Journal ArticleDOI
Influence of methyl substituents on the chemical shift of the ring protons in mono‐, di‐ and trimethylcyclohexanes a 300 MHz study of the 1H NMR spectrum of cis‐1,3‐dimethylcyclohexane
TLDR
In this paper, a 300 MHz spectral study of mono-to trisubstituted cyclohexanes was conducted, allowing a re-examination of some of their 1H NMR spectral parameters.Abstract:
From a 300 MHz spectral study of mono-to trisubstituted cyclohexanes, allowing a re-examination of some of their 1H NMR spectral parameters, it is shown that it is possible to predict with reasonable accuracy the shifts (in CCl4) of the ring protons. A substantial feature in this is the validity of the (questioned) additivity of multiple effects. It is also shown that with respect to shift alterations, equatorial ring protons behave anomalously, which cannot be explained by any existing theoretical model.read more
Citations
More filters
Journal ArticleDOI
A Conformational Study of Hydroxymethyl Groups in Carbohydrates Investigated by 1H NMR Spectroscopy
Klaus Bock,Jens Ø. Duus +1 more
TL;DR: In this paper, the conformation of the C5-C6 linkage determines the overall shape of oligosaccharides with glycosidic linkages and the bonds to the exocyclic groups, e.g., the hydroxymethyl groups and N-Acetyl groups.
Journal ArticleDOI
Stereochemical aspects of proton chemical shifts. III—Configurational assignments in pentacyclic systems without recourse to a karplus equation
TL;DR: In contrast to the use of coupling constants, chemical shift criteria may lead to unambiguous structural elucidations in pseudorotational frameworks (pentacycles, heptacycles etc.).
Journal ArticleDOI
Bicadinane, a C 30 pentacyclic isoprenoid hydrocarbon found in crude oil
H.C. Cox,J.W. de Leeuw,P.A. Schenck,H. van Koningsveld,Johannes C. Jansen,B. van de Graaf,V. J. van Geerestein,Jan A. Kanters,C. Kruk,A. W. H. Jans +9 more
TL;DR: In this paper, the structure of a C30H52 pentacyclic isoprenoid hydrocarbon present in some Far Eastern crude oils has been established as 2,6a,12-trimethyl-4,9-diisopropyl-perhydrobenzo[de]naphthacene by joint application of Chromatographie methods, mass spectrometry (MS), nuclear magnetic resonance (NMR), molecular mechanics and X-ray diffraction.
Journal ArticleDOI
A model for the calculation of proton chemical shifts in non-conjugated organic compounds
Journal ArticleDOI
Diastereoselektivität der Geruchswahrnehmung von Alkoholen der Iononreihe
TL;DR: The characteristic odour of the diastereoisomers 1 and 2 of 1-(2,2,6-trimethylcyclohexyl)-3-hexanol is configuration dependent, the trans-alcohol 1 being identified as the sensorily active component.
References
More filters
Journal ArticleDOI
Dependency of Vicinal Coupling Constants on the Configuration of Electrongegative Substituents
Journal ArticleDOI
Proton magnetic resonance studies of cyclic compounds—iv : The influence of alkyl substituents on the chemical shifts of the ring protons in cyclohexane compounds
TL;DR: In this article, the effects of alkyl substituents on the chemical shifts of ring protons in cyclohexane compounds are summarized and applied to explain a number of general features, including the variation in broadness of the resonance signal observed for ring-protons in cis and trans disubstituted cyclo-hexanes, and in cis-and trans fused bicyclic systems.
Journal ArticleDOI
NMR experiments on ketals VI. PMR spectra of alkyl substituted 1, 3‐dioxanes with rigid or anancomeric structures
TL;DR: In this article, the PMR coupling values and shifts of twenty three 1, 3-dioxanes with rigid structure have been determined and the coupling data are in accordance with a chair conformation which is less buckled than that of cyclohexane derivatives.