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‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide) colorimetric assay. All of them were well characterized by spectroscopic techniques. Among the screened compounds, 9 i (2‐(2,5‐dimethoxyphenyl)‐5‐(5‐phenylthiophen‐2‐yl)‐1,3,4‐oxadiazole) demonstrated superior activity against MDA231 cells. Products 9 i displayed excellent activity against DU145, HCT15 and 10 i (2‐(3,4‐dimethoxyphenyl)‐5‐(5‐phenylthiophen‐2‐yl)‐1,3,4‐oxadiazole) against MDA231 cells. Structure of 10 c (2‐(3,4‐dimethoxyphenyl)‐5‐(2,4,6‐trimethoxyphenyl)‐1,3,4‐oxadiazole) was further authenticated through single crystal X‐ray diffraction. Analogue 9 i have come out to be the best anticancer and antimycobacterial agent. To the best of our knowledge, it is the first report which describes about comparative studies on two regio‐isomers: Veratric acid and 2,5‐Dimethoxybenzoic acid bioisosteres 1,3,4‐oxadiazole analogues. Dual biological assays namely anticancer and antimycobacterial activities can be found. Highlights triple synthetic approaches for the accomplishment of the title compounds. Further, X‐ray data validates their construction/formation.