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  • Artikel: DFG Deutsche Nationallizenzen  (1.362)
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  • Analytical Chemistry and Spectroscopy  (1.362)
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  • ZIB Katalog
  • Artikel: DFG Deutsche Nationallizenzen  (1.362)
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  • Digitale Medien  (1.362)
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  • 201
    Digitale Medien
    Digitale Medien
    Thiosugars. VI - mass spectrometry of 2,3-epithio-D-allose derivatives (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 113-118 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The behaviour under electron impact of methyl 2,3-dideoxy-2,3-epithio-α-D-allopyranoside, methyl 2,3-dideoxy-2,3-epithio-β-D-allofuranoside, 1,6-anhydro-2,3-dideoxy-2,3-epithio-β-D-allopyranose, 1,6-anhydro-2,3-dideoxy-2,3-epithio-β-D-allofuranose and 2,3-dideoxy-2,3-epithio-β-D-allofuranose has been examined. The fragmentation pathways have been deduced by determination of the fragment ions elemental compositions, assignment of the metastable ions fröm the mass number shifts resulting from deuterium replacement, and by the comparison with an epoxide analogue.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130210
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  • 202
    Digitale Medien
    Digitale Medien
    Hydrogen migrations in mass spectrometry. V - loss of olefin from n-propyl esters following chemical ionizationPresented, in part, at the American Society for Mass Spectrometry, 23rd Annual Conference on Mass Spectrometry and Allied Topics, Houston, Texas, May 1975. For Part IV, see Ref. 12. (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 128-132 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The sources of the migrating hydrogen in the elimination of propylene from the protonated and ethylated n-propyl acetate and n-propyl benzoate molecules have been determined by studying the CH4 and H2 chemical ionization mass spectra of esters specifically deuterated in the propyl group. It is shown that the migrating hydrogen originates from C-1 ( ∼ 27%), C-2 ( ∼ 23%) and C-3 ( ∼ 50%) of the propyl group, independent of ester and mode of ionization. It is argued that the observed reaction involves specific competing H-migration reactions from each propyl position to the ether oxygen in a keto-protonated (ethylated) ester molecule.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130303
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  • 203
    Digitale Medien
    Digitale Medien
    Mass spectral studies on steroidal compounds. VIII - a comparative study of 6- and 7-oxalactones (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 382-385 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The mass spectra of three steroidal ring B 7-oxalactones and one 6-oxalactone have been examined and comparison made with previously studied spectra of 6-oxa isomers. Whereas the mass spectra of 6-oxalactones are conspicuous by an intense peak at m/e 318, no such peak was found for 7-oxalactones. On the contrary, the 7-oxalactones showed characteristic [M — CH2O]+ ions. Thus, mass spectrometry offers an excellent means of differentiating between isomeric 6- and 7-oxa ∊-lactones in the cholestane and β-sitostane series. The fragmentation pathways suggested are supported by accurate mass measurement of some of the salient fragment ions.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130704
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  • 204
    Digitale Medien
    Digitale Medien
    Stable gaseous aziridinium ions (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 666-670 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Gaseous protonated aziridine ions are produced at the threshold from β-phenoxyethylamine molecular ions. The evidence for this is collisional activation spectra, using various precursors (including labelled analogues) under electron impact and field ionization conditions. Partial conversion to the acyclic \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 3} {\rm CH = }\mathop {\rm N}\limits^ + {\rm H}_{\rm 2} $\end{document} isomer occurs at higher electron energies and is rationalized by means of a potential energy surface constructed from energetic data.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210131110
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  • 205
    Digitale Medien
    Digitale Medien
    Electron impact induced formation of ions by skeletal rearrangement of some phenyl substituted cyclic ketones (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 584-590 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The base peak at 70 eV for 7-phenylbicyclo [3.1.1] heptan-6-one is due to the ion only. The direct formation of this ion from the molecular ion, as deduced from metastable ion decompositions in the field free regions, involves a rearrangement of 7-phenylbicyclo [3.1.1] heptan-6-one to its 7-phenylbicyclo [3.2.0]-heptan-6-one isomer. Evidence for this rearrangement has been obtained from 13C labelling of 7-phenyl-bicyclo [3.1.1] heptan-6-one, from investigation of its independently synthesized bicyclic [3.2.0] isomer and of related compounds, and from measurements of kinetic energy release in fragmentations generating the various ions.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210131007
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  • 206
    Digitale Medien
    Digitale Medien
    Chemical ionization spectra of trimethylsilylated amino acids and oligopeptides (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 608-610 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The isobutane chemical ionization mass spectra of trimethylsilylated amino acids and oligopeptides are discussed.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210131011
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  • 207
    Digitale Medien
    Digitale Medien
    Electron impact mass spectra of some enols and their alkyl ethers (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 629-635 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The mass spectra of α-arylamino-β-hydroxycrotonic acid anilides and their O-methyl and O-ethyl ethers have been determined and the characteristic fragmentation pathways are discussed. The proposed fragmentation patterns are supported by the appropriate metastables and deuterium labelling.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210131104
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  • 208
    Digitale Medien
    Digitale Medien
    Chemical ionization of aliphatic nitro compounds (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 611-617 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The chemical ionization mass spectra of various aliphatic nitro compounds have been studied. Almost all the nitro compounds form stable [M+H]+ ions in sharp contrast to the instability of their ions produced by other ionization techniques. The fragmentations of the [M+H]+ ions are discussed, the mechanisms and structures of fragment ions proposed being supported by quantum mechanical calculations. Correlations between chemical ionization mass spectra and structures of compounds studied are outlined. Reliable identification of mono- and polynitroalkanes and some related derivatives may be made by analysis of their chemical ionization mass spectra.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210131102
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  • 209
    Digitale Medien
    Digitale Medien
    Identifikation der Partialstrukturen von unbekannten Steroiden mit einer Schlüsselionenkartei und einem rechnerunterstützten Retrieval-System (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 646-652 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Frequently the presence of a certain structural element in a compound causes the production of a sequence of key ions which when considered together are of high structural specificity. Therefore, the combination of particular key ions can often be connected with a distinct partial structure. On this basis a computer aided search system was developed, allowing the determination of partial structures of unknown compounds.
    Notizen: Die Anwesenheit eines Strukturelementes verursacht oft die Bildung einer Folge von Schlüsselionen, die in threr Gesamtheit von hoher struktureller Spezifität sind. Auf dieser Basis wurde für Steroide ein rechnerunterstütztes Suchsystem geschaffen, das die Bestimmung von Teilstrukturen in unbekannten Verbindungen ermöglicht.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210131107
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  • 210
    Digitale Medien
    Digitale Medien
    Hydrogen rearrangement in the mass spectra of (E)-1-alkylsulfonyl-2-phenylethenes (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 675-676 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A novel McLafferty-type rearrangement has been found to be the most facile fragmentation of (E)-1-alkylsulfonyl-2-phenylethenes and the migratory aptitudes for different kinds of hydrogen involved has been qualitatively estimated as benzylic ∼tertiary〉secondary〉primary.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210131112
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  • 211
    Digitale Medien
    Digitale Medien
    Editorial (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 679-679 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210131202
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  • 212
    Digitale Medien
    Digitale Medien
    Mass spectrometry of heterocyclic compounds. XVPart XIV: L. Ceraulo, M. Ferrugia, S. Petruso, P. Agozzino and A. Selva. Ann. Chim. (Rome) 67, 721 (1977). - The mechanism of the fragmentation under electron impact of 3-p-NH2-phenyl-5-phenyl-1,2,4-oxadiazole. A CNDO/2 treatment (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 695-696 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Molecular orbital calculations using the semi-empirical CNDO/2 method were carried out on the molecular ion of 3-p-NH2-phenyl-5-phenyl-1,2,4-oxadiazole, whose structure had been determined by X-ray diffraction. The calculated diatomic interaction energy values are consistent with the mechanistic proposals made previously in terms of the quasi-equilibrium theory concerning the cleavage of the heterocycle ring after electron impact.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210131206
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  • 213
    Digitale Medien
    Digitale Medien
    Masthead (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978) 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130101
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  • 214
    Digitale Medien
    Digitale Medien
    Massenspektren der von Aminosäuren bzw. Peptiden abgeleiteten Triazin-Derivate (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 4-13 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: A mass spectrometric study of about 30 triazine derivatives from amino acids and peptides is reported. These derivatives incorporated the C-terminal of amino acids and peptides in the ring. In contrast to the mass spectra of amino acids and peptide esters reported previously, they always showed characteristic fragments, denoting the presence of the terminal triazine ring. By using this peak as a marker, it is easy to estimate the C-terminal of peptides. In dipeptides, the N-terminal and C-terminal are determined simultaneously.
    Notizen: Die massenspektrometrische Untersuchung von etwa dreißig Triazin-Verbindungen, die das C-Ende (Car-boxylgruppe) von Aminosäuren und Peptiden in den Ring setzten, wird beschrieben. In Gegensatz zu den bisher untersuchten Massenspektren von Aminosäure-bzw. Peptidestern ergeben sie immer charakteristische Fragmente, die den Triazinring am Ende aufweisen. Unter Anwendung diese Peaks als Merkmal ist es leicht, das C-Ende von Peptiden festzustellen. Bei Dipeptiden werden N-Ende und C-Ende zugleich bestimmt.
    Zusätzliches Material: 6 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130103
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  • 215
    Digitale Medien
    Digitale Medien
    Untersuchung von 2.4.6-substituierten s-Triazinen durch Gaschromatographie-Massenspektrometrie (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 43-50 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Gas chromatography mass spectrometry was used to examine a large number of 2,4,6-trialkoxy-s-triazines. The fragmentation of these compounds upon electron impact is discussed. This method permits reliable and rapid identification of mixtures of triazines obtained by reaction of 2,4,6-trichloro-s-triazine with mixtures of alcohols.
    Notizen: Zahlreiche 2.4.6-Trialkoxy-s-triazine wurden mittels Gaschromatographie-Massenspektrometrie untersucht. Die Fragmentierung dieser Verbindungen bei Elektronenbeschuß wird diskutiert. Die Methode erlaubt, komplexe Triazingemische, die bei der Umsetzung von 2.4.6-Trichlor-s-triazin mit Alkoholgemischen entstehen, schnell und sicher zu identifizieren.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130111
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  • 216
    Digitale Medien
    Digitale Medien
    The mass spectrometric fragmentation of some diastereoisomeric 4-methyl-1,3,2-dioxaphosphorinanes (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 65-73 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The mass spectra of nine diastereoisomeric pairs of 4-methyl-2-X-2-Y-1,3,2-dioxaphosphorinanes have been examined. The differences between the intensities of particular ions in the mass spectra of geometrical isomers are reported and rationalized in terms of the conformations adopted by compounds.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130203
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  • 217
    Digitale Medien
    Digitale Medien
    The mass spectra of 1,2,5-triazapentadienium salts (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 214-217 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The mass spectra of some 1,2,5-triazapentadienium salts are described. The major breakdown pathways involve loss of Ph· from the 1-position of the azo form, and of PhNH· from the hydrazone tautomer of the conjugate base.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130410
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  • 218
    Digitale Medien
    Digitale Medien
    Rearrangements and fragmentations of [C2H5S]+ ions (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 232-235 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: [C2H5S]+ ions (m/e 61) with different initial structures were generated in the mass spectrometer from twelve precursor ions. Abundance ratios of competing metastable ion decompositions were used to determine whether these ions decompose through the same or different reaction channels. It was concluded that all [C2H5S]+ ions isomerize to a common structure or mixture of structures prior to decomposition in the first field free region. From 13C labelling experiments it was concluded that [C2H5S]+ ions generated from the molecular ions of 2-propanethiol-2-[13C], partially rearrange to a symmetrical structure before decomposition to [CHS]+ and CH4, whereas in [C2H5S]+ ions generated from the the molecular ions of 1,2-bis-(thiomethoxy-[13C]) ethane, the two carbon atoms become fully equivalent before CH4 loss occurs.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130413
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  • 219
    Digitale Medien
    Digitale Medien
    Die massenspektrometrische Fragmentierung von Neopentylpolyolestern. 1 - Pentaerythrittetrafettsäureester (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 248-253 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The fragmentation of the homologous fatty acid tetraesters of pentaerythritol (C-2 to C-14) upon electron impact was investigated. The main fragment ions are [M—RCOO]+ and [M—RCOOH]+, for which cyclic acetal structures are postulated. Subsequent fragmentation was elucidated by ‘direct analysis of daughter ion’ (DADI) measurements and high resolution measurements. Esters of branched fatty acids can be distinguished from esters of n-fatty acids by characteristic ions. Isomeric esters of n-fatty acids cannot be separated by gas chromatography but identification is also possible by mass spectrometry.
    Notizen: Die Fragmentierung der homologen Fettsäuretetraester des Pentaerythrits (C-2 bis C-14) bei Elektronenbeschuß wurde untersucht. Hauptspaltfragmente entstehen durch [M—RCOO]+ und [M—RCOOH]+. Diese Ionen liegen vermutlich als cyclische Acetale vor. Der weitere Zerfall dieser lonen wird anhand von DADI-Messungen und Massenfeinbestimmungen geklärt. Ester verzweigter Fettsäuren können anhand charakteristischer Ionen von solchen aus n-Fettsäuren unterschieden werden. Die massenspektrometrische Identifizierung von isomeren n- Fettsäureestern, die gaschromatographisch nicht aufgetrennt werden können, ist ebenfalls möglich.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130503
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  • 220
    Digitale Medien
    Digitale Medien
    Elimination reactions of ions in the gas phase. VPart IV: Th. Kuster and J. Seibl, Org. Mass Spectrom. 11, 644 (1976). - elimination of water in hydroxybornanes and related compounds (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 275-279 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Results of an investigation of deuterium labelled methylated norborneols and dihydrocarveols are presented to show that the 1,2 elimination of water in borneol and isoborneol is triggered by an initial ring cleavage reaction. Other eliminations of water in borneol and isoborneol are elucidated by specific and stereospecific deuterium labelling in different positions.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130509
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  • 221
    Digitale Medien
    Digitale Medien
    Masthead (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978) 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130601
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  • 222
    Digitale Medien
    Digitale Medien
    Mécanismes de fragmentation en spectrométrie de masse par ionisation chimique. III - ions formés par cyclisationPour Partie I, voir, Réf. 1.Pour Partie II, Voir Réf. 2. (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 315-318 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Chemical ionization mass spectrometry of bifunctional organic molecules can induce fragmentation involving the formation of cyclic ions.
    Notizen: La fragmentation en spectrométrie de masse par ionisation chimique de composés bifonctionnels peut conduire à la formation d'ions cycliques.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130604
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  • 223
    Digitale Medien
    Digitale Medien
    A mass spectrometric investigation of the reduction product of 3H-1,2-benzodithiole-3-thione (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 341-343 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A combination of electron impact, chemical ionization, field desorption and field ionization mass spectrometry has been employed to demonstrate that the LAH reduction product of 3H-1,2-benzodithiole-3-thione is the dimer, dibenzo[c,h]-3H,10H-dihydro-1,2,8,9-tetrathiecine.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130609
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  • 224
    Digitale Medien
    Digitale Medien
    Laser assisted field desorption mass spectrometry (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 361-365 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The method of indirectly heating the emitter wire with a laser is introduced into field desorption mass spectrometry. Use of this method results in improved sensitivity, more reliable high resolution performance, and extension of field desorption mass spectrometry to the area of high temperature chemistry.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130612
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  • 225
    Digitale Medien
    Digitale Medien
    On the interconversion of o-methoxybenzaldehyde and 2,3- dihydrobenzofuran-3-ol molecular ions (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 368-370 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Kinetic energy release measurements show that the similar primary fragmentation reactions in o-methoxybenzaldehyde and 2,3 dihydrobenzofuran-3-ol occur from common ion structures.
    Zusätzliches Material: 4 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130614
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  • 226
    Digitale Medien
    Digitale Medien
    Energetics of the loss of H2 from [C3H7]+ (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 386-388 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The internal energies of [C3H7]+ ions contributing to the metastable peak [C3H7]+ → [C3H5]+ + H2 are higher (by perhaps 〉 100 kJ mol-1) than those of the ion contributing to the threshold current in appearance energy measurements on [C3H5]+. The measured appearance energy may lead to an underestimation of the activation energy, i.e. negative ‘kinetic shift’, due to quantum, mechanical tunnelling. The distribution of energy released in the decomposition can be explained on the basis that much of the reverse activation energy and a statistical proportion of the excess energy is released as translation.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130705
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  • 227
    Digitale Medien
    Digitale Medien
    N.m.r. studies on aromatic compounds. I - 13C n.m.r. spectra of some mono- and disulpho-substituted hydroxycarboxylic acids (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 12-15 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Carbon-13 n.m.r. spectra of 3-hydroxy-4-sulpho-2-naphthoic, 3-hydroxy-5-sulpho-2-naphthoic, 3-hydroxy-7-sulpho-2-naphthoic, 5-sulphosalicylic, 3-hydroxy-5,7-disulpho-2-naphthoic, 1-hydroxy-4,7-disulpho-2-naphthoic, and 3,5-disulphosalicylic acids were recorded with and without proton noise-decoupling. Analyses of the spectra were carried out for all compounds except 3-hydroxy-5-sulpho-2-naphthoic acid which dimerized. The fine splitting caused by long-range coupling was used in identifying the lines of the 13C n.m.r. spectra.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110104
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  • 228
    Digitale Medien
    Digitale Medien
    An investigation of the utility of using n.m.r. lanthanide shift reagents for 13C assignments in selected aromatic ethers and ketones. A detailed description of the lanthanide induced shift ratio method for lanthanide shift reagent-substrate geometry analysis (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 1-8 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The 13C and 1H spectra of a series of aromatic ketones, ethers and keto-ethers were studied using the lanthanide shift reagent (LSR) Yb(fod)3 and the data analyzed using the lanthanide induced shift (LIS) ratio method. Studies were carried out on phenalenone, 6-methoxyphenalenone, 1- and 2-methoxynaphthalene, 1-indanone, 5- and 6-methoxy-1-indanone and flavone and the data obtained subjected to LSR-substrate geometry analysis as a means of making 13C assignments. The utility and limitations of the LSR method for making 13C assignments is discussed and the LIS ratio method for LSR-substrate geometry analysis is described in detail.
    Zusätzliches Material: 5 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110102
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  • 229
    Digitale Medien
    Digitale Medien
    1H and 13C n.m.r. study of butatriene-bis-tricarbonyliron complexes. Assignment of geometric orientation by comparative J(CCCH) values (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 31-33 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A number of substituted butatriene-bis-tricarbonyliron complexes have been studied by 13C and 1H n.m.r. spectroscopy. Long range coupling values, J(CCCH), have confirmed chemical shift results that methyl and phenyl groups assume opposite orientations at the coordinated double bonds with the methyl group preferentially trans to carbon and the phenyl group preferentially trans to iron.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110108
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  • 230
    Digitale Medien
    Digitale Medien
    A theoretical interpretation of 13C screening data in unsaturated molecules (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 34-37 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Carbon-13 screening constants are calculated within the INDO/S level of approximation to Pople's model. Satisfactory agreement is obtained in most cases between the calculated and observed screening results. An analysis of the contributions of the π → σ*, σ → π* and σ → σ* transitions to the paramagnetic term shows that a linear relationship between 13C chemical shifts and the lowest energy transition is not present. The average excitation energies are found to vary appreciably among the molecules studied.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110109
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  • 231
    Digitale Medien
    Digitale Medien
    Carbon-13 n.m.r. investigation of 2-arylaminothiazolines and analogous thiazines, thiazepines and their amides (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 9-11 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The 13C n.m.r. spectra of 2-arylaminothiazoline, -thiazine and -thiazepine derivatives, and also those of some N-substituted isomeric pairs were recorded and assigned. The structure of the individual isomers, which as a result of contradictory spectroscopic data had earlier been ambiguous, was established. In addition, the tautomeric structure of some N-unsubstituted compounds was determined.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110103
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  • 232
    Digitale Medien
    Digitale Medien
    Applications de la Résonance Dynamique du Proton et du Carbone-13 à l'Etude d'Azines Hétérocycliques. Mécanismes de Formation et d'Isomérisation (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 16-19 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: A 1H and 13C n.m.r. study of heterocyclic azines is presented and the influence of Z/E isomerism on the 13C chemical shifts is examined. The kinetic study of the formation and Z/E isomerization of these compounds has been carried out and mechanisms of these reactions are discussed.
    Notizen: Ce travail présente une étude structurale par RMN 1H et 13C d'azines hétérocycliques, l'influence de l'isomerie Z/E sur les déplacements chimiques 13C est examinée. L'étude cinétique de la formation et de l'isomérisation Z/E de ces composés a été effectuée et les mécanismes de ces réactions sont discutés.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110105
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  • 233
    Digitale Medien
    Digitale Medien
    Calculation of the nitrogen screening constants of some N-heterocycles (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 27-30 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Absolute nitrogen screening constants and chemical shifts of some N-heterocycles are calculated within the CNDO/S level of approximation to Pople's model. Satisfactory agreement between calculated and observed nitrogen chemical shifts is obtained in most cases. The application of the results to the study of tautomeric equilibria is discussed. ‘Pyridine-type’ nitrogen chemical shifts are dominated by n → π* transitions together with significant contributions from π → σ* and σ → π* transitions whereas the latter two are the dominant ones for ‘pyrrole-type’ nitrogen nuclei.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110107
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  • 234
    Digitale Medien
    Digitale Medien
    Carbon-13 NMR chemical shifts in some substituted 1,2,4-triazol-3-ones (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 137-142 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Carbon-13 NMR data for 15 substituted 1,2,4-triazol-3-ones are presented and discussed with regard to enolization in the neutral molecules. The coupling constant and chemical shift data show that the proton at N-2 is not exchanging rapidly in the DMSO-d6 solvent. Using D2O—OD- as a solvent, it is found that the C-3 and C-5 resonances are shifted downfield by nearly the same amount, suggesting that the proton at N-4 is being removed. Enolization in the neutral molecules does not occur to any significant extent.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110309
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  • 235
    Digitale Medien
    Digitale Medien
    Carbon-13 NMR studies of thyroid hormones and model compounds. The conformational analysis of diphenyl ethers (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 143-149 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The 13C spectra of a series of thyroid hormones and derivatives including thyroxine (T4) sodium salt, T4-N-acetyl methyl ester, triiodothyronine (T3), T3-sodium salt, T3-methyl ester hydrochloride, sodium triiodothyroacetate and ethyl triiodothyropropionate were assigned using chemical shift trends from model compounds, coupling constants and relaxation times. The 13C spectra of a series of diphenyl ethers were assigned and the chemical shift trends observed were analyzed on the basis of conformational changes engendered by mesomeric or steric effects.
    Zusätzliches Material: 6 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110310
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  • 236
    Digitale Medien
    Digitale Medien
    Masthead (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978) 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110401
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  • 237
    Digitale Medien
    Digitale Medien
    Long range substituent-induced chemical shifts in the 13C NMR spectra of N-benzylidenebenzylamines (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 160-161 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Carbon-13 chemical shifts for N-benzylidenebenzylamines are affected by substituents up to eleven bonds away from the substituent group. The data correlate well with Hammett constants.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110314
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  • 238
    Digitale Medien
    Digitale Medien
    Carbon-13 NMR spectra of some pentacyclic triterpenoids with the olean-12-ene and 18α-olean-12-ene skeleton (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 163-166 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The 13C NMR spectra of some pentacyclic triterpenoids, 3β-acetoxy-11-oxo-olean-12-ene-30-oic acid methyl ester, 3β-acetoxy-11-oxo-olean-12-ene-29-oic acid methyl ester, the corresponding 11-desoxo methyl esters, 3β-acetoxy-11-oxo-18α-olean-12-en-30-oic acid methyl ester and 3β-acetoxy-11-oxo-18α-olean-12-en-29-oic acid methyl ester are discussed. The shielding data are interpreted in term of the different orientation of the carbomethoxy group and of the change in configuration at the D/E ring junction and are diagnostically valuable for the differentiation of the mentioned compounds.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110402
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  • 239
    Digitale Medien
    Digitale Medien
    RMN 13C d'Alcynes Aliphatiques: Analyse Topologique des Effets de Substituants Alkyles sur les Déplacements Chimiques des Carbones sp par la Méthode DARC PELCO (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 87-96 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Alkyl substituent effects on the sp carbon chemical shifts of aliphatic alkynes have been analysed by the DARC/PELCO method estimating the perturbations linked to the introduction of localized sites in the Limited, Concentric, Ordered Environment of the carbons described by graduate generation from the centre -C≡C.-.A site correlation ‘Topology-δ’ is proposed and its ability to predict the chemical shifts is checked on a population of 55 linear to highly branched alkynes, over a range of 25.2 ppm.This work also shows (i) the independence of the effects of the alkyl groups linked to the C≡C bond; (ii) their attenuation with increasing branching of the alkyl substituents; (iii) the small values of the γπ effects; (iv) the additivity of site perturbation increments (without interaction terms) up to a frontier corresponding to the -C(H,Me,tBu) and -C(Me2,tBu) groups.A simplified model is derived from a partially ordered generation graph and, for rapid estimation of δ, the global effects of alkyl radicals are expressed as group parameters by summation of their site parameters.
    Notizen: Les effets de substitution alkyle sur les déplacements chimiques des carbones sp d'alcynes aliphatiques sont analysés par la méthode DARC PELCO estimant les perturbations liées à l'introduction de sites localisés dans l'Environnement Limité, Concentrique, Ordonné des carbones sp, décrit par génération progressive à partir du foyer origine -C≡C.—.Une corrélation de site ‘topologie-δ’ est proposée et son aptitude à la prévision des déplacements chimiques est vérifiée sur une population de 55 alcynes linéaires ou fortement ramifiés correspondant à un domaine expérimental de 25,2 ppm.Cette étude met aussi en éevidence (i) l'indépendance des effets des groupes alkyles portés par la triple liaison; (ii) leur atténuation lorsque croǐt la connectivité des sites substitués; (iii) la faible importance des effets γπ; (iv) l'additivité des incréments de perturbation de site - sans termes d'interaction - jusqu'à une frontière correspondant aux groupes -C(H,Me,tBu) et -C(Me2,tBu).Un modèle simplifié est proposé à partir d'un graphe partiellement ordonné et à des fins de calcul rapide des δ, les effets globaux des radicaux alkyles sont caractérisés et exprimés en paramètres de groupe par sommation de leurs paramétres de site.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110207
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  • 240
    Digitale Medien
    Digitale Medien
    Chemical shifts for tritons in the ortho, meta and para positions of toluene as determined by tritium NMR spectroscopy (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 213-214 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Chemical shifts for tritons in ortho, meta and para positions in toluene have been determined using a 64 MHz tritium NMR spectrometer. The order of shift is meta〉para〉ortho, whereas the calculated shift order for protons is meta〉ortho〉para.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110409
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  • 241
    Digitale Medien
    Digitale Medien
    Sur l'Utilisation de la Stéréospécificité des Couplages Magnétiques à Longue Distance dans la Détermination des Conformations d'Aziridines Bicycliques (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 133-136 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The study of long range coupling constants in the 1H NMR spectra (60 MHz) of aziridines with a 7-azabicyclo[4.1.0]heptane skeleton allows the determination of the conformation of these compounds and shows that some isomers have a rigid structure.
    Notizen: L'étude des couplages magnétiques à longue distance relevés dans les spectres RMN du proton à 60 MHz d'aziridines du type aza-7 bicyclo[4.1.0]heptane, permet de préciser la conformation de ces composés et de démontrer sans ambiguïté l'existence de structures bloquées pour certains isomères.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110308
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  • 242
    Digitale Medien
    Digitale Medien
    How does the accuracy of NMR conformational analysis depend on the equilibrium constant? (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 127-129 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Analytical expressions are derived for the analysis of the accuracy of NMR determinations of conformational equilibrium constants, K. The relative error, σK/K, shows a nearly linear increase with K for two commonly used modifications of the NMR approach to conformational analysis (based on measurements of integral intensities and averaged chemical shifts).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110306
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  • 243
    Digitale Medien
    Digitale Medien
    Etude par RMN de 29Si de Sila-1 Cyclopentènes-2 et -3 (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 150-151 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: 29Si chemical shift measurements of silacyclopentenes confirm the results obtained by 1H and 13C NMR.
    Notizen: Les mesures des déplacements chimiques de 29Si dans les silacyclopentènes vérifient les conclusions obtenues par RMN de 1H et 13C.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110311
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  • 244
    Digitale Medien
    Digitale Medien
    Carbon-13 spectra of polycyclic systemsPart 75 in the series 13C NMR studies; for part 74 see Ref. 21; for part 73 see Ref. 18b. Tricyclo[3.2.1.02,7]octanes as models for some tetracyclic sesquiterpenes and pentacyclic diterpenes. Ishwarane and trachylobane derivatives (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 252-257 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The 13C spectra of tricyclo[3.2.1.02,7]octane, its 1,5-dimethyl derivative and ten tricyclo[3.2.1.02,7]octan-6-ones have been recorded as model compounds to aid the interpretation of the spectra of the naturally occurring polycyclic terpenes, ishwarane, ishwarone, ishwarol and methyl trachylobanate. The assignments for specific carbons in this series are based on the internal consistency of the observed shielding trends together with the effects of shift reagent on the shieldings of some of these derivatives.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110507
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  • 245
    Digitale Medien
    Digitale Medien
    Presentation of NMR data for publication in chemical journals - B. Conventions relating to spectra from nuclei other than protons (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 267-267 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110510
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  • 246
    Digitale Medien
    Digitale Medien
    High resolution 13C NMR spectroscopy. IVFor Part III, see Ref. 14. - stereochemical assignments in butenedioic acids and 3-pentene-2-ones (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 197-203 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Vicinal 13C, H coupling constants 3J(CO, H) for butenedioic acids and 3J(CH3, H) for 3-pentene-2-ones have been determined and are correlated with the configuration of the corresponding C=C double bond. For both types the relationship 3J(CH) trans 〉 3J(CH)cis holds; in the case of the CH3, H couplings, however, the 3J(CH3, H) trans values are reduced because of steric reasons, so that configurational assignments seem possible only when both isomers are present. Additionally, the coupling constants 3J(COCH3,H) and the chemical shifts δCOCH3 have been evaluated for the pentenones and it is shown that these parameters give information about the predominating conformation of α, β-unsaturated methyl ketones.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110406
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  • 247
    Digitale Medien
    Digitale Medien
    Proton-coupled 13C NMR and {14N} - 1H-INDOR of highly-substituted 6-membered heterocycles. I - trisubstituted pyridones and isomeric aminopyrones; tetrasubstituted pyridines (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 204-210 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The structural elucidation by NMR spectroscopy of trisubstituted α-pyridones and the isomeric 2-amino-γ-pyrones as well as their internal and external pyrylium salts is described. The most useful parameter for the differentiation between α-pyridones and isomeric γ-pyrones is the geminal coupling constant 2J(C-6, H-5) which changes from ∼2.5 Hz to ∼7 Hz whenever the cyclic amide group is replaced by an oxa-function; this applies to both the γ-pyrones and their pyrylium salts. The value of J(C-6, H-5) in the pyridones resembles that of the analogous coupling in N-vinylacetamide, whose sign determination by the selective population inversion (SPI) technique is reported. The 13C chemical shifts of seven pyridones, pyrones and pyrylium salts are reported and their structural correlations are discussed. Quick structural assignments in these classes of compounds may also be performed by evaluating the 14N chemical shifts, which often are accessible by the {14N} - 1H-INDOR technique. The proton coupled 13C NMR spectra of two tetrasubstituted pyridines are also reported, and empirical correlations between long range C—H coupling constants and substituent electronegativity are discussed.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110407
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  • 248
    Digitale Medien
    Digitale Medien
    J. W. Emsley, L. Phillips and V. Wray. Fluorine coupling constants. Pergamon Press (Oxford), 1977. 672 pages. $75.00. £37·50 (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. iii 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110411
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  • 249
    Digitale Medien
    Digitale Medien
    Dynamic proton magnetic resonance studies on complex spin systems. Non-mutual three-spin exchange in four 1-substituted cyclohexanes-2,2,3,3,4,4,5,5-d8 and mutual four-spin exchange in cyclohexane-1,1,2,2,3,3,4,4-d8 (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 179-196 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The intrinsic advantage proffered by coupled three-proton spin systems in the quantitative study of conformational equilibria and equilibrations, as elaborated and exemplified in the preceding publication, is exploited for the determination of precise thermodynamic and dynamic parameters for octadeuteriocyclohexanes containing a cyano, chloro, bromo or deuteriomethoxy substituent and hydrogen atoms on the substituted and on one contiguous carbon. Dynamic quantities for the ring reversal of cyclohexane-1,1,2,2,3,3,4,4-d8, obtained by bandshape analysis of the deuterium-decoupled proton NMR spectra broadened by mutual four-spin exchange, are also reported. The measured standard entropy differences between the axial and equatorial conformational isomers of the monosubstituted cyclohexanes show that, in addition to the rotational entropy, there must be a significant contribution from the vibrational partition functions. The experimental activation entropies for the cyclohexane chair-to-twist-boat conversion are at variance with conclusions drawn from naive symmetry considerations, but agree with the more sophisticated treatment of Pickett and Strauss; the data establish that there is virtually free pseudorotation in the transition states of the ring reversal for cyclohexane itself as well as for the monosubstituted derivatives studied in this investigation.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110405
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  • 250
    Digitale Medien
    Digitale Medien
    Spectres RMN des Polysaccharides et de leurs Dérivés: Influence des Substituants sur le Déplacement Chimique 13C (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 344-349 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Methyl and acetyl substituent effects on 13C chemical shift have been determined on (α 1→3), (α 1→4), (β 1→3) and (β 1→4) linked polysaccharides such as pseudo-nigerane, β-cyclodextrine, amylose, laminarane and cellulose. Methyl α- and β-D-glucopyranoside have been used as monomer model compounds. Shift determination of hydroxylated and substituted polysaccharides requires unambiguous assignment of their 13C spectra. Selective heteronuclear spin decoupling and the isotope effect of deuterated hydroxyl have been used as assignment techniques.
    Notizen: L'influence des substituants méthyle et acétate sur le déplacement chimique 13C a été déterminée sur les polysaccharides liés par liaison glycosidique (α1→3), (α1→4), (β1→3) et (β1→4) suivants: pseudonigérane, β-cyclodextrine, amylose, laminarane et cellulose. Nous avons utilisé les méthyl α et β glucopyranosides comme composés modès. La détermination de l'effet des substituants sur le déplacement chimique 13C nécessite l'attribution non ambiguë des spectres 13C des polysaccharides hydroxylés et substitués. On a utilisé pour cela la technique d'irradiation sélective hétéronucléaire et l'effet isotopique d'hydroxyle deutérié.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110706
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  • 251
    Digitale Medien
    Digitale Medien
    Determination of the configuration of substituted 1,4:3,6-dianhydrohexitols by 13C NMR spectroscopy (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 357-359 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The configurations of 1,4:3,6-dianhydro-2,5-di-O-mesyl-D-mannitol, 1,4:3,6-dianhydro-2,5-di-O-mesyl-D-glucitol, 1,4:3,6-dianhydro-2,5-di-O-mesyl-L-iditol, 1,4:3:6-dianhtydro-2-deoxy-2-iodo-5-O-mesyl-D-mannitol, 1,4:3:6-dianhtydro-2-deoxy-2-iodo-5-O-mesyl-D-glucitol, 1,4:3,6-dianhydro-2-deoxy-2-iodo-5-O-mesyl-L-iditol, 1,4:3,6-dianhydro-2,5-dideoxy-2,5-diiodo-D-glucitol and 1,4:3,6-dianhydro-2,5-dideoxy-2,5-diiodo-L-iditol were determined by 13C NMR spectroscopy, by invoking the field-effect.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110708
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  • 252
    Digitale Medien
    Digitale Medien
    Masthead (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978) 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110801
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  • 253
    Digitale Medien
    Digitale Medien
    The carbon-13 nuclear magnetic resonance spectra of anthraquinone, eight polyhydroxyanthraquinones and eight polymethoxyanthraquinones (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 375-377 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The 13C NMR spectra of anthraquinone, eight hydroxyanthraquinones and eight methoxyanthraquinones are reported. Peak assignment for the carbon atoms of these compounds is achieved by using decoupling techniques and by intercomparison of the variously-substituted derivatives. Carbonyl chemical shifts in the hydroxyanthraquinones can be rationalized in terms of cross conjugation and intramolecular hydrogen bonding and in terms of cross conjugation in the methoxyanthraquinones. Hydroxy and methoxy substituent chemical shifts are also reported.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110802
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  • 254
    Digitale Medien
    Digitale Medien
    Elektronenstruktur und NMR-Parameter von substituierten 5-Phenyl-2,4-pentadiensäuren (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 390-394 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The 1H and 13C NMR chemical shifts as well as vicinal HH coupling constants of substituted 5-phenyl-2,4-pentadienoic acids Ar—CH=CH—CR=CR—COOH are reported and discussed in connection with the molecular structure. The 13C chemical shift values show an alternation along the chain and can be linearly correlated to the π-electron charge densities as calculated by use of the PPP-method. The effect of para-substituents and solvents upon the 13C chemical shifts can be described in terms of the mutual atom-atom polarizabilities.
    Notizen: 1H- und 13C-NMR-chemische Verschiebungen sowie vicinale HH-Kopplungskonstanten von verschieden substituierten 5-Phenyl-2,4-pentadiensäuren Ar—CH=CH—CR=CR—COOH werden mitgeteilt und im Zusammenhang mit der Molekülstruktur diskutiert. Die entlang der Molekülkette alternierenden 13C-chemischen Verschiebungen können linear mit den entsprechenden in PPP-Näherung berechneten π-Elektronenladungsdichten korreliert werden. Die ebenfalls alternierenden Einflüsse der paraständigen Substituenten bzw. der Lösungsmittel auf die 13C-chemischen Verschiebungen sind mittels Atom-Atom-Polarisierbarkeiten beschreibbar.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110805
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  • 255
    Digitale Medien
    Digitale Medien
    A dynamic NMR study of Z, E-isomerization in solutions of indolyl-substituted α-nitroacrylates (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 308-312 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Fast Z, E-isomerization of α-nitro-β-indolylacrylates in polar solvents has been studied by dynamic 1H NMR spectroscopy. With indolylnitroacrylates having no substituents at the ring nitrogen atom, isomerization proceeds via intermediate formation of a mesomeric anion and ionization of the N—-H bond as the rate determining step. For methyl-substituted indolylnitroacrylates, no general isomerization mechanism can be suggested, and isomerization pathways depend on the structures of isomerizing species.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110609
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  • 256
    Digitale Medien
    Digitale Medien
    Downfield γ-gauche and γ-antiperiplanar effects on 13C NMR chemical shifts exerted by thiophene sulphur (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 316-318 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The γ-effects of sulphur on 13C NMR chemical shifts have been measured in a series of steroidal compounds containing the thiophene ring in different configurations with respect to the rest of the molecule. The data constitute the first example of downfield effects exerted by sulphur on both gauche and antiperiplanar γ-carbons. The γ-gauche effect of sulphur amounts to 1.6-1.8 ppm, the γ-antiperiplanar effect from practically zero to almost 1 ppm.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110611
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  • 257
    Digitale Medien
    Digitale Medien
    Conformational study of phosphothreonine in aqueous solution. H and 13C NMR results (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 319-321 
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    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The 270 MHz 1H and 22.6 MHz 13C NMR spectra of DL-phosphothreonine in D2O have been measured and analysed as a function of pD. The trans-trans conformation of the fragment H-α—C-α—C-β—O—P predominates at all pD values. The C-β - O gauche contribution is notably larger for pD values in the range 7≤pD〈10 than for acidic or more basic solutions which is in accordance with earlier results for phosphoserine (PSer).
    Zusätzliches Material: 4 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110612
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  • 258
    Digitale Medien
    Digitale Medien
    Nuclear magnetic resonance. Specialist Periodical Reports produced by the Chemical Society (London) 1977, Vol. 6. 269 pages. £21.00 (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. iii 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110614
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  • 259
    Digitale Medien
    Digitale Medien
    Structure elucidation with lanthanide-induced shifts. 4For Part 3, see Ref. 1. - Bound shifts vs relative shifts (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 323-328 
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    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The use of lanthanide shift reagents (LSR's) to obtain additional structural information from nuclear magnetic resonance studies has gained widespread acceptance. However, there has not been general agreement with regard to the most appropriate methodology for analysis of the shifted NMR spectra. We present arguments that only the bound shifts (Δ1) corresponding to the LS complex should be used for correlation of lanthanide-induced shifts with molecular structure by means of the pseudocontact equation. Several examples are discussed of compounds for which the relative induced shifts are dependent on the concentration of LSR. For such cases it is not possible for both Δ1 and Δ2 (the bound shift corresponding to the LS2 complex) to correlate successfully with the correct structure. Alternative methods of obtaining bound shifts are critically evaluated.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110702
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  • 260
    Digitale Medien
    Digitale Medien
    Etudes Conformationnelles par Résonance Magnétique Nucléaire d'Ethanes Disubstitués par un Hétéroatome appartenant aux Colonnes IV, V et VI et par un Groupement Fonctionnel (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 329-332 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: In this paper results obtained in the conformational analysis of ethers, sulphides, selenoethers, amines, arsine, germanes and stannanes such as R—X—CH2—CH2—Y are given. The AA′BB′ part (-CH2—CH2-) of the NMR spectra was studied by a method using chemical shifts. The electronegativity of the heteroatom was connected with the difference of the chemical shifts of AA′BB′. Following this, conformational analysis based on NMR spectra obtained at different temperatures permitted us to show that in the temperature range used (230 K-320 K) triphenylstannyl-3 propionitrile has a ‘blocked structure’.
    Notizen: Dans ce travail, nous présentons les résultats obtenus dans l'analyse conformationnelle d'ethers, de sulfures, de sélénoéthers, d'amines, d'arsine, de germanes et de stannanes du type R—X—CH2—CH2—Y. La partie AA′BB′ (-CH2—CH2-) des spectres a été analysée par une méthode basée sur les déplacements chimiques. Nous avons pu d'abord relier l'électronégativité de l'hétéroatome à la différence des déplacements chimiques des protons AA′BB′. Ensuite, une analyse conformationnelle par variation de température nous a permis de montrer que, dans le domaine étudié (230 K à 320 K), le triphénylstannyl-3 propionitrile possède une structure ‘bloquée’.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110703
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  • 261
    Digitale Medien
    Digitale Medien
    Carbon-13 NMR spectra of monosulphones and disulphones: Substitution rules and conformational effects (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 360-369 
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    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Carbon-13 NMR spectra have been obtained for 27 aliphatic monosulphones and 13 aliphatic disulphones. Substitution rules have been formulated which allow the prediction of chemical shifts when a CH2 group in a hydrocarbon is replaced by an SO2 group, or when an H atom in a sulphone is replaced by an alkyl group. Carbon atoms β to a sulphone group show a marked upfield shift effect which is sensitive to the conformation about the C—S bond; atoms in the trans position experience an upfield shift (-9.39±1.64 ppm) compared with those in the gauche position. An assignment of the meso (m) and racemic (r) β-carbon peaks in di-sec-butyl sulphone was made by synthesis of the optically active compound. |δm-δLr| decreases with increasing temperature for both β-carbon atoms; this effect was interpreted in terms of two available conformers for each of the m and r compounds, those for the m form having the same energy and entropy, and those for the r form having ΔS=0.6 J K-1 mol-1 and ΔH=0.8 kJ mol-1. Observed chemical shifts for the disulphones were compared with those estimated by the application of the first set of substitution rules.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110709
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  • 262
    Digitale Medien
    Digitale Medien
    A carbon-13 NMR study of benzonorbornene isomers (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 370-372 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The carbon-13 NMR spectra of a series of exo-and endo-epimers of 2-substituted benzonorbornene (2-substituent = OH, OCHO, Br, NH2, NHMe or NMe2) have been examined. The spectra are readily assigned by comparison with the coupled and off-resonance proton decoupled spectra as well as by the use of shift reagents. Interesting and diagnostic features of the spectra allow the distinction between epimers.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110710
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  • 263
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    Digitale Medien
    Application of artificial intelligence for chemical inference. XXV.For Part XXIV see Ref. 1. A computer program for automated empirical 13C NMR rule formation (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 378-384 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A computer program which generates empirical rules associating 13C NMR shifts with local structural environments is described. The program uses a heuristic method to search for common structural features for those carbon atoms exhibiting similar shifts. Rules have been generated by our program from a combined set of acyclic amine and paraffin data. Examples of these rules are presented, and their performance as a tool for structure elucidation is examined.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110803
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  • 264
    Digitale Medien
    Digitale Medien
    Nitrogen nuclear magnetic resonance spectroscopy. Nitrogen-15 and proton chemical shifts of methylanilines and methylanilinium ions (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 401-405 
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    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Nitrogen and carbon electron densities of the toluidines and xylidines have been recalculated by the INDO method; previously published errors have been corrected. Although the nitrogen-15 chemical shifts of these compounds still display the earlier suggested correlation with σ and total electron densities, the calculated inverse correlation with proton electron densities has been shown to be incorrect. Methyl proton chemical shifts of these compounds display no meaningful correlation with the nitrogen shifts. The nitrogen chemical shifts of the toluidinium and xylidinium ions correlate moderately well with the 13C chemical shifts of the analogous di- and tri-methylbenzenes.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110808
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  • 265
    Digitale Medien
    Digitale Medien
    1H, 13C, 31P NMR and conformational study of 7-membered ring organophosphorus compounds. 1,3,2-dioxaphosphepanes (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 411-417 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The 1H, 13C and 31P NMR data of several 2-R-2-thiono-1,3-dioxa organophosphorus molecules with 7-membered rings [R = Cl, OC6H5, C6H5, CH3, N(CH3)2] are reported. The conformation of the 7-membered ring is discussed by reference to the 3J(POCH) coupling constants which are compared with those observed in 6-membered 1,3,2-dioxaphosphorinanes. It is shown that caution must be exercised in using the 3J(POCH) angular dependence as a stereochemical tool. The 31P spin lattice relaxation times of some of these 7-membered rings have been measured and the values are discussed.
    Zusätzliches Material: 7 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110810
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  • 266
    Digitale Medien
    Digitale Medien
    Carbon-13 nuclear magnetic resonance spectroscopy of methyl-substituted piperidines and their hydrochloride salts (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 418-423 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Carbon-13 chemical shifts and 1J(CH) coupling constants of piperidine, 4-t-butylpiperidine, five C-methyl substituted piperidines and of the corresponding N-methyl compounds have been measured. These NMR parameters have also been determined for the fourteen corresponding hydrochlorides. The N-methyl-C-methyl piperidinium salts showed two stereoisomers on the positive nitrogen atom. The effect of protonation is discussed in relation to charge and steric effects and the methyl substituent effects are compared with those of methyl-substituted cyclohexanes. Deviations from the general tendencies in the series are correlated with changes in ring conformations around the highly crowded substituted carbons.
    Zusätzliches Material: 9 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110811
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  • 267
    Digitale Medien
    Digitale Medien
    The torsional barrier in aromatic carbonyl compounds. VSee Ref. 4 for Part IV.. Carbon-13 DNMR study of stable protonated p-substituted acetophenones (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 438-442 
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    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The barrier to internal rotation around the phenyl-carbonyl bond in a series of stable protonated p-substituted acetophenones has been determined by means of low temperature 13C NMR and total bandshape analysis resulting in a value of ΔG273K≠ = 48.1 kJ mol-1 for the unsubstituted protonated compound. The energy results and the 13C chemical shifts are in good agreement with the quasi-planarity of the ground state in p-substituted protonated acetophenones. The barrier heights are discussed in terms of contributions from steric and resonance effects.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110904
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  • 268
    Digitale Medien
    Digitale Medien
    An 1H and 13C NMR study of pentane-2,4-dione tellurium(II) compounds; chemical shifts, 125Te—1H and 125Te—13C couplings (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 449-452 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 1H and 13C NMR data are reported for pentane-2,4-dione tellurium(II) compounds which contain a 6-membered tellurane ring bearing methyl or ethyl substituents. The 125TeCH coupling constants are particularly interesting in that they are highly stereospecific, viz. ∼60 Hz and 0-8 Hz for equatorial and axial protons, respectively, in the chair conformation. 1J(TeC) and 2J(TeCC) couplings lie in the ranges 118-146 Hz and 44-49 Hz, respectively. Geminal HCH couplings in these compounds (9-11 Hz) are lower than analogous values in tellurane or in cyclohexane-1,3-diones.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110906
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  • 269
    Digitale Medien
    Digitale Medien
    Substituent effects on 1H NMR spectra of N,N-dialkylanilines (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 475-477 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Correlations with reactivity constants and quantum chemical parameters were used to characterize the substituent effects on the 1H NMR spectra of a series of N,N-dimethylanilines and N,N-diethylanilines. The results indicate that the variations of the chemical shifts of the methyl and methylene protons are largely determined by resonance effects.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110911
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  • 270
    Digitale Medien
    Digitale Medien
    A contradistinction in the magnetic (13C NMR spectroscopy) and chemical behaviour of 4-Oxo-4,5,6,7-tetrahydroindole derivatives (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 471-474 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Carbon-13 NMR data are reported for a series of 1,2-diaryl-4-oxo-4,5,6,7-tetrahydroindoles, 6-methyl-2-phenyl-4-oxo-4,5,6,7-tetrahydrobenzofuran and 1-,6-dithiaindan-4-one. The chemical shifts δ 193-196, δ 195.5 and δ 184 are identified for the carbonyl carbon (C-4) in the tetrahydroindoles, tetrahydrobenzofuran and dithiaindan derivatives, respectively. These shifts are located in the same region as that reported for the corresponding carbonyl carbon in aryl conjugated ketones. An excellent correlation between the chemical shift for the carbonyl carbon and the chemical reactivity of the ketonic function is noticed in the case of the latter two series of ketones while such a correlation is typically absent in the case of the 4-ketotetrahydroindole derivatives.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270110910
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  • 271
    Digitale Medien
    Digitale Medien
    Etude en RMN du 13C de Mérocyanines Benzimidazoliniques (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 493-498 
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    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: A series of α-oxobenzimidazolinic merocyanines differently substituted on the ‘phenolate’ part and bearing a paraffinic chain on one heterocyclic nitrogen, has been studied by 13C NMR. Electron donating substituents bring about an increase of the electronic density on the 3 methine carbon and an increase of the alternation of electron density on the 3,4-dimethine bridge. A bathochromic shift of the lower energy electronic transition is also observed. Furthermore, the low field resonance of the 3 methine proton is probably due to a specific interaction between this proton and the ‘phenolate’ oxygen atom. This implies the existence of a favoured trans configuration for merocyanine dyes.
    Notizen: Une série de mérocyanines α-oxo benzimidazoliniques diversement substituées sur la partie ‘phénolate’ et possédant une chaǐne grasse sur l'un des azotes hétérocycliques, a été étudiée en RMN du carbone- 13. Des substituants donneurs d'électrons provoquent une augmentation de la densité électronique sur le carbone méthinique C-3 et une augmentation de l'alternance de la distribution de charge sur le pont diméthinique 3,4. Corrélativement un déplacement bathochrome de la transition électronique de plus basse énergie est observé. Par ailleurs, l'apparition de la résonance à champ faible du proton méthinique H-3 semble due à une interaction spécifique intervenant entre ce proton et l'atome d'oxygène ‘phénolate’, ce qui suppose l'existence d'une configuration trans privilégiée pour les mérocyanines.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270111004
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  • 272
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    Digitale Medien
    Applications of NMR spectroscopy of chiral association complexes 5.For Part 4 of this series, see Ref. 8.Chiral Butadienes 7. For Part 6 of this series, see Ref. 5. Stereodynamics and diastereotopism in chiral 1,3-dienes \documentclass{article}\pagestyle{empty}\begin{document}${\rm HOCMe}_{\rm 2} \rlap{--} ({\rm CCl =\!= CCl\rlap{--})}_{\rm 2} {\rm X}$\end{document} (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 481-486 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The barriers to partial rotation around the central single bond in chiral dienes \documentclass{article}\pagestyle{empty}\begin{document}${\rm HOCMe}_{\rm 2} \rlap{--} ({\rm CCl =\!= CCl\rlap{--})}_{\rm 2} {\rm X}$\end{document} have been determined by coalescence of either 1H NMR signals (X = CH2OCH3) or 13C NMR signals (X = H). In the presence of the optically active shift reagent (+) - Eu(hfbc)3 all 1H signals were split at temperatures where the interconversion of enantiomers is slow. The temperature dependence of these spectra also yielded free activation enthalpies for the enantiomerizations which were in agreement with the ones obtained without Eu(hfbc)3. The assignment of the four methyl resonances appearing in the presence of (+) - Eu(hfbc)3 at low temperature was possible by gradually increasing the rate of enantiomerization or gradually replacing the optically active auxiliary compound by the racemic one.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270111002
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  • 273
    Digitale Medien
    Digitale Medien
    Identification et Etude en Résonance Magnétique Nucléaire du Carbone-13 des Produits de la Réaction de Quaternisation en Série Thiazolo[3,2-d]tétrazolique (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 507-509 
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    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: We have demonstrated that the compounds obtained by quaternization of thiazolo[3,2-d]tetrazole, and two of its derivatives, 3-phenyl-thiazolo[3,2-d]tetrazole and tetrazolo[5,1-b]benzothiazole, are tetrazolium salts. The quaternization effects are discussed as a function of the 13C NMR results.
    Notizen: Nous avons montré que les produits obtenus lors de la quaternisation du thiazolo[3,2-d]tétrazole, et de deux de ses dérivés, phényl-3 thiazolo[3,2-d]tétrazole et tétrazolo[5,1-b]benzothiazole, sont des sels de tétrazolium. Nous avons discuté des effets dus à la quaternisation en fonction des résultats de la RMN du 13C.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270111007
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  • 274
    Digitale Medien
    Digitale Medien
    Cage compounds IVFor Part III see, Ref. 1.. 1H and 13C NMR study of 3,6-epoxypentacyclo-[6.2.2.02,7.04,10.05,9]dodecane and 3,6-epoxypentacyclo-[6.2.1.02,7.04,10.05,9]undecane (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 520-523 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The complete 1H and 13C NMR assignments for 3,6-epoxypentacyclo[6.2.2.02,7.04,10.05,9]dodecane and 3,6-epoxypentacyclo[6.2.1.02,7.04,10.05,9]undecane are reported. The difference between the 1H and 13C chemical shifts and one-bond proton-carbon coupling constants of these two compounds are adequately explained by the difference in the hybridization of the C—H bonds.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270111010
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  • 275
    Digitale Medien
    Digitale Medien
    Masthead (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978) 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270111101
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  • 276
    Digitale Medien
    Digitale Medien
    Carbon-13 NMR spectra of some chlorinated polycyclodiene pesticides (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 541-546 
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    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Carbon-13 NMR spectra have been obtained for aldrin, dieldrin, isodrin, endrin, heptachlor, heptachlor oxide and 24 of their degradation/conversion products. Chemical shifts were assigned on the basis of (1) comparison among the spectra, (2) single frequency, off-resonance decoupling experiments, (3) substituent effects derived for norbornanes and (4) spectra obtained with an added lanthanide shift reagent. The substituent effects previously reported for norbornanes were found to be applicable for establishing trends in the chemical shifts for many of the compounds studied.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270111103
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  • 277
    Digitale Medien
    Digitale Medien
    Additivity of proton and carbon nmr chemical shifts in protonated benzene carboxylic acids (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 587-589 
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    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The additivity of the proton and carbon chemical shift increments due to structural changes in a series of conjugate acids derived from benzene polycarboxylic acids is reported. In the acids, two sets of increments had been applied, one to the ortho diacids and one to acids which do not bear ortho substituents. In the conjugate acids only one set of increments is required. The disappearance of the ‘ortho’ effect may be the outcome of properties inherent to these conjugate acids.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270111202
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  • 278
    Digitale Medien
    Digitale Medien
    Carbon-13 chemical shifts of some model carboxylic acids and esters (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 590-597 
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    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Selected model carboxylic acids and esters dissolved in deuteriochloroform have been studied by carbon-13 nuclear magnetic resonance under standardized conditions. Assignments of the chemical shifts have been made for all samples, and the spin-lattice relaxation times and nuclear Overhauser effects measured for a few selected esters. The results are intended to provide a practical aid for the analysis of carboxylic acids and esters of a more complex nature (e.g. polymers, natural products, etc.).
    Zusätzliches Material: 4 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270111203
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  • 279
    Digitale Medien
    Digitale Medien
    Fragmentation en Spectrométrie de Masse D'Imidazobenzodiazépines (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 141-154 
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    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The mass spectra of a series of imidazo[4,5,1-jk]1,4-benzodiazepines and imidazo[1,5,4-ef]1,5-benzodiazepines have been examined. The differences in the fragmentation patterns permit the isomeric structures to be identified.
    Notizen: L'étude des benzodiazépines a fait apparaǐtre des modes de fragmentations différents pour les imidazo[4,5,1-jk]benzodiazépines-1,4 et les imidazo[1,5,4-ef]benzodiazépines-1,5. Les ruptures caractéristiques dans ces deux séries ont été identifiées. Elles mettent en évidence l'influence de la nature du cycle diazépine sur les processus caractéristiques de fragmentation et rendent possible l'identification et la différenciation des structures isomères.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130306
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  • 280
    Digitale Medien
    Digitale Medien
    Studies in chemical ionization mass spectrometry of some flavonoids (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 167-171 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Formation of ions in chemical ionization mass spectrometry of flavonoid compounds has been studied. Production of adduct ions and fragment ions as a function of ring substituents and of reagent gas has been observed. Pressure and repeller field dependence of ions has been found as a function of ring substituents.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130310
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  • 281
    Digitale Medien
    Digitale Medien
    Field ionization mass spectrometry of higher n-alkenes (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 181-183 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: In a strong electric field the molecular ions of n-alkenes ≤C-12 decompose via cleavage of the C—C bond β to the double bond to form the characteristic alkenyl ions that may be used for the identification of positional isomers. For 3-alkenes (〉C-10), 4-, 5- and 6-alkenes the formation of the ions with m/e 54 via double β-cleavage is typical. The field ionization mass spectra of the cis and trans isomers are indistinguishable.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130402
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  • 282
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    Digitale Medien
    Stereochemisch kontrollierte Cope-analoge Zerfallsprozesse von Sulfinylverbindungen im MassenspektrometerHerrn Professor Dr. phil. Alexander Schönberg zum 85. Geburtstag gewidmet.XV. Mitteilung ‘Spektroskopische Untersuchungen’; XIV. Mitteilung: C. Bak, K. Praefcke, K. A. Muszkat und M. Weinstein, Z. Naturforsch. Teil B 32, 674 (1977). Gleichzeitig XXVI. Mitteilung ‘Organische Schwefelverbindungen’; XXV. Mitteilung, s. Lit. 1. (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 179-180 
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    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The extent of elimination of HX (X = SOCH3, SCH3) from the [M—STol]+ as well as [MH—HSTol]+ cations (Tol = CH3C6H4) from 2-sulfinyl substituted cyclopentane thiocarbonic acid S-aryl esters under electron impact and chemical ionization is strongly influenced by the stereochemical relationship of the vicinal substituents.
    Notizen: Das Ausmaß der Eliminierung von HX (X = SOCH3, SCH3) aus [M—STol]+-bzw. [MH—HSTol]+-Ionen (Tol = CH3C6H4), die sowohl durch Elektronenstoßionisation als auch durch chemische Ionisation aus 2-sulfinylsubstituierten Cyclopentanthiocarbonsäure-S-arylestern erzeugt werden, wird in entscheidender Weise durch die Stereochemie der vicinalen Substituenten bestimmt.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130313
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  • 283
    Digitale Medien
    Digitale Medien
    Dissociations Induites par Collisions d'Ions Générés par Echange de Charges (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 207-208 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Collision induced dissociations of some molecular ions generated by electron impact or charge exchange from methane plasma are compared.
    Notizen: Les dissociations induites par collisions d'ions moléculaires créés par impact d'électrons et par échange de charges dans une source d'ionisation chimique (méthane) sont comparés.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130408
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  • 284
    Digitale Medien
    Digitale Medien
    Das [C8H8]+-Problem: Der Verlust von Äthylen aus dem Molekülion von TetralinSiehe Lit. 1. (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 25-29 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Ethylene elimination from the molecular ion of tetralin is shown to be a complex process involving in addition to complete C- and H-scrambling (about 10%) at least two further competing processes.
    Notizen: Es wird gezeigt, daß die Abspaltung von Äthylen aus Tetralin ein komplexer Prozeß íst, bei dem neben, vollständigem C- und H-Scrambling (etwa 10%) wenigstens zwei konkurrierende Prozesse ablaufen.
    Zusätzliches Material: 8 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130107
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  • 285
    Digitale Medien
    Digitale Medien
    The electron impact induced fragmentation of 1,3-diphenyl-2-pyrazoline (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 30-34 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The electron impact induced fragmentation of 1,3-diphenyl-2-pyrazoline was studied by nitrogen-15, carbon-13 and deuterium labelling, substitution in the para position of one of the phenyl rings by fluoro and methoxy groups, and ion kinetic energy spectroscopy, as well as accurate mass measurements. In the fragmentation pathway observed all the ions in the mass spectrum of 1,3-diphenyl-2-pyrazoline (except m/e 103) originate from the molecular ion, which in all compounds is the base peak. The formation of prominent fragment ions is discussed.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130108
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  • 286
    Digitale Medien
    Digitale Medien
    Studies in negative ion mass spectrometry. VIIIPart VII: Org. Mass Spectrom. 12, 370 (1977). - Electron capture by some monomeric and dimeric η5 - cylcopentadienyl transition metal carbonyls (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 20-24 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The negative ion mass spectra of a series of monomeric and dimeric η5-cyclopentadienyl transition metal carbonyls have been examined. The base peak in the case of the monomeric compounds (η5-C5H5)V(CO)4, (η5-C5H5)Mn(CO)3 and (η5-CH3C5H4)Mn(CO)3 arises from a reductive decarbonylation of the parent molecule - the resulting radical anion [M-CO]- is formally isoelectronic with the molecular cations [M]- observed in the positive ion mass spectra of these compounds and subsequently undergoes successive decarbonylations to the ‘aromatic’ cyclopentadienyl anions. For the compound (η5-C5H5)Co(CO)2, however, a molecular anion was observed as the base peak which has been formulated as [(η3-C5H5)Co(CO)2]- in the light of considerations based on the rare gas rule. As expected, the dimeric molecules [(η5-C5H5)M(CO)3]2 (where M = Cr or Mo) and [(η5-C5H5)Fe(CO)2]2 (and its methyl analogue) undergo reductive cleavage of their metal-metal bonds to give the anions [(η5-C5H5)M(CO)3]- and [(η5-C5H5)Fe(CO)2]- as the base peaks in their negative ion mass spectra. The dimeric nickel compound [(η5-C5H5)Ni(CO)]2, however, reductively decarbonylates to the [M-CO]- radical anion as its predominant fragmentation in the gas phase. Very low abundances of [(η5-C5H5)Fe(CO)2]2- and [(η5-CH3C5H4)Fe(CO)2]2- were also observed.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130106
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  • 287
    Digitale Medien
    Digitale Medien
    Fragmentation in chemical ionization mass spectrometry and the proton affinity of the departing neutral (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 35-38 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Chemical ionization mass spectra of six 5,6-dihydro-2-methyl-1,4-oxathiins, and some of the sulfoxides and sulfones derived therefrom, have been determined employing hydrogen, methane and isobutane as reagent gases. The major fragmentation reaction of the protonated molecule, [R′COX·H]+, involves loss of the neutral HX molecule. For the sulfides and sulfones, with X ranging from OH to N(CH3)C6H5, it is observed that the importance of this fragmentation is inversely correlated with the proton affinity of the departing HX molecule in both the H2 and CH4 chemical ionization. For the sulfoxides no consistent correlation is observed and this is attributed to the interference of competing and/or consecutive fragmentation reactions. In the isobutane chemical ionization mass spectra only the protonated molecule is observed for most of the compounds studied.
    Zusätzliches Material: 6 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130109
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  • 288
    Digitale Medien
    Digitale Medien
    Transfert d'Hétéroatomes (Cl, Br, OH) lors de la Fragmentation d'Acétyléniques δ-Fonctionnalisés (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 54-56 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The mass spectra of three δ-functionalized alkynes provide evidence for the migration of chlorine, bromine and hydroxyl towards the unsaturated portion of the molecules. The strong resemblance between these spectra and those of the isomeric allenes suggests that an acetylene→allene isomerization occurs after electron impact.
    Notizen: Les spectres de masse de trois alcynes δ-fonctionnalisés montrent qu'il y a migration de chlore, de brome et. d'hydroxyle vers l'insaturation. La similitude existant entre ces spectres et ceux des composés alléniques isomères suggère qu'il y a transformation acétylène→allène après l'impact électronique.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130113
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  • 289
    Digitale Medien
    Digitale Medien
    Mass spectrometry of steroid systems. XXIVFor part XXIII see: Z. V. I. Zaretskii, in Advances in Mass Spectrometry, Vol. 7, ed. by N. R. Daly, Heyden, London (1978).-The origin of [M - 28]+ and [M - 43]+ ions in equilenin and its 14β-isomer (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 59-60 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The formation of the [M—43]+ ion in equilenin is due mainly to elimination of Me radical from the [M—CO]+ ion and, to a lesser extent, to CO loss from the [M—Me]+ ion. In 14β-isoequilenin the [M—CO]+ ion is absent, and the formation of [M—43]+ occurs via the [M—Me]+ ion. This makes the determination of the mode of junction of the rings C and D in the equilenin series possible, using high resolution mass spectra, even when only one stereoisomer is available.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130115
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  • 290
    Digitale Medien
    Digitale Medien
    Excitation in ion-molecule collisions. A study of protonated aromatic molecules by ion kinetic energy spectrometry (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 106-110 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Collision induced dissociation of protonated aromatic ions formed in a chemical ionization source has been studied using the technique of mass analyzed ion kinetic energy spectrometry. The observed fragmentations are concordant with those seen in the photodissociation spectra of the same ions with one significant exception. Loss of H is always a major collision induced dissociation process but is not observed in photodissociation spectra. This differences is not due to differences in the total amount of energy transferred in ionic excitation but to differences in the form in which the energy is supplied. Collision induced dissociation can lead to processes forbidden in photoexcitation, particularly those associated with electron unpairing in violation of the even→even+even rule for fragmentations.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130208
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  • 291
    Digitale Medien
    Digitale Medien
    Masthead (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978) 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130301
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  • 292
    Digitale Medien
    Digitale Medien
    Etude par Spectrométrie de Masse de la Fragmentation d'une Série de Diols Aliphatiques (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 135-140 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The mass spectrometric fragmentation of a series of diols having the general formula HO—(CH2)n—OH with n = 2-11 has been studied. Extensive labelling of n-butane-1,4 diol and n-hexane-1,6 diol with deuterium allows fragmentation modes to be proposed. The labelling reveals that intramolecular exchange of H atoms often precedes the fragmentation and becomes more important when the length of the chain increases.
    Notizen: La fragmentation d'une série de diols aliphatiques de formule générale HO—(CH2)n—OH avec n = 2-11 a été étudiée à l'aide de molécules marquées avec du deutérium. Les marquages du n-butanediol-1,4 et du n-hexanediol-1,6 ont notamment permis de mettre en évidence des réactions d'échange intramoléculaire d'hydrogène; ces échanges deviennent plus importants avec l'allongement de la chaîne.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130305
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  • 293
    Digitale Medien
    Digitale Medien
    Chemical ionization mass spectra of some 2-norbornyl derivatives (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 163-166 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Chemical ionization mass spectra of exo- and endo-2-norbornanols and their phenylurethane derivatives have been obtained with several reactant ions. Small differences are noted in the abundances of norbornyl and [M+H]+ ions for the phenylurethane derivatives: more norbornyl ions with the exo compounds. Relative rate constants for decomposition of [M+H]+ ions, kexo/kendo ≅ 1-2. No evidence was found for s̰-participation in the decomposition of these ions. The i-C4H10 chemical ionization spectrum of endo-2-norbornanol contains a much greater abundance of [M-H]+ ions than the i-C4H10 chemical ionization spectrum of exo-2-norbornanol. This difference presumably results from steric hindrance toward attack of the endo hydrogen.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130309
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  • 294
    Digitale Medien
    Digitale Medien
    Nachbargruppenbeteiligung bei der elektronen-stoßinduzierten Fragmentierung von elektronenarmen 2,2′-Biphenolbenzoaten (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 177-178 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Electron deficient 2,2′-biphenyl benzoates decompose under electron impact conditions by loss of benzoic anhydride. Both stepwise and pericyclic mechanisms are observed as confirmed by the ‘direct analysis of daughter ions’ (DADI) technique.
    Notizen: Beim elektronenstoßinduzierten Zerfall von elektronenarmen 2,2′-Biphenolbenzoaten wird die Abspaltung von Benzoesäureanhydrid beobachtet. Die Messung nach der DADI-Methode macht für diese Abspaltung sowohl einen Synchronprozeß als auch einen schrittweisen Zerfall wahrschinlich.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130312
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  • 295
    Digitale Medien
    Digitale Medien
    Ionisation et Fragmentation en Spectrométrie de Masse. VII - Structure de l'Ion [C6H6O]+ Issu de la Décomposition du Phényléthyléther Sous Impact Electronique (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 184-187 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The activation energy is calculated for the fragmentation [C6H5OC2H5]+ → [C6H6O]+ +C2H4. Estimation of the enthalpy difference between the final state and the molecular ion supports the formation of a phenol-like structure for the [C6H6O]+ ion. The activation energy for backward reaction is compared with the mean kinetic energy release. Whether this is a concerted or non-concerted fragmentation is discussed.
    Notizen: L'energie d'activation de la fragmentation [C6H5OC2H5]+ → [C6H6O]+ +C2H4 est calculée. Après évaluation de la variation d'enthalpie correspondante, une structure de type phénol est déterminée pour l'ion [C6H6O]+. L'énergie d'activation de la réaction inverse est comparée à l'énergie moyenne de translation des fragments [C6H6O]+ et C2H4. L'aspect concerté ou non concerté du mécanisme de cette fragmentation est discuté.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130403
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  • 296
    Digitale Medien
    Digitale Medien
    Electron impact studies on α,β-unsaturated carbonyl oximes (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 218-223 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Electron impact studies on eight α,β-unsaturated carbonyl oximes revealed many interesting hydrogen and skeletal rearrangements which were substantiated by deuterium labelling, exact mass measurements and metastable studies. Loss of H· and OH· as well as formation of the indenyl and fluorenyl cations and the [C9H6N]+ fragment proceed through cyclic intermediates. All the ionized oximes undergo a Beckmann rearrangement in the gaseous phase leading to intense aroyl cation peaks. Formation of the styrene radical ions and cleavage of the bond α to the oxime function have also been noticed.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130411
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  • 297
    Digitale Medien
    Digitale Medien
    Mass spectra of some oxadiazole derivatives (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 236-242 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The mass spectra of some substituted oxadiazoles have been determined and analysed with the aid of high resolution mass spectrometry. Some characteristic and major differences between their spectra have been noted, and possible rationalizations have been advanced. The main fragmentation patterns of the 1,3,4-oxadiazole derivatives have been interpreted in terms of diazirine intermediates. Specific skeletal rearrangement processes have been observed in the spectra of the 1,3,4- and 1,2,4-oxadiazoles, and possible mechanisms are proposed.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130414
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  • 298
    Digitale Medien
    Digitale Medien
    Three-dimensional representation of metastable peaks at high mass resolution (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 243-247 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Isobaric daughter ions formed from a common metastable ion have been analysed at high mass resolution. A three-dimensional representation is used to summarize the data for competitive CO and C2H4 losses and competitive CHO· and C2H5· losses from metastable molecular ions of cyclohexanone.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130502
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  • 299
    Digitale Medien
    Digitale Medien
    Studies directed toward synthesis of quassinoids. VIFor Part V, see Ref. 1. - mass spectral fragmentation of D-ring seco esters and δ-lactone derivatives of cholic acid (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 307-314 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Analogy and deuterium labeling demonstrate that considerable remote group interaction occurs between functional groups at positions 7 and 16 in 16, 17-secosteroids. It is proposed that ion-dipole interact̂ions separations of distances of 10 to 2 Å will involve energies of 1-30 kcal mol-1 and can play a significant role in fragmentation processes. Successive loss of one, two and three HOAc molecules from a milecular or daughter ion increase progressively in relative intensity; irregularity in this pattern indicates the operation of special factors or multiple genesis of daughter ions having the same m/e. Evidence is presented which suggests that facile ketene ejection from the acetate functional group only occurs from a radical ion and must be preceded by transfer of a hydrogen radical from the acetate group to the site of charge localization.
    Zusätzliches Material: 4 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130603
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  • 300
    Digitale Medien
    Digitale Medien
    Nitrile elimination and hydrogen rearrangement upon electron impact in schiff base peptide esters (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 540-543 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A series of Schiff base peptide esters were examined by gas chromatography mass spectrometry. Electron impact induced elimination of aryl nitriles (ArCN) from Schiff bases , where R, R′ …are amino acid sidechains formed from aromatic aldehydes and peptide esters was shown to be associated with formation of C-terminal peptide fragments. Schiff base derivatives prepared from benzaldehyde and α-deuterobenzaldehyde with several peptide esters indicated that aryl nitrile elimination was accompanied by H(D) transfer to the α-C of the N-terminal amino acid residue. Of the many Schiff base peptide esters of different aldehydes studied, HCN elimination of the type observed in some nonpeptide Schiff bases could only be found among N-methyl pyrrolemethylidene derivatives.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210130911
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