Synthesis and antioxidant activities of some new 4-(4-hydroxybenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-one derivatives with their acidic properties


YUKSEK H., KUCUK M., ALKAN M. Z. , BAHCECI S., KOLAYLI S., OCAK Z., ...More

ASIAN JOURNAL OF CHEMISTRY, vol.18, no.1, pp.539-550, 2006 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 18 Issue: 1
  • Publication Date: 2006
  • Journal Name: ASIAN JOURNAL OF CHEMISTRY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.539-550
  • Keywords: synthesis, 4,5-dihydro-1H-1,2,4-triazol-5-one, Schiff base, methylation, acetylation, acidity, potentiometric titrations, pK(a), antioxidant, TITRATIONS
  • Karadeniz Technical University Affiliated: Yes

Abstract

Fourteen new compounds having 4,5-dihydro-1H-1,2,4-triazol-5-one ring, namely six new 3-alkyl(aryl)-4-(4-hydroxybenzylidenamino)-4,5dihydro-1H-1,2,4-triazol-5-ones (3), four new 1-acetyl-3-alkyl(aryl)-4-(4acetyloxybenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones (4), two new 1-methyl-3-alkyl-4-(4-methoxybenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones (5) and two new 3-alkyl(aryl)-4-[4-(p-tolylsulfonyl)oxybenzylidenamino]-4,5-dihydro-1H-1,2,4-triazol-5-ones (6), were synthesized. The structures of the newly synthesized compounds were determined by elemental analysis as well as IR, H-1 NMR, C-13 NMR and UV spectral data and their antioxidant activities, except compounds 3e and 4f, were investigated. In addition, compounds 3a-f were titrated potentiometrically with tetrabutylammonium hydroxide in three non-aqueous solvents such as isopropyl alcohol, t-butyl alcohol and N,N-dimethyl formamide. The half-neutralization potential values and the corresponding pK(a) values were determined for all the cases.