Bisferrocene-containing ionic liquid supported on silica coated Fe3O4: A novel nanomagnetic catalyst for the synthesis of dihydropyrano[2,3-c]coumarin derivatives

Nanomagnetic bisferrocene-containing ionic liquid supported on silica coated Fe3O4 (Fe3O4@SiO2@imidazol-bisFc[HCO3]) as a novel heterogeneous catalyst was synthesized and the structure and morphology of nanomagnetic catalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction patterns (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The newly synthesized catalyst was found to be an efficient nanocatalyst for the synthesis dihydropyrano[2,3-c] coumarin derivatives via the one-pot three-component condensation reaction of various aromatic aldehydes, malononitrile and 4-hydroxycoumarin under solvent-free conditions. Pyranocoumarin products were identified by H-1 NMR, C-13 NMR, FT-IR and CHNS analysis. This new procedure has the notable advantages such as operational simplicity, excellent yields, short reaction time, easy work-up, eco-friendly and nontoxic catalyst. Also, the catalyst can be easily recovered by an external magnetic field and reused for six consecutive reaction cycles without significant loss of activity. (C) 2018 Elsevier B.V. All rights reserved.