Synthesis and application of chitosan supported vanadium oxo in the synthesis of 1,4-dihydropyridines and 2,4,6-triarylpyridines via anomeric based oxidation†
Chitosan, as a biopolymer, exhibits a strong affinity for complexation with suitable metal ions. Thus, it has received increased attention for the preparation of stable bioorganic–inorganic hybrid heterogeneous catalysts. Herein, a novel chitosan based vanadium oxo (ChVO) catalyst was prepared and fully characterized by several techniques such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), derivative thermal gravimetric (DTG), differential thermal analysis (DTA), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma mass spectrometry (ICP-MS). The synthesized catalyst has been successfully used as a reusable catalyst in the synthesis of dihydropyridines and triarylpyridines.