Reactions of arylaminomethylenemalonates with amines

Abstract

The reaction of arylaminomethylenemalonates with amines can in some cases lead to ami-dines, e.g. reaction of diethyl N-[4-(3-methyl-4-isothiazolyl)-2-thiazolyl]aminomethylenemalonate (IV) with morpholine and pyrrolidine gives the corresponding-amidines besides 2-amino-4-(3-methyl-4-isothiazolyl) thiazole (III), the starting substrate for the preparation of (IV). The reaction of IV with N-methylpiperazine gives only III. Mechanism to explain the regeneration of III in the reaction of IV with amines has been suggested.