Synthesis and In Vitro Antioxidant Evaluation of New 1,3,5-Tri-{2-methoxy-4-[(4,5-dihydro-1H-1,2,4-triazol-5-on-4-yl)-azomethine]-phenoxycarbonyl}-Benzene Derivatives

Nine new 4,5-dihydro-1H-1,2,4-triazol-5-one derivatives were synthesized and characterized by elemental analyses and IR, H-1-NMR, C-13-NMR and UV spectral data. The synthesized compounds were analyzed for their in vitro potential antioxidant activities in three different methods. Those antioxidant activities were compared to standard antioxidants such as BHA, BHT and ?? -tocopherol. Compounds 4e, 5a and 5d showed best activity for iron binding. In addition, the compounds 4 were titrated potentiometrically with tetrabutylammonium hydroxide (TBAH) in four non-aqueous solvents (isopropyl alcohol, tert-butyl alcohol, acetone and N,N-dimethyl formamide). Thus, the half-neutralization potential values and the corresponding pK(a) values were determined in all cases.