Cryoscopic and nuclear magnetic resonance studies of interaction between acetylacetone and water in benzene

1977 ◽  
Vol 55 (9) ◽  
pp. 1473-1479 ◽  
Author(s):  
Masanao Kato ◽  
Hitoshi Watarai ◽  
Nobuo Suzuki
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Association Constant ◽  
Freezing Point ◽  
Benzene Solution ◽  
Resonance Spectroscopy ◽  
Freezing Point Depression ◽  
Magnetic Resonance Studies ◽  
Enol Tautomer ◽  
Nuclear Magnetic

The interaction between acetylacetone and water in benzene solution has been examined by freezing point depression and nuclear magnetic resonance spectroscopy. The experimental results suggest that a 1:1 associated complex between acetylacetone and water is formed in benzene solution saturated with water, and the association constant is estimated to be 2.4 ± 0.1 (kg solvent/mol). By comparison with the results of methylacetylacetone and dimethylacetylacetone, it is suggested that the enol tautomer of acetylacetone preferentially associates with water.

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.

Studies of specifically fluorinated carbohydrates. Part IV. Addition of the elements of "CIF" to D-glucal triacetate

1969 ◽  
Vol 47 (3) ◽  
pp. 379-385 ◽  
Author(s):  
L. D. Hall ◽  
J. F. Manville
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Benzene Solution ◽  
Major Product ◽  
Magnetic Resonance Studies ◽  
Nuclear Magnetic

Reaction of chlorine with a suspension of D-glucal triacetate and silver monofluoride in an acetonitrile/benzene solution, affords a mixture of the four possible 2-chloro-2-deoxy-D-glycopyranosyl fluoride triacetates. The structures of these derivatives have been established by nuclear magnetic resonance studies and confirmed by independent syntheses. The major product is 2-chloro-2-deoxy-β-D-glucopyranosyl fluoride triacetate. These results are compared with those from the related "BrF" and "IF" additions.

Nuclear magnetic resonance studies of the interaction of inhibitors with chymotrypsin. N-Trifluoroacetyl derivatives of phenylalanine

1973 ◽  
Vol 26 (1) ◽  
pp. 135 ◽  
Author(s):  
BC Nicholson ◽  
TM Spotswood
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shift ◽  
Magnetic Resonance Spectroscopy ◽  
Active Site ◽  
Molar Ratio ◽  
Resonance Spectroscopy ◽  
Magnetic Resonance Studies ◽  
Derivatives Of ◽  
Nuclear Magnetic

The binding of N-trifluoroacetyl derivatives of phenylalanine to the enzyme chymotrypsin has been studied by 19F nuclear magnetic resonance spectroscopy. Separate resonances are observed for the D- and L- enantiomers in the presence of chymotrypsin and their difference in chemical shift is dependent on the molar ratio of inhibitor to enzyme. The results are interpreted in terms of the known structure of the active site and possible modes of reorientation of the aromatic ring in its binding site. Approximate and accurate methods of quantifying the data are discussed and values for the dissociation constant (KI) of the EI complex, and the change in chemical shift on binding, are reported for the D-isomers.

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