Spectroscopic Determination of Acid Dissociation Constants of N-Substituted-6-acylbenzothiazolone Derivatives

SIDIR Y. G., SIDIR İ., Berber H.

JOURNAL OF PHYSICAL CHEMISTRY A, vol.115, no.20, pp.5112-5117, 2011 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 115 Issue: 20
  • Publication Date: 2011
  • Doi Number: 10.1021/jp2018549
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.5112-5117
  • Anadolu University Affiliated: Yes


The acid dissociation constants of twelve novel drug precursor N-substituted-6-acylbenzothiazolone derivatives were determined by using the UV-vis spectroscopic technique. The protonation and deprotonation behaviors of the investigated molecules were researched from the super basic to super acid regions (i.e., 8 mol.L-1 KOH to 98% H2SO4) including the pH region. It is observed that all of the molecules are protonated in the super acidic region. The calculated relative stability values of possible tautomer structures indicate that the keto form of investigated molecules is favored over the enol form. It was predicted that protonation occurs at the amide (oxo) group found in the keto form.