摘要:

AbstractThe17O NMR data of thio analogues of chromanones, chromones, flavanones and flavanones are compared with those of corresponding oxygen analogues. Substituent effects are discussed in terms of steric and electronic interactions and also the conformational behaviour of some substituents and the hetero ring.

ISSN:0749-1581    

DOI:10.1002/mrc.1260300112

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractThe application of a chemical shift selective filter in 1D INADEQUATE and HCC relay experiments is proposed. It is demonstrated that highly selective filtering can be the equivalent of low‐power excitations. Applications to the selective detection of carbon–carbon connectivities are pr

ISSN:0749-1581    

DOI:10.1002/mrc.1260300113

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractComplete13C spectral assignments were made for 1‐ and 2‐R‐naphthalenes (R = Me, Et,i‐Pr,t‐Bu) in CDCl3solution (5 mol%) by the use of 2D techniques including 2D INADEQUATE. Contradictory assignments from the literature were clarified and incomplete data completed. Substituent effects on13C shifts are briefly discussed.1H chemical shifts were determined by13C/1H shift co

ISSN:0749-1581    

DOI:10.1002/mrc.1260300114

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractPyrrolyl‐1‐oxyl, 3‐phenylpyrrolyl‐1‐oxyl and a number of deuterium‐substituted derivatives were generated by hydrogen abstraction from the correspondingN‐hydroxypyrroles, and observed by EPR spectroscopy. They were all transient with lifetimes ≤ 10−2s. The hyperfine splittings showed that unpaired spin was delocalized around the five‐membered ring with significant density at N‐1, C‐3 and C‐4, but very low density at C‐2 and C‐5.N‐Hydroxpyrrole and pyrrolyl‐1‐oxyl were studied by the semi‐empirical AM1 method, and the radical by the INDO method. The transient pyrrolinyl‐1‐oxyl was also generated from the correspondingN‐hydrox

ISSN:0749-1581    

DOI:10.1002/mrc.1260300115

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractThe13C NMR signals for some 2‐ethylthio‐, 2‐ethylsulphinyl‐ and 2‐ethylsulphonyl‐4′‐substituted acetophenones were assigned. The carbonyl carbons exhibit a progressive upfield shift on going from the ketosulphides to the ketosulphoxides and to the ketosulphones. The α‐methylene carbons fro the three classes of compounds are shielded by almost the same amount in relation to the corresponding calculated values. The chemical shifts of the aromatic ring carbons are in close agreement with those calculated using substitue

ISSN:0749-1581    

DOI:10.1002/mrc.1260300116

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractDehydrogenation of 2,5‐dihydro‐1,2,3,5‐thiatriazole 1‐oxides with thermally formed bis(4‐methylphenyl)aminyl generated 2,3‐dihydro‐1‐oxo‐1λ4,2,3,5‐thiatriazol‐3‐yl radicals. ESR, ENDOR and triple resonance studies in combination with15N labelling yielded the magnitude and assignment of all1H and14N hyperfine coupling (HFC) constants. The radicals have a basic five‐π‐electron amidrazon‐2‐yl structure wit

ISSN:0749-1581    

DOI:10.1002/mrc.1260300117

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractThe peaks have been assigned in the1H NMR spectrum (250 MHz) and in the13C NMR spectrum in solution of polysiloxane with phenyl benzoate side‐chain

ISSN:0749-1581    

DOI:10.1002/mrc.1260300118

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

ISSN:0749-1581    

DOI:10.1002/mrc.1260300119

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

ISSN:0749-1581    

DOI:10.1002/mrc.1260300120

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

ISSN:0749-1581    

DOI:10.1002/mrc.1260300121

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY