RESUMO
A series of novel 11,12-cyclic carbonate azithromycin 4''-O-carbamate derivatives were designed, synthesized and evaluated for their in vitro antibacterial activities. Compounds 7b and 7d were the most effective (0.5 and 0.5 microg ml(-1)) against two strains of erythromycin-resistant Streptococcus pneumoniae whose resistance was encoded by the erm gene and the erm and mef genes, respectively. Compounds 7a, 7e and 7g showed significantly potent activity against erythromycin-susceptible strains such as Staphylococcus aureus and S. pyogenes. These results suggest that the introduction of the prolonged arylalkylcarbamoyl group to the C-4'' position can dramatically enhance the activity against erythromycin-resistant bacteria encoded by the erm gene or the erm and mef genes.