urea immobilized silica-coated fe3o4 mnps as a heterogeneous magnetic nanocatalyst for the synthesis of 2-amino-4h-benzo[b]pyran derivatives

in this work, a novel urea immobilized silica-coated fe3o4 mnp (fe3o4@sio2@(ch2)3-urea) as a magnetically recoverable and metal-free nanocatalyst was designed and synthesized, and characterized using ft-ir, xrd, fe-sem, tem, edx, and vsm. this system was explored in a threecomponent reaction to synthesize 2-amino-4h-benzo[b]pyran derivatives of dimedone, malononitrile, and aromatic aldehydes in ethanol at 80 °c. this new method has numerous merits, such as using a green and nontoxic catalyst, excellent yield, shorter reaction time, broad substrate scope, operational simplicity, and functional group compatibility. moreover, the synthesized nanocatalyst was recovered by a magnetic field, and it was reused eight times without any appreciable change in the catalytic activity. © 2022 by spc (sami publishing company), asian journal of nanoscience and materials, reproduction is permitted for noncommercial purposes.