Green Approach for Highly Efficient Synthesis of Polyhydroquinolines Using Fe3O4@PEO-SO3H as a Novel and Recoverable Magnetic Nanocomposite Catalyst

A novel and green heterogeneous nanocomposite, polyethylene oxide sulfonic acid coated on magnetic nanoparticles surface (Fe3O4@PEO-SO3H), was successfully synthesized and completely characterized by Fourier-transforms infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX), vibrating sample magnetometry (VSM), inductively-coupled plasma (ICP), Brunauer– Emmett-Teller (BET), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses. Then, its catalytic activity was investigated in a one-pot four-component synthesis of polyhydroquinolines (PHQs). The present work includes various advantages such as high-to-excellent yields, short reaction times and availability of the substrates, reusability of the catalyst, operational simplicity and environmentally-benign conditions.