Synthesis of Tetrahydrobenzo[b]pyran and Pyrano[2, 3-d]pyrimidinone Derivatives Using Fe3O4@Ph-PMO-NaHSO4 as a New Magnetically Separable Nanocatalyst

Abstract

Immobilized NaHSO4 on core/shell phenylene bridged periodic mesoporous organosilica magnetic nanoparticles (Fe3O4@Ph-PMO-NaHSO4) as a new acidic magnetically separable nanocatalyst was successfully prepared in three steps: (i) preparation of Fe3O4 nanoparticles by a precipitation method, (ii) synthesis of an organic–inorganic periodic mesoporous organosilica structure with phenyl groups on the surface of Fe3O4 magnetic nanoparticles (MNPs) and (iii) finally adsorption of NaHSO4 on periodic mesoporous organosilica (PMO) network. The prepared organic–inorganic magnetic reagent was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption–desorption and energy-dispersive X-ray (EDX) techniques. Finally, it was used as a reusable and new catalyst to promote the synthesis of tetrahydrobenzo[b]pyran and pyrano[2,3-d]pyrimidinone derivatives as important biologically active compounds. Eco-friendly protocol, high yields, short reaction times and easy and quick isolation of the products are the main advantages of this procedure.