Research Information System
Revue Roumaine de Chimie, vol.69, no.5-6, pp.321-329, 2024 (SCI-Expanded)
The acid ionization constants (pKa) of the N-benzoylthiourea / 2-thiohydantoin-pyrrolidines were determined by the potentiometric titration method. Titrations were performed by adding sodium chloride, which gives ionic strength, and hydrochloric acid, which is required for the protonation of the ionizable groups, to 2x10–4 M solutions of the synthesized compounds prepared in an acetonitrile-water (20:80, v / v) solvent system at 25 ± 0.1 °C and sodium hydroxide was used as a titrant. The HYPERQUAD computer program was utilized to determine acid ionization constants based on the data obtained from the Molspin Titration System. Analyzing the obtained results, it is possible to propose three pKa (pKa1, pKa2, and pKa3) values that correspond to the enol, thiol, and NH species for N-benzoylthiourea derivatives in the range of 3.02– 10.91 and carboxyl, enol and enthiol species for thiohydantoin derivatives in the range of 2.13–10.96.