Process for the preparation of amino methyl cyclo alkane acetic acids
AssigneeHikal Limited
InventorsNagarajan Kuppuswamy, Sivaramakrishman Hariharan, Arulselvan Mariadas
Life of this patent
Estimating the term…
Abstract
This invention relates to an improved process for the preparation of amino methyl cyclo alkane acetic acids. This invention particularly relates to an improved process for the preparation of gabapentin (which is chemically known as 1-aminomethyl-1-cyclohexaneacetic acid), which is a very well known agent useful for the treatment of epilepsy and other cerebral disorders. In the chemical series of 1-amino methyl cyclo alkane-1-acetic acids, Gabapentin, which is 1-amino methyl cyclo hexane-1-acetic acid has been developed as a drug having anti convulsive properties.
Claims12
An improved process for the preparation of gabapentin of the formula 1
- which comprises
- (i) preparing an aqueous solution of Gabapentin hydrochloride in water in the ratio of one part by weight of the former to 0.5 to 3 parts by weight of the later,
- (ii) preparing an aqueous solution of an alkali metal base in a concentration in the range of 40-50% w/w
- (iii) adding 0.08 to 0.3 parts by weight of the solution obtained in step (ii) to 1.5 to 4 parts by weight of the solution obtained in step (i) at a temperature in the range of 0 to 20 degree C.
- (iv) heating the resulting solution gradually to a temperature in the range of 50-90 degree C.
- (v) gradually cooling the resulting solution to a temperature in the range of 0 to 15 degree C. to obtain a precipitate,
- (vi) aging the precipitate for a period in the range of 0.5 hrs to 8 hrs at a temperature in the range of 0 to 15 degree C.
- (vii) Separating the precipitate from the mother liquor by conventional methods and
- (viii) recrystallising the precipitate from a mixture of IPA, methanol & water to get Gabapentin of over 99.5% purity and a mother liquor
A novel improved process for the preparation of Gabalactam of the formula 3 which comprises treating the mother liquors obtained in steps (vii) & (viii) of the above mentioned process with aq.sodium hydroxide in a concentration in the range of 5 to 20% at a temperature in the range of 80 to 100 degree C., recovering the gabalactam by extraction with organic solvents.
A novel improved process as claimed in claim wherein the recovery of gabalactam is effected by extracting the reaction mixture with solvents such as toluene, ethylene dichloride, methylene dichloride or hexane, preferably toluene.
Dependencies are inferred from the claim text.