Design, Synthesis, and Characterization of Quinoxaline Derivatives as a Potent Antimicrobial Agent

A series of quinoxalinone derivatives were synthesized by the reaction of o‐phenylenediamine with oxalic acid to yield 1, 4‐dihydro quinoxaline‐2, 3‐dione (1) and then treated with thionyl chloride to yield 2, 3 dichloro quinoxaline (2). This was further reacted with hydrazine hydrate to produce 2, 3‐dihydrazinyl quinoxaline (3). This was finally reacted with substituted aromatic aldehydes to produce 2,3‐bis[2‐(sustituted benzylidine) hydrazinyl] quinoxalines (4). These quinoxalinone derivatives were characterized by infrared spectroscopy and nuclear magnetic resonance spectroscopy and MASS spectral data. All the synthesized compounds were evaluated for their antimicrobial activity. The results of the antimicrobial study revealed that compounds 4c, 4d, and 4i were active and exhibited better inhibitory activities as compared to standard drug ciprofloxacin. The results were further checked with protein legend interaction by using docking studies, and all the compounds exhibited good docking scores between −8.72 and −11.29 kcal/mol against dihydrofolate reductase protein fragment from Staphylococcus aureus (PDB ID‐4XE6). Among all compound, 4c has shown maximum docking score and found in agreement to in vitro studies.