Fe3O4@cysteine nanocomposite: An efficient and reusable catalyst for the facile, green, one-pot synthesis of 1,4-dihydropyridine via Hantzsch reaction

ABSTRACT An efficient, clean, and environmentally friendly three-component/one-pot protocol was developed for the synthesis of 1,4-dihydropyridines using Hantzsch reaction by a reaction of aldehydes, ethyl acetoacetate, and ammonium carbonate using Fe3O4@cysteine magnetic nanoparticles as a catalyst. This strategy provides several advantages such as good to high yields (79 to 96%), short reaction time, a simple work-up procedure, less tedious workup, mild condition, avoidance of hazardous organic solvents, minimal waste, recyclability of catalyst, ability to tolerate a variety of functional groups which gives economical as well as ecological rewards and no chromatographic purification. The present protocol takes advantage of the fact that water, a green solvent is used in combination with Fe3O4@cysteine nanoparticles as a catalyst which can be easily recovered magnetically and reused for further runs. Also, this efficient and practical protocol proceeded smoothly in gram scale at lower catalytic concentration.