Tandem One-Pot Synthesis of Polysubstituted 1,3-Thiazine Derivatives.

A tandem one-pot synthesis of polysubstituted 1,3-thiazines has been developed by reacting with cyanoacetamide and isothiocyanate derivatives to give rise to 2-cyano-3-mercaptoacrylamides, which are trapped in situ by various aldehydes or diversely substituted ketones through intermolecular cyclization, providing polysubstituted 1,3-thiazine derivatives in short reaction times with good to excellent yields. The salient features of this novel protocol are operational simplicity, accessing the desired products from the readily available starting materials and easy of product isolation and may find wide spread applications in medicinal chemistry.