Wiley
0030-4921
Cơ quản chủ quản: N/A
Các bài báo tiêu biểu
13C n.m.r. spectra of steroids —a survey and commentaryAbstract The literature on 13 C n.m.r. examinations of steroids has been reviewed and the shielding data for over 400 examples are tubulated. The assignments for each compound have been considered and, where necessary, revised in the light of more recent evidence and for consistency throughout each series. The methods available for assignments ar... ...
Tập 9 Số 8 - Trang 439-464 - 1977
Theoretical and empirical calculations of the carbon chemical shift in terms of the electronic distribution in moleculesAbstract The principles of the theoretical calculations of the carbon atom screening constant are reviewed. The Independent Electron, SCFMO and Valence Bond formulae are briefly discussed, and the relative importance of the different terms involved in an approximate decomposition of σ13 C are pointed out. The variations of the excitation energy ... ...
Tập 7 Số 1 - Trang 2-17 - 1975
Stereochemical aspects of proton chemical shifts. III—Configurational assignments in pentacyclic systems without recourse to a karplus equationAbstract It is shown that in contrast to the use of coupling constants, chemical shift criteria may lead to unambiguous structural elucidations in pseudorotational frameworks (pentacycles, heptacycles, etc.).
Tập 7 Số 7 - Trang 345-348 - 1975
The 1H, 13C and 31P NMR spectra of EZ pairs of some phosphorus substituted alkenesAbstract The olefins Ph2 P(X)CHCHR [X=lone pair, O, S, Ch3 I ; RCh3 , ph, P(X)ph2 ] have been prepared and their 1 H, 13 C and 31 P NMR spectra measured. trans 3...
Tập 15 Số 1 - Trang 37-42 - 1981
Détermination des Axes Propres et des Valeurs Principales du Tenseur ḡ dans deux Radicaux Libres Nitroxydes par Étude de MonocristauxAbstract La structure de la phase basse température du radical nitroxyde tétraméthyl‐2,2,6,6 pipéridine oxyle‐1 (Tanane) a été déterminée. Ce radical libre est isomorphe du tétraméthyl‐2,2,6,6 pipéridinol‐4 oxyle‐1 (Tanol). Une étude en résonance paramagnétique électronique de monocristaux a permis de déterminer les valeurs principales et l'orientation des axes prop... ...
Tập 5 Số 1 - Trang 47-52 - 1973
13C NMR spectra of benzofuroxan and related compoundsAbstract The 13 C n.m.r. spectrum of benzofuroxan at −15°C is assigned on the basis of selective decoupling experiments and by comparison with the 13 C chemical shifts of model compounds. The 13 C spectra were also measured in trifluoroacetic acid as a solvent. From the temperature dependence of the ...
Tập 8 Số 3 - Trang 158-160 - 1976
1H and 13C NMR study of 8‐hydroxyquinoline and some of its 5‐substituted analoguesAbstract 1 H and 13 C NMR spectra of 8‐hydroxyquinoline (oxine) and its 5‐Me, 5‐F, 5‐Cl, 5‐Br and 5‐NO2 derivatives have been studied in DMSO‐d 6 solution. The 1 H and 13 C chemical shifts and proton–proton, proton–fluor...
Tập 15 Số 3 - Trang 280-284 - 1981
Conformational analysis of the tropane analogue of pethidine and related compounds by 1H NMR spectroscopyAbstract The preferred solute conformation of ethyl 3α‐phenyltropane‐3β‐carboxylate hydrochloride, the tropane analogue of pethidine, is shown to be a piperidine chair with an axial 3‐phenyl substituent by analysis of its 1 H NMR characteristics and spectral comparisons with model compounds. Conformational studies of synthetic intermediates are a... ...
Tập 6 Số 8 - Trang 441-444 - 1974
Fast searching for identical 13C NMR spectra via inverted filesAbstract Inverted files of spectral features should be employed when searching for identical or similar spectra. The efficiency of interescting the entries for chemical shifts with a small deviation is very high for larger molecules and incomplete spectra. A novel spectral code describing the spectral appearance in hierarchical order (SAHO) facilitates the search fo... ...
Tập 15 Số 2 - Trang 178-187 - 1981
Modelling of the alkyl environment effects on the 13C chemical shiftAbstract Using a topological parameter, λR , to characterize the effects of a variable mono or polyalkyl environment, R , on widely varied types of 13 C sites gives rise to a homogeneous description of their chemical shifts over the entire range of δ13 C variation (220 ppm/TMS). Th... ...
Tập 14 Số 4 - Trang 264-271 - 1980