Regioselective Synthesis of New 2-(E)-Cyano(thiazolidin-2-ylidene)thiazoles

Abstract

Cyclocondensation of 2-[bis(methylthio)methylene]malononitrile (1) and cysteamine (2) afforded 2-(thiazolidin-2-ylidene)malononitrile (3). This compound on treatment with NaSH gave the corresponding thioamide derivative 4a in a regioselective manner on the basis of its single crystal X-ray diffraction analysis. Reaction of this compound with several α-bromocarbonyl compounds gave new 2-(E)-cyano(thiazolidin-2-ylidene)thiazoles 5a-g.

Keywords

• thiazole
• thiazolidine
• Hantzsch’s synthesis
• heterocyclization
• regioselective synthesis
• X-ray crystallography