgpubs.org/OC/2011/Volume%204/Issue%201/13-OC-1106-199.pdf
………………………………………………..
1H NMR in DMSO-D6 : 7.68 (d. 2H, Ar-H), 7.52 (d, 2 H, Ar-H), 7.08 (s, 4 H, Ar-H), 4.68(s, 2H, -CH2), 2.69(t,2H,-CH2),2.18(m,2H,-CH2),1.83(m,2H,-CH2),1.81 (t, 2H, -CH2), 1.65 (t, 2H, -CH2), 1.45 (m, 2 H, -CH2), 1.24(m , 2H, -CH2), 0.77 (t, 3H, -CH3),
IR (KBR): 3061 (Aromatic C-H stretching), 2960 (Aliphatic C-H stretching), 3443 (N-H stretching), 1733 (C=0 stretching), 1617(CN stretching), 1337.99(CN stretching), 1407(N=N stretching) cm“1.
……………………….
HPLC condition:
Column: Alltima C18 (Alltech 88050) 15.0cm in length x 4.6mm in internal diameter and 5 micron particle size;
Column temperature: 40 C;
Solvent A: Buffer solution A 1.1 g of heptanesulfonic acid in 1 liter of water and adjust the pH to 2.5;
Solvent B: Methanol Flow rate: 1.2mL/min;
Gradient Elution Condition:
Time% A % %B
0 min 50 50
35 min 15 85
Detector: 240 nm;
Injection volume: 10 uL.
The chromatographic purity of
the compounds was analyzed using Agilent 1200 series HPLC instrument under the following conditions:
Column : Symmetry C18, 4.6 × 75 mm, 3.5 µm
Mobile phase : Eluent A: Deionized water, Eluent B: HPLC grade Methanol
Chromatographic Conditions
a. Column temperature : Ambient
b. Sample compartment : Ambient
c. Detector : 225 nm
d. Injection volume : 10 µL
e. Run time : 45 minutes
f. Flow rate :1.0 mL/min
g. Injector :Auto sampler with variable volume injector
h. Diluent : HPLC grade Acetonitrile
Human Stem Cells Elucidate the Mechanisms of Beta-Cell Failure in Diabetes
Wolfram syndrome is a rare form of diabetes characterized by high blood sugar levels that result from insufficient levels of the hormone insulin. The chronically high blood sugar levels cause degeneration of the optic nerve, leading to progressive vision loss (optic atrophy). Wolfram syndrome patients often also have abnormal pituitary glands that release abnormally low levels of the hormone vasopressin (also known as antidiuretic hormone or ADH), which causes hearing loss caused by changes in the inner ear (sensorineural deafness), urinary tract problems, reduced amounts of the sex hormone testosterone in males (hypogonadism), or neurological or psychiatric disorders.
Diabetes mellitus is typically the first symptom of Wolfram syndrome, usually diagnosed around age 6. Nearly everyone with Wolfram syndrome who develops diabetes mellitus requires insulin replacement therapy. Optic atrophy is often the next symptom to appear, usually around age 11. The first signs of optic atrophy are loss of color vision…
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Argatroban
Argatroban
Molecular Formula: C23H36N6O5S
Formula Weight: 508.63
CAS No.: 74863-84-6
(2R,4R)-1-[(2S)-5-(diaminomethylideneamino)-2-
[[(3R)-3-methyl-1,2,3,4-tetrahydroquinolin-8-yl]
sulfonylamino]pentanoyl]-4-methyl-piperidine-2-
carboxylic acid
PATENT
US 7,589,106, 7,687,516, EP 0008746; US 4258192, US 4201863
Argatroban is an anticoagulant that is a small molecule direct thrombin inhibitor.[1] In 2000, argatroban was licensed by the Food and Drug Administration (FDA) for prophylaxis or treatment of thrombosis in patients with heparin-induced thrombocytopenia (HIT). In 2002, it was approved for use during percutaneous coronary interventions in patients who have HIT or are at risk for developing it. In 2012, it was approved by the MHRA in the UK for anticoagulation in patients with Heparin-Induced Thrombocytopenia Type II (HIT) who require parenteral antithrombotic therapy.[2]
Argatroban is given intravenously and drug plasma concentrations reach steady state in 1-3 hours.[3] Argatroban is metabolized in the liver and has a half-life of about 50 minutes. It is monitored by PTT. Because of its hepatic metabolism, it may be used in patients with renal dysfunction. (This is in contrast to lepirudin, a direct thrombin inhibitor that is primarily renally cleared).
Argatroban is used as an anticoagulant in individuals with thrombosis and heparin induced thrombocytopenia. Often these individuals require long term anticoagulation. If warfarin is chosen as the long term anticoagulant, this poses particular challenges due to the falsely elevated prothrombin time and INR caused by argatroban. The combination of argatroban and warfarin may raise the INR to greater than 5.0 without a significant increased risk of bleeding complications.[4] One solution to this problem is to measure the chromogenic factor X level. A level < 40-45% typically indicates that the INR will be therapeutic (2-3) when the argatroban is discontinued.
……………………………………………………….
Argatroban monohydrate
Argatroban is a synthetic direct thrombin inhibitor and the chemical name is 1-[5-[(aminoiminomethyl) amino]-1-oxo2[[(1,2,3,4-tetrahydro-3-methyl-8-quinolinyl)sulfonyl]amino]pentyl]-4-methyl-2- piperidinecarboxylic acid, monohydrate. Argatroban has 4 asymmetric carbons. One of the asymmetric carbons has an R configuration (stereoisomer Type I) and an S configuration (stereoisomer Type II). Argatroban consists of a mixture of R and S stereoisomers at a ratio of approximately 65:35.
The molecular formula of argatroban is C23H36N6O5S•H2O. Its molecular weight is 526.66 g/mol. cas 141396-28-3
Argipidine, Argatroban monohydrate, GN1600, DK-7419, MDI-805 Acova, Slonnon, Novastan
Mitsubishi Chemical (Originator), Encysive Pharmaceuticals (Licensee), Mitsubishi Pharma (Distributor), Daiichi Pharmaceutical (Codevelopment), GlaxoSmithKline (Codevelopment), Mitsubishi Pharma (Codevelopment), Sanofi-SynthLabo (Codevelopment)
Antithrombocytopenic, CARDIOVASCULAR DRUGS, Cerebrovascular Diseases, Treatment of, HEMATOLOGIC DRUGS, Hematopoiesis Disorders Therapy, Ischemic Stroke, Treatment of, NEUROLOGIC DRUGS, Peripheral Vascular Disease, Treatment of, Stroke, Treatment of, Treatment of Peripheral Obstructive Vascular Disease, Thrombin Inhibitors
Synthesis of argatroban on the method reported in the literature there are two synthetic routes, patent EP8746, US4258192, US4201863, JP8115267 relates to a route is: with 4 – methyl-piperidine as a starting material was prepared first intermediate body (2R, 4R) -4 – methyl-2 – ethyl-piperidine, and the first and a t-BOC protected amino nitro-L-arginine condensation, and then the 3 – methyl – 8 – quinoline sulfonyl chloride condensation after hydrolysis, hydrogenation, hydration be argatroban. This entry route synthesis process complicated procedure to be carried out under the protection of nitrogen, the raw material is highly toxic gas phosgene, the operation more difficult.
US4117127, JP02-212473, EP823430, EP8746, JC S Perk Transl 1981 (5), JP02-212473 relates to an alternative route is: nitro L-arginine prior to the 3 – methyl-8 – subsequent condensation quinoline sulfonyl chloride Intermediate (2R, 4R) -4 – methyl-2 – piperidinecarboxylate condensation, and then after hydrolysis, hydrogenation, hydration be argatroban. This synthetic route despite the relatively simple process method, to obtain raw materials, but this method using reagents such as phosphorus oxychloride, phosphorus trichloride has a pungent odor, easy to absorb moisture in humid air, intense smoke, environmental pollution, greater stimulation of the body’s respiratory tract, can cause eye and skin irritation and burning, and the use of this method, complex operation, low yield, high cost.
Patent CN100586946C Argatroban discloses a method for separating optically active isomeric compounds, the feedstock argatroban mixed solvent of alcohol and water was heated to reflux 5-10 hours, cooled and allowed to stand, and filtered to give White crystalline product, dried, repeated 2-6 times. [0008] Patent CN101033223A discloses a Argatroban is the main by-product (2R, 4R)-l_ [N2-(3_ methyl-8 – quinolinesulfonyl)-L-arginyl] -4 – methyl-2 – carboxylic acid, argatroban, and the byproducts are difficult to isolate, argatroban two diastereomeric isomer 21 (S) and 21 (R) separation of work attracted a lot of research persons. Because both physical and chemical properties are very similar, so separation is very difficult. 1993 Rawson, Thomas E.; VanGorp, Kimmie A.; Yang, Janet so first by high pressure liquid chromatography and column chromatography separation to obtain a single 21 (S) and 21 (R) argatroban [ Journal of Pharmaceutical Sciences vol. 82, No. 6,672]; Thibaudeau Karen et al. reported Protein A chromatographic separation [US6440417]. However, due to the separation of these methods a small amount of low efficiency, so there is no practical value industrialization. 2006 China Tianjin Weijie Technology Co., Ltd. Song Honghai et al. Reported using recrystallization Separation 21 (S) and 21 (R) argatroban way [0 With 951,936 it], so that the mass 21 (5) Aga music classes as possible, but the law of low yield, complicated operation, high cost, and a large amount of a small amount of 21 (S) of 21 (R)-product argatroban, from the viewpoint of industrial production, is still a ideal method. [0009] These methods can be effectively prepared argatroban, but the purity of the desired product is not high, poor color, content is low, affecting the quality of the results of its preparation.
U.S. Pat. No. 4,201,863 (6 May 1980) and EP 8746 (filed on 22 Aug. 1979 with priority based on the application for the cited US patent) describe a class of N2-arylsulphonyl-L-argininamide drugs, with anti-thrombotic activity, and the processes for obtaining them. Of these, the compound 4-methyl-1-[N2-(3-methyl-1,2,3,4-tetrahydro-8-quinolinesulphonyl)-L-arginyl]-2-piperidine carboxylic acid (argatroban, isomers mixture) is described. The described process comprises the synthesis of an intermediate NG-substituted-N2-quinolinesulphonyl-L-argininamide from which the desired compound is obtained by catalyzed hydrogenolysis or acidolysis and catalyzed hydrogenation. The general conditions provided for the hydrogenolysis and hydrogenation reaction are: i) inert solvents (methanol, ethanol, tetrahydrofuran or dioxane); ii) presence of a catalyst (Raney nickel, palladium, platinum, ruthenium, rhodium); iii) hydrogen atmosphere at a pressure between 1 and 100 kg/cm2 and preferably between 5 and 50 kg/cm2; iv) temperature between 0° C. and 200° C. and preferably between 50° C. and 150° C.; v) reaction temperature from 2 hours to 120 hours. The crude product obtained is then purified by trituration or by re-crystallization from diethyl ether-tetrahydrofuran, diethyl ether-methanol or from water-methanol or by chromatography. No example is given of this purification step. In particular, both U.S. Pat. No. 4,210,863 and EP 8746 in example 1(E) describe the preparation of argatroban, isomers mixture. This compound is obtained in amorphous form by hydrogenation of [NG-nitro-N2-(3-methyl-8-quinolinesulphonyl)-L-arginyl]-4-methyl-2-piperidine carboxylic acid in ethanol in the presence of Pd/C with hydrogen pressure of 10 kg/cm2 at 100° C. for 8 hours. The catalyst is removed by filtration of the ethanol solution which is then evaporated without further purification and/or re-crystallization steps. In the US patent at issue as indeed in patent application EP 8746, no mention is made of polymorphic forms of the compounds and, for the obtained compound, the following characteristics are reported: Amorphous solid, I.R. (KBr) (cm−1) 3400; 1620; 1460; 1380; Molecular composition (%): theoretical C 54.31; H 7.13; N 16.52; found (%) C 54.01; H 6.98; N 16.61.
U.S. Pat. No. 4,258,192 (24 Mar. 1981) (continuation-in-part of the aforesaid patent application U.S. Pat. No. 4,201,863) and the same patent application EP 8746 describe the stereoisomers and the preparation thereof, including argatroban used as an active principle in medicaments, i.e. the stereoisomer (2R,4R)-4methyl-[4N2-(3-methyl-1,2,3,4-tetrahydro-8-quinolinesulphonyl)-L-arginyl]-2-piperidine carboxylic acid, with the following characteristics: melting point (m.p.). 188-191° C.; I.R. (KBr) (cm−1) 3400, 1620, 1460, 1380; Molecular composition (%): theoretical C 54.31; H 7.13; N 16.52; found (%) C 54.05; H 6.94; N 16.65. The compound is prepared according to the description given in examples 1(E) in U.S. Pat. No. 4,258,192 and 2(E) and 3 in EP 8746 respectively by hydrogenation of (2R,4R) 1-[NG-nitro-N2-(3-methyl-1,2,3,4-tetrahydro-8-quinolinesulphonyl)-L-arginyl]-2-piperidine carboxylic acid in ethanol in presence of acetic acid catalyzed by Pd/C. After filtering the mass to remove the catalyst, the solvent is evaporated and the residue suspended in chloroform, the solution treated with a saturated sodium bicarbonate solution or 1N sodium hydroxide solution and after washing, the solvent is evaporated. The compound is then re-crystallized from ethanol. Again in this case, no reference is made to the obtainment of monohydrate polymorphic forms.
Said polymorphic forms are described instead in the publication Biochem. Biophys. Res. Comm. 1981, 101, 440-446 in the context of stereoisomer preparation. The monohydrate polymorph of the (2R,4R) stereoisomer is prepared by re-crystallization from ethanol/water and the reported characteristics are: m.p. 176-180° C.; [α]D 27 +76.1° (c 1, 0.2N HCl).
U.S. Pat. No. 5,925,760 (20 Jul. 1999) and EP 0823430 (filed 4 Aug. 1997) subsequently describe a new method for preparing argatroban by means of a new intermediate N2-(3-methyl-8-quinolinesulphonyl)-NG-nitro-L-arginine. In particular the patent makes reference to the preparation of a crystalline monohydrate form of argatroban, referring back to examples (D) and (E) of Japanese patent publication No. (Hei)-2-31055/1990 and generically to an I.R. spectrum identical to that of the commercially available argatroban compound. The relevant example in the cited patent publication is example (E), while example (D) concerns the preparation of (2R,4R)-1-[NG-nitro-N2-(3-methyl-8-quinolinesulphonyl)-L-arginyl]-4-methyl-2-piperidine carboxylic acid. This compound represents the starting compound for argatroban preparation by catalytic reduction in the presence of Pd/C. The crude argatroban obtained is then purified by extraction with chloroform, treatment with a saturated sodium bicarbonate solution and, after solvent evaporation, re-crystallization from ethanol or from 15% alcohol in water. It should be noted however that the Japanese patent makes no mention of the monohydrate form of argatroban being obtained and that for the compound the following characteristics are reported: m.p. 188-191° C.; molecular composition (theoretical/found) (%): C 54.31/54.01; H 7.13/6.98; N 16.52/16.61; I.R. (KBr) (cm−1) 3400; 1620; 1460; 1380. These analytical data, with the exception of the unreported melting point, are the same as those indicated in the cited patent documents describing a mixture of (2R,4R)-4methyl-[4N2-(3S-methyl-1,2,3,4-tetrahydro-8-quinolinesulphonyl)-L-arginyl]-2-piperidine carboxylic acid and (2R,4R)-4methyl-1-[N2-(3R-methyl-1,2,3,4-tetrahydro-8-quinolinesulphonyl)-L-arginyl]-2-piperidine carboxylic acid isomers of argatroban, but do not correspond to the melting point given in the publication, being the only document that identifies the monohydrate form of argatroban.
More recently, patent application CN 1,951,937 (filing date 10 Nov. 2006) described a method for preparing hydrated argatroban by treating argatroban with large quantities of water (more than 60 and up to 80 volumes of distilled water per gram of argatroban) at a temperature of 80-100° C. for a time of 0.5-1 hour and crystallization by cooling. The water content reported is comprised between 3.3 and 3.8% and the ratio of dextroisomer R to levoisomer S is R:S=63-67: 37-33.
Argatroban is a compound of wide therapeutic use, for which reason the need still exists to provide a compound of pharmaceutically acceptable quality obtained by easily industrialized and economically convenient methods. With regard to the monohydrate, this form is preferable for the applicative purpose since the anhydrous form is unstable and tends to become hydrated and/or wet. Moreover it crystallizes only with difficulty at the correct ratio between the diastereoisomers.
…..
the protection of 4-methylpiperidine (I) with (Boc)2O gives the carbamate (II), which is condensed with benzyl chloroformate by means of sec-butyl lithium and TMEDA in ethyl ether to yield (?-trans-1-(tert-butoxycarbonyl)-4-methylpiperidine-2-carboxylic acid benzyl ester (III). Deprotection of the NH group of (III) with HCl in ethyl acetate affords (?-trans-4-methylpiperidine-2-carboxylic acid benzyl ester (IV), which is condensed with the protected arginine derivative (V) by means of isobutyl chloroformate and TEA to provide the corresponding amide as a diastereomeric mixture. Resolution of this mixture by flash chromatography furnishes the desired diastereomer (VI), which is treated with HCl in ethyl acetate in order to remove the Boc-protecting group to yield compound (VII). Condensation of compound (VII) with 3-methylquinoline-8-sulfonyl chloride (VIII) by means of TEA in dichloromethane affords the expected sulfonamide (IX). Finally, this compound is submitted to hydrogenation with H2 over Pd/C in AcOH/ethanol in order to produce debenzylation, cleavage of the NO2 group and hydrogenation of the pyridine ring to yield argatroban.
………….
Argatroban, i.e., (2R,4R)-1-((2S)-5-((Aminoiminomethyl)amino)-1-oxo-2-((1,2,3,4-tetrahydro-3-methyl-8-quinolinyl)sulfonyl)amino) pentyl)-4-methyl-2-piperidine carboxylic acid, has two diastereoisomers: 21(R) and 21(S). Usually the ratio of 21(R) to 21(S) is 64-65: 36-35 (U.S. Pat. No. 6,440,417, Cossy. J., et al, Bioorganic & Medicine Chemistry Letters, 11 (2001), 1989-1992, Journal of pharmaceutical Sciences, Vol. 82, No. 6, 672 (1993)).
The structure formula of Argatroban is reported below:
-
- 21(S) Argatroban, X=CH3, Y═H;
- 21(R) Argatroban, X=H, Y=CH3;
- Argatroban, 21(S): 21 (R)=35:65.
The chemical names of the two diastereoisomers mentioned above are:
- 21(S) Argatroban: (2R,4R)-1-((2S)-5-((Aminoiminomethyl)amino)-1-oxo-2-((((3S)-1,2,3,4-tetrahydro-3-methyl-8-quinolinyl)sulfonyl)amino)pentyl)-4-methyl-2-piperidine carboxylic acid (121785-72-6); and
- 21(R) Argatroban: (2R,4R)-1-((2S)-5-((Aminoiminomethyl)amino)-1-oxo-2-((((3R)-1,2,3,4-tetrahydro-3-methyl-8-quinolinyl)sulfonyl)amino)pentyl)-4-methyl-2-piperidine carboxylic acid (121785-71-5).
In 1978, S. Akamoto et al from Japanese Mitsubishi Chemical Corporation first disclosed the anti-thrombin activity of Argatroban monohydrate (U.S. Pat. No. 4,101,653). In the next 20 years, numerous researchers had in-depth studies on Argatroban about its biological activity and medicine values. In 1981, S. Akamoto compared Argatroban with heparin in vivo (Okamoto, S. et al., Biochem. Biophys. Res. Commun. 101, 440 (1981)); T. Kumoto disclosed its three-dimensional selective activity (Kumada, T. et al., Thromb. Res. 24, 285 (1981)). In 1984, R. Kumato made a clinical evaluation of hemodialysis of Argatroban (Kikumoto, R. et al., Biochemistry 23, 85 (1984)), and in 1986, he further disclosed that Argatroban can inhibit the thrombin activity of mammals, and can be used as active ingredient to treat and prevent thrombosis and as an inhibitor of platelet aggregation. Argatroban monohydrate can be used as a selective anti-thrombosis agent for treatment of chronic arterial blockage and cerebral thrombosis, etc (JP 61-48829). In 1992 and 1993, Taparelli and Jakubowski separately disclosed the reversibility of Argatroban in anti-thrombin (Taparelli, C., Trends Pharmacol. Sci., 1993, 14, 366, Jakubowski, J. A. et al, Rep. Med. Chem., 1992, 27, 99). In 1990s, many researchers such as L. R. Buch reported other related research (Buch, L. R., Cadiosvasc. Drug Rev., 1991, 9, 247, Strupcnewski, J. D. et al., Academic: San Diego, 1991; Vol. 26, p 299, Brundish, D. et al., J. Med. Chem. 1999; 42, 4584, Shebuski, R. J., Academic: San Diego, 1999; Vol. 26, p 98). In 1992, Argatroban monohydrate was first approved as an anti-thrombin medicine in Japan (Hijikata-Okunomiya, A., et al, Thromb. Hemostasis, 1992, 18, 135).
Updated in sept 2015, reader there may be duplication
| Argatroban |
| AC1L99H9; AC-15185; TL8005144; C04931; | |
| Molecular Formula: | C23H36N6O5S |
|---|---|
| Molecular Weight: | 508.63414 g/mol |
(2R,4R)-1-[5-(diaminomethylideneamino)-2-[(3-methyl-1,2,3,4-tetrahydroquinolin-8-yl)sulfonylamino]pentanoyl]-4-methylpiperidine-2-carboxylic acid, cas 74863-84-6
| Patent | Submitted | Granted |
|---|---|---|
| Prodrugs of (2R)-2-Propyloctanoic Acid For the Treatment of Stroke [US7495029] | 2008-06-05 | 2009-02-24 |
Tomiya Mano, Jin Shiomura, “Argatroban preparations for ophthalmic use.” U.S. Patent US5506241, issued October, 1986.
Argatroban is an anticoagulant that is a small molecule direct thrombin inhibitor.[1] In 2000, argatroban was licensed by the Food and Drug Administration (FDA) for prophylaxis or treatment of thrombosis in patients with heparin-induced thrombocytopenia (HIT). In 2002, it was approved for use during percutaneous coronary interventions in patients who have HIT or are at risk for developing it. In 2012, it was approved by the MHRA in the UK for anticoagulation in patients with Heparin-Induced Thrombocytopenia Type II (HIT) who require parenteral antithrombotic therapy.[2]
Argatroban is given intravenously and drug plasma concentrations reach steady state in 1-3 hours.[3] Argatroban is metabolized in the liver and has a half-life of about 50 minutes. It is monitored by PTT. Because of its hepatic metabolism, it may be used in patients with renal dysfunction. (This is in contrast to lepirudin, a direct thrombin inhibitor that is primarily renally cleared).
Argatroban is a direct, selective thrombin inhibitor. The American College of Cardiologists (ACC) recommend using bivalirudin or argatroban in patients who have had, or at risk for, heparin induced thrombocytopenia (HIT) and are undergoing percutaneous coronary intervention. Argatroban is a non-heparin anticoagulant shown to both normalize platelet count in patients with HIT and prevent the formation of thrombi. Parental anticoagulants must be stopped and a baseline activated partial thromboplastin time must be obtained prior to administering argatroban.
Transitioning to warfarin in individuals with heparin induced thrombocytopenia
Argatroban is used as an anticoagulant in individuals with thrombosis and heparin induced thrombocytopenia. Often these individuals require long term anticoagulation. If warfarin is chosen as the long term anticoagulant, this poses particular challenges due to the falsely elevated prothrombin time and INR caused by argatroban. The combination of argatroban and warfarin may raise the INR to greater than 5.0 without a significant increased risk of bleeding complications.[4] One solution to this problem is to measure the chromogenic factor X level. A level < 40-45% typically indicates that the INR will be therapeutic (2-3) when the argatroban is discontinued.
http://www.google.com/patents/WO2009124906A2?cl=en
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NMR paper
Complete 1H and 13C assignments of (21R) and (21S) diastereomers of argatroban
Article first published online: 20 DEC 2007
DOI: 10.1002/mrc.2122, http://onlinelibrary.wiley.com/doi/10.1002/mrc.2122/abstract
click on image for clear view
1H NMR PREDICT
13C NMR PREDICT
References
1 Di Nisio M, Middeldorp S, Buller HR. Direct thrombin inhibitors. N Engl J Med 2005;353:1028-40. PMID 16148288
2http://www.pharmatimes.com/Article/12-07-03/UK_launch_for_Mitsubishi_s_blood_thinner_Exembol.aspx
3Dhillon S. Argatroban: A Review of its Use in the Management of Heparin-Induced Thrombocytopenia. Am J Cardiovasc Drugs 2009; 9 (4): 261-82. Link text
- Hursting MJ, Lewis BE, Macfarlane DE. (2005). “Transitioning from argatroban to warfarin therapy in patients with heparin-induced thrombocytopenia.”. Clin Appl Thromb Hemost 11 (3): 279–87. doi:10.1177/107602960501100306. PMID 16015413.
External links
| EP0823430A1 * | Aug 4, 1997 | Feb 11, 1998 | Mitsubishi Chemical Corporation | Method for preparing n2-arylsulfonyl-l-argininamides |
| US4201863 * | Aug 31, 1978 | May 6, 1980 | Mitsubishi Chemical Industries, Limited | N2 -Arylsulfonyl-L-argininamides and the pharmaceutically acceptable salts thereof |
| Reference | ||||
|---|---|---|---|---|
| 1 | None | |||
| 2 | * | OKAMOTO S ET AL: “Potent inhibition of thrombin by the newly synthesized arginine derivative No. 805. The importance of stereo-structure of its hydrophobic carboxamide portion” BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, ACADEMIC PRESS INC. ORLANDO, FL, US, vol. 101, no. 2, 30 July 1981 (1981-07-30), pages 440-446, XP024844713 ISSN: 0006-291X [retrieved on 1981-07-30] cited in the application | ||
| 3 | * | SONG H: “Method for preparing argatroban monohydrate in pure water” CASREACT,, 25 April 2007 (2007-04-25), XP002493272 & CN 1 951 937 A (TIANJIN WEIJIE TECHNOLOGY CO L [CN]) 25 April 2007 (2007-04-25) | ||
| Citing Patent | Filing date | Publication date | Applicant | Title |
| WO2012136504A1 | Mar 26, 2012 | Oct 11, 2012 | Lundbeck Pharmaceuticals Italy S.P.A. | Method for the preparation of process intermediates for the synthesis of argatroban monohydrate |
| CN102408468A * | Sep 20, 2011 | Apr 11, 2012 | 海南灵康制药有限公司 | Argatroban compound and preparation method thereof |
| EP2752412A1 | Mar 26, 2012 | Jul 9, 2014 | Lundbeck Pharmaceuticals Italy S.p.A. | Intermediates for the synthesis of Argatroban monohydrate |
Argatroban is a synthetic direct thrombin inhibitor and the chemical name is 1-[5[(aminoiminomethyl)amino]1-oxo-2-[[(1,2,3,4-tetrahydro-3-methyl-8-quinolinyl)sulfonyl]amino]pentyl]-4methyl-2-piperidinecarboxylic acid, monohydrate. Argatroban has 4 asymmetric carbons. One of the asymmetric carbons has an R configuration (stereoisomer Type I) and an S configuration (stereoisomer Type II). Argatroban consists of a mixture of R and S stereoisomers at a ratio of approximately 65:35.
The molecular formula of argatroban is C23H36N6O5S•H2O. Its molecular weight is 526.66 g/mol. The structural formula is:
|
Argatroban Injection is a sterile, non-pyrogenic, clear, colorless to pale yellow isotonic solution. It is supplied in a single use polyolefin bag containing 250 mg of argatroban in 250 mL sodium chloride solution (1 mg/mL). Each mL contains 1 mg argatroban, 9 mg sodium chloride, USP, and 3 mg sorbitol, NF in water for injection, USP. The pH of the solution is between 3.2 to 7.5.
 |
|
| Systematic (IUPAC) name | |
|---|---|
|
(2R,4R)-1-[(2S)-5-(diaminomethylideneamino)-2-
[[(3R)-3-methyl-1,2,3,4-tetrahydroquinolin-8-yl] sulfonylamino]pentanoyl]-4-methyl-piperidine-2- carboxylic acid |
|
| Clinical data | |
| Trade names | Argatroban |
| AHFS/Drugs.com | monograph |
| Routes of administration |
intravenous |
| Pharmacokinetic data | |
| Bioavailability | 100% (intravenous) |
| Protein binding | 54% |
| Metabolism | hepatic |
| Biological half-life | 39 and 51 minutes |
| Identifiers | |
| CAS Registry Number | 74863-84-6  |
| ATC code | B01AE03 |
| PubChem | CID: 440542 |
| DrugBank | DB00278 |
| ChemSpider | 389444 |
| UNII | OCY3U280Y3 |
| KEGG | C04931 |
| ChEMBL | CHEMBL1166  |
| Chemical data | |
| Formula | C23H36N6O5S |
| Molecular mass | 508.635 g/mol |
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EMA introduces new fee reductions for orphan drugs aimed at big companies
December 04, 2013 | By Márcio Barra
The European medicines Agency (EMA) announced yesterday that, starting January 2014, there will be greater fee-reduction rates for orphan medicines in 2014 for big companies, something that was previously only in place for micro, small or medium-sized enterprises (SMEs).
View original post 266 more words
DRUG SPOTLIGHT …… DOXOFYLLINE
DOXOFYLLINE
LAUNCHED 1987, Istituto Biologico Chemioterapico ABC
69975-86-6 CAS NO
7-(1,3-dioxolan-2-ylmethyl)-1,3-dimethylpurine-2,6-dione
1H-Purine-2,6-dione, 3,7-dihydro-7-(1,3-dioxolan-2-ylmethyl)-1,3-dimethyl- (9CI)
7-(1,3-Dioxolan-2-ylmethyl)-3,7-dihydro-1,3-dimethyl-1H-purine-2,6-dione; 7-[1,3-(Dioxolan-d4)-2-ylmethyl)]theophylline; 2-(7�-Theophyllinemethyl)-1,3- dioxolane; ABC 12/3; ABC 1213; Ansimar; Dioxyfilline; Doxophylline; Maxivent; Ventax;
Synonyms
-
2-(7′-Teofillinmetil)-1,3-diossolano
-
2-(7′-Teofillinmetil)-1,3-diossolano [Italian]
-
2-(7′-Theophyllinemethyl)-1,3-dioxolane
-
5-26-14-00120 (Beilstein Handbook Reference)
-
7-(1,3-Dioxolan-2-ylmethyl)theophylline
| Formula | C11H14N4O4 |
|---|---|
| Mol. mass | 266.25 g/mol |
- ABC 12/3
- Ansimar
- BRN 0561195
- Dioxyfilline
- Doxofilina
- Doxofilina [INN-Spanish]
- Doxofylline
- Doxofyllinum
- Doxofyllinum [INN-Latin]
- Doxophylline
- EINECS 274-239-6
- Maxivent
- UNII-MPM23GMO7Z
- Ventax
Doxofylline (INN), (also known as doxophylline) is a xanthine derivative drug used in the treatment of asthma.[1]
Doxofylline is a xanthine molecule that appears to be both bronchodilator and anti-inflammatory with an improved therapeutic window over conventional xanthines such as Theophylline and the evidence supporting the effects of Doxofylline in the treatment of lung diseases
It has antitussive and bronchodilator[2] effects, and acts as aphosphodiesterase inhibitor.[3]
In animal and human studies, it has shown similar efficacy to theophylline but with significantly fewer side effects.[4]
Unlike other xanthines, doxofylline lacks any significant affinity for adenosine receptorsand does not produce stimulant effects. This suggests that its antiasthmatic effects are mediated by another mechanism, perhaps its actions on phosphodiesterase.[1]
Doxofylline, [7-(1, 3-dioxolan-2-ylmethyl)-3, 7-dihydro-1, 3-dimethyl-1H-purine-2, 6-dione] is a new bronchodilator xanthine based drug which differs from theophylline by the presence of dioxalane group at position 7. It is used in the treatment of bronchial asthma, chronic obstructive pulmonary disease (COPD), and chronic bronchitis . The mechanism of action is similar to that of theophylline in that it inhibits phosphodiesterase (PDE-IV), thereby preventing breakdown of cyclic adenosine monophosphate (cAMP). Increase in cAMP inhibits activation of inflammatory cells resulting in bronchodilating effect [52]. In contrast to theophylline, doxofylline has very low affinity towards adenosine A1 and A2 receptors which explain its better safety profile
Doxofylline (7-(l,3-dioxalan-2-ylmethyl)-theophylline) is a drug derived from theophylline which is used in therapy as a bronchodilator, with anti-inflammatory action, in reversible airway obstruction. It is commonly administered in doses ranging from 800 to 1200 mg per day, orally, according to a dosage which provides for the intake of two to three dosage units per day in order to maintain therapeutically effective haematic levels. The doxofylline tablets commercially available generally contain 400 mg of active ingredient and release almost all the drug within one hour from intake. The half- life of the drug is around 6-7 hours and for this reason several administrations are required during the 24-hour period.
Obviously a drop in haematic concentration of the drug in an asthmatic patient or patient suffering from COPD (chronic obstructive pulmonary disease) can result in serious consequences, in which case the patient must have recourse to rescue medication, such as salbutamol inhalers.
Pharmaceutical techniques for obtaining the modified release of drugs have been known for some time, but no modified release formulation of doxofylline is known. In fact the present inventors have observed that there are significant difficulties in the production of a doxofylline formula that can be administered only once a day and in particular have encountered problems correlated with bioequivalence.
Various attempts to formulate doxofylline in modified release systems, with different known polymers, have not provided the desired results, i.e. a composition that can be administered once a day, bio equivalent to the plasmatic concentration obtained with the traditional compositions currently on sale. In fact currently, dosage units containing 400 mg of active ingredient are currently administered two/three times a day for a daily average of approximately 1000 mg of active ingredient, a dosage considered necessary to maintain the therapeutic haematic levels of doxofylline.
Such a dosage unit is currently marketed by Dr. Reddy’s Laboratories Ltd as DOXOBID and has the following quali-quantitative composition: doxofylline (400 mg), colloidal silicon dioxide (13 mg), corn starch (63 mg), mannitol (40 mg), povidone (7 mg), microcrystalline cellulose (64 mg), talc (30 mg), magnesium stearate (3 mg) and water (0.08 ml).
Xanthine is a dioxypurine that is structurally related to uric acid. Xanthine can be represented by the following structure:
Caffeine, theophylline and theobromine are methylated xanthines. Methylated xanthines such as caffeine and theophylline are typically used for their bronchodilating action in the management of obstructive airways diseases such as asthma. The bronchodilator effects of methylxanthines are thought to be mediated by relaxation of airway smooth muscle. Generally, methylxanthines function by inhibiting cyclic nucleotide phosphodiesterases and antagonizing receptor-mediated actions of adenosine.
Theophylline can be represented by the following structure:
However, when administered intravenously or orally, theophylline has numerous undesired or adverse effects that are generally systemic in nature. It has a number of adverse side effects, particularly gastrointestinal disturbances and CNS stimulation. Nausea and vomiting are the most common symptoms of theophylline toxicity. Moderate toxicity is due to relative epinephrine excess, and includes tachycardia, arrhythmias, tremors, and agitation. Severe toxicity results in hallucinations, seizures, dysrhythmias and hypotension. The spectrum of theophylline toxicity can also include death.
Furthermore, theophylline has a narrow therapeutic range of serum concentrations above which serious side effects can occur. The pharmacokinetic profile of theophylline is dependent on liver metabolism, which can be affected by various factors including smoking, age, disease, diet, and drug interactions.
Generally, the solubility of methylxanthines is low and is enhanced by the formation of complexes, such as that between theophylline and ethylenediamine (to form aminophylline). The formation of complex double salts (such as caffeine and sodium benzoate) or true salts (such as choline theophyllinate) also enhances aqueous solubility. These salts or complexes dissociate to yield the parent methylxanthine when dissolved in aqueous solution. Although salts such as aminophylline have improved solubility over theophylline, they dissociate in solution to form theophylline and hence have similar toxicities.
Dyphylline is a covalently modified derivative of xanthine (1,3, -dimethyl-7-(2,3-dihydroxypropl)xanthine. Because it is covalently modified, dyphylline is not converted to free theophylline in vivo. Instead, it is absorbed rapidly in therapeutically active form. Dyphylline has a lower toxicity than theophylline. Dyphylline can be represented by the following structure:
Dyphylline is an effective bronchodilator that is available in oral and intramuscular preparations. Generally, dyphylline possesses less of the toxic side effects associated with theophylline.
U.S. Pat. No. 4,031,218 (E1-Antably) discloses the use of 7-(2,3-dihydroxypropyl)-1,3-di-n-propylxanthine, a derivative of theophylline, as a bronchodilator. U.S. Pat. No. 4,341,783 (Scheindlin) discloses the use of dyphylline in the treatment of psoriasis and other diseases of the skin by topical administration of dyphylline. U.S. Pat. No. 4,581,359 (Ayres) discloses methods for the management of bronchopulmonary insufficiency by administering an N-7-substituted derivative of theophylline, including dyphylline, etophylline, and proxyphylline.
At present, domestic synthetic Doxofylline composed of two main methods: one is by the condensation of theophylline prepared from acetaldehyde and ethylene glycol, but this method is more complex synthesis of acetaldehyde theophylline, require high periodate oxidation operation. Another is a halogenated acetaldehyde theophylline and ethylene glycol is prepared by reaction of an organic solvent, the method were carried out in an organic solvent, whereby the product Theophylline caused some pollution, conducive to patients taking.
current domestic Doxofylline synthetic methods reported in the literature are: 1, CN Application No. 94113971.9, the name “synthetic drugs Doxofyllinemethod” patents, the patent is determined by theophylline with a 2 – (halomethyl) -1,3 – dimethoxy-dioxolane in a polar solvent, with a base made acid absorbent,Doxofylline reaction step. 2, CN Application No. 97100911.2, entitled “Synthesis of Theophylline,” the patent, the patent is obtained from 7 – (2,2 – dialkoxy-ethyl) theophylline with ethylene glycol in N, N-dimethylformamide solvent with an alkali metal carbonate to make the condensing agent, p-toluenesulfonic acid catalyst in the condensation Doxofylline.
Doxofylline of xanthine asthma drugs, and its scientific name is 7 – (1,3 – dioxolan – ethyl methyl) -3,7 – dihydro-1,3 – dimethyl-1H – purine-2 ,6 – dione. The drug developed by the Italian Roberts & Co. in 1988, listed its tablet tradename Ansimar. This product is compared with similar asthma drugs, high efficacy, low toxicity, oral LD50 in mice is 1.5 times aminophylline, non-addictive. Adenosine and its non-blocking agents, it does not produce bronchial pulmonary side effects, no aminophylline like central and cardiovascular system. U.S. patent (US4187308) reported the synthesis of doxofylline, theophylline and acetaldehyde from ethylene glycol p-toluenesulfonic acid catalyst in the reaction of benzene as a solvent Doxofylline. Theophylline acetaldehyde by the method dyphylline derived reaction with a peroxy periodate or 7 – (2,2 – dialkoxy-ethyl) ammonium chloride aqueous solution in the decomposition of theophylline converted to acetaldehyde theophylline . Former method is relatively complex, and the high cost of using periodic acid peroxide, low yield after France. And theophylline acetaldehyde and ethylene glycol solvent used in the reaction of benzene toxicity, harm to health, and the yield is low, with an average around 70%, not suitable for industrial production.
SYN 1
Theophylline-7-acetaldehyde (I) could react with ethylene glycol (II) in the presence of p-toluenesulfonic acid in refluxing benzene to produce Doxofylline.
SYN 2
Doxofylline can be prepared by N-alkylation of theophylline (I) with bromoacetaldehyde ethylene glycol acetal (II) using Na2CO3 in refluxing H2O (1).
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Synthesis
EXAMPLE
A mixture of 15 g of theophyllineacetic aldehyde, 30 ml of ethylene glycol and 1.5 g of p-toluenesulphonic acid in 600 ml of benzene is heated under reflux in a flask provided with a Marcusson apparatus.
After two hours the separation of the water is complete.
The reaction mixture is washed with 200 ml of a 3.5% aqueous solution of sodium bicarbonate.
The organic phase is dried and concentrated to dryness under reduced pressure, to leave a product residue which is taken up in ethyl ether, separated by filtration and purified by ethanol.
2-(7′-theophyllinemethyl)-1,3-dioxolane is obtained.
M.P. 144
Average yield 70%
Analysis: C.sub.11 H.sub.14 N.sub.4 O.sub.4 : M.W. 266.26: Calculated: C%, 49.62; H%, 5.30; N%, 21.04. Found: C%, 49.68; H%, 5.29; N%, 21.16.
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the reaction is:
a, anhydrous theophylline and bromoacetaldehyde ethylene glycol as the basic raw material, purified water as a solvent with anhydrous sodium carbonate as acid-binding agent;
Doxofylline
UV (95% C2H5OH, nm) λmax273 (ε9230); λmin244 (ε2190)
IR (KBr, cm-1) 1134 (CO); 1233 (CN) ; 1547 (C = N); 1656 (C = C); 1700 (C = O); 2993 (CH)
1H-NMR [CDCl3, δ (ppm)] 3.399 (s, 3H, N-CH3); 3.586 (S, 3H, N-CH3); 3.815-3.885 (m, 4H, OCH2 × 2); 4.581 (d, 2H, CH2); 5.211 (t, 1H, CH ); 7.652 (S, 1H, CH = N)
13C-NMR [CDCL3, δ (ppm)] 27.88 (CH3); 29.69 (CH3); 47.87 (CH2); 65.37 ( OCH2); 100.76 (CH); 107.26 (C = C); 142.16 (CH = N); 148.22 (C = C); 151.59 (C = O); 155.25 ( C
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HPLC
http://www.scipharm.at/download.asp?id=1401
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- Cirillo R, Barone D, Franzone JS (1988). “Doxofylline, an antiasthmatic drug lacking affinity for adenosine receptors”. Arch Int Pharmacodyn Ther 295: 221–37.PMID 3245738.
- Poggi R, Brandolese R, Bernasconi M, Manzin E, Rossi A (October 1989). “Doxofylline and respiratory mechanics. Short-term effects in mechanically ventilated patients with airflow obstruction and respiratory failure”. Chest 96 (4): 772–8.doi:10.1378/chest.96.4.772. PMID 2791671.
- Dini FL, Cogo R (2001). “Doxofylline: a new generation xanthine bronchodilator devoid of major cardiovascular adverse effects”. Curr Med Res Opin 16 (4): 258–68.doi:10.1185/030079901750120196. PMID 11268710.
- Sankar J, Lodha R, Kabra SK (March 2008). “Doxofylline: The next generation methylxanthine”. Indian J Pediatr 75 (3): 251–4. doi:10.1007/s12098-008-0054-1.PMID 18376093.
- Dali Shukla, Subhashis Chakraborty, Sanjay Singh & Brahmeshwar Mishra. Doxofylline: a promising methylxanthine derivative for the treatment of asthma and chronic obstructive pulmonary disease. Expert Opinion on Pharmacotherapy. 2009; 10(14): 2343-2356, DOI 10.1517/14656560903200667, PMID 19678793
- Farmaco, Edizione Scientifica, 1981 , vol. 36, 3 pg. 201 – 219, mp 144 – 144.5 °C
- Drugs Fut 1982, 7(5): 301
| US6313131 | 16 feb 2000 | 6 nov 2001 | Upsher-Smith Laboratories, Inc. | Method of kidney treatment |
| US6348470 * | 20 maart 1998 | 19 feb 2002 | Korbonits Dezsoe | Antitussive compositions |
| US6423719 | 16 feb 2000 | 23 juli 2002 | Upsher-Smith Laboratories, Inc. | Method for treating benign prostate hyperplasia |
| CN101647776B | 2 sept 2009 | 20 april 2011 | 吴光彦 | Doxofylline venous injection with small volume as well as preparation method and quality control method thereof |
| DE3114130A1 * | 8 april 1981 | 28 jan 1982 | Abc Ist Biolog Chem Spa | Neue theophyllinylmethyldioxolan-derivate, verfahren zu ihrer herstellung und sie enthaltende pharmazeutische ansaetze |
| EP0272596A2 * | 16 dec 1987 | 29 juni 1988 | ISTITUTO BIOLOGICO CHEMIOTERAPICO “ABC” S.p.A. | Theophyllinemethyldithiolan and theophyllinemethyldithianyl derivates, a method for their preparation and pharmaceutical compositions in which they are included |
| WO2011146031A1 | 16 mei 2011 | 24 nov 2011 | Bilgic Mahmut | Pharmaceutical composition comprising n- acetylcysteine and a xanthine |
| WO2013055302A1 | 14 mei 2012 | 18 april 2013 | Mahmut Bilgic | Effervescent composition comprising n- acetylcysteine and doxophylline or theophylline |
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Although various bioanalytical methods for estimation of doxofylline in …. 1H and 13C-NMR spectra of doxofylline and its degradation products were recorded by….. CLICK ABOVE
SPECTRAL DATA
The ESI mass spectrum exhibited a protonated molecular ion peak at m/z 267 in positive ion mode indicating the molecular weight of 266. The tandem mass spectrum showed the fragment ions m/z 223, 181.2, 166.2, 138.1, 124.1 and 87.1.
The FT-IR spectrum, two strong peaks at 1697cm-1 and 1658cm-1 indicated presence of two carbonyl groups. A strong peak at frequency 1546cm-1 indicated presence of C=N stretch. A medium peak at 1232cm-1 was due to C-O stretch
FT IR
1H and 13C-NMR spectra of doxofylline and its degradation products were recorded by using Bruker NMR 300MHz instrument with a dual broad band probe and z-axis gradients. Spectra were recorded using DMSO-d6 as a solvent and tetramethylsilane as an internal standard.
4.2.6 Validation
1H NMR
13 C NMR
COMPARISONS
DR ANTHONY MELVIN CRASTO
ORGANIC SPECTROSCOPY
New Drug Approvals 