Synthesis of 2,5-Disubstituted-1,3,4-oxadiazole Derivatives and Their Evaluation as Anticancer and Antimycobacterial Agents

A series of regioisomeric (2,5-dimethoxybenzoic acid, veratric acid) analogues were prepared by swapping the carboxylic motif to its oxadiazole bioisostere and have been screened for in vitro anticancer studies by using MTT (3-(4,5-dimethylthiazol2-yl)-2,5-diphenyltetrazolium bromide) colorimetric assay. All of them were well characterized by spectroscopic techniques. Among the screened compounds, 9i (2-(2,5-dimethoxyphenyl)5-(5-phenylthiophen-2-yl)-1,3,4-oxadiazole) demonstrated superior activity against MDA231 cells. Products 9i displayed excellent activity against DU145, HCT15 and 10i (2-(3,4-dimethoxyphenyl)- 5-(5-phenylthiophen-2-yl)-1,3,4-oxadiazole) against MDA231 cells. Structure of 10c (2-(3,4-dimethoxyphenyl)- 5-(2,4,6-trimethoxyphenyl)-1,3,4-oxadiazole) was further authenticated through single crystal X-ray diffraction. Analogue 9i have come out to be the best anticancer and antimycobacterial agent.