Substituent effects of (transition metallo)methyl groups by fluorine-19 nuclear magnetic resonance

1973 ◽  
pp. 986 ◽  
Author(s):  
Clifford W. Fong ◽  
Michael D. Johnson
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Substituent Effects ◽  
Methyl Groups ◽  
Nuclear Magnetic

The Complete Stereostructure of Capsidiol. X-Ray Analysis and 13C Nuclear Magnetic Resonance of Eremophilane Derivatives Having trans-Vicinal Methyl Groups

1974 ◽  
Vol 52 (6) ◽  
pp. 993-1005 ◽  
Author(s):  
George I. Birnbaum ◽  
A. Stoessl ◽  
S. H. Grover ◽  
J. B. Stothers
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Structure Analysis ◽  
Substituent Effects ◽  
Methyl Groups ◽  
Model Compounds ◽  
X Ray ◽  
13C Nuclear Magnetic Resonance ◽  
Nuclear Magnetic

To define the stereochemistry of capsidiol (1), an antifungal sesquiterpene isolated from sweet peppers, a detailed 13C n.m.r. investigation was carried out. From the results for 1 and a series of its derivatives (2–6) compared with those for several well-defined model compounds (7–21) it has been established that the vicinal methyl groups are trans, in contrast to all other previously described eremophilanes. This was confirmed by an X-ray structure analysis of 1 which also established the stereochemistry of the isopropenyl group as well as the detailed conformations of the two rings.The 13C spectra for the series 1–21 have been completely analyzed and these results are discussed in terms of the observed substituent effects. Further evidence of deshielding syn-axial δ effects is presented.

Nuclear Magnetic Resonance Chemical Shifts of some Monosubstituted Isothiazoles

1975 ◽  
Vol 53 (4) ◽  
pp. 596-603 ◽  
Author(s):  
Roderick E. Wasylishen ◽  
Thomas R. Clem ◽  
Edwin D. Becker
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Charge Densities ◽  
Monosubstituted Benzenes ◽  
Proton Chemical Shifts ◽  
Nuclear Magnetic

Carbon-13 and proton chemical shifts have been measured for several monosubstituted isothiazoles. Substituent effects upon these chemical shifts are compared with those observed for monosubstituted benzenes, pyridines, and thiophenes. In general the observed substituent effects in the isothiazoles and thiophenes closely parallel one another. Correlations between the observed carbon-13 Chemical shifts and CNDO/2 calculated charge densities are examined.

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