Synthesis and Biological Studies of New 2-Benzoxazolinone Derivatives as Antibacterial Agents

In the present study, new series of benzoxazolin-2-one linked to a variety of hydrazones and azoles were synthesized and assessed for their antibacterial properties against different bacterial microorganisms. All the synthesized target compounds were characterized by H-1 NMR, C-13 NMR and IR spectroscopy, and elemental analysis as well. The antibacterial activity of the synthesized compounds was evaluated according to the bacteriostatic and bactericidal activity against the tested pathogen strains by determining the minimum inhibition (MIC) and minimum bactericidal (MBC) concentrations and MBC/MIC ratios. The MIC was evaluated by the broth dilution and the MBC was evaluated by plating methods. The in vitro analysis suggested that some compounds, namely, amide, 5-chlorobenzimidazole, hydrazones with a 3-chloro substitution on the additional phenyl ring, and hydrazones with 2-furyl and 5-nitro-2-furyl substituents, demonstrated wide antibacterial activity against Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and Salmonella Enteritidis. The most sensitive strains appeared to be Gram-negative E. coli and Gram-positive B. subtilis, while S. aureus showed some resistance. The most resistant pathogen was found to be S. enteritidis. The remaining compounds demonstrated moderate to low antibacterial potential. The research results have shown that benzoxazolinone-based derivatives are suitable for the development of a library of compounds and can be used in the future development of antibacterial drugs against various Gram-positive and Gram-negative pathogens, which is of great importance in therapy practice.