Synthesis and Potentiometric Titrations of Some New 4-(Benzylideneamino)-4,5-dihydro-1H-1,2,4-triazol-5-one Derivatives in Non-Aqueous Media

Abstract

The synthesis of 3-alkyl(aryl)-4-[4-(dimethylamino)benzylideneamino]-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 4-(dimethylamino)benzaldehyde is described. The newly synthesized 3 type compounds were titrated potentiometrically with tetrabutylammonium hydroxide in three non-aqueous solvents, including acetonitrile, isopropyl alcohol and N,N-dimethylformamide. The half-neutralization potential values and the corresponding pKa values were determined for all cases. Thus, the effects of solvents and molecular structure upon acidity were investigated. In addition, N-acetyl derivatives of 3 type compounds were also obtained. The new synthesized compounds in the study were fully characterized.

Synthesis and Determination of pKa Values of Some New 3,4-Disubstituted-4,5-Dihydro-1H-1,2,4-triazol-5-one Derivatives in Non-aqueous Solvents

“…As it is well known, the acidity of a compound depends on some factors. The two most important factors are the solvent effect and molecular structure [18][19][20][21][22][26][27][28]. Table 1 shows that the HNP values and the corresponding pK a values obtained from potentiometric titrations depend on the nonaqueous solvents used.…”

“…We have previously described the synthesis and potentiometric titrations of some new 4,5-dihydro-1H-1,2,4-triazol-5-one derivatives in different nonaqueous medium [21,22], where we determined the pKa values of these compounds for each nonaqueous solvent.…”

“…For each new compound synthesized, the halfneutralization potential (HNP) and the corresponding pK a value were determined in the four mentioned non-aqueous solvents. The data obtained from the potentiometric titrations were interpreted, and the effect of the C-3 substituent and solvent effects were studied [17][18][19][20][21][22]. Determination of pK a values of active constituents of certain pharmaceutical preparations is important, because their distribution, transport behavior, bonding to receptors, and contributions to metabolic behavior depend on the ionization constant [23].…”

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

“…Several articles concerning the acylation of some 4,5-dihydro-1H-1,2,4-triazol-5-one derivatives have been published [1][2][3][4][5][6][7]. 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].…”

Use of the sulfide minerals pyrite and chalcopyrite as electrochemical sensors in non-aqueous solutions. The potentiometric titration of weak acids in alcohols

“…Therefore, like tert-butyl alcohol, iso-propyl alcohol is a very useful solvent for the titration of weak acids [3,12], for the determination of many organic compounds [4,9,[16][17][18][19], for the determination of pK a values of azlactone dyes [8] and for the potentiometric titration of some hydroxylated benzoic acids and cinnamic acids [20] using TBAH under a nitrogen atmosphere at 25°C. Aktaş et al [21] conductimetrically and potentiometrically titrated hydroxycinnamic acids using triethylamine and TBAH.…”