Synthesis and antibacterial activities of 6-O-methylerythromycin A 9-O-(3-aryl-2-propenyl) oxime ketolide, 2,3-enol ether, and alkylide analogues.

ABSTRACT

A facile and efficient route was presented to achieve 3-keto-clarithromycin 9-O-(3-aryl-E-2-propenyl) oxime derivatives 8, 2,3-dehydro-3-O-allyl-clarithromycin 9-O-(3-aryl-E-2-propenyl) oxime derivatives 11, and 3-O-allyl-clarithromycin 9-O-(3-aryl-E-2-propenyl) oxime derivatives 12. Among them, compound 8, particularly 8d (Ar = 6-quinolyl), exhibited improved antibacterial activities against erythromycin-susceptible Staphylococcus aureus and Streptococcus pneumoniae, and greatly enhanced activities against the resistant strains encoded by erm and mef genes, as compared to clarithromycin and azithromycin.