VIBRATIONAL CIRCULAR DICHROISM AND RAMAN OPTICAL ACTIVITY IN EPHEDRINE MOLECULES
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Date
1991
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Publisher
Ohio State University
Abstract
The vibrational circular dichroism (VCD) spectra in the OH-, NH- and CH-stretching regions, and the dual circular polarization $(DCP_{I}$) Raman optical activity (ROA) spectra in the 800-1700 $cm^{-1}$ region of (1S,2R)-ephedrine, (1S,2R)-norephedrine, (1S,2S)-pseudoephedrine, and (1S,2S)-norpseudoephedrine will be presented. The hydrogen stretching absorption spectra of the free base molecules in dilute $C_{2}Cl_{4}$ solution reflect differences in intramolecular hydrogen bonding among these amino alcohol drug molecules. The corresponding VCD features, which uniquely characterize each stereoisomer, will be correlated with the rotameric populations deduced from NMR studies. The Raman spectra, obtained for aqueous solutions of the hydrochloride salts, are nearly identical for the four ephedrines. In contrast, the ROA spectra are quite different. Several ROA features can be identified that serve as configurational markers.""
Description
Author Institution: Department of Chemistry, Syracuse University; Department of Chemistry, Syracuse University