ISSN:
0749-1581
Schlagwort(e):
Indirect heteronuclear NOEs
;
1H-19F-1H and 1H-19F-13C systems
;
Three-spin effects
;
Anomalous intensity effects
;
Conformational analysis
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
Indirect nuclear Overhauser enhancements through 19F have been determined for the three-spin systems 1H-19F-1H and 1H-19F-13C by steady-state presaturation of the appropriate proton, and applied to the conformational analysis of 5-bromo-2-fluoro-4-nitroacetanilide. The 1H NOE difference spectra at 400 MHz showed antiphase doublets for protons undergoing simultaneous dipolar relaxation with, and scalar coupling to, 19F. Similarly, in the 13C selective NOE difference spectrum at 100 MHz, the two lines of the fluorine-bearing carbon showed negative enhancement factors of different magnitude on presaturation of the appropriate proton. The use of these anomalous intensity effects in conformational analysis is illustrated.
Zusätzliches Material:
4 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/mrc.1260250617
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