Synthesis of New Three-Component Derivatives of 1, 3, 4-Oxadiazole and Evaluation of Their In Vitro Antibacterial and Antifungal Properties

Antibiotic resistance is a major public health challenge. The pervasive antibiotic misuse can lead to increased antibiotic resistance. Thus, there is a need for discovery of new compounds against drug-resistant microorganisms. We synthesized new series of 1, 3, 4-oxadiazole derivatives (4a-4d) and evaluated the antibacterial and antifungal activity of the derivatives against Staphylococcus aureus, Staphylococcus epidermidis, Acinetobacter baumannii, Klebsiella pneumoniae, Aspergillus fumigatus and Aspergillus flavus.

The new derivatives of 1, 3, 4-oxadiazole were synthesized using a single-stage, high-yield method. The structure of the new compounds was confirmed by infrared spectroscopy, carbon-nuclear magnetic resonance and hydrogen- nuclear magnetic resonance. Then, antibacterial and antifungal activities of the prepared derivatives (1 mg/ml) were evaluated by determining minimum inhibitory concentration and minimum bactericidal/fungicidal concentration using the agar well diffusion method.

All synthesized compounds, especially (4d) with methoxyphenyl group, exhibited powerful antibacterial activity against the tested bacteria. However, the compounds had no antifungal effect.

Our findings indicate the antibacterial potential of the novel synthetic 1, 3, 4-oxadiazole compounds.