摘要:

AbstractThe NMR spectra of the cycloaddition adducts between tetracyanoethylene oxide (TCNEO) and norbornadiene derivatives have been studied. It was shown that there was significant long‐range coupling between 7‐antiandendohydrogens in the adducts and that this long‐range coupling was solvent dependent. Based on the present study it is concluded that the long‐range coupling betweenendoandantihydrogens can be as high as 4·1 Hz when an electronegative substituent is attached to the carbon which bearsendo

ISSN:0030-4921    

DOI:10.1002/mrc.1270030402

出版商:John Wiley&Sons Limited    

年代:1971

数据来源: WILEY

摘要:

AbstractThe NMR spectra of the nonaromatic protons in several benzo‐substituted five‐ and six‐membered rings have been analyzed at 60‐ and 90‐MHz. The vicinal coupling constants from theCH2CH2fragments give a quantitative assessment of the degree of ring flattening. The distortions are discussed in terms of the structural components o

ISSN:0030-4921    

DOI:10.1002/mrc.1270030403

出版商:John Wiley&Sons Limited    

年代:1971

数据来源: WILEY

摘要:

AbstractInfinite dilution data for six sulphur heterocycles have been obtained from second order analyses of their NMR spectra in CS2, CDCl3, CD3COCD3, or C6D6. Use of LAOCOON3 leads to accurate chemical shifts, but substantial errors remain in some of the coupling constants. Evidence is presented of specific association of chloroform with the sulphur heterocycles and of the interaction of acetone with the sulphur atom. An apparently anomalous geometry for the complex of benzene with thiophen and with other solutes is discussed. Dilution effects are considered in relation to the formation of solute dimers.

ISSN:0030-4921    

DOI:10.1002/mrc.1270030404

出版商:John Wiley&Sons Limited    

年代:1971

数据来源: WILEY

摘要:

AbstractProton spin‐spin coupling values measured for a wide range of tetrasubstituted tetrahydropyran ring‐systems obtained from aldopentopyranose sugars have been correlated with values calculated from a generalized version of the Karplus equation which takes into account the electronegativities of the various atoms in the molecule and the configurations of these substituents. Minor discrepancies between observed and calculated values can be attributed to slight flattening of the tetrahydropyran ring as a result of steric interactions of the substituents. The magnitude of the geminal couplingJ5e,5aof these aldopentopyranose derivatives provides a rough measure of the conformational population; when H‐4 is axial [Cl(D) or1C(L) conformation]J5e,5ais ∼10.9 Hz, and is ∼13.4 Hz when H‐4 is equatorial [1C(D) orCl(L) co

ISSN:0030-4921    

DOI:10.1002/mrc.1270030405

出版商:John Wiley&Sons Limited    

年代:1971

数据来源: WILEY

摘要:

AbstractThe methylene protons of dibenzyl sulphoxide are magnetically equivalent in low dielectric and non‐equivalent in high dielectric constant solvents, while for diphenacyl sulphoxide this behaviour is reversed. In both cases, the variation in the magnitude of the non‐equivalence reflects a greater downfield shift of one methylene proton than the other on passing from non‐polar to polar solvents. By contrast, the chemical shift difference between the benzyl methylene protons or between the phenacyl methylene protons of benzyl phenacyl sulphoxide varies only slightly with solvent pol

ISSN:0030-4921    

DOI:10.1002/mrc.1270030406

出版商:John Wiley&Sons Limited    

年代:1971

数据来源: WILEY

摘要:

AbstractThe compound 2,4‐dichloro‐1‐pentene‐1‐d1(1) was synthesized starting from and CHCNa. In the last stage of the synthesis on activated carbon‐HgCl2catalyst), (3) were formed together with (1).The NMR parameters of (1), itscisandtransisomers and (2) were obtained in C6D6solution at 100 MHz. Theoretical spectra of (1) at 60 MHz were simulated with the aid of a computer, using as input the NMR parameters obtained at 100 MHz and good agreement with the experiment

ISSN:0030-4921    

DOI:10.1002/mrc.1270030407

出版商:John Wiley&Sons Limited    

年代:1971

数据来源: WILEY

摘要:

AbstractLes spectres RMN d′éthers disubstitués de formule (XCH2CH2)2O avec X = Cl, Br, I, d′une part, à température ambiante et à l′état pur et, d′autre part, en solution dans CS2et à différentes températures, ont été analysés avec précision. Les déplacements chimiques de chacun des groupements CH2ont pu ětre attribués. Les rotaméres prépondérants ont été déterminés à l′état pur et à différentes températures. De plus, il est montré que pour ces trois halogénures dissous dans CS2, les formes gauches relatives à chaque branche deviennent plus stables en refroidissant. Les auteurs ont mis au point une procédure permettant, par décomposition de raies, de traiter les spectres de type

ISSN:0030-4921    

DOI:10.1002/mrc.1270030408

出版商:John Wiley&Sons Limited    

年代:1971

数据来源: WILEY

摘要:

AbstractThe1H and19F NMR spectra of the CH2FCHF group in FCH2CHFCO2C2H5were analysed on the basis of an ABCXY spin system. The non‐equivalence of the methylene protons is discussed in terms of rotational isomerism. It is concluded that the dominant rotamer is probably considerably distorted from a perfectly staggered orientation. The variation of3JHFwith substituent electronegativity is reviewe

ISSN:0030-4921    

DOI:10.1002/mrc.1270030409

出版商:John Wiley&Sons Limited    

年代:1971

数据来源: WILEY

摘要:

AbstractSome shielding and deshielding effects by an adjacent cyclopropyl ring and the effect of the ring on geminal coupling constants α‐ to the ring are reported and discuss

ISSN:0030-4921    

DOI:10.1002/mrc.1270030410

出版商:John Wiley&Sons Limited    

年代:1971

数据来源: WILEY

摘要:

AbstractProton magnetic resonance chemical shifts and coupling constants for some 5‐substituted dihydrofurans, dihydrofuran and dihydrothiophene fused rings are reported, the substituents being methyl, ethyl and phenyl.The observed coupling constants are consistent with buckled rings, in which it appears that a conformation with pseudo‐equatorial substituents is predomin

ISSN:0030-4921    

DOI:10.1002/mrc.1270030411

出版商:John Wiley&Sons Limited    

年代:1971

数据来源: WILEY