Novel magnetic nanoparticles Fe3O4-immobilized domino Knoevenagel condensation, Michael addition, and cyclization catalyst

The synthesis, characterization and applications of guanidine supported on magnetic nanoparticles Fe3O4 (MNPs-Guanidine) as a novel magnetically separable base nanocatalyst are described. We have studied the application of this new catalyst for the Knoevenagel condensation reaction of aromatic aldehydes with malononitrile or cyanoacetate in PEG/water = 1:1 at room temperature. Also, the three-component and one-pot synthesis of 2-amino-4H-chromenes and 2-amino-4H-benzo[h]chromenes by condensing aldehydes, malononitrile and cyclic 1,3-dicarbonyl/alpha-naphthol, in the presence of catalytic amount of MNPs-Guanidine under same conditions is investigated. The supported catalyst could simply be separated and recovered from the reaction mixture with the assistance of an external magnet and reused several times. (C) 2013 Elsevier B.V. All rights reserved.