Synthesis Of Novel Imidazole-Based Triheterocycles Via A Domino Ugi/Michael Reaction And Silver-Catalyzed Heteroannulation

An efficient and diversity-oriented synthetic strategy for novel triheterocyclic imidazo-pyrrolo-pyrazine/diazepine/diazocine derivatives is elaborated. The process utilizes a domino four-component Ugi reaction/Michael reaction of imidazole-2-carbaldehyde, propargyl amines, 2-alkynoic acids and isonitriles to deliver functionalized imidazole-pyrrolones, which upon a silver-catalyzed heteroannulation in aqueous medium under microwave irradiation furnishes the desired triheterocycles in good to excellent yields.