Preparation of choline chloride–urea deep eutectic solvent‐modified magnetic nanoparticles for synthesis of various 2‐amino‐4H‐pyran derivatives in water solution

A novel hybrid magnetic nanocatalyst was synthesized by covalent coating of Fe3O4 magnetic nanoparticles with choline chloride-urea deep eutectic solvent using 3-iodopropyltrimethoxysilane as a linker. The structure of this new catalyst was fully characterized via elemental analysis, transmission and scanning electron microscopies, X-ray diffraction and Fourier transform infrared spectroscopy. It was employed in the synthesis of various 2-amino-4H-pyran derivatives in water solution via an easy and green procedure. The desired products were obtained in high yields via a three-component reaction between aromatic aldehyde, enolizable carbonyl and malononitrile at room temperature. The employed nanocatalyst was easily recovered using a magnetic field and reused four times (in subsequent runs) with less than 8% decrease in its catalytic activity.