Synthesis and in vitro evaluation of donepezil-based reactivators and analogues for nerve agent-inhibited human acetylcholinesterase

Poisoning by organophosphorus nerve agents and pesticides is a serious public and military health issue with over 200 000 fatalities annually worldwide. Conventional emergency treatment consists of rapid administration of atropine and pyridinium oxime as an antidote. The reactivation of acetylcholinesterase (AChE) in the central nervous system (CNS) by the oxime is inefficient due to the fact that positively charged pyridiniums do not readily cross the blood brain barrier (BBB). Herein, we described the synthesis and in vitro evaluation of four donepezil-based non quaternary reactivators. The compounds 1–4 have been prepared in 7–8 linear steps in 1–9% overall yields and oximes 1–3 show better ability (8 fold higher) than pralidoxime to reactivate VX-inhibited human AChE (VX-hAChE). Besides, oxime 2 is 5 to 11 fold more efficient than pralidoxime and HI-6 respectively for the reactivation of VX-inhibited human butyrylcholinesterase (VX-hBChE).