Synthesis of Four New Bis-hydrazone Derivatives: Characterization, Antibacterial Assessments, Docking, ADMET, and DFT Calculations

Four new bis-hydrazone derivatives were successfully synthesized and structurally characterized. The synthesis of these hydrazones involved an alkylation reaction of methyl-4-hydroxybenzoate with 1,4-dichlorobutane. The obtained compound was reacted with hydrazine to produce the corresponding dibenzohydrazide intermediate, which then underwent condensation reactions with several aldehydes, affording the desired bis-hydrazone derivatives. All synthesized hydrazone derivatives were identified using FT-IR and 1H,13C NMR spectroscopic techniques. The antibacterial activity of the produced compounds was preliminarily evaluated against Escherichia coli (gram-negative) and Staphylococcus aureus (gram-positive) using the disc diffusion method. Among the tested compounds, two of the created derivatives exhibited moderate inhibitory activity against S. aureus, while no significant effect was observed against E. coli. To support the experiment findings, molecular docking studies were performed against E. coli and S. aureus DNA gyrase subunit B (4p8o) using the MOE 2019 program, revealing favorable binding interactions of one of the synthesized derivatives with the enzyme active site. In addition, density functional theory (DFT) calculations at the [6-311/B3LYP++G(d,p)] level were conducted to analyze the electronic properties and relative reactivity trends of the synthesized compounds in the gas phase. Overall, both experimental and computational results suggest that the produced bis-hydrazone scaffold represents a promising lead-like for further structural optimization rather than a fully drug-like candidate.