title: High-performance liquid chromatographic enantioseparation of cyclic β-aminohydroxamic acids on zwitterionic chiral stationary phases based on Cinchona alkaloids.
abstract: Cyclic β-aminohydroxamic acid enantiomer pairs were stereoselectively separated by high-performance liquid chromatography on the recently developed Cinchona alkaloid-based zwitterionic chiral stationary phases Chiralpak ZWIX(+)™, ZWIX(-)™, ZWIX(+A) and ZWIX(-A). The results of variation of the applied chromatographic conditions, such as the bulk solvent composition, the concentrations and ratio of the acid and base additives, the presence of water as mobile phase additive and the counter-ion concentration furnished a better understanding of the retention mechanism. A thermodynamic study in the temperature range 5-50 °C revealed enthalpy-controlled enantiodiscrimination in all cases. The structure-selectivity relationships clearly indicated the importance of the strereochemistry of the functional groups. From an enantiorecognition aspect, the diexo position of the functional groups always proved more favorable than the diendo position. The elution sequence was determined in all cases and was found to reversed when ZWIX(+)™ was changed to ZWIX(-)™ or ZWIX(+A) to ZWIX(-A).
authors.affiliation: Department of Inorganic and Analytical Chemistry, University of Szeged, H-6720 Szeged, Dóm tér 7, Hungary; Institute of Pharmaceutical Chemistry, University of Szeged, H-6720 Szeged, Eötvös u. 6, Hungary.
authors.forename: Gyula
authors.initials: G
authors.lastname: Lajkó
authors.affiliation: Department of Inorganic and Analytical Chemistry, University of Szeged, H-6720 Szeged, Dóm tér 7, Hungary.
authors.forename: Tímea
authors.initials: T
authors.lastname: Orosz
authors.affiliation: Department of Inorganic and Analytical Chemistry, University of Szeged, H-6720 Szeged, Dóm tér 7, Hungary; Institute of Pharmaceutical Chemistry, University of Szeged, H-6720 Szeged, Eötvös u. 6, Hungary.
authors.forename: Nóra
authors.initials: N
authors.lastname: Grecsó
authors.affiliation: Institute of Pharmaceutical Chemistry, University of Szeged, H-6720 Szeged, Eötvös u. 6, Hungary.
authors.forename: Beáta
authors.initials: B
authors.lastname: Fekete
authors.affiliation: Institute of Pharmaceutical Chemistry, University of Szeged, H-6720 Szeged, Eötvös u. 6, Hungary.
authors.forename: Márta
authors.initials: M
authors.lastname: Palkó
authors.affiliation: Institute of Pharmaceutical Chemistry, University of Szeged, H-6720 Szeged, Eötvös u. 6, Hungary.
authors.forename: Ferenc
authors.initials: F
authors.lastname: Fülöp
authors.affiliation: Department of Analytical Chemistry, University of Vienna, Währingerstrasse 38, A-1090 Vienna, Austria.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Lindner
authors.affiliation: Department of Inorganic and Analytical Chemistry, University of Szeged, H-6720 Szeged, Dóm tér 7, Hungary.
authors.forename: Antal
authors.initials: A
authors.lastname: Péter
authors.affiliation: Department of Inorganic and Analytical Chemistry, University of Szeged, H-6720 Szeged, Dóm tér 7, Hungary. Electronic address: ilisz@chem.u-szeged.hu.
authors.forename: István
authors.initials: I
authors.lastname: Ilisz
mesh_terms: D000586:Amination; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002930:Cinchona Alkaloids / Q000737:chemistry*; D003500:Cyclization; D006877:Hydroxamic Acids / Q000737:chemistry / Q000302:isolation & purification*; D013237:Stereoisomerism; D013696:Temperature; D013816:Thermodynamics
chemical_list: D002930:Cinchona Alkaloids; D006877:Hydroxamic Acids
keywords: Chiral zwitterionic ion-exchangers; Direct chiral separations; Enantiomers of cyclic β-aminohydroxamic acids; HPLC; Temperature dependence of chiral separation