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

Abstract

• Fe 3 O 4 @cysteine magnetic nano particle were prepared. • The catalyst used for Hantzsch reactions for preparing 1, 4-dihydropyridine derivatives with high efficiencies. • Key advantages are high yields, short reaction time and simple work-up procedure. • The nanomagnetic catalyst could be recovered from solution with an external magnet at once, allowing undemanding recovery and reuse. • The catalyst was reused for five times with no considerable decrease in catalytic activity. 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 Fe 3 O 4 @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 Fe 3 O 4 @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. 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 Fe 3 O 4 @cysteine magnetic nanoparticles as a catalyst. The advantages of methods are shorter reaction time, milder conditions, easy work-up and purification of products by non-chromatographic methods.