Process and intermediate for preparation of donepezil

摘要

The invention relates to new compounds of formula (III): wherein R is a C-C linear or branched alkyl group. The invention also relates to new compounds of formula (IV) wherein M is a metal. The invention also relates to methods of making compounds of formulas (III) and (IV) and to methods of making donepezil and pharmaceutically acceptable salts thereof, such as donepezil hydrochloride, using the compounds.