ISSN:
0749-1581
Keywords:
1H and 13C NMR
;
2D NMR
;
Spectral assignment
;
Oxymorphone series
;
X-ray
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The 1H (400 MHz) and carbon 13C (100 MHz) NMR peak assignments of two oxymorphone alkaloids including the free base and the hydrochloride (HCl) salt and four oxycodone alkaloids including the free base, the HCl salt, the N-oxide and the methyl iodide quaternary salt were assigned using a variety of two-dimensional NMR techniques. Proton coupling constants provide evidence that the cyclohexanone (D) and the piperidine (E) rings adopt slightly distorted chair conformations. Nuclear Overhauser enhancement difference experiments indicate that the conformation of the N-methyl group is equatorial and the O-methyl group prefers a cis orientation relative to C-2. The minor component observed in aqueous 1H and 13C NMR spectra of each HCl salt and the N-oxide is produced by the reaction of the alkaloid with water at the C-6 carbonyl, forming a gem-diol, and is not due to the presence of the axial isomer. The first complete solution and solid conformational analyses of oxycodone N-oxide by NMR and x-ray crystallography have been investigated. The data indicate that the C-14-OH proton is intramolecularly hydrogen bonded to the NO oxygen.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260310318
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