Synthesis, Characterization, and Exploring the Antibacterial and Antifungal Potential of 1,4-Dihydropyrimido[1,2-a]benzimidazole Derivatives

Objective: This study aims to synthesize and evaluate the antimicrobial efficacy of a series of 1,4-dihydropyrimido[1,2-a]benzimidazole derivatives (IVa–IVo) as potential therapeutic agents against antibiotic-resistant bacteria and fungi. The increasing prevalence of drug-resistant pathogens necessitates the discovery of novel antimicrobial compounds. Methods: The 1,4-dihydropyrimido[1,2-a]benzimidazole derivatives (IVa–IVo) were synthesized and characterized using various spectroscopic techniques. Their antimicrobial activity was assessed through the minimum inhibitory concentration (MIC) method against a spectrum of Gram-positive bacteria (Staphylococcus aureus, Streptococcus pyogenes), Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa), and fungal strains (Candida albicans, Aspergillus niger, Aspergillus clavatus). Results and Discussion: Among the synthesized compounds, derivatives (IVj), (IVb), and (IVl) demonstrated significant antimicrobial activity, particularly against Staphylococcus aureus, Streptococcus pyogenes, and Escherichia coli, with MIC values comparable to those of standard antibiotics. While the overall activity of the 1,4-dihydropyrimido[1,2-a]benzimidazole derivatives was lower than that of the standard drugs, these compounds show promise as lead structures for further optimization and development in the quest to combat drug-resistant pathogens. Conclusions: The study successfully synthesized and identified 1,4-dihydropyrimido[1,2-a]benzimidazole derivatives with notable antimicrobial properties, especially against specific bacterial strains. These findings suggest that with further development, these compounds could contribute to the discovery of new antimicrobial agents to address the growing challenge of drug-resistant infections.