Magnetic Resonance in Chemistry

doi: 10.1002/mrc.1270050516pmid: N/A

doi: 10.1002/mrc.1270050515pmid: N/A

doi: 10.1002/mrc.1270050501pmid: N/A

Pouzard, Guy; Rajzmann, Michel; Bodot, Hubert; Pujol, Louis

doi: 10.1002/mrc.1270050502pmid: N/A

Les constantes de couplage RMN 3J, 4J et 5J entre protons ont été calculées par les deux méthodes citées, pour le cyclohexane et pour les conformères de ses dérivés monosubstitués (substituants: Li, CH3, OH, F). La comparaison des deux méthodes sur la base de la théorie des groupes met en évidence la nécessité d'utiliser la méthode des perturbations finies dont les résultats sont confrontés avec les données expérimentales de la littérature.

Shape'ko, N. N.

doi: 10.1002/mrc.1270050503pmid: N/A

The hydroxyl proton chemical shifts of β‐dicarbonyl compounds involving various β‐substituents have been studied. An additive influence of β‐substituents on the δOH shift values has been found. The results obtained suggested the existence of only one potential proton energy minimum in the intramolecular hydrogen bond of the enol forms of the β‐diketones. It has been shown that the enol forms of β‐keto esters do not follow the additivity of the δOH values for the same substituents, which may be due to a change in the proton distribution potential function in the intramolecular hydrogen bond.

Franck‐Neumann, Michel; Sedrati, Madjid

doi: 10.1002/mrc.1270050504pmid: N/A

Le complexe Eu (FOD)3 constitue un bon réactif de déplacement en spectroscopie de RMN de Δ1‐pyrazolines. Les 5 exemples décrits ici ont été choisis en série polycyclique pour mettre en évidence l'utilité de cette technique en vue de l'attribution des stéréochimies.

Ignatenko, A. V.; Kessenikh, A. V.; Glukhovtsev, V. G.; Nadtochii, M. A.

doi: 10.1002/mrc.1270050505pmid: N/A

The CIDNP effects observed during thermal decomposition of 2‐hydroperoxide‐2‐methyltetrahydrofuran at 150° in C6H5COH are described.

Filleux‐Blanchard, M. L.; Fieus, J.; Hallé, J. C.

doi: 10.1002/mrc.1270050506pmid: N/A

Dans les anilines une non équivalence des protons aminés, due à la rotation empêchée autour de CN apparait à basse température. Les relations entre les paramètres d'activation et les effets électroniques des substituants sont étudiés et les paramètres RMN sont discutés.

Kessenikh, A. V.; Petrovskii, P. V.; Rykov, S. V.

doi: 10.1002/mrc.1270050507pmid: N/A

13C CIDNP effects in the decomposition of acetylbenzoyl peroxide in cyclohexanone are described. A comparison between our data, and those on the 1H CIDNP effects and the 13C CIDNP observed in the decomposition of ABP in C2Cl41 leads to definite conclusions on the signs of the HFI constants of the benzoyl radical and to an identification of the separate products of the radical‐induced reactions with the solvent.

Mauger, A. B.; Rzeszotarski, W. J.; Ford, R. A.

doi: 10.1002/mrc.1270050508pmid: N/A

The PMR spectra of several cyclic and acyclic dipeptide derivatives representing portions of the actinomycin structure have been studied. In the spectra of the acyclic compounds temperature‐dependent duplicity resulted from the equilibration of conformers possessing cis and trans peptide bonds. The lanthanide shift reagent Eu(FOD)3 was utilized to distinguish N‐methyl groups in the two conformations and observations were made on the steric dependence of the observed shifts. The origin of the wide variation in chemical shift of N‐methylvalyl α‐protons is discussed in relation to the conformation of actinomycin.