Cs-ECH-TMA: A novel and efficient bifunctional organocatalyst for green synthesis of polyhydroquinolines and acridinediones under mild conditions (original) (raw)
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2020
Here, an efficient and biodegradable catalytic system prepared through a simple procedure is presented by using chitosan (Cs), epichlorohydrin (ECH) and trimesic acid (TMA). The obtained bio-based Cs/ECH-TMA was characterized by using different spectroscopic and analytical methods. The Cs-ECH-TMA biopolymeric materials were used, as a bifunctional heterogeneous and green catalyst, for efficient synthesis of biologically-active scaffolds including polyhydroquinolines (PHQs) and acridinediones through Hantzsch reaction in a one-pot reaction. Both PHQs and acridinediones were synthesized in the presence of heterogeneous Cs/ECH-TMA catalyst from their corresponding substrates in EtOH under reflux conditions in high to quantitative yields. The Cs/ECH-TMA catalyst is recyclable and can be reused at least five times.
2021
Trimesic acid-functionalized chitosan (Cs/ECH-TMA) material was prepared through a simple procedure by using chitosan (Cs), epichlorohydrin (ECH) and trimesic acid (TMA). The obtained bio-based Cs/ECH-TMA material was characterized using energy-dispersive X-ray (EDX) and Fourier-transform infrared spectroscopy (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) analysis. The Cs/ECH-TMA material was successfully used, as a multifunctional heterogeneous and sustainable catalyst, for efficient and expeditious synthesis of medicinally important polyhydroquinoline (PHQ) and polyhydroacridinedione (PHA) scaffolds through the Hantzsch condensation in a one-pot reaction. Indeed, the heterogeneous Cs/ECH-TMA material can be considered as a synergistic multifunctional organocatalyst due to the presence of a large number of acidic active sites in its structure as well as hydrophilicity. Both PHQs and PHAs were synthesized in the presence of biod...
Proceedings of The 24th International Electronic Conference on Synthetic Organic Chemistry, 2020
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 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.
ChemCatChem, 2017
We report the synthesis of a new microporous copolymer PPN using triphenylamine and ,-dibromo-p-xylene via Friedel-Crafts alkylation process promoted through anhydrous FeCl3 as an oxidising agent and after the sulfonation of PPN we got sulfonated polymer SPPN having high surface acidity with high BET surface area. We have characterized the PPN and SPPN materials thoroughly by using powder XRD, FT IR, 13 C solid state MAS NMR, FE SEM, HR TEM and N2 sorption techniques. This sulfonated material SPPN has been employed as a heterogeneous, reusable and environmentally benign organic solid acid catalyst for the onepot synthesis of biologically important polyhydroquinoline derivatives under microwave irradiation. Scheme 2. Synthesis of PPN and SPPN.
Supramolecular carbohydrate scaffold-catalyzed synthesis of tetrahydroquinolines
Tetrahedron Letters, 2010
Natural supramolecular carbohydrate scaffold-catalyzed synthesis of tetrahydroquinoline derivatives by the reaction of aromatic amine and cyclic enol ether in excellent yield with high diastereoselectivity has been developed. Carbohydrates, cellulose, and starch were converted into their sulfonic acid derivative and these scaffolds exhibit efficient catalytic properties, along with excellent cost effectivity and recyclability.
A Facile and efficient one pot, four component synthesis of polyhydroquinoline derivatives via the Hantzsch condensation reaction using sulphamic acid as heterogeneous catalyst by green approach is described herein. The present methodology offers several advantages such as Excellent yields, economy of cost and time, absence of side products and operational simplicity, ecofriendly, recyclability and reusability of the catalyst are some of the salient features of this reaction.
ChemCatChem, 2018
Incorporation of nitrogen functionality onto the high surface area porous polymeric network are very demanding in designing suitable heterogeneous organocatalyst having surface basicity. Here we report the synthesis of a new aminal-linked triazine based microporous organic polymer (TrzMOP) through a simple and efficient condensation pathway involving the reaction between 1,4bis(4,6-diamino-s-triazin-2-yl)-benzene (SL-1) and 2,5-thiophene dicarboxaldehyde. The material has been characterized by using powder XRD, FTIR spectroscopy, solid state magic-angle spinning 13 C NMR, CHN analysis, FESEM, CO2-TPD and N2 adsorption/desorption techniques. This nitrogen-rich new porous organic polymer showed very high catalytic efficiency for one-pot proficient synthesis of polyhydroquinoline derivatives via microwave assisted condensation reaction. As little as 8 mg of catalyst was found to be effective under the optimum reaction conditions. In addition, TrzMOP catalyzed synthesis of biologically active polyhydroquinoline derivatives are very cost effective, scalable, less time consuming, and environmentally benign compared to those of currently used as heterogeneous catalysts.