A CMC- g -poly(AA- co -AMPS)/Fe 3 O 4 hydrogel nanocomposite as a novel biopolymer-based catalyst in the synthesis of 1,4-dihydropyridines.

A CMC- g -poly(AA- co -AMPS)/Fe 3 O 4 hydrogel nanocomposite was successfully designed and prepared via graft copolymerization of AA and AMPS on CMC followed by the cross-linking addition of FeCl 3 /FeCl 2 . The synthesized hydrogel nanocomposite was characterized by Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) spectroscopy, elemental mapping, thermogravimetric analysis/differential thermal analysis (TGA/DTA), and vibrating sample magnetometry (VSM). The CMC- g -poly(AA- co -AMPS)/Fe 3 O 4 hydrogel nanocomposite was employed as a biocompatible catalyst for the green synthesis of 1,4-dihydropyridine (1,4-DHP) derivatives under thermal and ultrasound-assisted reaction conditions. High efficiency, low catalyst loadings, short reaction time, frequent catalyst recovery, environmental compatibility and mild conditions were found in both methods.