Abstract
The conformations of the macrolide antibiotics erythromycin A, clarithromycin and azithromycin in aqueous solution have been determined. All three drugs were found to exist predominantly in a "folded-out" conformation with the sugars in the chair-chair up-up form. In the case of clarithromycin this result is in agreement with the published literature; previous reports suggest that the erythromycin A sugars adopt boat conformations and that azithromycin has a significant folded-in contribution. The discrepancies are discussed in full. Erythromycin A 9-ketone was found to be flexible in the C6-C12 region. We present evidence for a new minor conformation (the 8-endo folded-out conformation) intermediate between the folded-out and folded-in conformations. Evidence for traces of other minor conformations s presented for erythromycin and azithromycin, whereas clarithromycin is conformationally very stable.
Original language | English |
---|---|
Pages (from-to) | 1645-1652 |
Number of pages | 7 |
Journal | Journal of the Chemical Society. Perkin Transactions 2 |
Issue number | 8 |
Publication status | Published - Aug 2000 |