Microwave‐Assisted Synthesis of Substituted Dibenzo[b,f][1,4]thiazepines, Dibenzo[b,f][1,4]oxazepines, Benzothiazoles, and Benzimidazoles

Abstract

A highly efficient synthesis for possessing 7‐membered rings with two heteroatoms is described, using efficient microwave‐assisted one‐pot method to synthesize (substituted) dibenzo[b,f][1,4]thiazepines [1] and dibenzo[b,f][1,4]oxazepines [2] in high yields (up to 99%) by cyclocondensations of o‐aminothiophenol or o‐aminophenol with o‐halobenzaldehydes, o‐fluoroacetophenone, and o‐fluorobenzophenone. In the absence of base, o‐aminothiophenol reacted with o‐halobenzaldehydes to afford benzothiazoles.