Ultra-Sonicated One-Pot Synthesis of Potent Bioactive Biscoumarin and Polycyclic Pyranodichromenone Scaffolds in Aqueous Media: A Complementary Tool to Organic Synthesis

Abstract

Present study involves the synthesis of bis-coumarins and novel polycyclic pyranodichromenones using a catalyst-free approach under ultrasonic irradiation in an aqueous medium. The chemical structures of the synthesized compounds were characterized using FTIR, 1H NMR, and 13C NMR spectroscopy. The antibacterial and antifungal activities of the compounds were evaluated against Gram-positive (S. aureus, B. cereus) and Gram-negative bacteria (P. aeruginosa, E. coli), as well as the fungus C. albicans, using the disc diffusion method. Several compounds exhibited excellent activity against the tested microorganisms. Moreover, the antioxidant potential of the synthesized products was assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethyl­benzothiazoline-6-sulfonic acid) (ABTS) free radical scavenging, and total antioxidant capacity (TAC) assays. Promising antioxidant activity was observed for certain compounds. Computational studies using density functional theory (DFT) were conducted to investigate the molecular reactivity and electronic properties of the synthesized compounds. Quantum mechanical parameters such as Ionization Potential (IP), Electron Affinity (EA), Mulliken Electronegativity (χ), Chemical Potential (μ), and Electrophilicity Index (ω) were calculated. The study highlights the efficiency and eco-friendliness of ultrasonic-assisted processes, contributing to the advancement of sustainable chemistry.

Unsymmetrical Bis‐Coumarin Based on o‐Hydroxy Aldehydes and 4‐Hydroxy Coumarin: Expedient Synthesis, Single Crystal X‐rays and DFT Studies

“…They have shown lot of biological applications [8] and some of the derivatives of bis‐coumarin have been extensively studied as analytes [9] . Recent research [10–13] also emerges the significant importance of the bis‐coumarin type compounds in various occasions. Most of the reported methods rely on the involvement of a three component condensation of 4‐hydroxy coumarin ( 1 ) units and an aldehyde ( 2 ) through Knoevenagel condensation followed by Michael addition in the presence of various catalysts under room temperature or elevated temperature [5b,6b,15] .…”