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  • 1995-1999  (7)
  • mass spectrometry  (4)
  • Analytical Chemistry and Spectroscopy
  • Inorganic Chemistry
  • 1
    ISSN: 1573-904X
    Keywords: fluphenazine ; stable isotope ; deuterium labeled ; mass spectrometry ; schizophrenics ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-1561
    Keywords: Alkaloids ; mass spectrometry ; infrared spectroscopy ; amphibians ; ants ; decahydroquinolines ; quinolizidines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Three alkaloids—two minor decahydroquinolines (DHQs) and a major quinolizidine—were detected in an extract of a Brazilian myrmicine ant (Solenopsis (Diplorhoptrum) sp. picea group). One DHQ (3) was identical to a known frog-skin alkaloid, cis-195A (cis-5-methyl-2-propyldecahydroquinoline), while the second DHQ, an isomer of 3, designated 195J, was assigned a tentative cis-2-methyl-5-propyldecahydroquinoline structure (2) based on mass and infrared spectra. The third alkaloid proved identical to the frog-skin alkaloid 195C, for which a structure had not been previously proposed. Mass and infrared spectral analysis, including chemical ionization tandem mass spectrometry, indicated a 4-methyl-6-propylquinolizidine structure (1) for 195C. The four possible diastereomers were synthesized and the (6Z,10E)-4-methyl-6-propylquinolizidine diastereomer (1b) was identical to the natural alkaloid. Skin extracts of a population of a Madagascan mantelline frog contained, among other alkaloids, minor amounts of the same alkaloid triad 1–3 with 1 again predominating. The common occurrence of alkaloids 1–3 in both ant and frog supports the hypothesis that ants are a likely dietary source for sequestered frog-skin alkaloids and brings to six, the alkaloid classes common to ant and frog.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 521-525 
    ISSN: 0009-2940
    Keywords: Liquid crystals ; Siloxanes ; Phase behaviors ; Defined topology ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is shown that supermolecules with a tetrahedral symmetry and appropriate side-chains exhibit liquid-crystalline phase behaviour. The use of an optimised hydrosylation reaction allows for the synthesis of materials that have four mesogenic groups attached to a siloxane core, where the conformation and the configuration are unambiguous. The materials show low glass transition temperatures and, depending on the spacer length, complex liquid-crystalline morphologies.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-904X
    Keywords: adinazolam mesylate ; gradient reversed-phase liquid chromatography ; mass spectrometry ; decomposition products assay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A gradient high performance liquid chromatographic method was developed to determine degradation products of adinazolam mesylate in a sustained release tablet formulation. Sample preparations were chromatographed on a YMC-Basic column using a formate buffer/acetonitrile gradient with absorbance detection at 254 nm. Adinazolam mesylate was found to degrade at high relative humidity and temperature to form a major product, the 6-aminoquinoline analog, plus numerous other compounds. Five of these compounds were identified and their structures indicate that the solid-state degradation of adinazolam, in the presence of sufficient moisture, involves not only a hydrolytic mechanism, but also an oxidative mechanism. Potential process impurities were resolved from the drug and degradation products. Recovery was near 100% over the 0.5 to 10% range for the major degradate (6-aminoquinoline) and over the 0.5 to 1% range for the other analytes. The method was applied to tablet samples stressed at high relative humidity and temperature. The relative standard deviation of the assay for the 6-aminoquinoline was less than 2% and less than 13% for the minor components. Calculated mass balances (sum of adinazolam plus degradation products in the degraded tablet divided by the same sum in the undegraded tablet) were less than 100% and were dependent on the extent of degradation in the tablet. The average mass balance result obtained for samples that were an average of 9.5% degraded was 95.0 ± 1.5%. It is possible that the decrease in mass balance with increase in percent degradation may be explained by the formation of many components at trace levels due to degradation by various permutations of hydrolytic and oxidative reaction pathways.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0044-2313
    Keywords: Uranium-sulfilimine chemistry ; uranium-oxo cluster ; crystal structures ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Uran-Sulfilimin-Chemie Darstellung von Cp2*UCl2(HNSPh2) und dessen Hydrolyse mit HNSPh2 · H2ODie Reaktion von Cp2*UCl2 mit HNSPh2 ergibt Cp2*UCl2(HNSPh2), das den ersten strukturell charakterisierten Komplex eines Sulfilimins darstellt. Die Hydrolyse von Cp2*UCl2(HNSPh2) mit HNSPh2 · H2O ergibt einen Tetrauran-Cluster, dessen Schweratomstruktur röntgenographisch bestimmt wurde und der als UIV/UV-Komplex [Cp*(Cl)(HNSPh2)U(μ3-O)(μ2-O)2U(Cl)(HNSPh2)2]2 formuliert wird.
    Notes: The reaction of Cp2*UCl2 with HNSPh2 produces Cp2*UCl2(HNSPh2), which is the first structurally characterized complex of a sulfilimine. The hydrolysis of Cp2*UCl2(HNSPh2) with HNSPh2 · H2O yields a tetrauranium cluster whose heavy atom structure has been determined by x-ray diffraction and which is formulated as a UIV/UV complex: [Cp*(Cl)(HNSPh2)U(μ3-O)(μ2-O)2U(Cl)(HNSPh2)2]2.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0570-0833
    Keywords: fluorine compounds ; mass spectrometry ; NMR spectroscopy ; phosphorus compounds ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 26 (1995), S. 1077-1081 
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Micro-Raman spectra of picogram to sub-femtogram quantities of several chromophoric substances adsorbed from dilute solution on silver were measured and compared with similar measurements on some non-chromophoric substances. The silver surface enhanced resonance Raman measurements require no redox roughening of the surface, sometimes no applied potential and only 1-2 mW of defocused laser power. The new method by which silver surface enchancement is achieved requires contact of the surface with halide ion solution for several hours. The most astounding results thus far were achieved with 1, 1′-diethyl-2,2′-cyanine iodide (2,2′-cyanine). Raman spectra of the adsorbate from 20 ml of 1 × 10-17 M solution of the dye were measured using the method. Further characteristics of the phenomenon were obtained based on extensive Raman measurements on 2,2′-cyanine. Some further details resulting from these measurements are described.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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