Facile synthesis of substituted 2-aroylbenzo[b]thiophen-3-ols to form novel triazole hybrids using click chemistry

Abstract

An efficient one-pot method is proposed for the synthesis of 2-aroylbenzo[b]thiophen-3-ols from 2-mercaptobenzoic acid and various substituted aryl bromomethyl ketones in the presence of triethylamine. The reaction is likely to proceed through S_N2-type nucleophilic attack of the sulfhydryl group in thiosalicylic acid on bromomethyl ketone in the presence of a base to afford sulfanylbenzoic acid, which undergoes an intramolecular cyclization in situ to furnish 2-aroylbenzo[b]thiophen-3-ol in high yield. To investigate the utility of the synthesized benzothiophene scaffold, an alkyne moiety was introduced at the 3-hydroxy position and subsequently subjected to a click reaction to form novel benzothiophene-triazole hybrids in good yields. A simple and straightforward approach to synthesizing 2-aroylbenzo[b]thiophen-3-ols can open new avenues for discovering novel biological and pharmaceutical compounds.