NiFe 2 O 3 @SiO 2 -Pr-DBU: A novel efficient magnetically retrievable catalyst for one-pot synthesis of dihydropyrano[c]chromene

In the present work, NiFe 2 O 3 @SiO 2 -Pr-DBU was synthesized as a novel magnetically separable nanocatalyst and characterized by various techniques like Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM), Vibrating-sample magnetometry (VSM), Transmission electron microscopy (TEM) and Elemental analysis by energy dispersive X-ray (EDX). The catalytic efficiency of NiFe 2 O 3 @SiO 2 -Pr-DBU was explored in the synthesis of dihydropyrano[ c ]chromenes through a one-pot three-component reaction of 4-hydroxycoumarin, malononitrile, and aromatic aldehydes in aqueous solution at ambient condition. The nano-sized catalyst was simple to remove from the synthesized reaction mixture using an external magnet, and it could be employed again without appreciably losing catalytic activity.