Synthesis and Antimicrobial Evaluation of New Series of 1,3,4-Oxadiazole Containing Cinnamic Acid Derivatives

New drugs must be designed and synthesized for combating resistant pathogens. In this study, antibacterial and antifungal activities of 4 new derivatives of 1,3,4-oxadiazole were assessed against 8 bacterial and 2 fungal pathogens.

To this end, the cinnamic acid derivatives were dissolved in acetonitrile solvent and N-iso-cianoimino-triphenyl-phosphorane was added to the above-mentioned solution, followed by applying Petroleum ether and Ethyl acetate as solvent and base. Then, antimicrobial susceptibility tests were used to determine inhibition zone diameter, minimum inhibitory concentration, the minimum bactericidal concentration (MBC), and minimum fungicidal concentration (MFC) values.

The chemical structure of all compounds was characterized with infrared spectra, 1H-NMR, and 13C-NMR. A variety of inhibitory effects were observed by the synthesized compounds. Methoxyphenyl derivative (3c) affected bacterial strains, especially Streptococcus mutans. Other compounds also had antibacterial properties. Additionally, compound 3c showed the greatest effect on fungal samples, especially Aspergillus flavus.

In general, our new derivatives of 1,3,4-oxadiazole are able to destroy Gram-positive bacteria. In addition, developing new derivatives of 1,3,4-oxadiazole in future research can improve therapeutic properties. It seems that with the addition of other functional groups and increasing the destructive power of compounds, inhibitory effects on fungal samples can also be observed