One-step synthesis of 4-methyl-2-substituted quinazoline-3-oxides via polyphosphoric acid catalyzed acylation of electron-rich anilides with nitroethane

Abstract

A diverse set of 4-methyl-2-substituted quinazoline-3-oxides has been prepared using polyphosphoric acid both as a reaction medium and a Brønsted-acid catalyst. The reaction proceeds in a domino fashion via the formation of a corresponding oxime followed by exo-trig cyclization and elimination of a water molecule which leads, ultimately, to the target N-oxide heterocycles.