A selective nanocatalyst for an efficient Ugi reaction: Magnetically recoverable Cu(acac)2/NH2-T/SiO2@Fe3O4 nanoparticles

A novel, magnetically recoverable nanocatalyst is fabricated through simple immobilization of copper(II) acetylacetonate on the surface of amine-terminated silica-coated Fe3O4 nanoparticles: Cu(acac)(2)/NH2-T/SiO2@Fe(3)O(4)NPs. Unambiguous bonding of Cu to the terminal amine is indicated by X-ray photoelectron spectroscopy (XPS). Further characterizations are carried out by different techniques. Selectivity of this catalyst is demonstrated through one-pot synthesis of fourteen alpha-aminoacyl amides using Ugi four-component reaction of cyclohexyl isocyanide, acetic acid, amines and various aldehydes. Interestingly, all aromatic aldehydes react with short reaction times and high yields, but heteroaromatic aldehydes do not yield any product. Catalyst efficiency remains unaltered through three consecutive experiments.