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  • Cyclodextrin derivatives  (5)
  • Essential oils  (5)
  • cyclodextrin derivatives  (5)
  • Cyclodextrins  (2)
  • Dynamic gas chromatography  (2)
  • 2,8-dimethyl-1,7-dioxaspiro[5.5]undecane
  • Wiley-Blackwell  (16)
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  • 11
    ISSN: 0935-6304
    Schlagwort(e): Enantioselective capillary gas chromatography ; Cyclodextrins ; Inverse substitution pattern ; Mechanism of chiral recognition ; Applications ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Transferring the site of specific substitution of dipentylated cyclodextrins with methyl or acyl residues from the secondary 3-hydroxyl group to the primary 6-hydroxyl group was expected to provide new information on the mechanism of chiral recognition. The 3-position points towards and the 6-position points away from the cyclodextrin cavity which via inclusion complex formation is supposed to play a major role in chiral separation. The “inverse” 6-O-acyl-2,3-di-O-pentyl-cyclodextrins displayed almost no enantioselectivity but the corresponding 6-O-methyl derivatives are a versatile supplement to the chiral capillary GC phases nowadays available. Among the compounds that could be enantiomerically resolved are alcohols, amino acids, alkyl halides, bicyclic ethers, acetals, olefins, other hydrocarbons and chiral pharmaceuticals.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 12
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Microcolumn Separations 7 (1995), S. 355-363 
    ISSN: 1040-7685
    Schlagwort(e): basic drugs ; capillary electrophoresis ; cyclodextrin derivatives ; separation of enantiomers ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The influence of seven differently methylated β-cyclodextrin derivatives and of pure β-cyclodextrin (β-CD) on the enantiomeric resolution by capillary electrophoresis of six basic chiral pharmaceuticals is investigated. The methyl substitution pattern affects enantioselectivity much more than other experimental parameters. The purity of the used cyclodextrin derivatives is analyzed by successive hydrolysis, reduction, acetylation, and GC/MS of each CD derivative and by MALDI-TOF mass spectrometry. © 1995 John Wiley & Sons, Inc.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 13
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Microcolumn Separations 5 (1993), S. 35-40 
    ISSN: 1040-7685
    Schlagwort(e): Enantiomers ; gas chromatography ; cyclodextrin derivatives ; temperature dependence ; capillary columns ; selectivity ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The effect of dilution of the chiral stationary phase octakis (3-O-butyryl-2, 6-di-O-pentyl)-γ-cyclodextrin in the achiral polysiloxane OV-1701 on the separation factor was investigated over a wide concentration range. The loss in enantioselectivity was only negligible down to a dilution of 50% (w/w), since the separation factor vs. concentration curves levels off at higher concentrations. Because of the strong temperature dependence of the separation factors, the properties of short columns (10 m and 4.5 m) were evaluated. These short columns, which allow operation at low temperatures and lead to enhanced separation factors were found to be appropriate for the separations of simple mixtures, because the gain in selectivity exceeded the loss in separation efficiency. For complex mixtures, the higher efficiencies of columns of at least 25 m in length were still necessary. A plot of In α vs. 1/T did not yield straight lines, but showed a significant curvature, leading to considerable relative errors if thermodynamic data were derived from these plots.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 14
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 20 (1997), S. 55-61 
    ISSN: 0935-6304
    Schlagwort(e): Enantioselective gas chromatography ; Essential oils ; Authenticity control ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The potential of enantioselective capillary gas chromatography with modified cyclodextrins as chiral stationary phases for authenticity control is demonstrated for a selection of economically important essential oils. Adulteration can be easily detected in cases where enantiomerically pure constituents are present in natural oils. In cases of (naturally) varying enantiomeric compositions of chiral constituents, enantioselective gas chromatography may prove insufficient.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 15
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 21 (1998), S. 113-120 
    ISSN: 0935-6304
    Schlagwort(e): Enantioselective GC of chlorinated bis(propyl) ethers ; environmental analysis ; contamination of the Elbe River ; cyclodextrin derivatives ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: ---Cyclodextrin derivatives are evaluated as chiral stationary phases for the enantiomer separation of chlorinated bis(propyl) ethers (BPE). The enantiomeric composition of the 2,3,2′,3′- and 1,3,2′,3′-isomers of tetrachlorobis(propyl) ether in the Elbe River has been quantitatively determined by enantioselective gas chromatography and coupled gas chromatography/mass spectrometry in selected-ion-monitoring mode. Significant enantiomeric discriminations are observed in selected water samples, indicating that enantioselective bio-degradation mechanisms are at least partly responsible for the overall degradation processes.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 16
    ISSN: 0935-6304
    Schlagwort(e): Enantioselective gas chromatography ; Two-dimensional GC ; Essential oils ; Lavandulol ; α-Bisabolol ; Nerolidol ; Methyl jasmonate ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: New β- and γ-cyclodextrin derivatives, selectively substituted with n-pentyl and methyl groups, e.g. heptakis(2,6-di-O-methyl-3-O-pentyl)-β-cyclodextrin, octakis(2-O-methyl-3,6-di-O-pentyl)-γ-cyclodextrin, and octakis(2,6-di-O-methyl-3-O-pentyl)-γ-cyclodextrin, have been prepared from specifically protected intermediates. The new cyclodextrin derivatives exhibit unique enantioselectivity towards important chiral constituents of essential oils. The enantiomers of lavandulol, α-bisabolol, nerolidol, and other terpenoid alcohols could be resolved and their presence in different essential oils could be proved. Methyl jasmonate and epi-methyl jasmonate could, in addition, be detected in jasmine concrete by two-dimensional gas chromatography. The enantiomers of the macrocyclic ketone muscone have been separated for the first time.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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