Synthesis, Characterization, and Biological Evaluation of New Oxadiazole Analogues: A Comprehensive Experimental and Computational Investigation

Abstract A new series of fourteen derivatives, N ‐(substituted phenyl)‐2‐((5‐phenyl‐1,3,4‐oxadiazol‐2‐yl)thio)acetamides derivatives , were synthesized via nucleophilic substitution reaction by reacting 2‐chloro‐N‐(aryl)acetamides derivative s with 5‐phenyl‐1,3,4‐oxadiazole‐2‐thiol in N, N ‐dimethylformamide. The parent compound, 5‐phenyl‐1,3,4‐oxadiazole‐2‐thiol, is well‐documented for its broad pharmacological activities, including antibacterial, antiviral, and antifungal properties. The structures of the synthesized compounds were confirmed through elemental analysis and spectral techniques (NMR, IR, and mass spectrometry). The biological activity of the derivatives was evaluated against bacterial strains ( Bacillus subtilis , Staphylococcus aureus , Escherichia coli , and Pseudomonas aeruginosa ), fungal strains ( Candida albicans and Aspergillus niger ), and Mycobacterium smegmatis . Among the tested derivatives, N ‐(3‐nitrophenyl)‐2‐((5‐phenyl‐1,3,4‐oxadiazol‐2‐yl)thio)acetamide (3j) displayed exceptional antimicrobial properties, exhibiting the lowest minimum inhibitory concentration (MIC) values of 1.56 µg/mL against all bacterial strains, 3.25 µg/mL against fungal strains, and 3.96 µg/mL against Mycobacterium smegmatis . Furthermore, docking and simulation studies on the most active compound, 3j , revealed significant binding affinity within the active sites of glucosamine‐6‐phosphate synthase (PDB ID: 2VF5) and Mycobacterium tuberculosis enoyl‐ACP reductase (PDB ID: 2 × 22). The docking results provide insights into the compound's potential mechanisms of action and its promising therapeutic relevance. This study highlights the significant antimicrobial properties of N ‐(substituted phenyl)‐2‐((5‐phenyl‐1,3,4‐oxadiazol‐2‐yl)thio)acetamides, supporting their advancement through detailed mechanistic investigations and in vivo efficacy assessments.