Synthesis of new tetrazole derivatives, characterization, determination of their protonation constants by potentiometric titration method, investigation of biological activities, cytotoxic properties and total antioxidant capacities

At the first stage of this work which was planned in five stages, thirty new compounds containing tetrazole were synthesized and characterized. In the characterization, instrumental techniques such as IR, 1H NMR, 13C NMR and DSC have been used. At the second stage of the work, protonation constants of all the synthesized compounds were determined by potentiometric titration method in % 60 dioxane - % 40 water and % 80 DMSO - % 20 water media at 25 ± 0.1°C under argon and at constant ionic strength of μ = 0.1 M. Obtained data from the titrations were evaluated by a computer programme, BEST. After that, by using potentiometric titrations values, the distribution diagrams which are indicating the changes of concentrations of the emerging species were plotted as a function of pH by using computer program SPEXY-C, which developed by Martell-Motekaitis. It has been observed that the tetrazole ligands containing thiazole titrated here have a different number of protonation constants depending on non-aqueous media. At the third stage of the work, the biological activities of the synthesized twenty four new tetrazole compounds containing thiazole were investigated by screening against gram positive and gram negative bacteria. Among the tested compounds, the most effective one was found to be compound coding as 14 against P. Aeruginosa. At the fourth stage of the work, the antioxidant capacities of the synthesized twenty four new tetrazole compounds containing thiazole were investigated and discussed. In this study, the total antioxidant capacities of all compounds containing thiazole were evaluated by their free radical scavenging, metal chelating. and reducing power. At the final stage of the work, the cytotoxic effects of the synthesized three new tetrazole compounds containing nitro group were determined on cancer cells by using WST-1 method, commonly used to evaluate the cytotoxicity, after 48 hours of incubation.