title: Development of the high-performance liquid chromatographic method for the enantioseparation of unusual glycine ester analogs on polysaccharide-based chiral stationary phases.
abstract: The stereoisomers of ten unusual amino acid analogs, 1- and 2-naphthol-substituted glycine and its ester derivatives, were separated on chiral stationary phases containing the chiral selectors cellulose tris-(3,5-dimethylphenylcarbamate) (Cellulose-1), cellulose tris-(3-chloro-4-methylphenylcarbamate) (Cellulose-2), cellulose tris-(4-methylbenzoate) (Cellulose-3), cellulose tris-(4-chloro-3-methylphenylcarbamate) (Cellulose-4) and amylose tris-(5-chloro-2-methylphenylcarbamate) (Amylose-2). Experiments were performed in normal-phase mode with n-heptane/alcohol/diethylamine mobile phases in a wide temperature range: 5-50°C. Thermodynamic parameters were calculated from plots of lnk or lnα vs. 1/T. Δ(ΔH°) ranged from -10.1 to 6.2kJmol(-1), Δ(ΔS°) from -31.5 to 22.5Jmol(-1)K(-1) and -Δ(ΔG°) from 0.4 to 1.4kJmol(-1), and both enthalpy and entropy-controlled enantioseparations were observed. The latter was advantageous with regard to the shorter retention and greater selectivity at high temperature. The sequence of elution of the stereoisomers was determined in some cases.
authors: Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary.
authors: Anita
authors: A
authors: Aranyi
authors: István
authors: I
authors: Ilisz
authors: Nóra
authors: N
authors: Grecsó
authors: Renáta
authors: R
authors: Csütörtöki
authors: István
authors: I
authors: Szatmári
authors: Ferenc
authors: F
authors: Fülöp
authors: Antal
authors: A
authors: Péter
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D019277:Entropy; D004952:Esters / Q000737:chemistry*; D005998:Glycine / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry; D013237:Stereoisomerism; D013696:Temperature; D013816:Thermodynamics
chemical_list: D004952:Esters; D011134:Polysaccharides; D005998:Glycine