Process and intermediate for preparation of donepezil

摘要

A process for preparing a benzyl protected piperidine compound of formula (III) wherein R is a linear or branched alkyl group, said process comprising reacting N-benzyl 4-piperidone with a compound of formula X-CH2COOR' wherein X is CI, Br or I, and R' is a linear or branched alkyl group. Also disclosed is a process to prepare intermediate compounds (II) (IV), a process to prepare (+/-)-2,3-dihydro-5,6-dimethoxy-2-[[1-(phenylmethyl)-4-piperdinyl]methyl]-1H-inden-1-one hydrochloride (donepezil hydrochloride) from these intermediates, donepezil obtained from these processes, compositions comprising said donepezil, a compound of formula (III) and a compound of formula (IV).