Synthesis of Fe3O4 Nanoparticles Bound with Polyethylene Glycol Substituted 1-Methyl Imidazolium Bromide and Their Application as Nanomagnetic and Recyclable Phase-transfer Catalysts for the Green and Efficient Synthesis of 4H-pyrans

Immobilization of polyethylene glycol substituted 1-methylimidazolium bromide on the surface of Fe3O4 magnetic nanoparticles led to the synthesis of powerful and recyclable heterogeneous phase-transfer catalysts which were successfully used for the one-pot three-component condensation of aryl aldehydes, malononitrile and 1,3-dicarbonyl compounds, to afford the corresponding 2-amino-3- cyano-4H-pyrans. The catalysts can be readily recovered by simple magnetic decantation, and they can be reused several times with no considerable loss in their activity.