Iron-catalyzed unprecedented formation of benzo[d]imidazo[2,1-b]thiazoles under solvent-free conditions

The unprecedented formation of benzo[ d ]imidazo[2,1- b ]thiazole during iron-catalyzed coupling of 2-aminobenzothiazole, aldehydes with nitroalkane in air has been observed. This unique transformation possibly occurs through a sequential aza-Henry reaction and subsequent intramolecular cyclization, followed by denitration. A variety of substituted benzo[ d ]imidazo[2,1- b ]thiazole are obtained using this protocol.