A. Awan et al., The conformations of the macrolide antibiotics erythromycin A, azithromycin and clarithromycin in aqueous solution: a H-1 NMR study, J CHEM S P2, (8), 2000, pp. 1645-1652
Citations number
34
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2
The conformations of the macrolide antibiotics erythromycin A, clarithromyc
in and azithromycin in aqueous solution have been determined. All three dru
gs were found to exist predominantly in a "folded-out" conformation with th
e sugars in the chair-chair up-up form. In the case of clarithromycin this
result is in agreement with the published literature; previous reports sugg
est that the erythromycin A sugars adopt boat conformations and that azithr
omycin has a significant folded-in contribution. The discrepancies are disc
ussed in full. Erythromycin A 9-ketone was found to be flexible in the C6-C
12 region. We present evidence for a new minor conformation (the 8-endo fol
ded-out conformation) intermediate between the folded-out and folded-in con
formations. Evidence for traces of other minor conformations is presented f
or erythromycin and azithromycin, whereas clarithromycin is conformationall
y very stable.