Cyclization of o-(S-phenacyl)-substituted N-phenylquinone imine occurring with the insertion of an additional carbon unit

Abstract

A new approach to the synthesis of 2-aroyl-4-aryl-4H-benzo[b][1,4]thiazines was proposed via a three-component reaction of 2,6-di-tert-butyl-4-[(2-sulfanylphenyl)imino]-cyclohexa-2,5-dien-1-one with phenacyl bromides and N,N′-dimethylformamide in the presence of KOH. The structure was established by 1H and 13C NMR spectroscopy, HRMS, and X-ray diffraction analysis.