No abstract

A green, benign, heterogeneous, superparamagnetic catalyst (Glu.@Fe 3 O 4 ) was synthesized and characterized using Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy and vibrating sample magnetometry. The prepared catalyst was used to achieve a high-efficiency, low-cost, eco-friendly and easy-to-handle protocol for synthesizing substituted pyrazole derivatives from aldehydes, malononitrile and phenylhydrazine. The catalyst was also used in chromene synthesis. Glucose coated on magnetic nanoparticles provided excellent catalytic activity. The catalyst could be recycled for up to four runs without significant loss in catalytic activity.

A highly efficient Fe 3 O 4 @VitB 1-Ag(I) magnetic catalyst has been obtained using surface modification of Fe 3 O 4. To this end, silver chloride was immobilized on Fe 3 O 4 nanoparticles via vitamin B 1 biomolecules. The synthesized biocompatible magnetic catalyst was applied in an A 3-coupling reaction in the presence of aldehyde, amine and phenyl acetylene under solvent-free conditions and afforded the desired products in excellent yields. Also, interactions between metal and ligand in the Fe 3 O 4 @VitB 1-Ag(I) were studied using theoretical calculations.

Superparamagnetic CuCl nanoparticles were prepared and identified as an effective heterogeneous catalyst for the tandem transformation of methylarenes and 1,3‐dicarbonyl compounds into the corresponding enole esters by the use of tert‐butyl hydroperoxide as an external oxidant. The catalyst can be removed from the reaction medium simply by use of an external magnet. As a consequence, various derivatives of enol esters were synthesized in moderate to good yields.