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  • 1
    Electronic Resource
    Electronic Resource
    Dielektrische Messungen an Cyclanonen. I. Dielektrische Eigenschaften der Cyclanone mit 5, 6, 7 und 10 Ringgliedern im festen und flüssigen Zustand bei tiefen Frequenzen (1956)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 39 (1956), S. 132-144 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dielectric behaviour of liquid and solid phases of cyclopentanone, cyclohexanone, cycloheptanone and cyclodecanone has been investigated at frequencies below 300 kcps. It has been found that cyclopentanone and cyclodecanone show a very sharp decrease of the dielectric constant at the melting point. Both, cyclohexanone and cycloheptanone show two solid phases of different dielectric behaviour, the ones existing just below the melting point have high dielectric constant and probably free dipole orientation.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19560390116
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Détermination de la forme la plus stable de l'ortho-dichlorofluorure de benzyle par RMN en phase nématique (1975)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 7 (1975), S. 633-634 
    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 value of direct couplings in o-dichlorobenzylfluoride, obtained from nematic phase NMR, lead to the conclusion that the most stable form is such that the fluorine atom is in a plane perpendicular to the benzene ring. However, the complete intepretation of these couplings in terms of geometrical parameters tends to indicate a modification of orientation with internal rotation of CH2F.
    Notes: La valeur des couplages directs dans l'ortho-dichlorofluorure de benzyle, obtenus par RMN en phase nématique, permet d'affirmer que la position la plus stable du CH2F est telle que le fluor se trouve dans un plan perpendiculaire au cycle benzénique. L'interprétation complète de ces couplages en fonction de la géométrie de la molécule laisse cependant supposer une modification de l'orientation intervenant en même temps que la rotation du groupement CH2F.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270071216
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  • 3
    Electronic Resource
    Electronic Resource
    Fluoro-α-amino acids. 1 - use of 19F NMR spectroscopy for the configurational determination of β-fluoro-α-amino acids through complexation by 18-crown-6 ether (1982)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 20 (1982), S. 78-82 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Erythro and threo configurational assignments have been made for 11 β-fluoro-α-amino acids or esters using the effect of complexation of the ammonium group by 18-crown-6 ether on the 19F NMR parameters. For the erythro configurations, 3J(HF) increases and a high-field 19F chemical shift is generally observed; these phenomena are accompanied by a decrease in 3J(HH) and 3J(CF). The opposite effects are observed for the threo configurations. These observations can be explained by a change in the relative population of the conformers around the Cα-Cβ bond on complexation of the ammonium group. This complexation impairs the interactions between the ammonium and fluorine groups and, concomitantly, the steric hindrance between the ammonium and R (methyl, phenyl or carboxylate) groups is increased.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270200204
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  • 4
    Electronic Resource
    Electronic Resource
    Fluoroimines from the reaction of fluoro amino acids or fluoroketo acids with the aldehyde or amine form of vitamin B6: 2Part 1: C. Beguin and S. Hamman, Org. Magn. Reson. 16, 129 (1981). - Stereochemical aspects of their formation from β-fluoroaspartates or β-fluorooxaloacetate, using 19F NMR (1983)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 21 (1983), S. 265-270 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The fluorine NMR spectra of systems initially containing 0.05-0.1 M of pyridoxal 5′-phosphate and erythro-β-fluoroaspartate (or threo-β-fluoroaspartate) in D2O solution were examined over the pD range 1-12. The formation of the aldimine Schiff base gave only one stereoisomer, whcih was trapped with sodium borohydride. Reactions of pyriodoxamine 5′-phosphate and fluorooxaloacetate were examined under the same conditions. A mixture of two products was given, identified as two ketimine Schiff bases (E and Z isomers) with well characterized fluorine chemical shifts and 2J(DF) values. This mixture, trapped with sodium borohydride, gives the two reduced erythro and threo aldimines. The configurations and conformations of all reaction products were determined using the 3J(HF) values and their correlation with the fluorine chemical shift. The role of the 3-phenolate oxygen of the pyridine ring, of the conjugate acid of the iminium nitrogen and of the carboxylate oxygen in ionic or hydrogen bond interactions in the determination of the stereochemistry is discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/omr.1270210409
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  • 5
    Electronic Resource
    Electronic Resource
    Configurational assignment of β-phenylaspartic acids in solution by 1H and 13C nuclear magnetic resonance (1988)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 26 (1988), S. 683-686 
    Details
    ISSN: 0749-1581
    Keywords: β-Phenylaspartic acids ; Configurational assignment ; 1H and 13C NMR ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Vicinal 3J(HH) and 3J(13CH) coupling constants are reported for the two diastereoisomers of β-phenylaspartic acid at various pH values. A comparison between these coupling constants and those expected from the possible conformations of these molecules allows configurational assignments to be made. In strong acidic medium we observed intermediate values for 3J(HH) for both isomers, for one isomer two intermediate values for 3J(Co-α, H-β) and 3J(Co-β, H-α), and for the other isomer a very small value for 3J(CO-α, H-β) and an intermediate value for 3J(Co-β, H-α). The discussion shows that the former has the RR/SS configuration and the latter the RS/SR configuration.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260260809
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