Synthesis and catalytic evaluation of PVP-CeO2/rGO as a highly efficient and recyclable heterogeneous catalyst for multicomponent reactions in water.

A highly efficient and eco-friendly route for the reduction of graphene oxide (GO) to reduced graphene oxide (rGO) was developed by using polyvinylpyrrolidone coated CeO2 NPs (PVP-CeO2) as a reducing and stabilizing agent. The resulting carbonaceous material, PVP-CeO2/rGO, was well characterized with different spectroscopic techniques such as Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), elemental mapping, Transmission Electron Microscopy (TEM), Raman spectroscopy, powder X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), X-ray Photoelectron Spectroscopy (XPS), and Thermal Gravimetric (TG) analyses. The material exhibited high catalytic potential towards multicomponent reactions for the synthesis of biologically relevant benzodiazepine derivatives in aqueous media. The efficiency of the material for the desired reaction was shown in the form of an excellent product yield (96-98%) and a very short reaction time period (7-10 min). The use of water as solvent and recyclability of the catalyst made the present protocol acceptable from a green perspective.

Novel Ionic Liquid-Functionalized Chitosan [DSIM][AlCl3] x -@CS: Synthesis, Characterization, and Catalytic Application for Preparation of Substituted Pyrazine Derivatives.

Pyrazines are renowned heterocyclic compounds that have played an important role in drug design and are part of many polycyclic compounds of biological and industrial significance. In this article, a novel chitosan-immobilized ionic liquid, [DSIM][AlCl3] x -@CS, has been synthesized easily at ambient temperature and used for catalyzing the synthesis of a series of biologically relevant pyrazine derivatives. The catalyst is well characterized by various techniques such as Fourier transform infrared spectroscopy, Raman spectroscopy, solid-state 13C MAS nuclear magnetic resonance, scanning electron microscopy/energy-dispersive X-ray, elemental mapping, transmission electron microscopy, powder X-ray diffraction, and thermal gravimetric analyses. The advantageous features of the present energy-sustainable methodology include high yield of product (>99%), shorter reaction time periods, and recyclability of the catalyst.