𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Configurations and conformations in acyclic, unsaturated hydrocarbons. A 13C NMR study

✍ Scribed by J. W. de Haan; L. J. M. Van de Ven

Publisher
John Wiley and Sons
Year
1973
Tongue
English
Weight
856 KB
Volume
5
Category
Article
ISSN
0749-1581

No coin nor oath required. For personal study only.

✦ Synopsis

Abstract

^13^C NMR (CMR) spectra of a number of di‐ and trisubstituted ethylenes have been measured. Very consistent values are found for the differential shieldings of allylic carbons in a number of linear, (Z)‐ and (E)‐disubstituted ethylenes. The discrepancies between the several structural elements are explained tentatively by assuming different rotational preferences in the (Z)‐isomers, the (E)‐isomers, or both. The results obtained for some branched olefins are qualitatively in agreement with conclusions reached in previous ^1^H NMR (PMR) investigations, with the possible exception of 2,5‐diMe‐3‐hexene.

Differential shieldings in trisubstituted ethylenes are larger than in disubstituted ethylenes, probably as a consequence of steric interaction between geminal substituents.

It is confirmed, that API's recent relabelling of the isomers of 3‐Me‐2‐hexene was justified. Furthermore, the (E)‐configuration is assigned to the high‐boiling isomer of 3,4,4‐triMe‐2‐pentene. On the other hand, the high‐boiling isomer of 3‐Et‐4‐Me‐2‐pentene is shown to be the (Z)‐isomer. For the isomeric pair of geraniol and nerol, the (E)‐configuration is assigned to the former and the (Z)‐configuration to the latter, in agreement with our recent PMR investigations.

📜 SIMILAR VOLUMES

13C and 15N NMR study of acyclic vicinal
13C and 15N NMR study of acyclic vicinal diastereoisomers. Conformational effects
✍ George C. Levy; T. Pehk; E. Lippmaa 📂 Article 📅 1980 🏛 John Wiley and Sons 🌐 English ⚖ 568 KB

## Abstract Conformations of aliphatic diastereoisomers with vicinal asymmetric centers (2,3‐disubstituted butanes and 5,6‐disubstituted __n__‐decanes) are discussed in terms of their ^13^C and, in some cases, ^15^N chemical shifts and spin‐lattice relaxation times. Solvent and protonation effects

Configurational and conformational studi
Configurational and conformational studies of N,N-dimethylpiperidinium derivatives by 13C and 1H NMR spectroscopy
✍ A. F. Casy; F. O. Ogungbamila 📂 Article 📅 1982 🏛 John Wiley and Sons 🌐 English ⚖ 449 KB

## Abstract The ^13^C and ^1^H NMR spectra of a series of methiodides of mono‐ and di‐C‐methyl derivatives of 1‐methyl‐4‐phenyl‐4‐piperidinols are reported and chemical shift data analysed in terms of configurations and conformations of isomeric sets. Results demondtrate the value of quaternary sal

A 1H and 13C NMR conformational study of
A 1H and 13C NMR conformational study of methyl-substituted isochromanes
✍ K. Pihlaja; J. Mattinen; E. Kleinpeter; R. Meusinger; Ch. Duscheck; R. Borsdorf 📂 Article 📅 1985 🏛 John Wiley and Sons 🌐 English ⚖ 426 KB

The 'H and the noise-decoupled =C NMR spectra of isochromane and 13 of its methyl-substituted derivatives were recorded and analysed. The collected data were used to assign the configurations and to determine the position of the conformational equilibria based on the vicinal ' I 3 coupling constants

Conformational study of phosphothreonine
Conformational study of phosphothreonine in aqueous solution. H and 13C NMR results
✍ L. Pogliani; D. Ziessow 📂 Article 📅 1978 🏛 John Wiley and Sons 🌐 English ⚖ 250 KB 👁 1 views

## Abstract The 270 MHz ^1^H and 22.6 MHz ^13^C NMR spectra of DL‐phosphothreonine in D~2~O have been measured and analysed as a function of pD. The __trans__‐__trans__ conformation of the fragment H‐αC‐αC‐βOP predominates at all pD values. The C‐β—O __gauche__ contribution is notably larger fo