Design, synthesis and antibacterial activity of a novel alkylide: 3-O-(3-aryl-propenyl)clarithromycin derivatives.

A series of novel 3-O-(3-aryl-propenyl)clarithromycin derivatives were designed, synthesized and evaluated for their in vitro antibacterial activities. Regioselective allylation at 3-OH was efficiently achieved in the presence of 9-oxime ether, compared with 9-keto. Most of the side chains were identified as the 3-O-(3-aryl-Z-prop-1-enyl) group, not the expected 3-O-(3-aryl-E-prop-2-enyl) group. Some derivatives of this series showed improved activities against erythromycin-resistant Staphylococcus aureus and Staphylococcus pneumoniae compared with the reference compound, clarithromycin, but weaker activities against susceptible strains.