Preparation of magnetic decorated polyacrylonitrile-grafted chitosan as a new bio-inspired nanocatalyst for the synthesis of dihydropyrano[2,3-c]pyrazole and 2-amino-3-cyano-4H-pyran derivatives

This research reports a novel magnetized polyacrylonitrile-modified chitosan (CS-g-PAN/Fe₃O₄) nanomaterial, as a heterogeneous catalyst, for multicomponent reactions (MCRs). Appropriate characterization using techniques such as Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and field emission scanning electron microscopy, as well as N₂ adsorption-desorption isotherms, and vibrating sample magnetometer techniques confirmed the successful synthesis and structure of the CS-g-PAN/Fe₃O₄ nanocomposite. This multifunctional catalyst combines basic and Lewis acidic active sites, enhancing its catalytic performance. The catalytic ability of CS-g-PAN/Fe₃O₄ nanomaterial was demonstrated in MCRs for the synthesis of biologically active dihydropyrano[2,3-c]pyrazole (DHPPs) and 2-amino-3-cyano-4H-pyran derivatives. These reactions afforded excellent yields of the desired products with a simplified work-up process. Additionally, the catalyst exhibited almost facile recyclability, as well as maintaining its activity for at least five consecutive runs in both MCRs without a considerable decrease in its catalytic activity. This work highlights the development of a sustainable and efficient magnetic nanocatalyst for the synthesis of valuable heterocyclic compounds. Its simple recovery and reusability offer significant advantages over traditional catalysts, making it a promising candidate to address green chemistry principles.