ISSN:
0749-1581
Keywords:
1H NMR
;
13C NMR
;
Roxithromycin
;
Solution-state conformation
;
Macrolide Antibiotic
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
A complete assignment of the 1H and 13C NMR spectra of roxithromycin in deuteriochloroform, methanol-d4 and D2O was made using different two-dimensional (2D) chemical shift correlation methods. The coupling constants observed by 1H NMR and the NOEs show that the predominant conformation of roxithromycin in CDCl3 solution is very similar to that in the crystalline state. However, variable-temperature and variable-solvent NMR experiments show that the major conformation of roxithromycin presents a conformational flexibility in the C-2-C-8 region and, particularly, in the C-4-C-5 bond of the molecule. The NOE data indicate that the 9-[O-(2,5-dioxahexyl)oxime] chain is directed towards the 6-OH, certainly involving an intramolecular hydrogen bond. This results in a globular structure for roxithromycin with less freedom for the macrolactone ring and the sugar units.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260281003
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