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Mn(III)–pentadentate Schiff base complex supported on multi-walled carbon nanotubes as a green, mild and heterogeneous catalyst for the synthesis of tetrahydrobenzo[b]pyrans via tandem Knoevenagel–Michael cyclocondensation reaction

Research paper by Jamshid Rakhtshah, Sadegh Salehzadeh, Mohammad Ali Zolfigol, Saeed Baghery

Indexed on: 12 Jan '17Published on: 11 Jan '17Published in: Applied Organometallic Chemistry



Abstract

Mn(III)–pentadentate Schiff base complex supported on multi-walled carbon nanotubes as a recyclable and reusable, green and nano-heterogeneous catalyst was designed and fully characterized using infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma mass spectrometry, elemental analysis and thermogravimetric analysis. A facile, eco-friendly, mild and green procedure was developed for the one-pot three-component synthesis of tetrahydrobenzo[b]pyrans via tandem Knoevenagel–Michael cyclocondensation reactions between aromatic aldehydes, 1,3-diones and malononitrile using a catalytic amount of Mn(III)–pentadentate Schiff base complex supported on MWCNTs as an efficient recyclable heterogeneous catalyst under solvent-free conditions at room temperature. This process has the advantages of easy availability, stability, recyclability and eco-friendliness of the catalyst, short reaction times, high to excellent yields and simple work-up procedure.