Introducing a new magnetic nanocomposite based on the chitosan modified by sulfonic acid-containing moieties for synthesis of 1,4-dihydropyridines and polyhydroquinolines

Abstract

AbstractDue to environmental concerns, the development of bio-inspired nanocatalysts is growing increasingly. Hence, in this study an acidic magnetic nanocatalyst was prepared through a simple and efficient method. In this regard, chitosan (CS) was anchored by 4-amino-3-hydroxy-naphthalen-1-sulfonic acid (SA) and then magnetized by Fe3O4. Successful synthesis of magnetic CS-SA nanocomposites was confirmed with the help of FTIR, XRD, FESEM, EDX, VSM, and TGA techniques. The as-synthesized magnetic CS-SA nanocomposites exhibited a very good activity for the multicomponent synthesis of 1,4-dihydropyridine and polyhydroquinoline compounds in the ethanol at 50°C. The synergistic effect of –SO3H groups and Fe3O4nanoparticles justified the remarkable activity of magnetic CS-SA nanocomposites. The catalyst was reusable 5 times and remained stable based on the hot filtration test. Some of the salient features of this method are easy catalyst separation, short reaction times, high to excellent efficiencies, safe and green solvent.