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  • Enantioselective gas chromatography  (9)
  • Cyclodextrins  (2)
  • gas chromatography  (2)
  • 2,8-dimethyl-1,7-dioxaspiro[5.5]undecane  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Andrena wilkella male bees discriminate between enantiomers of cephalic secretion components (1990)
    Springer
    Journal of chemical ecology 16 (1990), S. 429-441 
    Details
    ISSN: 1573-1561
    Keywords: Enantiomer discrimination ; male patrolling ; odor marking ; Hymenoptera ; Apoidea ; Andrena wilkella ; bee ; EAG ; spiroacetal ; absolute configuration ; 2,8-dimethyl-1,7-dioxaspiro[5.5]undecane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Diastereomers of the spiroacetal, 2,8-dimethyl-1,7-dioxaspiro [5.5]undecane, represent main components of the cephalic secretion from males of the solitary bee,Andrena wilkella. The major compound proved to be of high enantiomeric purity, showing (2S,6R,8S) configuration. Only the naturally occurring enantiomer attracted patrolling males in the field; its antipode was behaviorally inactive and in a racemic mixture did not inhibit response. The (E,Z) diastereomers were also found to be almost inactive. EAG studies gave the same result as the behavioral tests. The biological function of the spiroacetal is discussed in view of the evolution of the mating behavior inA. wilkella.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01021775
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  • 2
    Electronic Resource
    Electronic Resource
    Determination of the enantiomeric composition of mexiletine and its four hydroxylated metabolites in urine by enantioselective capillary gas chromatography (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 8 (1996), S. 30-34 
    Details
    ISSN: 0899-0042
    Keywords: gas chromatography ; modified β-cyclodextrin column ; chiral separation ; assay ; mexiletine ; hydroxylated metabolites ; urine ; conjugation/deconjugation ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The enantiomers of mexiletine and four of its hydroxylated metabolites were directly separated by capillary gas chromatography using a heptakis(6-O-tert-butyl-dimethylsilyl-2,3-di-O-methyl)-β-cyclodextrin column. The method was applied to the analysis of urine samples from cancer patients who were treated with racemic mexiletine as part of a study of the use of mexiletine in the relief of neuropathic pain. Samples analyzed before and after deconjugation of the urine with β-glucuronidase/arylsulfatase showed a high stereoselectivity in the formation and conjugation of these compounds. © 1996 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Stereochemical analysis of constituents of essential oils and flavor compounds by enantioselective capillary gas chromatography (1990)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 13 (1990), S. 328-332 
    Details
    ISSN: 0935-6304
    Keywords: Enantioselective gas chromatography ; Cyclodextrin derivatives ; Terpenoid hydrocarbons ; Chiral carbonyl compounds ; Flavor alcohols ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Modified cyclodextrins interact enantioselectively with a great variety of volatile chiral constituents of essential oils by forming diastereomeric inclusion complexes. Capillary gas chromatography is used for resolving the enantiomers of terpenoid hydrocarbons (camphene, α-pinene, limonene, α-phellandrene), carbonyl compounds (carvone, fenchone, menthone, isomenthone, piperitone, camphor, myrtenal), and alcohols (trifluoroacetylated β-citronellol, myrtenol, trans-pinocarveol, 1-octen-3-ol, and underivatized linalool). The enantiomeric composition of some of these compounds in a variety of essential oils is investigated.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240130507
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  • 4
    Electronic Resource
    Electronic Resource
    Gas chromatographic enantiomer separation of agrochemicals and polychlorinated biphenyls (PCBs) using modified cyclodextrins (1994)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 859-864 
    Details
    ISSN: 0935-6304
    Keywords: Enantioselective gas chromatography ; Cyclodextrin derivatives ; Polychlorinated pesticides ; Polychlorinated biphenyls (PCBs) ; Pyrethroid insecticides/Allethrin ; Organophosphorus pesticides/Acephate, Malaoxon ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The enantiomers of the polychlorinated polycyclic xenobiotics heptachlor, cis- and trans-chlordane, cis- and trans-heptachlorepoxide, oxychlordane, and bromocyclen have been resolved by gas chromatography with selectively substituted cyclodextrins. The order of elution of these compounds and of α-hexachlorocyclohexane (α-HCH) was determined by comparison with enantiomerically enriched reference compounds obtained by preparative enantioselective gas chromatography.A separation of the eight stereoisomers of the pyrethroid insecticide allethrin into seven peaks was achieved. Both trans-diastereomers were separated into their enantiomers and the order of elution could be determined by comparison with commercially available (S)-bioallethrin and trans-bioallethrin. Also one cis-diastereomer was separated, wheras the other cis-isomer could not be resolved. In addition 15 out of 19 stable atropisomeric polychlorinated biphenyls with 5, 6 and 7 chlorine substituents, some chiral organophosphorus pesticides, including acephate and malaoxon and the herbicide bromoacil were separated.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240171209
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  • 5
    Electronic Resource
    Electronic Resource
    Diluted versus undiluted cyclodextrin derivates in capillary gas chromatography and the effect of linear carrier gas velocity, column temperature, and length on enantiomer separation (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Microcolumn Separations 5 (1993), S. 35-40 
    Details
    ISSN: 1040-7685
    Keywords: Enantiomers ; gas chromatography ; cyclodextrin derivatives ; temperature dependence ; capillary columns ; selectivity ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mcs.1220050105
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  • 6
    Electronic Resource
    Electronic Resource
    Unusual retention behavior of methyl lactate and methyl 2-hydroxybutyrate enantiomers on a modified cyclodextrin (1991)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 14 (1991), S. 694-695 
    Details
    ISSN: 0935-6304
    Keywords: Enantioselective gas chromatography ; Reversal of elution order ; Isoenantioselective temperature ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240141013
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  • 7
    Electronic Resource
    Electronic Resource
    Gas chromatographic enantiomer separation with modified cyclodextrins: Carboxylic acid esters and epoxides (1993)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 16 (1993), S. 175-181 
    Details
    ISSN: 0935-6304
    Keywords: Enantioselective gas chromatography ; 2,6-di-O-methyl-3-O-pentyl-β- and y-cyclodextrins ; α and β hydroxy acids ; Branched carboxylic acids ; Non-steroidal anti-inflammatory drugs ; Abscisic Acid ; Epoxides ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The wide range of application of 2,6-di-O-methyl-3-O-pentyl-β-and y-cyclodextrins is demonstrated by the resolution of the enantiomers of the methyl esters of chiral carboxylic acids: α and β hydroxy acids with up to 18 carbon atoms, hydroxy di- and tricarboxylic acids, and alkyl/aryl-substituted carboxylic acid methyl esters, including the plant hormone abscisic acid, insect juvenile hormones, and some non-steroidal anti-inflammatory drugs can be resolved with generally large separation factors. The new cyclodextrin derivatives also exhibit high selectivity for epoxides.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240160309
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  • 8
    Electronic Resource
    Electronic Resource
    Enantiomer separation by capillary SFC and GC on immobilized octakis(2,6-di-O-methyl-3-O-pentyl)-γ-cyclodextrin (1994)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 779-783 
    Details
    ISSN: 0935-6304
    Keywords: Enantioselective gas chromatography ; Enantioselective supercritical fluid chromatography ; Immobilized chiral stationary phases ; Modified cyclodextrin ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Heptakis(2,6-di-O-methyl-3-O-pentyl) (2-O-methyl-6-O-oct-1-enyl-3-O-pentyl)-γ-cyclodextrin was immobilized to narrow-bore fused silica capillaries after selective modification. One tert-butyldimethylsilyl group was introduced into octakis-(2-O-methyl-3-O-pentyl)-γ-cyclodextrin in order to get a pure monofunctionalized cyclodextrin derivative. During synthesis the tert-butyldimethylsilyl group was replaced by an anchoring group to bind the cyclodextrin to a polysiloxane. After thermal immobilization of the modified polysiloxane this new chiral stationary phase was applied in GC and SFC. High efficiency separations were obtained in GC. In SFC very polar compounds could be chromatographed at low temperatures resulting in higher separation factors as compared to GC.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240171110
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  • 9
    Electronic Resource
    Electronic Resource
    Cyclodextrins as chiral stationary phases in capillary gas chromatography. Part VII: Cyclodextrins with an inverse substitution pattern - synthesis and enantioselectivityPart VI, see reference [6]. (1990)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 13 (1990), S. 702-707 
    Details
    ISSN: 0935-6304
    Keywords: Enantioselective capillary gas chromatography ; Cyclodextrins ; Inverse substitution pattern ; Mechanism of chiral recognition ; Applications ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240131010
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  • 10
    Electronic Resource
    Electronic Resource
    Enantiomeric composition of the chiral constituents in essential oils. Part 1: Monoterpene hydrocarbons (1992)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 15 (1992), S. 184-189 
    Details
    ISSN: 0935-6304
    Keywords: Enantioselective gas chromatography ; Cyclodextrin derivatives ; Monoterpene hydrocarbons ; Essential oils ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Using a dual column gas chromatograph equipped with two capillary columns coated with heptakis(6-O-methyl-2,3-di-O-pentyl)-β-cyclodextrin (6-me-2,3-pe-β-CD) and octakis(6-O-methyl-2,3-di-O-pentyl)-γ-cyclodextrin (6-me-2,3-pe-γ-CD), respectively, all important olefinic monoterpene hydrocarbons occurring in essential oils, including α-thujene, α- and β-pinene, camphene, sabinene, α- and β-phellandrene, Δ-3-carene and limonene can be resolved into enantiomers. With the chromatographic system described the characteristic enantiomeric composition of these monoterpene hydrocarbons in essential oils can be determined.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240150310
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