Synthesis and Non-Aqueous Medium Titrations of Some New 4-Benzylidenamino-4,5-dihydro-1H-1,2,4-triazol-5-one Derivatives

Abstract

The synthesis of 3-alkyl(aryl)-4-(3-ethoxy-4-hydroxybenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones 3 from the reactions of 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones 2 with 3-ethoxy-4-hydroxybenzaldehyde is described. The acetylation and methylation reactions of the compounds 3 giving compounds of type 4 and 5, respectively, were investigated. The newly synthesized compounds were characterized using elemental analyses and IR, 1H-NMR, 13C-NMR and UV spectral data. In addition, to investigate the effects of solvents and molecular structure upon acidity, compounds 3 were titrated potentiometrically with tetrabutylammonium hydroxide in four non-aqueous solvents (isopropyl alcohol, tert-butyl alcohol, acetonitrile and N,N-dimethylformamide). The half-neutralization potential values and the corresponding pKa values were determined for all cases.

A Study on 4-Acylamino-4,5-dihydro-1H-1,2,4-triazol-5-ones

“…As it is well known, the acidity of a compound depends on several factors. The two most important ones are the solvent effect and molecular structure [4][5][6][7][11][12][13][14][15][16][17][18]. Table 1 and Figure 1 show that the HNP values and corresponding pK a values obtained from the potentiometric titrations rely on the non-aqueous solvents used and the substituents at C-3, in 4,5-dihydro-1H-1,2,4-triazol-5-one ring.…”

“…On the other hand, it is known that 1,2,4-triazole and 4,5-dihydro-1H-1,2,4-triazol-5-one rings have weak acidic properties, so some 1,2,4-triazole and 4,5-dihydro-1H-1,2,4-triazol-5-one derivatives were titrated potentiometrically with tetrabutylammonium hydroxide (TBAH) in non-aqueous solvents, and the pK a values of the compounds were determined [4][5][6][7][11][12][13][14][15][16][17][18].…”

“…In addition, 1,2,4-triazole and 4,5-dihydro-1H-1,2,4-triazol-5-one derivatives are reported to show a broad spectrum of biological activities such as antifungal, antimicrobial, hypoglycemic, antihypertensive, analgesic, antiparasitic, hypocholesteremic, antiviral, anti-inflammatory, antioxidant, antitumor and anti-HIV properties [3,[8][9][10][11][12].…”

“…Moreover, we also examined the potentiometric titrations of the synthesized type 2 compounds with tetrabutylammonium hydroxide (TBAH) in four non-aqueous solvents (isopropyl alcohol, tert-butyl alcohol, acetonitrile and N,N-dimethylformamide) to determine the corresponding half-neutralization potentials (HNP) and the corresponding pK a values. The data obtained from the potentiometric titrations was interpreted, and the effect of the C-3 substituent in 4,5-dihydro-1H-1,2,4-triazol-5-one ring as well as solvent effects were studied [4][5][6][7][11][12][13][14][15][16][17][18].…”

Synthesis and In Vitro Antioxidant Evaluation of Some Novel 4, 5‐Dihydro‐1H, 2, 4‐triazol‐5‐one Derivatives

“…Compounds containing 1,2,4-triazole ring have been reported to possess different biological activities such as antimicrobial, antifungal, anti-inflammatory, antioxidant, antiviral, anticancer, analgesic, and anticonvulsant activity depending on the substituents in the ring system [1][2][3][4][5][6][7][8][9] . Moreover several articles reporting the synthesis of some N-arylidenamino-4,5dihydro-1H-1,2,4-triazol-5-one derivatives have been published 5,[10][11][12][13][14] .…”