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  • Analytical Chemistry and Spectroscopy  (3)
  • Wiley-Blackwell  (3)
  • 1
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 16 (1993), S. 530-535 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Resolution of enantiomers ; Stereoselectivity ; Chiral stationary phase ; Derivatized cyclodextrin ; Trifluoroacetylated cyclodextrin ; Thermodynamic properties ; Derivatization ; Alcohols ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Two acyl and three fluoroacyl derivatives of 32 chiral alcohols have been chromatographed on a GC column coated with octakis(2,6-di-O-n-pentyl-3-O-trifluoroacetyl)- γ-cyclodextrin. Significant differences were observed between the stereoselectivity obtained for the derivatives and that for the underivatized alcohols. Of the derivatives, only the fluoroacylated compounds were separated into enantiomers. Derivatization with fluoroacyl groups reversed the elution order for at least some of the analytes. Stereoselectivity towards simple 2- and 3-hydroxy alkanes and their fluoroacyl derivatives was highest for those alcohols with a four-carbon chain attached to the stereogenic center. For longer-chain fluoroacyl derivative groups stereoselectivity was higher for the 2- and 3-hydroxy alkanes. Differences in stereoselectivity towards alcohols with a methyl-branched alkane chain and their fluoroacyl derivatives was related to the distance between the methyl group and the hydroxyl or fluoroacyl groups. Different degrees of saturation in the carbon chain resulted in differences in stereoselectivity. Thermodynamic data calculated for a number of analytes suggest that the alcohols and trifluoroacetate derivatives are interacting with the stationary phase by similar mechanisms. The stereospecific interaction appears to have a hydrogen bonding or dipole-dipole contribution and some form of steric component, depending upon the shape and/or size of the solute.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 15 (1992), S. 696-697 
    ISSN: 0935-6304
    Schlagwort(e): Capillary GC ; Impurities ; 11-Bromoundecyl methacrylate ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 25 (1987), S. 31-35 
    ISSN: 0749-1581
    Schlagwort(e): Morphine ; 3-O-Acetylmorphine ; 6-O-Acetylmorphine ; Diacetylmorphine ; Heroin ; 500 MHz ; 1H NMR spectra ; COSY spectrum ; Complete coupling and chemical shift data ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: High-resolution 1H NMR (500 MHz) spectra were recorded for morphine, 3-O-acetylmorphine, 6-O-acetylmorphine and diacetylmorphine (heroin). Complete assignment of all proton resonances was made for these substances following determination of accurate chemical shift and coupling data by spectral simulation of all tightly coupled proton resonance patterns. Chemical shifts and proton couplings are discussed in terms of the conformation of rings C and D. From a varied collection of morphine analogs, torsion angles for ring D protons were obtained from crystallographic studies. The corresponding coupling constants were calculated, they demonstrate similar conformation of the ring D for the compared morphine compounds.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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