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US 7,442,834 B2Granted
Process suitable for industrial scale production of gabapentin
AssigneeZhejiang Chiral Medicine Chemicals Co. Ltd.
InventorsTianchun Liu, Youming Huang, Weirong Fan
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Abstract
This invention relates to an improved process for the preparation of substantially pure, stable anhydrous gabapentin. Thus, cyclohexane 1,1-diacetic acid monoamide is first treated with NaOH/NaClO to form 3,3-pentamethylenebutyrolactam, which is treated with aqueous HCl solution under reflux to provide gabapentin HCl salt, which is then neutralized with NaOH followed by a dehydration step to provide substantially pure, storage-stable, pharmaceutical grade gabapentin.
Claims31
A process for the preparation of highly pure, stable compound of formula
- comprising:
- (a) converting cyclohexane 1,1-diacetic acid monoamide to 3,3-pentamethylenebutyrolactam by reacting cyclohexane 1,1-diacetic acid monoamide with hypochlorite;
- (b) hydrolyzing 3,3-pentamethylenebutyrolactam to gabapentin salt under acidic condition at 50-120° C., cooling the reaction mixture to precipitate gabapentin salt, and collecting the gabapentin salt from the mother liquor by filtration;
- (c) adding gabapentin salt to purified water and adjusting the pH to 8-8.5 with a base, cooling the mixture to 10-20° C. to precipitate gabapentin hydrate, and collecting the gabapentin hydrate from the mother liquor by filtration;
- (d) dehydrating gabapentin hydrate in alcohol or water-alcohol solvent at below 50° C.;
- and
- (e) collecting the pure gabapentin from the mother liquor by filtration;
- provided that process does not include ion exchange chromatography as a processing step.
5 more elements
Dependencies are inferred from the claim text.