Magnetically recyclable magnetite–ceria (Nanocat-Fe-Ce) nanocatalyst – applications in multicomponent reactions under benign conditions†
A novel magnetite nanoparticle-supported ceria catalyst (Nanocat-Fe-Ce) has been successfully prepared by a simple impregnation method and was characterized by XRD, SIMS, FEG-SEM-EDS, and TEM. The exact nature of Nanocat-Fe-Ce was confirmed by X-ray photoelectron spectroscopy and it is noted that CeO2 nanoparticles are supported on magnetite, with evidence of secondary ion mass spectrometry. Catalytic activity of the nano-catalyst was explored for the synthesis of dihydropyridines under benign conditions; a greener protocol is described that provides a simple and efficient method for the synthesis of functionalized 1,4-dihydropyridines using a recyclable nanocatalyst. Notably, 5.22 mol% of the catalyst is sufficient to catalyze the multicomponent reaction in ethanolic medium at room temperature. Importantly, the catalyst could be easily separated from the reaction mixture by using an external magnet and recycled several times without loss of activity.