Fabrication and characterization of copper complex immobilized on magnetic nanoparticles: an efficient and ecofriendly nanomagnetic catalyst for synthesis of imidazo[1,2-a]pyridines and pyranopyrazoles

Imidazopyridine and pyranopyrazole derivatives include a very important class of heterocyclic compounds that have many biological properties and have been observed in the structure of many drugs and bioactive molecules. In this research project, we first successfully made copper catalyst immobilized on magnetic iron nanoparticles modified with dopamine and 1H-benzo[d]imidazole-2-carboxylic acid (as magnetic ligand) and confirmed its structure with a series of spectroscopic techniques; then in the next step, the catalytic activity of this nanocomposite [Fe₃O₄@Dop/Amide-BenzImid-CuBr₂] was evaluated the nanocomposite in the multicomponent synthesis of imidazo[1,2-a]pyridine and pyranopyrazole derivatives. The results clearly showed that this magnetic nanocatalyst in water solvent under reflux conditions is a very efficient catalytic system for the synthesis of imidazo[1,2-a]pyridines and pyranopyrazoles because all the products were synthesized with high to excellent yields in a suitable period of time. Also, the recovery tests confirmed that the Fe₃O₄@Dop/Amide-BenzImid-CuBr₂ catalyst can be reused up to 8 times without significantly reducing its catalytic efficiency. VSM and ICP-OES analyses confirmed the stability, magnetism and high efficiency of the catalyst after repeated use of the catalyst.