Ring‐Opening‐Recombination Strategy Based on 2‐Methylbenzothiazole Salts: Syntheses of Thiazinopyrrole Fused‐Ring Derivatives

Abstract

This study presents a method for the synthesis of thiazinopyrrole fused ring derivatives utilizing a ring‐opening recombination strategy with benzothiazole salts. Thiazolium salts, aldehydes, and amines undergo a cascade cyclization reaction in a one‐pot under the solvent conditions of ethanol.

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

“…Recently, our group has successfully developed a [2 + 1 + 2] cyclization of 2-methylbenzothiazolium salts, aldehydes and amines through a ring-opening recombination strategy for the synthesis of thiazinopyrrole fused ring derivatives. [13] We considered the feasibility of extending this strategy to the construction of 1,3-diazaphenothiazines, as part of our ongoing project. Herein, we proposed the [2 + 1 + 3] cyclization of 2-methylbenzothiazolium salts, aldehydes, and amidine hydrochlorides for the preparation of 1,3-diazaphenothiazines under mild conditions.…”