Dehydrodeoxy Donepezil

Dehydrodeoxy Donepezil is a structurally related impurity of the cholinesterase inhibitor Donepezil, characterized by a fully dehydrogenated tetrahydronaphthalene core and a desoxygenated piperidine side chain. Its aromatic phthalane ring system exhibits conjugated double bonds at positions C1=C2 and C4=C5, while the nitrogen-containing heterocycle retains a tertiary amine functionality. This compound arises via oxidative degradation pathways of the parent drug, featuring a 1,2-dihydrophthalane scaffold with a substituted 3-piperidinyl group. It serves as a critical HPLC reference standard for quantifying process-related impurities in Donepezil formulations.