Synthesis, Acidity and Antioxidant Properties of Some Novel 3,4-disubstituted-4,5-dihydro-1H-1,2,4-triazol-5-one Derivatives

Abstract

3-Alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones 2a-g reacted with4-diethylaminobenzaldehyde to afford the corresponding 3-alkyl(aryl)-4-(4-diethylaminobenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones 3a-g. The acetylationreactions of compounds 3a-e were investigated and compounds 4a-e were thus obtained.The new compounds were characterized using IR, ¹H-NMR, ¹³C-NMR, UV and MSspectral data. In addition, the newly synthesized compounds 3a-g were titratedpotentiometrically with tetrabutylammonium hydroxide in four non-aqueous solvents suchas isopropyl alcohol, tert-butyl alcohol, acetone and N,N-dimethylformamide (DMF), andthe half-neutralization potential values and the corresponding pKa values were determinedfor all cases. Moreover, 3 and 4 type compounds were also screened for their antioxidantactivities.