Cyclocondensation of o-phenylenediamines with α-ketothioesters: a novel approach for the synthesis of 2-acylbenzimidazoles

Abstract

We herein present a novel and an unexpected method for the synthesis of α-ketothioesters by the reaction of pyrrolidine with α-oxodithioesters followed by treatment with methyl iodide in methanol. One of the synthetic applications of α-ketothioesters for the synthesis of 2-acylbenzimidazoles by acid-catalyzed cyclocondensation with benzene-1,2-diamines is described. The probable mechanisms of formation of α-ketothioesters and 2-acylbenzimidazoles are proposed.