4-Dialkylaminopyridine modified magnetic nanoparticles: as an efficient nano-organocatalyst for one-pot synthesis of 2-amino-4H-chromene-3-carbonitrile derivatives in water†
A novel heterogeneous magnetic nano-organocatalyst was developed using immobilization of 4-dialkylaminopyridine moieties on Fe3O4 magnetic nanoparticles (MNP–DMAP). It was synthesized using the reaction of MNP-oxiran (MNPO) with N-methylpyridin-4-amine. The MNPO substrate was produced via oxidation of vinyl groups on the surface of vinyl-functionalized MNP (VMNP) using H2O2. To synthesis VMNP, silica-coated magnetic nanoparticles (Fe3O4@SiO2) were reacted with trimethoxy(vinyl)silane. The MNP–DMAP catalyst shows remarkable activity in the synthesis of 2-amino-4H-chromene-3-carbonitrile derivatives using a multicomponent reaction under mild conditions in water as a green solvent. The MNP–DMAP was reusable in this process for at least 10 times without any treatment in its catalytic activity.