Tritium labelling and tritium N.M.R. II. Labelled methyl (Z)-Octadec-9-enoate obtained by partial hydrogenation on Lindlar catalyst, and its reduction to(Z)-Octadec-9-en-1-ol

The selectivity of tritium labelling of double bonds by partial hydrogenation of the acetylenic analogue on Lindlar catalyst is investigated by 3H and 13C n.m.r. Examples of both the secondary isotope effect on chemical shift and the usefulness of 3H n.m.r, measurements to calculate proton-proton coupling constants are described. In the absence of proton coupling a finite difference (0.014 ppm) in the chemical shift of tritons at positions 9 and 10 of methyl (Z)-[9,10-3H]octadec-9-enoate is observed.

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Separation of nuclear magnetic resonance signals of internally enantiotropic protons using a chiral shift reagent. Deuterium isotope effect on geminal proton-proton coupling constants

Journal of the American Chemical Society ◽

10.1021/ja00764a070 ◽

1972 ◽

Vol 94 (9) ◽

pp. 3253-3254 ◽

Cited By ~ 51

Author(s):

Robert R. Fraser ◽

Michel A. Petit ◽

Maurice Miskow

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Isotope Effect ◽

Shift Reagent ◽

Coupling Constants ◽

Deuterium Isotope Effect ◽

Proton Proton ◽

Proton Coupling ◽

Chiral Shift Reagent ◽

Geminal Proton

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The relationship between carbon-13 substituent chemical shifts and proton coupling constants in aza-aromatic systems

Australian Journal of Chemistry ◽

10.1071/ch9840311 ◽

1984 ◽

Vol 37 (2) ◽

pp. 311 ◽

Cited By ~ 2

Author(s):

IB Cook ◽

S Pengprecha ◽

B Ternai

Keyword(s):

Experimental Data ◽

Chemical Shift ◽

Chemical Shifts ◽

Coupling Constants ◽

Coupling Constant ◽

Proton Proton ◽

Proton Coupling ◽

Substituted Pyridines ◽

Aromatic Systems ◽

The Relationship

An equation which relates the ortho carbon-13 substituent chemical shift α-SCS in aza-aromatics to the ortho proton-proton coupling constant 3J(HH) in the corresponding carbocyclic compound is derived from experimental data. The implications for N-N bond fixation in diaza-aromatics are discussed. When the equation is applied to 2-substituted pyridines, an electronegativity parameter must be included to explain the results.

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Pertrimethylsilylation as a method for improvement of chemical shift additivity through conformational homogenization. 1H and 13C NMR spectra of pertrimethylsilylated derivatives of methyl β-D-xylopyranosides

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19831829 ◽

1983 ◽

Vol 48 (7) ◽

pp. 1829-1841 ◽

Cited By ~ 6

Author(s):

Jan Schraml ◽

Eva Petráková ◽

Otomar Pihar ◽

Ján Hirsch ◽

Václav Chvalovský

Keyword(s):

Chemical Shift ◽

Nmr Spectra ◽

Chemical Shifts ◽

Population Analysis ◽

Coupling Constants ◽

Proton Proton ◽

1H And 13C Nmr ◽

Proton Coupling ◽

Derivatives Of ◽

C Nmr

All possible mono-, di-, and tri- O-methyl, O-benzyl, O-benzoyl, and O-acetyl derivatives of methyl β-D-xylopyranoside were fully trimethylsilylated and their 1H and 13C NMR spectra measured in deuteriochloroform solutions. The spectra were analysed and the chemical shifts completely assigned on the basis of decoupling experiments. The proton-proton coupling constants vary only very little throughout the series. Conformer population analysis by the method of average coupling constants shows that trimethylsilylation increases the C1 conformer population and makes the series conformationally homogenous. Owing to this conformational homogeneity chemical shifts (both 1H and 13C) satisfy very well direct additivity rule. It is suggested that pertrimethylsilylation should be employed whenever deviations from chemical shift additivity are caused by conformational mobility of the investigated series of compounds and when bulky groups can stabilize one of the conformers.

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Solvents effects on the proton chemical shift and H—H, H—F coupling constants in 1-chloro-1-fluoroethylene. Reaction field and dispersion interactions

Canadian Journal of Chemistry ◽

10.1139/v67-188 ◽

1967 ◽

Vol 45 (10) ◽

pp. 1111-1118 ◽

Cited By ~ 14

Author(s):

H. M. Hutton ◽

T. Schaefer

Keyword(s):

Dielectric Constant ◽

Chemical Shift ◽

Coupling Constants ◽

Proton Chemical Shift ◽

Coupling Constant ◽

Dispersion Interactions ◽

Proton Proton ◽

Reaction Field ◽

Proton Coupling ◽

Solvent Molecules

The proton chemical shift and the geminal proton–proton and cis proton–fluorine coupling constants in 1-chloro-1-fluoroethylene depend primarily on the dielectric constant of the medium, although this dependence is not given by the Onsager reaction field model. A roughly linear relationship is found with the square root of the dielectric constant. The proton coupling constant decreases algebraically while the cis proton–fluorine coupling constant increases as the dielectric constant of the medium increases. The trans proton–fluorine coupling depends on dispersion interactions with the solvent molecules and increases as these interactions increase. The geminal coupling constant varies between − 3.8 and − 4.8 c.p.s., the cis coupling between 7.6 and 12.3 c.p.s., and the trans coupling between 36.9 and 38.6 c.p.s.

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21,22-Disubstituted 18α,19βH-Ursane Derivatives with Oxabicyclooctane System in Ring E

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19930173 ◽

1993 ◽

Vol 58 (1) ◽

pp. 173-190 ◽

Cited By ~ 1

Author(s):

Eva Klinotová ◽

Jiří Klinot ◽

Václav Křeček ◽

Miloš Buděšínský ◽

Bohumil Máca

Keyword(s):

Spectral Data ◽

Spin Systems ◽

Coupling Constants ◽

Complete Analysis ◽

Nmr Spectrum ◽

Proton Proton ◽

H Nmr ◽

Proton Coupling ◽

C Nmr

Reaction of 3β-acetoxy-21,22-dioxo-18α,19βH-ursan-28,20β-olide (IIIa) and 20β,28-epoxy-21,22-dioxo-19α,19βH-ursan-3β-yl acetate (IIIb) with diazomethane afforded derivatives XII-XIV with spiroepoxide group in position 21 or 22, which were further converted into hydroxy derivatives XV and XVII. Ethylene ketals VIII-X were also prepared. In connection with the determination of position and configuration of the functional groups at C(21) and C(22), the 1H and 13C NMR spectral data of the prepared compounds are discussed. Complete analysis of two four-spin systems in the 1H NMR spectrum of bisethylenedioxy derivative Xb led to the proton-proton coupling constants from which the structure with two 1,4-dioxane rings condensed with ring E, and their conformation, was derived.

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Proton magnetic resonance study of the conformation of the pyrrolidine ring in some proline-thiohydantoins

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19882503 ◽

1988 ◽

Vol 53 (11) ◽

pp. 2503-2510 ◽

Cited By ~ 3

Author(s):

Jef J. M. Sleeckx ◽

Marc J. O. Anteunis ◽

Frans A. M. Borremans

Keyword(s):

Present Model ◽

Coupling Constants ◽

Proton Proton ◽

Proton Coupling ◽

Proton Magnetic Resonance Study ◽

Vicinal Proton ◽

Different Temperatures ◽

Experimental Justification ◽

State Assumption ◽

Methyl Phenyl

The conformational behaviour of a series of N-substituted thiohydantoins of proline was studied by proton NMR. The pseudorotational parameters of the proline moiety were calculated from the ten vicinal proton-proton coupling constants assuming a two state equilibrium (N ⇋ S). The effect of the different substituents (methyl, phenyl, para-nitrophenyl) at the thiohydantoin nitrogen on the conformation of the pyrrolidine rings is discussed. The spectra of proline-N-methylthiohydantoin were recorded at different temperatures in octadeuterotoluene solution. The conformational analysis of these spectra showed that the ratio of the populations of the N and S forms changes considerably with temperature, while the conformational identity of both the N and S forms remains strictly preserved. These facts provide an additional experimental justification of the two-state assumption, at least so for the present model compounds.

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