Preparation and characterization of copper/polysulfonamide complex immobilized on geraphene oxide as a novel catalyst for the synthesis of pyrimido[1,2-a]benzimidazoles

Copper–polysulfonamide complex immobilized on geraphene oxide as a novel heterogeneous catalyst (GO@PSA-Cu) was synthesized and the structure and morphology of catalyst were characterized with various analytical techniques such as Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray, N₂ isotherms, elemental mapping, inductively coupled plasma–MS, and thermogravimetric analysis. The GO@PSA-Cu catalyst demonstrated good to excellent yields for the synthesis new derivatives of pyrimido[1,2-a]benzimidazoles via one-pot three-component condensation reaction of various aromatic aldehydes, 2-aminobenzimidazole, and ethyl acetoacetate in ethanol. The method presented herein has several prominent advantages such as cost-effectiveness, operational simplicity, short reaction times, high yields, and reusability of the catalyst even after six consecutive runs.