| abstract |
Novel macrolide antibiotics (I) comprise 3,6-hemiketals of 9a-azalides. Macrolides of formula (I) and their addition salts with inorganic or organic acids are new. [Image] R1OH or L-cladinosyl of formula (a); R2H or silyl; R3H; R6OH; or R3+R6ether group; R4H, 1-4C acyl or COO(CH2)nAr; n : 1-7; Ar : optionally substituted up to 18C aryl; R5H, Me or COO(CH2)nAr; R7, R8H, l-12C alkyl or silyl; or R7+R8cyclic carbonate. [Image] An independent claim is also included for the preparation of (I) from azithromycin. ACTIVITY : Antibacterial. 12-O-Methyl-azithromycin (Ia) exhibited MIC values (in mu g/ml) of 0.25, 0.12, 0.25, 1 and 0.5 against Staphylococcus aureus ATCC 6538 P, Micrococcus flavus ATCC 12228, Streptococcus faecalis ATCC 8043, Bacillus subtilis ATCC 11778 and Escherichia coli ATCC 10536 respectively. Corresponding values for azithromycin were (mu g/ml): 1, 0.25, 0.5, 0.5 and 1 respectively. MECHANISM OF ACTION : None given. |