Bakir, T.K.Ashweeqi, M.A.A.Muglu, H.2024-05-202024-05-202024.01.010022-2860https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=dspace_ku&SrcAuth=WosAPI&KeyUT=WOS:001218778200001&DestLinkType=FullRecord&DestApp=WOS_CPLhttps://hdl.handle.net/20.500.12597/33161In this study, new 1,3,4-thiadiazole-2-amine derivatives containing different substitution groups were synthesized in order to increase the free radical quenching ability of alpha-lipoic acid. The target thiadiazole amines were derived from thiosemicarbazide reagent. Structural analysis for the synthesized compounds (1-8) was carried out using modern spectroscopic techniques including FTIR, NMR, EIMS spectral analyses. The antioxidant properties of each molecule were elucidated by calculating% inhibition as well as significant IC50 values using the 1,1diphenyl-2-picryl hydrazyl (DPPH) free radical scavenging method. The antioxidant activities of the compounds were compared against ascorbic acid, a water-soluble antioxidant, and against alpha-lipoic acid, the starting molecule of the synthesis step, which actually showed a low DPPH quenching activity. While lipoic acid had a reference standard value of 15,625.02 +/- 0.96 mu M, compound 8 was the compound with the highest antioxidant activity with an IC50 value of 433.69 +/- 0.04 mu M. The obtained data suggested that the (N-H) proton in the thiadiazole structure bound to lipoic acid plays an important role in binding to the DPPH radical. This study may provide a source for the synthesis of alpha-lipoic acid-based thiadiazole derivatives, new compounds with antioxidant properties that can be used in medicine and pharmacy.eninfo:eu-repo/semantics/openAccessalpha-Lipoic acidFTIR analysesEIMS spectroscopiesThiadiazoleDPPH radical scavenging methodArticle10.1016/j.molstruc.2024.13798000121877820000113071872-8014