Trimesic Acid-Functionalized Chitosan: A Novel And Efficient Multifunctional Organocatalyst For Green Synthesis of Polyhydroquinolines And Acridinediones Under Mild Conditions

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 biodegradable heterogeneous Cs/ECH-TMA catalytic system from their corresponding substrates in EtOH under reflux conditions and high to quantitative yields. The Cs/ECH-TMA catalyst is recyclable and can be reused at least four times without significant loss of its catalytic activity.

Synthesis of polyhydroquinolines and 2-amino-4H-chromenes and their alkylene bridging derivatives using Sulfonic acid functionalized heterogeneous nanocatalyst based on modified poly (styrene-alt-maleic anhydride)

: A highly efficient heterogeneous nanocatalyst based on modified poly (styrene-alt-maleic anhydride) (MPSAMA) in three steps was fabricated. Then, the MPSAMA surface was modified using chlorosulfonic acid (CAS) to achieve a sulfonated MPSAMA (SMPSAMA) with high acidity and efficiency. FT-IR spectroscopy, CHNS analysis, FESEM, and TGA were employed to characterize the prepared nanocatalyst. The catalytic activity of the SMPSAMA was examined for the formation of the polyhydroquinoline derivatives through Hantzsch condensation and the synthesis of 2-amino-4H-chromene derivatives. This new heterogeneous nanocatalyst has been efficiently used for the synthesis of bifunctional bis polyhydroquinoline, and new alkylene bridging bis 2-amino-5-oxo-5,6,7,8-tetrahydro-4H-benzo[b]pyran derivatives.

Water Extract of Dragon Fruit Peel Catalyzed Synthesis of Dihydropyridines By Hantzsch Condensation

Nowadays, natural substances are increasingly used in organic synthesis for their safety aspects towards the environment. That is why we identified a natural substance through which it promoted the organic reaction, and it could be sustainable and from plant sources obtained, and through this natural substance, it promotes the synthesis of dihydropyridine and its derivatives under solvent-free conditions. We have resorted to this method, being economical, free of minerals and solvents, to create highly functional dihydropyridine derivatives. It is promoted by the water extract of dragon Fruit (WED) at a temperature of (800C) . these (WED) promoted reactions are found to afford high yield for the desired products and this method is Protocol an alternative to the current procedures.