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  • 1
    Electronic Resource
    Electronic Resource
    Mass spectrometric studies of sulfur compounds. Some 1-(5-ethyl-2-thienyl)-1-thiaalkanes (1979)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 6 (1979), S. 260-265 
    Details
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fragmentation studies of the mass spectra of 15 high purity compounds of the 1-(5-ethyl-2-thienyl)-1-thiaalkane series are presented. The molecular weight range covered is from 158 to 284. These substances are of importance to those utilizing fossil fuels which contain them and also to those studying natural products. The molecular ion intensities are moderately strong and easy to verify due to the presence of two sulfur atoms in the molecule. Prominent ions occur in all spectra at m/z 144 and 129. A total of six different ion species are base peaks for the compounds reported, including alkyl and alkenyl ions. The methyl and ethyl compounds are exceptions to the correlations developed in this work and are discussed in detail. Metastable and low ionization voltage data are presented in support of the suggested mechanisms of fragmentation. Those using only three to four peaks in selected ion monitoring should anticipate experiencing difficulties with positive identification of these types of molecules due to the plethora of alkylions. An integration of the correlations developed with those of other sulfur containing moieties is presented.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200060607
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  • 2
    Electronic Resource
    Electronic Resource
    Capillary gas chromatographic mass spectrometric and microbore liquid chromatographic mass spectrometric studies of a test well sample from a landfill site (1983)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 10 (1983), S. 338-342 
    Details
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The acid fraction from an extract of a test well sample obtained from a landfill site has been examined by capillary gas chromatography mass spectrometry, and liquid chromatography mass spectrometry. In the latter case conventional and glass-lined stainless steel microbore liquid chromatography columns were used. Desorption chemical ionization and field desorption mass spectrometry have been used to profile the major components present in the mixture. This combined approach enables a more detailed characterization of the sample to be obtained and the techniques have been found to be mutually complementary. Glass-lined stainless steel microbore columns used with a gradient system are shown to provide high quality liquid chromatographic mass spectrometric data.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200100506
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  • 3
    Electronic Resource
    Electronic Resource
    Metabolism of aminoglutethimide in humans: Identification of hydroxylaminoglutethimide as an induced metabolite (1983)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 10 (1983), S. 620-625 
    Details
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hydroxylaminoglutethimide (3-ethyl-3-(4-hydroxylaminophenyl)-2,6-piperidinedione) has been identified as a novel metabolite of aminoglutethimide (3-(4-aminophenyl)-3-ethyl-2,6-piperidinedione) in the urine of patients treated chronically with this drug. The metabolite was isolated by reverse-phase thin-layer chromatography, and characterized by comparison of its mass spectrum and chromatographic properties with those of the synthetic compound. Hydroxylaminoglutethimide is unstable; it is readily oxidized to nitroso-glutethimide and disproportionates in the mass spectrometer into this compound and aminoglutethimide. In none of four patients studied was the metabolite detected in the urine after the first dose of the drug. In one patient it appeared after the second dose and in two more within seven to eight days suggesting that its formation is drug-induced, and that it may be the metabolite responsible for the diminished half-life of aminoglutethimide during chronic therapy. The profile of metabolites from one patient, examined by high-performance liquid chromatography after the first dose and again after six weeks of therapy afforded evidence that the formation of hydroxylaminoglutethimide was at the expense of a major metabolite N-acetylamino-glutethimide. Hydroxylaminoglutethimide was not an induced metabolite in the rat.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200101108
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  • 4
    Electronic Resource
    Electronic Resource
    Metabolism of 1,1,1,2,2-pentafluorohexane and 1,1-difluorocyclohexane by rat liver microsomes in vitro (1984)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 11 (1984), S. 512-521 
    Details
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metabolism of 1,1,1,2,2-pentafluorohexane with liver microsomes from phenobarbital-treated rats gave only one metabolite, namely, the 5-hydroxy derivative. Under similar conditions 1,1-difluorocyclohexane was metabolized to give mainly the 3- and 4-hydroxy derivatives in the ratio 1:∼5.5 The structures of these metabolites were established by chemical ionization (CI) and/or electron impact (EI) mass spectrometry and confirmed by synthesis in the case of 1,1-difluorocyclohexan-4-ol. Oxidation of 1,1-difluorocyclohexane with lead tetrakis(trifluoroacetate) also gave, inter alia, the 3- and 4-hydroxy derivatives. In saturated hydrocarbons complete replacement of hydrogen by fluorine at one particular carbon will not only block microsomal hydroxylation thereat but will also inhibit hydroxylation at neighbouring hydrogen-bearing carbons, (α almost completely, β markedly, γ slightly).
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200111005
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  • 5
    Electronic Resource
    Electronic Resource
    Mass spectroscopic fragmentation pathways of 1,8-nonadiyneIn partial fulfilment of the requirements for the degree of Doctor of Philosophy at Texas Woman's University. This paper was also presented at the 30th Annual Conference on Mass Spectrometry and Allied Topics by the American Society for Mass Spectrometry held in Honolulu, Hawaii in June (1982). (1985)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 20 (1985), S. 189-193 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cleavage α to triple bonds in straight-chain hydrocabons with only one triple bond is a very minor process. The mass spectrum of 1,8-nonadiyne (mol. wt 120) shows strong peaks at around m/z91, which points to a major fragmentation pathway of cleavage α to triple bonds in straight-chain diynes. This study attempts to explain this paradox. Through-space interaction was indicated through the use of carbon-13 labelling of the terminal carbon atoms in 1,8-nonadiyne, 1,2,8,9-13C-1,8-Nonadiyne and 3,7-13C-1,8-nonadiyne were prepared to determine which carbon atoms were lost in the process of [M]+· and [M—1]+ going to m/z91. These two molecules were chosen for ease of synthesis. Low-resolution mass spectra and low-voltage studies determined that a major portion of carbon atoms being lost were from the middle of the carbon chain. This points to a fragmentation pathway that results from through-space interaction of the two terminal triple bonds. It is likely that ionization enhances this through-space interaction of the two triple bonds.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210200304
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  • 6
    Electronic Resource
    Electronic Resource
    The proton magnetic resonance spectra of cyclopentadiene trimers at 220 MHz (1969)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 1 (1969), S. 203-208 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Detailed interpretations of the spectra of four of the possible isomeric cyclopentadiene trimers are given. It is shown that the geometry of the ring fusion can be determined by measuring the chemical shifts of the bridge protons and of the allylic proton on the cyclopentene ring 3a-H.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270010305
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  • 7
    Electronic Resource
    Electronic Resource
    The mass spectrum of 1-(2-thienyl) hexane-1-13C (1968)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 1 (1968), S. 191-198 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectrum of 1-(2-thienyl) hexane-1-13C is reported. The principal fragmentation routes ofthe parent ion are delineated. Beta cleavage of the alkyl chain predominates, and the label retention indicates that the alpha carbon atom remains with the charged ring moiety. A substantial part of the m/e 97 ion undergoes a ring expansion to a six membered ring. A small amount of alpha cleavage of the alkyl chain occurs with the expected loss of the label. Further fragmentation of the ions from initial alpha or beta cleavage produces similar fragment ions. It is noted that many of the neutral particles lost in the formation of the fragment ions are typical of those encountered in the alkylbenzenes or other aromatic ion systems.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210010202
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  • 8
    Electronic Resource
    Electronic Resource
    Fluorinated carbohydrates - IXFor Part VIII, see Ref. 1. The mass spectra of deoxyfluorohexopyranose derivatives (1971)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 5 (1971), S. 437-445 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of some deoxyfluorohexopyranose acetates bearing the fluorine substituent at positions 2,3,4, or 6 were determind. The fragmentation pathways were analogous with those for hexopyranose acetates, except that the cleavage of bonds between carbon atoms was hindered by the attachment of a fluorine substituent to one of the carbon atoms.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210050409
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  • 9
    Electronic Resource
    Electronic Resource
    Fluorinated carbohydrates - X:For Part IX, see Ref. 1. The mass spectra of acetylated deoxyfluoro-D-glucitols (1971)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 5 (1971), S. 865-875 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The deoxyfluoro-D-glucopyranoses with the fluorine substituent severally at positions 6, 4, 3 and 2 were converted into the corresponding deoxyfluoro-D-glucitol pentaacetates (I to IV) and their 1-deuterated analogues (V to VIII). The mass spectra of these derivatives were rationalised in terms of the position of the fluorine substituent on the carbon chain.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210050713
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  • 10
    Electronic Resource
    Electronic Resource
    Decomposition of 1-(2-thienyl)alkylalkanones under electron-impactIn part presented at the Southwest regional meeting of the American Chemical Society, meeting at Dallas, Texas, 6th to 8th December, 1962. (1969)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1969), S. 1005-1015 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The major fragmentation paths of the 1-(2-thienyl)alkylalkanones ionized by electron impact are delineated by means of isotopically labeled molecules, metastable ion peaks and low ionization voltage data. A prominent process is cleavage of the bond beta to the carbonyl group with the concurrent rearrangement of a hydrogen atom. Another important process is cleavage alpha to the carbonyl group to produce the thienoylium ion analogous to the benzoylium ion. As expected, the data show that increasing the chain length by two methylene groups increases the total ion current. The bulk of this increase is found in the increased ion current of the rearrangement ion with the remainder being associated with alkyl fragments and oxygenated ion species.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210021009
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