Synthesis and non-aqueus medium titrations of some new 3-alkyl(aryl)-4-[2-(4-methoxybenzoxy)-3-methoxy]-benzylidenamino-4,5-dihydro-1h-1,2,4-triazol-5-ones

In this study, seven new 3-alkyl(aryl)-4-[2-(4-methoxybenzoxy)-3-methoxy]-benzylidenamino-4,5-dihydro-1H-1,2,4-triazol-5-ones were synthesized from the reactions of 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones with 3-methoxy-2-(4-methoxybenzoxy)-benzaldehyde, which was obtained from the reaction of 2-hydroxy-3-methoxybenzaldehyde with p-methoxybenzoyl chloride by using triethylamine. The new compounds synthesized were characterized by using 1H-NMR, 13CNMR and UV spectral data. In addition, to investigate the effects of solvents and molecular structure upon acidity, the prepared 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones were titrated potentiometrically with tetrabutylammonium hydroxide in four non-aqueous solvents, including acetone, isopropyl alcohol, DMSO and N,N-dimethylformamide. The half-neutralization potential values and the corresponding pKa values were determined for all cases.