NOVEL PROCESS FOR PRODUCTION OF HIGHLY PURE POLYMORPH (I) DONEPEZIL HYDROCHLORIDE

摘要

The present invention provides a novel, industrially realisable and economically preferable process for production of highly pure l-benzyl-4-[(5,6-dimethoxy-l-indanon)-2-yl]methyl piperidine hydrochloride, i.e., donepezil hydrochloride shown in the following reaction scheme, in Polymorph (I) morphological crystal form. (I) In one of the key steps of the process, during the hydrogenation 5,6-dimethoxy-2-(pyridine-4-yhnethylene)indan-l-one hydrochloride is saturated using Pd carbon to get 4-[(5,6-dimethoxy-l-indanon)-2-yl]-methyl piperidine at more than 97 % HPLC purity. In the crystallization step donepezil-hydrochloride is crystallized from an aqueous alcoholic solvent to get Polymorph (I) in at least 99.95 % HPLC purity.