Base-Mediated Synthesis of 1,3-Diazaphenothiazines from 2-Methylbenzothiazoliums, Aryl Aldehydes and Amidines

Abstract

In this study, we developed a process for the [2+1+3] cyclization of 2-methylbenzothiazole salts, aldehydes and amidine hydrochlorides, which allows rapid synthesis of 1,3-diazaphenothiazines with moderate to good yields. The use of ethanol as solvent, oxygen as the terminal oxidant, mild reaction conditions, good functionality tolerance show the promising application in organic synthesis.