WO2003033498A2 - A process for the treatment of ganciclovir intermediate n2-acetyl-9-(1, 3-diacetoxy-2-propoxymethyl) guanine - Google Patents
A process for the treatment of ganciclovir intermediate n2-acetyl-9-(1, 3-diacetoxy-2-propoxymethyl) guanine Download PDFInfo
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- WO2003033498A2 WO2003033498A2 PCT/IB2002/004235 IB0204235W WO03033498A2 WO 2003033498 A2 WO2003033498 A2 WO 2003033498A2 IB 0204235 W IB0204235 W IB 0204235W WO 03033498 A2 WO03033498 A2 WO 03033498A2
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- isomer
- guanine
- formula
- reaction
- diacetoxy
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D473/00—Heterocyclic compounds containing purine ring systems
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D473/00—Heterocyclic compounds containing purine ring systems
- C07D473/02—Heterocyclic compounds containing purine ring systems with oxygen, sulphur, or nitrogen atoms directly attached in positions 2 and 6
- C07D473/18—Heterocyclic compounds containing purine ring systems with oxygen, sulphur, or nitrogen atoms directly attached in positions 2 and 6 one oxygen and one nitrogen atom, e.g. guanine
Definitions
- the present invention relates to a process for the preparation of N 2 -acetyl-9-(l,3- diacetoxy-2-propoxymethyl) guanine, referred to here as N-9 alkylated isomer, useful as an intermediate for the preparation of the antiviral compound ganciclovir.
- Ganciclovir chemically known as 9-(l,3-dihydroxy-2-propoxymethyl) guanine has the structural formula I,
- FORMULA I is an important nucleoside having significant antiviral properties, being especially effective against viruses of the herpes family and a few other DNA viruses.
- acylic purine nucleosides such as acyclovir and ganciclovir for example, methods which use guanine, diacetyl guanine, 2,6-dichloropurine, 2-amino-6-chloropurine (see United States Patent No. 4,146,715 to Schaeffer); tetraacetylguanosine (J. Boryski et. al., Nucleosides and Nucleotides, 1989, 8, 529); acetylguanine (Japanese Patent Application No. 84-80685) or 2-chloro-6-iodopurine (J. R. Barrio et al., J. Med. Chem., 1980, 23, 572) as starting materials.
- N-9 substituted guanine compounds involve the direct alkylation of appropriately substituted 2-aminopurines, for example, guanine derivatives.
- 2-aminopurines for example, guanine derivatives.
- N-7 N 2 -acetyl-7-(l,3-diacetoxy-2- propoxymethyl)guanine alkylation products.
- the undesirable N-7 isomers are produced in large amounts, which in turn necessitates tedious and inefficient methods of separation, such as silica gel chromatography, in order to obtain the desired N-9 isomer in acceptable purity.
- halogenated purines is not a method of choice for industrial production, as these starting materials are expensive and difficult to acquire, and they require reaction with ammonia at high temperature and pressure in order to obtain guanine nucleosides, such as acyclovir, ganciclovir, and the like. Hence, it is highly desirable to develop a regioscpecific process for the manufacture of ganciclovir.
- N-7 isomer to N-9 isomer by heating a suspension of the N-7 isomer in an alkylating agent was reported in United States Patent No. 6,043,364 to Kumar et al.
- United States Patent No. 5,583,225 to Chu et al. describes a process for the synthesis of purine nucleosides, particularly ganciclovir and acyclovir, where the deprotected guanine (diacetyl guanine) is reacted with the desired side chain in the presence of phosphoric or polyphosphoric acid at 120°C. Though the reaction time is short (3 hours) compared to prior processes, the product mixtures shows a low ratio of desired N-9 isomer in case of ganciclovir.
- the invention provides an improved process for the production of N -acetyl-9- (l,3-diacetoxy-2-propoxymethyl)guanine (referred to herein as the N-9 alkylated isomer), useful as an intermediate for the preparation of the antiviral compound ganciclovir.
- the invention results from the discovery that the presence of monoacetyl guanine (MAG) in the condensation reaction of diacetyl guanine with the side chain plays a crucial role in reaction completion.
- MAG monoacetyl guanine
- the time required for alkylation at high temperature was less (6-10 hours) but the yields were less due to decomposition of the product of higher temperature.
- Addition of the N-7 isomer during alkylation enhances the formation of N-9 isomer and suppresses the further formation of N-7 isomer. If the N-7 isomer has been obtained by recycling from a previous purification of an alkylation product mixture, the overall yield of the N-9 isomer is improved, and thus the overall yield of the desired product, that is, ganciclovir, is also improved.
- the described process is simple and produces the N-9 isomer in greater than 95% purity, and which can directly be used for the preparation of ganciclovir.
- the process is cost effective and obviates chromatographic separation.
- the present process provides an efficient process for the preparation of ganciclovir which is convenient to operate on a commercial scale, reduces overall production costs, and gives the desired product in good yield and quality.
- the present invention provides a process for the preparation of N-9 alkylated isomer of structural Formula V.
- FORH tfULA V The process includes reacting diacetyl guanine of structural Formula III
- the reaction is carried out at a temperature of from about 50 to about 150°C.
- the reaction is carried out at a temperature of from about 50 to about 120°C, and in some more preferred embodiments, the reaction is carried out at a temperature of form about 50 to about 100°C.
- the amount of monoacetyl guanine (MAG) of structural Formula II which is added to the alkylation reaction mixture can vary, and measured as the molar ratio of
- MAG.diacetyl guanine of structural formula III can vary from about 0.05 to about 10.0. In some embodiments, the molar ratio can vary from about 0.05 to about 1.0, or from about 0.10 to about 0.50. In some further embodiments, the molar ratio of MAG.diacetyl guanine can vary from about 0.25 to about 0.50, for example, about 0.3 mole equivalent.
- acetic acid may also be added to the alkylation mixture, in an amount which can vary, and measured as the molar ratio of acetic acid.diacetyl guanine of structural formula III, can vary from about 0.01 to about 2.0, or from about 0.10 to about 1.0, or from about 0.40 to about 0.80, for example, about 0.59 or about 0.68.
- Alkylation is desirably carried out in the presence of catalyst .
- Alkylation catalysts useful for the reaction are selected from sulfuric acid, methanesulfonic acid, -toluene sulfonic acid and the like. In some embodiments, the preferred catalyst is -toluene sulfonic acid.
- the formation of the ⁇ -9 isomer can be enhanced by adding the N-7 isomer, having structural Formula VI, to the reaction mixture.
- the amount of N-7 isomer which is added to the alkylation reaction mixture can vary, and measured as the molar ratio of N-7.diacetyl guanine of structural formula III, can vary from about 0.05 to about 10.0. In some embodiments, the molar ratio can vary from about 0.05 to about 1.0, or from about 0.10 to about 0.50. In some further embodiments, the molar ratio of N-7: diacetyl guanine can vary from about 0.25 to about 0.50.
- the alkylation reaction can be performed in an inert organic solvent followed by a suitable work up and crystallization of N-9 and N-7 isomers from organic solvent or a mixture thereof.
- Inert organic solventd for alkylation reaction are selected from benzene, toluene, xylene, acetonitrile, tetrahydrofuran, dimethylformamide, chloroform, dichloromethane, methyl iso-butyl ketone, and pyridine.
- the inert organic solvent is dimethylformamide.
- N-9 and N-7 alkylated isomers of structural Formulae V and VI are separated from each other by methods known in the literature or by crystallization methods such as the following method. Crystallization of a mixture including the N-7 and N-9 isomers will typically take place in an organic solvent, or a mixture of organic solvents. The choice of solvents is important for the separation of N-7 and N-9 isomers.
- the solvent system from which the isomers may be separated will desirably be selected from alcoholic solvents, which include lower alkanols, water-immiscible solvents, or a mixture thereof.
- the N-7 isomer will preferably be separated from the solvent system which has at least one lower alkanol.
- the lower alkanols include primary, secondary and tertiary alcohols having from one to six carbon atoms, for example, mefhanol, ethanol, n-propyl alcohol, isopropyl alcohol, isobutanol, n-butanol, tertiary butanol, or mixtures thereof. Most preferred being methanol, ethanol, or isopropyl alcohol.
- the N-9 isomer will preferably be separated from a solvent system which, in addition to alcoholic solvents, may contain water-immiscible solvents which include aromatic hydrocarbons such as benzene, toluene, or xylene, and chlorinated hydrocarbons such as chloroform, dichloromethane, or 1,2-dichloroethane.
- a solvent system which, in addition to alcoholic solvents, may contain water-immiscible solvents which include aromatic hydrocarbons such as benzene, toluene, or xylene, and chlorinated hydrocarbons such as chloroform, dichloromethane, or 1,2-dichloroethane.
- the concentration of the filtrate containing the N-9 isomer is adjusted by evaporation of the solvent or by dilution.
- the separation may comprise the last stage or stages of a reaction in which the mixture of N-7 and N-9 isomers is formed.
- the solution containing the mixture of N-7 and N-9 isomers may be heated for dissolution, or it may be cooled to separate out the product or the slurry may further be cooled prior to filtration.
- N-9 isomer obtained after separation can be hydrolyzed to yield ganciclovir by methods known in the literature, including for example, J.E. Martin et.al., J. Med. Chem., (1983), 26, 759-761.
- the invention will be further described in the following examples, which do not limit the scope of the invention described in the claims.
- Example 1 Preparation of N 2 -Acetyl-9-( 1,3 -diacetoxy-2-propoxymethyv) guanine To a mixture of diacetylguanine (8g, 34 mmol), monoacetylguanine (2g, 10 mmole) and 2-acetoxymethoxy- 1, 3 -diacetoxy propane (18g, 72 mmole) in dimethylformamide (30 ml) was added />-toluene sulphonic acid (0.5g, 2.6 mmole) at 90- 100°C, and the reaction mixture was stirred for 35-45 hours.
- Example 2 Preparation of N 2 -Acetyl-9-(l,3-diacetoxy-2-propoxymethw)guanine To a mixture of diacetylguanine (24g, 102 mmol), monoacetylguanine (6g, 31 mmole) and 2-acetoxymethoxy- 1,3 -diacetoxy propane (54g, 217 mmole) in dimethylformamide (90 ml) was added p-toluene sulphonic acid (1.5g, 7.9 mmole) and N- 7 isomer (15g, 39 mmole) at 90-100°C and the reaction mixture was stirred for 35-45 hours.
- p-toluene sulphonic acid 1.5g, 7.9 mmole
- N- 7 isomer 15g, 39 mmole
- Example 3 Preparation of N 2 -Acetyl-9-(l_,3-diacetoxy-2-propoxymethw guanine
- monoacetylguanine (20g, 103 mmole) and 2-acetoxymethoxy- 1,3- diacetoxypropane (36g, 145 mmole) in dimethylformamide (60ml) was added p-toluene sulphonic acid (lg, 5.2 mmole) and stirred at 90-100°C. Reaction was not complete and even after 38 hours.
- the reaction mixture was filtered to remove unreacted monoacetylguanine (MAG) (3.85g).
- Example 7 Preparation of N -Acetyl-9-(l,3-d ⁇ acetoxy-2-propoxymethw)guanine To a mixture of diacetylguanine (8g, 34 mmol), monoacetylguanine (2g, 10 mmole) and 2-acetoxymethoxy-l,3-diacetoxypropane (20g, 80 mmole) in dimethylformamide (30 ml) was added p-toluene sulphonic acid (0.5g, 10 mmole) and N-7 isomer (5g, 13 mmole) at 120-125°C and the reaction mixture was stirred for 6-10 hours.
- a mixture of diacetyl guanine (25g, 0.106mole), 2-acetoxymethoxy- 1,3-diacetoxy propane (40. Og, 0.161 mole), p-toluene sulfonic acid monohydrate (0.5g) in N,N- dimefhylformamide (75ml) is heated at 95°C to 100°C under continuous stirring for 42 hours. After completion of the reaction, the solvents are removed under vacuum yielding a dark brown syrup. The syrup is dissolved by heating in methanol (60ml). The resulting solution is stirred at room temperature, cooled to 0°C, stirred for 30 min. at 0-5°C.
- the solvent from the filtrate is removed completely by distillation under reduced pressure to give an oily syrup.
- the oily syrup is dissolved in isopropyl alcohol and filtered through celite.
- the solvent is distilled off completely under vacuum.
- the residue is heated with a mixture of methanol (20ml) and toluene (150ml) at 60°C, stirred at room temperature and then at 0-5°C for 30 minutes.
- the product is filtered and washed with a mixture of methanol and toluene (1 :4) to yield N 2 -acetyl-9-(l,3-diacetoxy-2- propoxymefhyl) guanine ( 11. Og) .
- Example 9 Preparation of N 2 -Acetyl-9-(l,3-diacetoxy-2-propoxymethvv)guanine
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Abstract
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Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP02775077A EP1453833A2 (en) | 2001-10-15 | 2002-10-15 | A process for the preparation of ganciclovir intermediate n2-acetyl-9-(1,3-diacetoxy-2-propoxymethyl) guanine |
AU2002341281A AU2002341281A1 (en) | 2001-10-15 | 2002-10-15 | A process for the treatment of ganciclovir intermediate n2-acetyl-9-(1, 3-diacetoxy-2-propoxymethyl) guanine |
US10/492,338 US20050176956A1 (en) | 2001-10-15 | 2002-10-15 | Process for the preparation of ganciclovir intermediate n2-acetyl-9-(1,3-diacetoxy-2-propoxymethyl) guanine |
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IN1050DE2001 | 2001-10-15 | ||
IN1050/DEL/01 | 2001-10-15 |
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WO2003033498A2 true WO2003033498A2 (en) | 2003-04-24 |
WO2003033498A3 WO2003033498A3 (en) | 2004-06-10 |
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PCT/IB2002/004235 WO2003033498A2 (en) | 2001-10-15 | 2002-10-15 | A process for the treatment of ganciclovir intermediate n2-acetyl-9-(1, 3-diacetoxy-2-propoxymethyl) guanine |
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US (1) | US20050176956A1 (en) |
EP (1) | EP1453833A2 (en) |
AU (1) | AU2002341281A1 (en) |
WO (1) | WO2003033498A2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2004039808A2 (en) * | 2002-10-31 | 2004-05-13 | Ranbaxy Laboratories Limited | Process for the preparation of ganciclovir |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7078524B2 (en) * | 2002-11-22 | 2006-07-18 | Ranbaxy Laboratories Limited | Process for the synthesis of ganciclovir |
WO2011114336A1 (en) * | 2010-03-15 | 2011-09-22 | Hetero Research Foundation | Process for the isolation of ganciclovir intermediate |
CN104761552B (en) * | 2015-03-06 | 2016-08-24 | 常州康丽制药有限公司 | A kind of processing method of ganciclovir condensation substance isomer |
CN113929580A (en) * | 2021-10-29 | 2022-01-14 | 湖北省宏源药业科技股份有限公司 | Method for recovering side chain in ganciclovir condensation compound mother liquor |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
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US5583225A (en) * | 1994-05-17 | 1996-12-10 | University Of Georgia Research Foundation, Inc. | Syntheses of acyclic guanine nucleosides |
EP0806425A1 (en) * | 1996-04-09 | 1997-11-12 | Lupin Laboratories Limited | An improved regiospecific process for synthesis of acyclic nucleosides |
US6043364A (en) * | 1996-02-22 | 2000-03-28 | Lupin Laboratories Limited | Regiospecific process for synthesis of acyclic nucleosides |
Family Cites Families (6)
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US4146715A (en) * | 1975-08-27 | 1979-03-27 | Burroughs Wellcome Co. | 2-amido-9-(2-acyloxyethoxymethyl)hypoxanthines |
US5792868A (en) * | 1991-09-18 | 1998-08-11 | Ajinomoto Co., Inc. | Process for producing acyclic nucleosides and process for separating purine nucleosides |
WO1995007281A1 (en) * | 1993-09-10 | 1995-03-16 | Recordati S.A. Chemical And Pharmaceutical Company | A process for the preparation of 9-(2-hydroxy)-ethoxymethyl-guanine |
US5565565A (en) * | 1994-08-04 | 1996-10-15 | Syntex (U.S.A.) Inc. | Preparation of N-9 substituted guanine compounds |
US20060142574A1 (en) * | 2002-10-31 | 2006-06-29 | Babu Jayachandra S | Process for the preparation of ganciclovir |
US7078524B2 (en) * | 2002-11-22 | 2006-07-18 | Ranbaxy Laboratories Limited | Process for the synthesis of ganciclovir |
-
2002
- 2002-10-15 EP EP02775077A patent/EP1453833A2/en not_active Withdrawn
- 2002-10-15 WO PCT/IB2002/004235 patent/WO2003033498A2/en not_active Application Discontinuation
- 2002-10-15 AU AU2002341281A patent/AU2002341281A1/en not_active Abandoned
- 2002-10-15 US US10/492,338 patent/US20050176956A1/en not_active Abandoned
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5583225A (en) * | 1994-05-17 | 1996-12-10 | University Of Georgia Research Foundation, Inc. | Syntheses of acyclic guanine nucleosides |
US6043364A (en) * | 1996-02-22 | 2000-03-28 | Lupin Laboratories Limited | Regiospecific process for synthesis of acyclic nucleosides |
EP0806425A1 (en) * | 1996-04-09 | 1997-11-12 | Lupin Laboratories Limited | An improved regiospecific process for synthesis of acyclic nucleosides |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2004039808A2 (en) * | 2002-10-31 | 2004-05-13 | Ranbaxy Laboratories Limited | Process for the preparation of ganciclovir |
WO2004039808A3 (en) * | 2002-10-31 | 2004-10-21 | Ranbaxy Lab Ltd | Process for the preparation of ganciclovir |
Also Published As
Publication number | Publication date |
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EP1453833A2 (en) | 2004-09-08 |
US20050176956A1 (en) | 2005-08-11 |
AU2002341281A1 (en) | 2003-04-28 |
WO2003033498A3 (en) | 2004-06-10 |
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