Donepezil Hydrochloride → Desbenzyl donepezil

Participants

Reaction Steps

US Patent Application published under the No. 2007/0135644A1 discloses the preparation of donepezil hydrochloride by reducing 5,6-dimethoxy-2-[1-(4-pyridinyl)methylidene]-1-indanone tosylate with 10% Pd/C catalyst in demi-water at 70-95° C., at 10 bar for 8 hours. The mixture is extracted three times with 1-butanol to afford a residue which is purified with methyl-tert-butyl ether to obtain 5,6-dimethoxy-2-(4-piperidinylmethyl)-1-indanone, followed by condensation with benzyl chloride in toluene for 8 hours at 145° C. to yield donepezil which is further converted to donepezil hydrochloride.

Provenance & Evidence