Enantiospecific Synthesis of Imidazoquinazolin-2-ones via Base-Catalyzed Tandem Cyclization

Abstract

A facile protocol for the enantiospecific synthesis of novel (S)‐3‐substituted imidazo[2, l‐b]quinazoline‐2‐ones via tandem reaction of substituted (S)‐3‐amino‐4‐aminomethylbenzoates and cyanogen bromide under basic conditions is explored. This tandem process involves addition reaction of substituted (S)‐3‐amino‐4‐aminomethylbenzoates to CNBr to yield 2‐imino tetrahydroquinazoline carboxylate intermediates followed by in situ intramolecular aminolysis to afford the triheterocyclic imidazo[2, l‐b]quinazoline‐2‐ones in good yields and high enantiomeric purity.