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  • 1
    Electronic Resource
    Electronic Resource
    Structure of 3-nitropyrazole in solution and in the solid state (1997)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 10 (1997), S. 637-645 
    Details
    ISSN: 0894-3230
    Keywords: 3-nitropyrazole ; structure ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: ---The molecular and crystal structure of 3-nitropyrazole was determined by X-ray analysis. The triclinic unit cell contains 12 molecules which form four hydrogen-bonded (N - H···N) trimers. Each trimer comprises of pseudo-ring in a flattened envelope distorted towards a chair conformation. The crystal packing consists of layers formed by centrosymmetric related trimers joined through C - H···O interactions. Ab initio calculations were performed on 3(5)-nitro- and 4-nitropyrazole and their corresponding protonated forms up to the MP2/6-31G** level of theory. The origin of the difference in aqueous basicities between both nitropyrazoles is discussed. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Host-guest chemistry. The structure and proton disorder of the three-component crystal formed by 3(5)-methyl-4-nitropyrazole, (R, R)-(-)-trans-4,5-bis (hydroxydiphenylmethyl)-2,2-dimethyl-1,3-dioxolane and toluene (1996)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 9 (1996), S. 611-618 
    Details
    ISSN: 0894-3230
    Keywords: Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The crystal structure at 200 K of the complex formed by the optically active host (R,R)-(-)-trans-4,5-bis(hydroxydiphenylmethyl)-2,2-dimethyl-1,3-dioxolane (2) and 4-nitro-5-methylpyrazole (1b) and toluene as guests was determined by x-ray analysis. Although only the NH protons corresponding to tautomer 1b were found in the structure, some anomalies in the bond angles involving the nitrogen atoms of the pyrazole ring suggested the presence of about 25% of a structure containing the 3-methyl-4-nitropyrazole tautomer (1a). This hypothesis was confirmed by 13C cross polarization magic angle spinning NMR spectroscopy.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 3
    Electronic Resource
    Electronic Resource
    Reduction of aromatic fluorine compounds in fast-atom bombardment mass spectrometry (1995)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 9 (1995), S. 156-159 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The second example of F/H reduction of a fluorine aromatic derivative in a fast-atom bombardment mass spectrometric experiment is described. It concerns a tetrafluorophenyl derivative bearing two 3,5-dimethylpyrazol-1-yl substituents.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290090210
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesis, Spectroscopy and Tautomeric Study of Thiazoles substituted in positions 2 and 4 by hydroxy, mercapto and amino groups (1985)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 327 (1985), S. 251-260 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thiazoles substituted in positions 2 and 4 by hydroxy, mercapto and amino groups were synthesized, as well as its carbamate derivates and formylhydrazones. The research of the reaction of the formylhydrazide with 4-imino-2-thiazolidinone has not given the pyrazolo [3,4-d]- thiazol-2-one, but the 4-formylhydrazono-2-thiazolidine. The detailed tautomeric study of each of the heterocyclic compounds has been carried out by infrared spectroscopy, nuclear magnetic resonance of proton and of 13-carbon, and of masses.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19853270210
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  • 5
    Electronic Resource
    Electronic Resource
    Fragmentation de Triazoles sous l'Impact Electronique-IIIVoir la Réf. 1. Benzotriazole et Derives Alkyles (1973)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 7 (1973), S. 1267-1277 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The behaviour of benzotriazole and some alkyl derivatives upon electron-impact has been studied. Evidence for the exclusive presence of the 1H-benzotriazole tautomer in the gaseous phase is presented. The 2H-benzotriazole ‘molecular ion’ is generated from 2-ethylbenzotriazole by ethylene elimination; isomerisation into the 1H tautomer precedes the fragmentation (nitrogen loss). A ring expansion reaction is proposed for the [M - CH3]+ ions of 1-ethyl- and 2-ethylbenzotriazoles.
    Notes: Les spectres de masse du benzotriazole et de quelques dérivés alkylés sont discutéS. Seul le tautomère 1H-benzotriazole est mis en évidence en phase gazeuse. L'‘ion moléculaire’ du 2H-benzotriazole est formé par érlimination d'éthylèene au départ du 2-éthylbenzotriazole; une isomérisation en tautomère 1H précède la fragmentation (perte d'azote). On observe une réaction d'extension cyclique au niveau des ions [M-CH3]+ des 1-éthyl-et 2-éthylbenzotriazoles.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210071107
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  • 6
    Electronic Resource
    Electronic Resource
    Profil de Pics Métastables (Pertes de NO·) en Série Nitroindazolique (1979)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1979), S. 114-116 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The kinetic energy releases associated with the loss of NO⋅ from nitroindazole molecular ions have been measured. The results show that, although the mass spectra are nearly identical, the corresponding metastable peak shapes can be used to differentiate the five isomers.
    Notes: Les libérations d'énergie cinétique associées aux fragmentations (pertes de NO·) des ions moléculaires de nitroindazoles ont été mesurées. Les résultats montrent que le profil des pics métastables correspondants permettent de différencier les cinq isomères.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210140211
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  • 7
    Electronic Resource
    Electronic Resource
    Détermination du Site de Protonation de l'Azido-2 thiazole et du Thiazolo[2,3-e]tétrazole à Partir de la Largeur des Raies des Signaux Protoniques (1977)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 10 (1977), S. 249-250 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The signals of protons bonded to carbon atoms in α position to the pyridinic nitrogen atom in thiazole and in γ position in thiazolo[2,3-e]tetrazole are broadened. This broadening disappears on irradiation at the 14N resonance frequency, on cooling, and in an acidic medium (in which the protonation sites in both molecules can be determined).
    Notes: Les signaux des protons fixés sur un atome de carbone en α d'un azote pyridinique en série thiazole et en γ en série thiazolo[2,3-e]tétrazolique sont élargis à cause de la présence d'atomes d'azote 14N; cet élargissement disparait par irradiation, par refroidissement et en milieu acide (dans ce cas, cela permet la détermination du site de protonation des deux molécules).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270100157
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  • 8
    Electronic Resource
    Electronic Resource
    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 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 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.
    Notes: 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.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270111007
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  • 9
    Electronic Resource
    Electronic Resource
    Fragmentation d'azoles sous l'impact electronique VII -N-ethylbenzimidazoles (1975)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 10 (1975), S. 313-316 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbon-13 and deuterium labelling experiments show that the [M — CH3]+ ion observed in the mass spectrum of l-ethylbenzimidazole rearranges quantitatively to a quinoxalinium structure prior to HCN loss.
    Notes: Par marquages isotopiques (13C et D), on montre que l'ion [M — CH3]+ observé dans le spectre de masse du l-éthylbenzimidazole se réarrange quantitativement en une structure quinoxalinium avant l'élimination d'acide cyanhydrique.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210100409
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  • 10
    Electronic Resource
    Electronic Resource
    Ionisation Chimique de Composés Aromatiques Nitrés (1979)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1979), S. 117-118 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The collision induced dissociations of [MH - 30]+ ions observed in the chemical ionization (methane) mass spectra of some nitro aromatic compounds show that these ions are formed by reduction in the ion source with subsequent protonation and not by the previously reported losses of NO· from the protonated molecular ions.
    Notes: Les dissociation induites par collisions d'ions [MH-30]+ observés lors de l'ionization chimique (méthane) de composés aromatiques nitrés indiquent que ces ions sont formés par réduction suivie de protonation et non par perte de NO⋅ des ions moléculaires protonés.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210140212
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