Linking quinoline ring to 5-nitrofuran moiety via sulfonyl hydrazone bridge: Synthesis, structural characterization, DFT studies, and evaluation of antibacterial and antifungal activity

In the present work, we report the synthesis, structural characterization, and computational studies of (E)-N'-((5nitrofuran-2-yl)methylene)quinoline-8-sulfonohydrazide (QNF) as a potential antimicrobial drug candidate. To design the target molecule, we utilized a molecular hybridization technique that connects two antimicrobial pharmacophores (quinoline and 5-nitrofuran rings) with a sulfonyl hydrazone moiety. QNF was synthesized by the condensation of quinoline-8-sulfonohydrazide with 5-nitrofuran-2-carbaldehyde, and characterized by various spectral techniques including single-crystal X-ray crystallography. QNF was extensively evaluated for its antibacterial and antifungal activity. The inhibition capacity of QNF on Candida albicans filamentation and biofilm formation was further investigated. Biofilm inhibition of QNF against C. albicans was supported by molecular docking studies in the binding site of agglutinin-like sequence 3 (Als3). Drug-like profile of QNF was confirmed by in silico calculation of its significant physicochemical properties. Additionally, the optimized geometrical structure, natural bond orbital calculations, frontier molecular orbital and molecular electrostatic potential analysis of QNF were carried out using the density functional theory method at the B3LYP with 6-31+G (d,p) basis set. The predictions of 1H and 13C NMR chemical shift values were performed using the gauge-independent atomic orbital method. Structural parameters and NMR values obtained experimentally were compared with the calculated values.