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  • Chemistry  (24)
  • Theoretical, Physical and Computational Chemistry  (2)
  • Benzene derivatives  (1)
  • 1
    Electronic Resource
    Electronic Resource
    The benzene ring as a dipolarophile: Reactions of monosubstituted benzenes with tetracyanoethylene oxide (1992)
    Springer
    Monatshefte für Chemie 123 (1992), S. 99-104 
    Details
    ISSN: 1434-4475
    Keywords: Benzene derivatives ; Tetracyanoethylene oxide ; 1,3-Dipolar cycloaddition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es wurden die Reaktionen von Tetracyanoethylenoxid mit Toluol, Chlorbenzol, Fluorbenzol, Anisol und Nitrobenzol untersucht. Toluol und die Halogenbenzole ergaben Mischungen von Monoaddukten, Anisol ergabp-Methoxyphenylmalononitril und sein Dimer, Nitrobenzol zeigte keine Reaktion. Diese Resultate werden mit Hilfe eines qualitativen Orbitalmodells diskutiert. Die Analyse einiger Monoaddukte erfolgte mittels1H-NMR-Analyse.
    Notes: Summary The reaction of tetracyanoethylene oxide on one hand and toluene, chlorobenzene, fluorobenzene, anisole, and nitrobenzene, on the other, has been studied. Toluene and the halogenobenzenes yield mixtures of monoadducts, anisole yieldp-methoxyphenylmalononitrile and its dimer and nitrobenzene does not react. These results are discussed with the help of a qualitative orbital model.1H-NMR analysis of some monoadducts has been carried out.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01045302
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  • 2
    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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  • 3
    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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  • 4
    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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  • 5
    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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  • 6
    Electronic Resource
    Electronic Resource
    Etudes d'Hétérocycles Pentagonaux Polyhétéroatomiques par RMN du 13C. Effets de Substituant, de la Benzocondensation et Etude de la Tautomèrie Prototropique en Série Benzothiazolique (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 617-627 
    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 13C NMR spectra of 43 benzothiazoles have been recorded in DMSO-d6. All carbon atoms have been attributed in an unambigous way owing to substituent effects in position 4, 5, 6 or 7. We discuss variations of chemical shifts as a function of the nature of the substituent in position 2 (equation of type: Δδ = aF+bR+cQ+d′), annelation in the benzoheterocyclic series, and prototropic tautomerism in the benzothiazolic series (in the case of the substituent in the 2-position being an OH, SH or NHR group).
    Notes: Les spectres de résonance magnétique nucléaire due carbone-13 de 43 benzothiazoles ont été enregistrés dans le diméthylsulfoxyde hexadeutérié. Tous les carbones ont été attribués de facon non ambiguë, grǎce aux effets de substituant sur les positions 4, 5, 6 ou 7. Nous discutons des variations des déplacements chimiques en fonction de la nature du substituant en 2 (équation triparamétrique du type: Δδ = aF+bR+cQ+d′), de l'annélation en série benzohétérocyclique et de la tautomérie prototropique en série benzothiazolique (dans le cas où le substituant en position 2 représente un groupement OH, SH ou NHR).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270111208
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  • 7
    Electronic Resource
    Electronic Resource
    Fragmentation D'azoles Sous L'impact Electronique. VVoir Réf. 1. - Isomerisation Du Benzimidazole Avant Degradation (1974)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 9 (1974), S. 1188-1193 
    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 mass spectrum of benzimidazole is investigated using deuterium and carbon-13 labelling. The [M - HCN]+· ion is the result of two competitive reaction. Isomerisation into a cyanoaniline structure which eliminates HCN from the amino group and also from the nitrile group (by an ortho effect) is confirmed by ions abundance ratios. Hydrogen scrambling does not occur to a significant extent in the ions under consideration.
    Notes: Le spectre de masse du benzimidazole est étudié à l'aide de marquages isotopiques (D et 13C). Après lyionisation il se produit une isomérisation en o-cyanoaniline, à partir de laquelle deux réactions compétitives conduisent à l'ion [M-HCN]+·. La perte de HCN au niveau de la fonction amino et, par effect ortho, au niveau de la fonction nitrile est confirmée par des mesures d'abondances ioniques. On n'observe pas de réarrangements statistiques d'hydrogènes avant l'élimination de HCN.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210091206
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  • 8
    Electronic Resource
    Electronic Resource
    Fragmentation d'azoles sous l'impact electronique VI-indazole (1975)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 10 (1975), S. 558-560 
    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: Molecular ion isomerisation precedes the fragmentation of indazole upon electron-impact.
    Notes: Une ismérisation des ions molécularies précéde la fragmentation de l'indazole sous l'impact.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210100711
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  • 9
    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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  • 10
    Electronic Resource
    Electronic Resource
    Basicity of azoles. 5 - Experimental gas phase basicities determined by mass spectrometry towards ab initio calculated protonation energies (1984)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 19 (1984), S. 627-630 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Using Cooks' method, the relative gas phase proton affinities of six azoles (imidazole, benzimidazole, pyrazole, indazole, 1-methylindazole and 2-methylindazole) have been determined. Ab initio calculations have been carried out for these six molecules and the corresponding cations, thus allowing the determination of protonation energies. Even the correlation between these quantities (-log K = 0.438+0.0744δΔEp) is far from perfect (r2 = 0.863), the order of basicity is the same. Aqueous basicities, pKa values, are totally uncorrelated.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210191208
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