Novel azithromycin derivatives with the C-4″ bisamide side chains: synthesis and biological evaluation against gram-positive bacteria

Abstract

Novel azithromycin (AZM) derivatives with the C-4″ bisamide side chains were synthesized and evaluated for their in vitro antibacterial activities. The 4″-O-(benzamido)alkyl carbamates showed excellent activity against the erythromycin-susceptible Streptococcus pneumoniae and exhibited greatly improved activity against erythromycin-resistant S. pneumoniae. Among them, compounds 5g and 6g, which had the same electron-withdrawing group, 3,5-dinitrophenyl, on the termination of their C-4″ bisamide side chains, demonstrated the most potent activity against erythromycin-resistant S. pneumoniae expressing the erm gene, the mef gene and the erm and mef genes, showing 128-fold, 33-fold and 32-fold improved activity in comparison with the parent AZM.The Journal of Antibiotics advance online publication, 15 February 2012; doi:10.1038/ja.2012.3.