title: Determination of Acid Dissociation Constants (pK a ) of Bicyclic Thiohydantoin-Pyrrolidine Compounds in 20% Ethanol-Water Hydroorganic Solvent.
abstract: The acid dissociation constants of potential bioactive fused ring thiohydantoin-pyrrolidine compounds were determined by potentiometric titration in 20% (v/v) ethanol-water mixed at 25 ± 0.1°C, at an ionic background of 0.1 mol/L of NaCl using the HYPERQUAD computer program. Proton affinities of potential donor atoms of the ligands were calculated by AM1 and PM3 semiempiric methods. We found, potentiometrically, three different acid dissociation constants for 1a-f. We suggest that these acid dissociation constants are related to the carboxyl, enol, and amino groups.
authors.affiliation: Department of Chemistry, Faculty of Pharmacy, Mersin University, 33169 Mersin, Turkey.
authors.forename: Yahya
authors.initials: Y
authors.lastname: Nural
authors.affiliation: Department of Chemistry, Faculty of Pharmacy, Mersin University, 33169 Mersin, Turkey ; Advanced Technology Research & Application Center, Mersin University, Yenisehir, 33343 Mersin, Turkey.
authors.forename: H Ali
authors.initials: HA
authors.lastname: Döndaş
authors.affiliation: Department of Chemistry, Faculty of Science and Arts, Gaziosmanpasa University, 60250 Tokat, Turkey.
authors.forename: Hayati
authors.initials: H
authors.lastname: Sarı
authors.affiliation: Department of Chemistry, Faculty of Science and Arts, Gaziosmanpasa University, 60250 Tokat, Turkey.
authors.forename: Hasan
authors.initials: H
authors.lastname: Atabey
authors.affiliation: Department of Chemistry, Faculty of Pharmacy, Mersin University, 33169 Mersin, Turkey.
authors.forename: Samet
authors.initials: S
authors.lastname: Belveren
authors.affiliation: Department of Chemistry, Faculty of Pharmacy, Mersin University, 33169 Mersin, Turkey.
authors.forename: Müge
authors.initials: M
authors.lastname: Gemili