Synthesis of 2-thioxoimidazolin-4-one and thiazolo[3,2-a]-benzimidazole derivatives from substituted maleimides

We describe here a hetero Michael-type reaction, involving maleimides and 2cyanoacetichydrazide or 2-mercaptobenzimidazole, followed by an opening cyclization reaction with isothiocyanates. This reaction allows the preparation of new 2-thioxoimidazolidin-4-one and thiazolo[3,2-a]benzimidazole derivatives depending on the nucleophile used.