Synthesis of Clausena Alkaloids Using Unique Ring Expansion of Dihydroisoquinolines and Their Cholinesterase Inhibitory Activity

Abstract

AbstractA facile and direct synthetic entry to the carbon skeleton of Clausena alkaloids, the benzo[d]azocin-4-one, is reported featuring the ring expansion of 1-phenyldihydroisoquinoline derivatives initially triggered by oxazolone under environmentally benign conditions in a one-pot procedure. Functionalization of the eight-membered lactam framework provided a set of Clausena alkaloid derivatives. Some derivatives show a promising inhibition toward acetylcholinesterase and a better selectivity index than the previously used Alzheimer’s disease (AD) drug, tacrine, and the currently used AD drug, galantamine.