Graphene oxide-THEIC-ECH-Chitosan network nanocomposite: a novel, efficient and recyclable catalyst for green synthesis of polyhydroquinoline derivatives

In this present research, two linkers have been utilized for the covalent attachment of graphene oxide with chitosan. Graphene oxide (GO) and chitosan (Cs) were crosslinked by using 1,3,5-tris(2-hydroxyethyl) isocyanurate (THEIC) and epichlorohydrin (ECH) which resulted in forming the expected biopolymer network nanocomposite. The obtained network was characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and thermal gravimetric analysis (TGA) technique. The catalytic application of the GO-THEIC-ECH-Cs nanocatalyst was then investigated in one-pot four-component Hantzsch condensation reaction for the synthesis of polyhydroquinoline derivatives in EtOH under reflux conditions. The obtained results indicated that the applied catalyst in this study exhibited some the significant advantages such as reusability and highly efficiency, stability, low required loading, avoiding the use of toxic transition metals, short reaction times, higher yields, easy separation and purification of the products.