C(19)-Substituted Steroids. IV.1Studies of Long Range Shielding by the Carbonyl Group with Nuclear Magnetic Double Resonance and Nuclear Magnetic Triple Resonance at 100 MC.

1962 ◽  
Vol 84 (24) ◽  
pp. 4976-4977 ◽  
Author(s):  
Norman. Bhacca ◽  
Manfred E. Wolef ◽  
Russell. Kwok
Keyword(s):  
Carbonyl Group ◽  
Long Range ◽  
Double Resonance ◽  
Triple Resonance ◽  
Nuclear Magnetic

Nuclear Magnetic Resonance Experiments on Acetals. 43. Reversal of Previous Conformational Assignment in 5-Fluoromethylated-5′-Me-1,3-dioxanes

1973 ◽  
Vol 51 (19) ◽  
pp. 3170-3172 ◽  
Author(s):  
M. Anteunis ◽  
F. Borremans
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Long Range ◽  
Double Resonance ◽  
Axial Position ◽  
Nuclear Magnetic

Additional n.m.r. investigations on 5-fluoromethylated-5′-Me-1,3-dioxanes have made it necessary for us to reverse the spectral assignments which were forwarded recently (1) in this journal. Thus, the 5-CF2H group prefers the axial position to the extent of ca. 900 cal/mol, whereas the 5-CFH2 group displays a similar preference for the axial position to the extent of ca. 200 cal/mol. An explanation for these unexpected results is advanced. Final structural assignments have been made possible by homo- and heteronuclear double resonance experiments and by ASIS-studies. The observed relative shifts for 5-CFnH3−n and 5-CH3 signals are shown to be normal (e.g. δ(5e) < δ(5a)). Also, the previously reported 4J(F,H) long range couplings follow a classical M-path.

scholarly journals Nuclear Magnetic Double Resonance in an ABX Spin System. The Signs of the Long-range Aldehyde Couplings in 2-Bromo-3-thiophenealdehyde.

1965 ◽  
Vol 19 ◽  
pp. 503-517 ◽  
Author(s):  
Sture Forsén ◽  
Bo Gestblom ◽  
Ragnar A. Hoffman ◽  
Sören Rodmar ◽  
Kjell Selin ◽  
...  
Keyword(s):  
Long Range ◽  
Spin System ◽  
Double Resonance ◽  
Nuclear Magnetic

Nuclear magnetic triple resonance studies on formamide-14N

1973 ◽  
Vol 5 (1) ◽  
pp. 43-45 ◽  
Author(s):  
V. Barboiu ◽  
V. Petrescu
Keyword(s):  
Triple Resonance ◽  
Nuclear Magnetic

scholarly journals Signs of proton–proton and proton–fluorine spin–spin coupling constants in 2-fluoro-3-methylpyridine. Sigma and pi contributions to coupling in a nitrogen heterocycle

1969 ◽  
Vol 47 (9) ◽  
pp. 1507-1514 ◽  
Author(s):  
T. Schaefer ◽  
S. S. Danyluk ◽  
C. L. Bell
Keyword(s):  
Nitrogen Atom ◽  
Long Range ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Nitrogen Heterocycle ◽  
Triple Resonance ◽  
Triple Resonance Experiments ◽  
Proton Proton ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

The signs of all proton–proton and proton–fluorine spin–spin coupling constants in 2-fluoro-3-methylpyridine have been determined by double and triple resonance experiments. The signs of the longrange coupling constants, JH,CH3 and JF,CH3 are the same as in fluorotoluene derivatives. Their magnitudes are consistent with the assumption that the nitrogen atom primarily polarizes the σ bonds in the molecule, leaving the π contribution to the long-range coupling relatively unaffected.

scholarly journals Nuclear Magnetic Double-Resonance Spectrum of a Strongly Coupled Two-Spin System

1965 ◽  
Vol 137 (5A) ◽  
pp. A1477-A1482 ◽  
Author(s):  
B. D. Nageswara Rao ◽  
J. D. Baldeschwieler ◽  
J. M. Anderson
Keyword(s):  
Spin System ◽  
Resonance Spectrum ◽  
Double Resonance ◽  
Strongly Coupled ◽  
Nuclear Magnetic
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