A process for the preparation of 1-benzyl-4-[(5,6-dimethoxy-1-indanon)-2-yl]
methyl
piperidine hydrochloride (Donepezil HCl) is disclosed. 5,6-Dimethoxy-2-(pyridin-4-yl)
methylene inda-1-one is hydrogenated with a noble metal catalyst or a non-oxide
derivative of a noble metal catalyst in a solvent at 20-100 C. and 10-90
psi gauge pressure. The resulting 4-[(5,6-dimethoxy-1-indanon)-2-yl] methyl piperidine
is alkylated with an alkylating agent in an organic solvent at 20-80 C.