Synthesis of (E)-N2-(3-Methylquinoxalin -2-yl)-N5-(1-Phenylethylidene) Pyridine-2,5-Diamine Derivatives and Evaluation of Their Antimicrobial Activity

Abstract

Background: Research on the synthesis of various quinoxaline derivatives has gained significant attention due to their remarkable chemical and biological properties. These compounds exhibit diverse reactivity, making them valuable in chemical synthesis, and they also show promising potential in medicinal chemistry, with applications in the development of new drugs. Consequently, ongoing studies focus on exploring novel methods to synthesise quinoxalines efficiently, aiming to enhance their therapeutic potential and broaden their scope in pharmaceutical and industrial applications. Objective: This study aimed to synthesise a series of (E)-N2-(3-methylquinoxalin-2-yl)-N5-(1-phenylethylidene) pyridine-2,5-diamine derivatives and evaluate their antimicrobial activity against various bacterial strains. Materials and Methods: Some (E)-N2-(3-methylquinoxalin-2-yl)-N5-(1-phenylethylidene) pyridine-2,5-diamine derivatives were synthesised via condensation reactions between N2-(3-methylquinoxalin-2-yl) pyridine-2,5-diamine and various substituted acetophenones. The compounds were tested for their potential antibacterial properties. Results: The synthesised compounds demonstrated a broad spectrum of antibacterial activity against ten different clinically isolated bacterial strains. The minimum inhibitory concentration (MIC) values for these compounds varied between 0.00781 mg/mL and 0.0625 mg/mL, indicating their potent ability to inhibit bacterial growth at low concentrations. Additionally, the minimum bactericidal concentration (MBC) values ranged from 0.0156 mg/mL to 0.125 mg/mL, further highlighting their effectiveness in completely eradicating the bacteria. This broad-spectrum activity suggests that the compounds could potentially be effective against various bacterial infections, making them promising candidates for further development as antimicrobial agents. Discussion and Conclusion: The study concluded that the synthesised (E)-N2-(3-methylquinoxalin-2-yl)-N5-(1-phenylethylidene) pyridine-2,5-diamine derivatives were bactericidal towards the clinically isolated bacterial strains and could therefore serve as potential broad-spectrum bactericidal agents to combat the development of multiple resistance by pathogens to available antimicrobial agents.