Ultrasound-accelerated arylthiomethylation of indole via multicomponent reaction in water catalyzed by acetic acid

Abstract

Multicomponent reactions (MCRs) play an important role to create the molecular complexity in a one-step process. Based on the mechanism and process of Mannich-type reactions in the synthesis of Grammin, arylthiomethylation reactions of indole were performed by using three components: indole, p-thiocresol and a solution of formaldehyde (36%) under two activation conditions, e.g. magnetic stirring and ultrasonic irradiation. The main product, 3-(p-tolylthiomethyl)-1H-indole, was obtained in a moderate yield (54%) under short irradiation (40 minutes) by probe sonicator.