title: Acid-base properties of pristinamycin IA and related compounds.
abstract: The pKa values of acid-base equilibria involved in the protonation of pristinamycin IA and its model compound, N-isobutyl-3-hydroxypicolinamide, were determined by UV-visible absorption spectrometry and potentiometric titration. The equilibrium between dipolar ionic and uncharged neutral forms was investigated spectrometrically in methanol-water solutions. With pristinamycin IA, the dipolar ionic form predominated in aqueous solutions buffered to the isoelectric pH. The effects of structure on the ionization constants are briefly discussed.
authors.affiliation: Laboratoire de Chimie Analytique et Electrochimie, Centre National de la Recherche Scientifique, 1310, Faculte de Pharmacie, Paris, France.
authors.forename: M
authors.initials: M
authors.lastname: Largeron
authors.forename: M B
authors.initials: MB
authors.lastname: Fleury
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002855:Chromatography, Thin Layer; D006863:Hydrogen-Ion Concentration; D007525:Isoelectric Focusing; D011199:Potentiometry; D013056:Spectrophotometry, Ultraviolet; D014769:Virginiamycin / Q000737:chemistry*
chemical_list: D014769:Virginiamycin