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1. |
The solvent‐induced shift in the proton NMR of some quinolizidine substituents |
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Organic Magnetic Resonance,
Volume 7,
Issue 5,
1975,
Page 191-193
Robert T. Lalonde,
Thomas N. Donvito,
Amy I‐M. Tsai,
Chunfook Wong,
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摘要:
AbstractThe proton chemical shift values for the methyl groups in the nine monomethylquinolizidines are determined in deuterochloroform and benzene solutions. This solvent change results in the shielding of all the methyl groups except those in 1(a)‐and 3(a)‐methylquinolizidine which become deshielded. These results are compared with those obtained earlier for equatoral and axial methyl and methylene groups attached to the quinolizidine systems in Nuphar alkaloids and related compou
ISSN:0030-4921
DOI:10.1002/mrc.1270070502
出版商:John Wiley&Sons Limited
年代:1975
数据来源: WILEY
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2. |
Hochauflösungs‐13C‐NMR‐Spektroskopie. I—Analyse der Spektren des 1,2,4‐ und 1,3,5‐Triazins sowie ihrer Methyl‐ und Phenylderivate |
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Organic Magnetic Resonance,
Volume 7,
Issue 5,
1975,
Page 194-198
S. Braun,
G. Frey,
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摘要:
AbstractMit Hilfe der Puls‐Fourier‐Transform‐Technik wurden die Hochauflösungs‐13C‐NMR‐Spektren des 1,2,4‐ und 1,3,5‐Triazins sowie ihrer Methylderivate aufgenommen, ferner auch die1H‐breitbandentkoppelten13C‐Spektren von phenyl‐ und methyl‐phenyl‐substituierten Triazinen. Die chemischen Verschiebungen der mehrfach substituierten 1,2,4‐Triazine verhalten sich weitgehend additiv; Abweichungen bei Phenylderivaten werden sterischen Ursachen zugeschrieben. Die13CH‐Kopplungskonstanten werden mit denen im Benzol, im Pyridin, in den Diazinen sowie in disubstituierten Äthylenen verglichen. Der starke Einfluß von Anzahl und Position der Stickstoffatome auf die Kopplungskonstanten läßt sich daran erkennen, daß im 1,2,4‐Triazin, entgegen der üblichen Reihenfolge, gemi
ISSN:0030-4921
DOI:10.1002/mrc.1270070503
出版商:John Wiley&Sons Limited
年代:1975
数据来源: WILEY
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3. |
Hochauflösungs‐13C‐NMR‐Spektroskopie. II—Die Spektren von (2‐Dimethylamino‐1‐propenyl)triazinen |
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Organic Magnetic Resonance,
Volume 7,
Issue 5,
1975,
Page 199-205
S. Braun,
G. Frey,
M. Bachmann,
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摘要:
AbstractDie unentkoppelten13C‐NMR‐Spektren der bei der Reaktion von Methyltriazinen mit 1‐Äthoxy‐1‐(dimethylamino)‐äthylen entstandenen Produkte wurden mit Hilfe der Puls‐Fourier‐Transform‐Technik aufgenommen und analysiert. Der Vergleich der beobachteten13C‐chemischen Verschiebungen und13CH‐Kopplungskonstanten mit denen der Ausgangstriazine und des 2‐Dimethylamino‐2‐penten‐4‐ons bestätigt die (2‐Dimethylamino‐1‐propenyl)triazin‐Struktur. Die Daten werden im Hinblick auf sterische Effekte sowie die Konfiguration
ISSN:0030-4921
DOI:10.1002/mrc.1270070504
出版商:John Wiley&Sons Limited
年代:1975
数据来源: WILEY
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4. |
Restricted rotation in amides. VII—methods of resonance assignment in tertiary amides—an evaluation |
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Organic Magnetic Resonance,
Volume 7,
Issue 5,
1975,
Page 206-225
Anita H. Lewin,
Melvin Frucht,
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摘要:
AbstractExamination and evaluation of various methods for resonance assignments in amides reveals that only three of these are reliable: (a) the nuclear Overhauser effect, which leads to unequivocal results in tertiary amides; (b) the aromatic solvent induced shift, which is rapid and accurate for tertiary amides without polar substituents; (c) the lanthanide‐induced shift, which although easy, can be applied only to tertiary amides with substituents that do not complex lanthanide
ISSN:0030-4921
DOI:10.1002/mrc.1270070505
出版商:John Wiley&Sons Limited
年代:1975
数据来源: WILEY
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5. |
Interactions intramoleculaires: XXII—Constantes de couplage, équilibres conformationnels et interactionsgauchesavec un groupementt‐butyle (molécules cyclohexéniques deutériées) |
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Organic Magnetic Resonance,
Volume 7,
Issue 5,
1975,
Page 226-236
Jean‐Pierre Aycard,
Hubert Bodot,
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摘要:
AbstractLes paramètres RMN d'une série de cyclohexènes disubstitués (R = CH3, (CH3)3C; X = COOCH3, CN) et spécifiquement deutériés sont déterminés. A partir des valeurs des constantes de couplage3J(HH),3J(HD),4J(HH) et5J(HH), les équilibres conformationnels sont évalués. Trois des cinq composés ayant un groupementt‐butyle en position allylique sont conformationnellement hétérogènes; les équilibres correspondants et les équilibres entre stéréoisomères permettent une analyse de ce phénomène dans le cadre de l'hypothèse de l'additivité des enthalpies libres conformationnelles
ISSN:0030-4921
DOI:10.1002/mrc.1270070506
出版商:John Wiley&Sons Limited
年代:1975
数据来源: WILEY
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6. |
13C NMR study of the enol forms of β‐diketones |
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Organic Magnetic Resonance,
Volume 7,
Issue 5,
1975,
Page 237-239
N. N. Shapet'ko,
S. S. Berestova,
G. M. Lukovkin,
Yu. S. Bogachev,
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摘要:
AbstractCarbon‐13 NMR spectra of a series of β‐diketones in the enol form with various β‐substituents have been studied. An additive influence of the β‐substituents on the chemical shifts of the carbon atoms in the hydrogen bonded chelate ring has been found. It is shown that the α‐ and β‐carbon chemical shifts can be calculated by means of a set of increments for arbitrary combinations of the X and Y substituents. Analysis of the experimental data enables the conclusions to be drawn that enol–enolic tautomerism with different populations of the forms (A) and (B) is absent in β‐diketones and that the carbon chemical shift changes are caused by electron density redistribution in the hydrogen bo
ISSN:0030-4921
DOI:10.1002/mrc.1270070507
出版商:John Wiley&Sons Limited
年代:1975
数据来源: WILEY
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7. |
Lanthanide‐induced shifts of diastereotopic groups |
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Organic Magnetic Resonance,
Volume 7,
Issue 5,
1975,
Page 240-243
Harold M. Bell,
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摘要:
AbstractThe chemical shift differences of diastereotopic protons in aliphatic acyclic alcohols, mostly of the type RCH2CR′R″(CH2)nOH, have been investigated. Fairly small amounts of Eu(dpm)3cause the spectra of these materials to simplify dramatically; indeed, even diastereotopic protons rather far removed form the hydroxyl group give discrete signals in the presence of the shift reagent. Large shift differences were realized in the γ‐protons (n= 1) and the δ‐protons (n= 2), particularly if R is bulky and R' and R″ have different steric requirements. Semi‐quantitative conformational preferences can be determined fro
ISSN:0030-4921
DOI:10.1002/mrc.1270070508
出版商:John Wiley&Sons Limited
年代:1975
数据来源: WILEY
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8. |
Long range13C1H coupling constants IV—methoxy‐, amino‐ and hydroxypyridines |
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Organic Magnetic Resonance,
Volume 7,
Issue 5,
1975,
Page 244-246
Yoshito Takeuchi,
Nicholas Dennis,
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摘要:
AbstractOne bond and long range13C1H coupling constants for some methoxy‐, amino‐ and hydroxypyridines are described. An unambiguous assignment of carbon‐13 resonances is carried out based on the analysis of the fine splitting caused by long range couplings.Jvalues for compounds other than 2‐ and 4‐hydroxy‐pyridines are explainable in terms of the values previouly obtained for cyano‐ and methylpyridines. The hydroxypyridine‐pyridone tautomerism affects2J(Hα), i.e.2Jassociated with the α proton. This effect can be used to differentiate pyridones fr
ISSN:0030-4921
DOI:10.1002/mrc.1270070509
出版商:John Wiley&Sons Limited
年代:1975
数据来源: WILEY
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9. |
Vicinal interproton couplings through two heteroatoms. II—Coupling3J(HNOH) occurring inm‐Nitrophenylhydroxylamines |
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Organic Magnetic Resonance,
Volume 7,
Issue 5,
1975,
Page 247-248
Philippe Bouchet,
Claude Coquelet,
José Elguero,
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摘要:
AbstractThe proton NMR spectra of certain arylhydroxylamines in DMSO‐d6show a vicinal coupling through nitrogen and oxygen. The assignment of OH and NH signals was made using a15N labelled derivativ
ISSN:0030-4921
DOI:10.1002/mrc.1270070510
出版商:John Wiley&Sons Limited
年代:1975
数据来源: WILEY
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10. |
Masthead |
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Organic Magnetic Resonance,
Volume 7,
Issue 5,
1975,
Page -
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PDF (87KB)
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ISSN:0030-4921
DOI:10.1002/mrc.1270070501
出版商:John Wiley&Sons Limited
年代:1975
数据来源: WILEY
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