Nuclear magnetic resonance spectroscopy. Ring-current effects upon carbon-13 chemical shifts

1973 ◽  
Vol 14 (2) ◽  
pp. 135-138 ◽  
Author(s):  
Ronald H. Levin ◽  
John D. Roberts
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Nuclear Magnetic Resonance Spectroscopy ◽  
Ring Current ◽  
Chemical Shifts ◽  
Resonance Spectroscopy ◽  
Nuclear Magnetic

Studies of specifically fluorinated carbohydrates. Part II. Nuclear magnetic resonance studies of pentopyranosyl fluoride derivatives

1969 ◽  
Vol 47 (1) ◽  
pp. 19-30 ◽  
Author(s):  
L. D. Hall ◽  
J. F. Manville
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Nuclear Magnetic Resonance Spectroscopy ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Resonance Spectroscopy ◽  
Magnetic Resonance Studies ◽  
Conformational Model ◽  
Nuclear Magnetic

Detailed studies, by 1H and 19F nuclear magnetic resonance spectroscopy, of a series of fully esterified pentopyranosyl fluorides, show that all such derivatives favor that conformer in which the fluorine substituent is axially oriented. This conclusion is supported by separate considerations of the vicinal and geminal19F–1H and 1H–1H coupling constants, of the long-range (4J) 1H–1H and 19F–1H coupling constants and of the 19F chemical shifts. The limitations of the above conformational model are discussed.

KETO–ENOL TAUTOMERISM IN β-DICARBONYLS STUDIED BY NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY: II. SOLVENT EFFECTS ON PROTON CHEMICAL SHIFTS AND ON EQUILIBRIUM CONSTANTS

1965 ◽  
Vol 43 (5) ◽  
pp. 1516-1526 ◽  
Author(s):  
Max T. Rogers ◽  
Jane L. Burdett
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Nuclear Magnetic Resonance Spectroscopy ◽  
Chemical Shifts ◽  
Equilibrium Constants ◽  
Tautomeric Equilibrium ◽  
Resonance Spectroscopy ◽  
Proton Chemical Shifts ◽  
Nuclear Magnetic

The effect of various solvents on the proton chemical shifts of a number of acyclic β-di-ketones and β-ketoesters has been observed by nuclear magnetic resonance spectroscopy. These shifts are discussed in terms of the dissociation of intramolecular and intermolecular hydrogen bonds on dilution. A complex of benzene with the enol tautomer of the β-dicarbonyl molecule is proposed. The effect of solvents on the position of the tautomeric equilibrium is discussed.

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