KOH-mediated intramolecular amidation and sulfenylation: A direct approach to access 3-(arylthio)imidazo[1,2-a]pyridin-2-ols

A simple and facile method for the synthesis of 3-(arylthio)imidazo[1,2-a]pyridin-2-ols has been developed by a KOH-mediated reaction of 2-aminopyridinium bromides with aryl thiols. The method afforded a wide range of 3-(arylthio)imidazo[1,2-a]pyridin-2-ols in moderate to excellent (56e95%) yields with excellent functional group tolerance. Synthetic utility of the protocol was demonstrated by gram-scale reaction and preparation of 2-aryl-3-(p-tolylthio)imidazo[1,2-a]pyridines from 3-(p-tolylthio) imidazo[1,2-a]pyridin-2-ol. (C) 2020 Elsevier Ltd. All rights reserved.