Oxidative Cyclization of 4‐(2‐Mercaptophenyl)‐Substituted 4H‐1,2,4‐Triazolium Species to Tricyclic Benzothiazolium Salts

Abstract

Herein we report a generally applicable method for the preparation of ,2,4]triazol-1-ium salts from air stable precursors. This transformation features selective deprotection of a para-methoxybenzyl protected thiol followed by CÀ H functionalization of the linked 1,2,4-triazolium salts under oxidative conditions.Using this procedure, we synthesized a variety of tricyclic thiazolium salts which contain both electron-withdrawing and electron-donating aromatic substituents as well as aliphatic substituents. Our approach also tolerates many functional groups including alkynes, alcohols, diols, amides, and polyethers.