Novel synthesis and cyclization reactions of 3-amino-2-mercaptopyrrole derivatives

Interaction of cyanothioformamides with chalcones gave 3-amino-2-mercaptopyrroles, which have the tautomeric structures (3-aminopyrroline-2-thiones and 5-iminopyrrolidine-2-thiones), The latter was reacted with chloroacetic acid, ethyl chloroacetate, chloroacetamide and 2,3-dichloro-1,4-naphthoquinone to give the corresponding pyrrolothiazines derivatives. On using phenylisocyanate or p-chlorobenzoyl chloride, the corresponding pyrrolothiazole derivatives could be isolated. Replacement of chalcones by maleimides furnished pyrrolopyrrolinediones.