Bis sulfamic acid functionalized magnetic nanoparticles as a retrievable nanocatalyst for the green synthesis of polyhydroquinolines and tetrahydrobenzopyrans

Synthesis of bis sulfamic acid-grafted on silica-coated nano-Fe3O4 particles (MNPs-TBSA) as a novel core/shell hybrid organic-inorganic magnetic nanostructures, and their performance as a retrievable heterogeneous acidic catalyst is disclosed. The catalytic performance of this novel material was studied for the green synthesis of pharmaceutically valuable polyhydroquinoline and tetrahydrobenzopyran derivatives via one-pot multi-component condensation of aryl aldehydes, dimedone, ethyl acetoacetate, malononitrile and ammonium actate in ethanol as a solvent and at 70 º C. Eco-friendly method, high yield and purity of the desired products, short reaction time along with the ease of the workup procedure outlines the advantages of these new methodologies over the earlier ones. Surface and magnetic properties of the core/shell hybrid nanoparticles were characterized via field emission scanning electron microscopy (FE-SEM), X-ray diffraction measurements (XRD), the energy dispersive X-ray spectroscopy (EDS), FT-IR spectroscopy and vibrating sample magnetometer (VSM). The crystallite size of the magnetic nanoparticle is calculated to be 15.5 nm.