PROCESS FOR PRODUCTION OF HIGHLY PURE DONEPEZIL HYDROCHLORIDE

摘要

The present invention provides a process for the preparation of highly pure Donepezil hydrochloride having a liquid chromatography purity (relative area method) of more than 97%, with a content of each individual impurity not exceeding 0.02 area %, which process comprises forming Donepezil base in solution and treating the Donepezil base solution with HCl without prior isolation of Donepezil base; and optionally re-crystallizing the hydrochloride to give Donepezil hydrochloride of desired liquid chromatography purity. Donepezil base in solution may be obtained by intramolecular cyclization of 2-(3,4-dimethoxybenzyl)-3-(N-benzyl- 4-piperidine)propionic acid or a salt thereof.