Synthesis, Characterization, and Antibacterial Activity of (2E)-1-(cyclohexyl(phenyl)methylene)-2-(4-chlorobenzylidene)hydrazine against Klebsiella

Abstract

In this work, a novel hydrazone Schiff base, (2E)-1-(cyclohexyl(phenyl)methylene)-2-(4-chlorobenzylidene)hydrazine was synthesized successfully with the help of a stepwise condensation procedure and was characterized with the help of spectroscopic analysis. The synthesized compound was identified by the structure through FT-IR and the use of the ¹H NMR spectroscopy which identified the typical azomethine (C=N) stretching vibrations and proton signal in line with the proposed structure. The two conjugated imine linkages, aromatic rings and a cyclohexyl moiety presence improves the structural rigidity, conjugation and lipophilicity. The agar disc diffusion and the broth microdilution techniques were used to determine the antibacterial activity of the compound against Klebsiella pneumoniae. The compound showed concentration dependent antimicrobial activity, with the highest zone of inhibition being 12.2 ± 0.4 mm at 8.0 mg/mL and minimum inhibitory concentration (MIC) is being 2.0 mg/mL. The observed anti-bacterial efficacy is attributed to the joint action of the azomethine functional groups and the chloro-substituted aromatic ring, which promote the membrane penetration and interfere with the bacterial metabolism. These results suggest that the synthesized hydrazone Schiff base represents a promising scaffold for the development new antibacterial agents against Gram-negative bacteria.