Synthesis and Characterization of Fe ₃ O ₄ @L‐Arginine Magnetic Nanocatalyst Immobilized on Nickel Oxide for One‐Pot Ultrasound‐Assisted Synthesis of 3,4‐Dihydropyrimidin‐2(1 <i>H</i> )‐ones

Abstract In this work, we synthesized a heterogeneous magnetic nanocatalyst using iron oxide (Fe 3 O 4 ) surface‐modified with L‐arginine@NiO (Fe 3 O 4 @L‐Arg@NiO). Several characterization techniques such as fourier transform infrared (FT‐IR), field emission scanning electron microscopy (FE‐SEM), X‐ray diffraction (XRD), high‐resolution transmission electron microscopy (HR‐TEM), electron dispersion spectra (EDS) and thermogravimetric analysis (TGA) were used to extensively analyze its structural and morphological properties. The Fe 3 O 4 @L‐Arg@NiO nanocatalyst was subjected to the one‐pot multi‐component synthesis of 3,4‐dihydropyrimidin‐2‐(1 H )‐ones derivatives under solvent‐free conditions. It was determined that nanocatalyst Fe 3 O 4 @L‐Arg@NiO demonstrating desired product 3,4‐dihydropyrimidin‐2‐(1 H )‐ones with 85%–95% yield, in shorter reaction time. Furthermore, simple work‐up, reusability of the catalyst up to five cycles and sustainability of the catalyst are characteristic features of this environment friendly protocol.