Acetylcholinesterase inhibition by fused dihydroquinazoline compounds

A new type of dihydroquinazoline-based inhibitor of acetylcholinesterase (AChE) is described. These compounds were designed to interact with the catalytic site of AChE in a manner similar to the known inhibitor tacrine. In a manner analogous to the potency enhancement obtained by addition of chlorine atoms to the tacrine molecule, a 3-chloro derivative of the parent hexahydroazepino[2,1-b]quinazoline structure was found to be about 8 times more potent as an AChE inhibitor than the unsubstituted compound.