摘要:

AbstractThe configuration of the insecticidal and medicinal lipid ‘affinin,’N‐isobutyldeca‐trans‐2,cis‐6,trans‐8‐trienamide, may be assigned in an unequivocal manner by NMR spectroscopy. The spectral data and the advantages of the multiple irradiation methods are presente

ISSN:0030-4921    

DOI:10.1002/mrc.1270030102

出版商:John Wiley&Sons Limited    

年代:1971

数据来源: WILEY

摘要:

AbstractThe spectra of Δ3‐ and Δ4‐pyrrolin‐2‐one were analysed and the sign of all the coupling constants determined by tickling and triple resonance experiments. A positive allylic interaction (Jxzin2) is reported and four‐bond couplings are discussed in particular. Deuterium exchange affords evidence for the tautomeric equilibrium b

ISSN:0030-4921    

DOI:10.1002/mrc.1270030103

出版商:John Wiley&Sons Limited    

年代:1971

数据来源: WILEY

摘要:

AbstractAssignment of all13C chemical shifts of perezone (1) and some derivatives was possible using time averaged 25·15 MHz spectra with the aid of proton noise modulated and CW decoupling. Rapid interconversion of tautomeric forms of 2,5‐dihydroxy‐1,4‐benzoquinones is deduced from the13C s

ISSN:0030-4921    

DOI:10.1002/mrc.1270030104

出版商:John Wiley&Sons Limited    

年代:1971

数据来源: WILEY

摘要:

AbstractDie Protonenresonanzspektren einiger Methyl‐, Acetyl‐ und Benzoylderivate der Polysaccharide Amylose und Dextran sowie der α‐D‐Glucose und β‐Maltose wurden analysiert. Aus den relativen Signallagen und den Kopplungskonstanten der Ringprotonen kann die Konfiguration und Konformation des Monomerbausteins sowie die Art der glycosidischen Bindung best

ISSN:0030-4921    

DOI:10.1002/mrc.1270030105

出版商:John Wiley&Sons Limited    

年代:1971

数据来源: WILEY

摘要:

AbstractThe preparation of 4‐phenyl‐1, 3‐oxathian, 6‐methyl‐1, 3‐oxathian, and some of their 2‐substituted derivatives is described. Significant features of their NMR spectra are discussed with particular reference to the influence of the heteroatoms on the coupling constants of adj

ISSN:0030-4921    

DOI:10.1002/mrc.1270030106

出版商:John Wiley&Sons Limited    

年代:1971

数据来源: WILEY

摘要:

AbstractNous avons étudié la variation, en fonction de la température, des spectres de RMN de six spirophosphoranes des types:Les résultats expérimentaux indiquent l'existence d'une isomérie intramoléculaire que nous avons interprétée en adoptant le mécanisme de pseudo‐rotation proposé par Berry.1Dans tous les cas, sauf un, le déplacement de l'équilibre tautomère spirophosphorane ⇌ phosphite s'ajoute an phénomène

ISSN:0030-4921    

DOI:10.1002/mrc.1270030107

出版商:John Wiley&Sons Limited    

年代:1971

数据来源: WILEY

摘要:

AbstractOn a réalisé l'analyse complète des spectres de RMN des fluorophospholanes (1à3). Les signes absolus des constantes de couplage3J(PH) et4J(FH) ont été déterminés, par rapport au signe absolu connu de la constante1J(PF), à partir d'expériences de double résonance hétéronucléaire sélective. Les constantes3J(POCH) et3J(PNCH) observées sont toutes positives. Les deux constantes3J(PSCH) du dithiaphospholane (2) présentent des faibles valeurs de signes opposés, la plus grande étant positive. Toutes les constantes4J(FPXCH) sont positive

ISSN:0030-4921    

DOI:10.1002/mrc.1270030108

出版商:John Wiley&Sons Limited    

年代:1971

数据来源: WILEY

摘要:

AbstractThe AA′BB′ and AA′BB′MX nuclear magnetic resonance spin systems for I = ½ nuclei have been analysed. Expressions for the transition frequencies and intensities have been obtained which have the maximum accuracy consistent with practicable use. The analyses have been applied respectively to a hypothetical AA′BB′ nuclear spin system and to the two moleculespara‐ fluoro‐phenyldichlorophosphine andtris‐para‐fluorophenylphosphine. Inconsistencies in earlier treatments of the AA′BB′ sy

ISSN:0030-4921    

DOI:10.1002/mrc.1270030109

出版商:John Wiley&Sons Limited    

年代:1971

数据来源: WILEY

摘要:

AbstractBoth the diphosphine CH3CF3PPCH3CF3and the thio‐bisphosphine CH3CF3PSPCH3CF3show19F and31P NMR spectra indicative of diastereomeric mixtures ofd,landmesoisomers. The temperature‐dependent reversible interconversions of the isomers have been attributed to the inversion at the phosphorus atom. The equilibrium constants for the isomerization reactions have been measured at various temperatures. The fluorine NMR spectra of themesoandd,lisomers of CD3CF3PSPCD3CF3have been analyzed as M3XX′M3′ spin systems. Good agreement is found between the observed and calculated spectra. The five‐bond fluorine‐fluorine coupling constant of the low‐field isomer is larger than that of the high‐field isomer. The19F NMR spectra of (CF3)2PP(CF3)2, (CF3)2POP(CF3)2, (CF3)2PSP(CF3)2, CH3CF3PPCH3CF3and CH3CF3PSPCH3CF3have been examined over a wide range of temperatures in an attempt to correlate the data to the geometries of

ISSN:0030-4921    

DOI:10.1002/mrc.1270030110

出版商:John Wiley&Sons Limited    

年代:1971

数据来源: WILEY

摘要:

AbstractThe charge distribution in several substituted aliphatic derivatives was determined by a parametric MOLCAO method. The charges were successfully employed to interpret NMR parameters, namely proton and carbon chemical shift and vicinal proton‐proton coupling constants in ethyl derivatives and carbon‐proton coupling constants.The linear correlations found between NMR parameters and charge densities are restricted to substituents of the same row of the periodic system. The decay along the aliphatic chain of the perturbation induced by substituents on proton chemical shift is also reproduced by charge distribution. Some results also seem to indicate that the substituents affect the hybridization of the attached carbon a

ISSN:0030-4921    

DOI:10.1002/mrc.1270030111

出版商:John Wiley&Sons Limited    

年代:1971

数据来源: WILEY