Biscoumarin Derivatives as Potent anti-Microbials: Graphene Oxide Catalyzed Eco-Benign Synthesis, Biological Evaluation and Docking Studies

Functionalized graphene oxide by 4-amino-3-hydroxy-1-naphthalenesulfonic acid as a heterogeneous nanocatalyst for the one-pot synthesis of tetraketone and tetrahydrobenzo[b]pyran derivatives under green conditions

4-Amino-3-hydroxy-1-naphthalenesulfonic acid-functionalized graphene oxide (GO-ANSA) was prepared and characterized using different spectroscopic, microscopic and analytical methods including energy-dispersive X-ray spectroscopy (EDS), EDS elemental mapping, Fourier-transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and thermogravimetry/differential thermogravimetry analysis (TGA/DTA). The obtained nanomaterial was used as a novel, highly efficient, and reusable solid acid carbocatalyst for the one-pot three-component synthesis of tetraketone, as well as tetrahydrobenzo[b]pyran derivatives via tandem Knoevenagel-Michael reactions under green conditions. All of the derivatives were prepared in EtOH, as a green solvent, under reflux conditions in high to excellent yields and very short reaction times. The nanocatalyst was recovered and reused at least five times without significant reduction in its activity. In addition, the absence of toxic transition metals, high to excellent yields, mild reaction conditions, simple procedure for the separation and purification of products, stability, and recycling of the catalyst are the most important advantages of this green procedure.

Exploring the synthetic potential of a g-C3N4·SO3H ionic liquid catalyst for one-pot synthesis of 1,1-dihomoarylmethane scaffolds via Knoevenagel-Michael reaction

A highly promising approach for the synthesis of functionalized 1,1-dihomoarylmethane scaffolds (bis-dimedones, bis-cyclohexanediones, bis-pyrazoles, and bis-coumarins) using g-C₃N₄·SO₃H ionic liquid via Knoevenagel-Michael reaction has been developed and the synthesized derivatives were well characterized using spectral studies. The method involved the reaction of C-H activated acids with a range of aromatic aldehydes, in a 2 : 1 ratio catalyzed by a g-C₃N₄·SO₃H ionic liquid catalyst. The use of g-C₃N₄·SO₃H as a catalyst has several benefits, such as low cost, easy preparation, and high stability. It was synthesized from urea powder and chloro-sulfonic acid and was thoroughly characterized using FT-IR, XRD, SEM, and HRTEM. The present work unveils a promising and environmentally friendly method for synthesizing 1,1-dihomoarylmethane scaffolds with high yield, selectivity, and efficiency, using mild reaction conditions, no need for chromatographic separation, and short reaction times. The approach adheres to green chemistry principles and offers a viable alternative to the previously reported methods.