Synthesis and non-aqueous medium titrations of some new 4-benzylidenamino-4,5-dihydro-1H-1,2,4-triazol-5-one derivatives

YUKSEK H., UCUNCU O., ALKAN M. Z., OCAK Z., Bahceci S.

Molecules, vol.10, no.8, pp.961-970, 2005 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 10 Issue: 8
  • Publication Date: 2005
  • Doi Number: 10.3390/10080961
  • Journal Name: Molecules
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.961-970
  • Keywords: 4,5-Dihydro-1H-1,2,4-triazol-5-one, Acetylation, Acidity, Methylation, Potentiometric titrations, Schiff base
  • Karadeniz Technical University Affiliated: Yes

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. © 2005 by MDPI.