Synthesis of N,N-Dibenzyl-2-(2-Benzylidenehydrazinyl)-3-oxo-3,4-Dihydroquinoxaline-6-Sulfonamide Derivatives and Evaluation of Their Antimicrobial Activity

Abstract

Quinoxaline derivatives are of considerable interest because of their diverse chemical and biological properties. This study Synthesized N,N-dibenzyl-2-(2-benzylidenehydrazinyl)-3-oxo-3,4-dihydroquinoxaline-6-sulfonamide derivatives and evaluated their antibacterial activity against selected clinically isolated bacterial strains. The target compounds were prepared through condensation reactions between N,N-dibenzyl-2-hydrazinyl-3-oxo-1,2,3,4-tetrahydroquinoxaline-6-sulfonamide and substituted aromatic aldehydes. Structural characterization was performed using infrared, ¹H NMR, and ¹³C NMR spectroscopic methods. Antibacterial activity was assessed by the agar-well diffusion method, while minimum inhibitory concentration and minimum bactericidal concentration assays were used to further evaluate antimicrobial activity. All eight Synthesized derivatives, designated 1a–1h, inhibited the growth of the ten bacterial isolates tested. The inhibition zones recorded for the Synthesized compounds ranged from 18 to 49 mm. Their minimum inhibitory concentrations ranged from 0.00781 to 0.0625 mg/mL, compared with 0.125 mg/mL for streptomycin and 0.250 mg/mL for tetracycline. Minimum bactericidal concentration testing also indicated bactericidal activity against the tested isolates. Under the reported in vitro conditions, the Synthesized N,N-dibenzyl quinoxaline-6-sulfonamide derivatives demonstrated broad antibacterial activity against both Gram-positive and Gram-negative bacterial isolates. These findings support further investigation of this compound series while remaining limited to the experimental conditions used in the present study.