The Synthesis and spectral studies of some bio-active aryl bis-enones

Seven series of bis-chalcones were synthesized via the Claisen–Schmidt condensation between various aromatic aldehydes and ketones under conventional heating conditions, utilizing nano fly ash-supported H₃PO₄ as a catalyst in an ethanol medium. The reaction afforded yields exceeding 60%. The resulting bis-chalcones were characterized based on their physical properties, elemental (micro) analyses, and spectroscopic data. The characteristic infrared absorption frequencies (ν, cm⁻¹) corresponding to C=O and νC=C (vinyl) groups, along with the NMR chemical shifts (δ, ppm) of vinyl protons, carbons, and carbonyl carbons in the bis-enones, were correlated using Hammett substituent constants (σ, σ⁺, σI, σR), field (F) and resonance (R) parameters, as well as Swain–Lupton constants through single and multiple regression analyses. The statistical results were used to establish quantitative structure–activity relationships (QSAR) for the substituent effects. Molecular docking studies were further performed to evaluate the protein–ligand interactions of the synthesized bis-chalcones with a target protein. The in vitro antimicrobial potential of compounds (8–13) was determined using the Bauer–Kirby disc diffusion assay, while their antimalarial efficacy was assessed against Plasmodium falciparum.