A Novel Cyclohexyl-Naphthyl Bis-Hydrazone Schiff Base: Synthesis, Characterization and Antibacterial Activity

Abstract

A novel bis-hydrazone Schiff base, (2E)-1-(cyclohexyl(phenyl)methylene)-2-(naphthalen-1-ylmethylene)hydrazine (CycPh–NapHz), was synthesized through a straightforward condensation reaction between (Z)-(cyclohexyl(phenyl)methylene)hydrazine and 1-naphthaldehyde in ethanol under reflux conditions. The synthetic procedure was efficient, yielding the target compound as a yellow crystalline solid in 81% yield. The synthesized compound (CycPh–NapHz) was characterized through FT-IR and 1H NMR spectroscopy. The antibacterial activity of the synthesized hydrazone was evaluated against the Gram-positive bacterium Staphylococcus aureus and the Gram-negative bacterium Pseudomonas aeruginosa using the disc diffusion assay. CycPh–NapHz exhibited moderate antibacterial effects, with inhibition zones of 14 mm against S. aureus and 12 mm against P. aeruginosa, in comparison with 28 mm observed for the standard antibiotic tetracycline. The antibacterial behavior of the compound can be attributed to the presence of the azomethine functionality along with an extended aromatic framework, which may enhance interactions with bacterial membranes and intracellular targets. Overall, these findings demonstrate that the synthesized molecule represents a useful structural framework for further modification, and that additional investigations, particularly minimum inhibitory concentration studies and the synthesis of related metal complexes, may contribute to improving its antibacterial efficacy, as metal coordination has been shown to enhance biological performance in comparable systems.