Process for the preparation of 1-(aminomethyl) cyclohexaneacetic acid
A method of producing gabapentin (1-amino-methyl)-1-cyclohexaneacetic acid) from its hydrochloric salt in an anhydrous medium, the method consisting of: dissolving gabapentin hydrochloride in a non-aqueous organic solvent in which gabapentin is insoluble to obtain a solution of gabapentin hydrochloride; adding an epoxide to the solution to remove the chloride ions thereby precipitating gabapentin out of the solution as a white solid; recovering the white solid by filtration; and drying the white solid.
1. A process for the preparation of gabapentin from gabapentin hydrochloride comprising:
dissolving gabapentin hydrochloride in a non-aqueous organic solvent to obtain a solution;
adding an epoxide to the solution to remove the chloride ions from the solution thereby precipitating gabapentin out of the solution as a white solid in its free amino acid form;
recovering the white solid by filtration; and
drying the white solid until no loss of weight is observed.
2. The process of claim 1 wherein the gabapentin hydrochloride is soluble in the solvent while the gabapentin is not soluble therein.
3. The process according to claim 1 wherein said non-aqueous organic solvent is selected from the group consisting of: methanol, ethanol, isopropyl alcohol and n-butanol.
4. The process of claim 1 wherein said epoxide is selected from the group consisting of ethylene oxide, 1,2-epoxybutane, and propylene oxide.
5. The process of claim 1 wherein said hydrochloride reacts with said oxide opens up the ring in the molecule and releases the gabapentin in its free amino acid form.
6. The process of claim 1 wherein the reaction of said oxide and said hydrochloride is carried out at a temperature of about 0°–50° C.
7. The process of claim 6 wherein said reaction is carried out at about 10°–25° C.
8. The process of claim 1 wherein said dried solid of gabapentin is at least about 99.0% pure.