Exploring the antimicrobial potential of novel 2-oxo-2-H-chromene conjugates with guanine, thiazole, and imidazole: Synthesis, characterization, and biological evaluation

Five derived forms of 2-oxo-2-H-chromene clubbed guanine, thiazole and imidazoline derivatives 10 (i–v), 11 (i–v), and 12 (i–v) were synthesized, characterized, and biologically tested for in vitro antimicrobial activity against two types of bacteria viz. Staphylococcus aureus (MTCC 87) and Escherichia coli (MTCC 40). The synthesized compounds demonstrated mild to moderate antibacterial activity against Escherichia coli and Staphylococcus aureus at all concentrations (100 μg/ml, 250 μg/ml, and 500 μg/ml) in comparison to standard drug ciprofloxacin. It was observed that the compounds 10i, 10v, 11i, 11v, 12i, 12ii, 12iv and 12v have noticeable activity at higher dose in comparison to standard drug. Zone of inhibition values indicated higher antimicrobial activity at 500 μg/ml against Escherichia coli and Staphylococcus aureus in case of imidazoline and thiazole clubbed coumarin derivatives in comparison to guanine derivatives. The guanine derivatives have been found to be potent at lower dose (100 μg/ml) in comparison to thiazole and imidazoline derivatives having negligible activity at 100 μg/ml. This suggests a differential efficacy profile among the synthesized compounds, with guanine derivatives showing promising activity at lower doses while thiazole and imidazole derivatives manifesting increased potency at higher concentrations. These findings underscore the potential of these novel compounds as antimicrobial agents, warranting further investigation into their mechanisms of action and therapeutic applications.