ISSN:
0749-1581
Keywords:
Proton NMR
;
Vicinal couplings
;
Conformational analysis
;
Hydrogen bonding
;
Amino alcohols
;
Ephedrine
;
Pseudoephedrine
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Proton NMR spectra suggest that the conformation with trans vicinal hydrogens is favored for ephedrine as the free base in deuterium oxide, although in non-polar solvents, such as deuteriotrichloromethane, the gauche vicinal hydrogen conformations are favored, as has been reported previously. The conjugate acid has primarily gauche hydrogens. In contrast, the trans-hydrogen rotamers of pseudoephedrine dominate for both the non-protonated and protonated forms in deuterium oxide. Hydrogen bonding is unlikely to be as important as usually assumed in determining the conformational preferences of these substances.
Additional Material:
1 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260300905
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