title: Enantioseparation of chiral N-imidazole derivatives by electrokinetic chromatography using highly sulfated cyclodextrins: mechanism of enantioselective recognition.
abstract: Baseline separation of ten new substituted [1-(imidazo-1-yl)-1-phenylmethyl)] benzothiazolinone and benzoxazolinone derivatives, with one chiral center, was achieved by CD-EKC using highly sulfated CDs (alpha, beta, gamma highly S-CDs) as chiral selectors. The influence of the type and concentration of the chiral selectors on the enantioseparations was investigated. The highly S-CDs exhibit a very high enantioselectivity power since they allow excellent enantiomeric resolutions compared to those obtained with the neutral CDs. The enantiomers were resolved with analysis times inferior to 2.5 min and resolution factors R(s) of 3.73, 3.90, 1.40, and 4.35 for compounds 1, 2, 3, and 5, respectively, using 25 mM phosphate buffer at pH 2.5 containing either highly S-alpha-CD, highly S-beta-CD, and highly S-gamma-CD (3 or 4% w/v) at 298 K, with an applied field of 0.30 kV/cm. The determination of the enantiomer migration order for the various analytes and the study of the analyte structure-enantioseparation relationships display the high contribution of the interactions between the analytes phenyl ring and the CDs to the enantiorecognition process. The thermodynamic study of the analyte-CD affinities permits us to improve our knowledge about the enantioseparation mechanism.
authors.affiliation: Laboratoire de Chimie Analytique EA 1043, Faculté des Sciences Pharmaceutiques et Biologiques, Université de Lille 2, Lille Cedex, France.
authors.forename: Cécile
authors.initials: C
authors.lastname: Danel
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Lipka
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Bonte
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Goossens
authors.forename: Claude
authors.initials: C
authors.lastname: Vaccher
authors.forename: Catherine
authors.initials: C
authors.lastname: Foulon
mesh_terms: D052160:Benzothiazoles / Q000302:isolation & purification; D001583:Benzoxazoles / Q000302:isolation & purification; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D003505:Cyclodextrins; D007093:Imidazoles / Q000302:isolation & purification*; D013237:Stereoisomerism
chemical_list: D052160:Benzothiazoles; D001583:Benzoxazoles; D003505:Cyclodextrins; D007093:Imidazoles