Synthesis, characterization and pharmacological evaluation of (Z)-2-(5-(biphenyl-4-yl)-3-(1-(imino)ethyl)-2,3-dihydro-1,3,4-oxadiazol-2-yl)phenol derivatives as potent antimicrobial and antioxidant agents

The oxadiazole pharmacophore is considered a viable lead structure for the synthesis of more efficacious and broad spectrum antimicrobial agents. The significance of this study was to prepare various oxadiazole derivatives by introducing the 1,3,4 oxadiazole core into several molecules to explore the possibilities of some altered biological activities. Therefore, the study presents the synthesis, antimicrobial and antioxidant evaluation of a series of 1,3,4 substituted oxadiazole derivatives. Antimicrobial evaluation revealed that eighteen compounds were able to display variable growth inhibitory effects on the tested Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus , Gram-negative bacteria Pseudomonas aeruginosa and Escherichia coli and fungal strains Candida albicans and Aspergillus niger . Among the synthesized derivative analogues 6f , 6l and 6r were found to be the most effective antibacterial agents. While the compounds 6c , 6l and 6q were found to be the most promising antifungal agents. On the other hand, all the synthesized compounds 6a–6r were subjected to antioxidant activity but only analogues 6l and 6q were found to exhibit potent antioxidant activity. Further compound 6l containing p -nitro phenyl moiety along with oxadiazole pharmacophore proved to be the most active antimicrobial and antioxidant agent.