Synthesis, crystal structures, and anti-drug-resistant Staphylococcus aureus activities of novel 4-hydroxycoumarin derivatives.

Four novel 4-hydroxycoumarin derivatives (4-MBH, 3-MBH, 4-MDT and 3-MDT) were successfully synthesized and their structures were verified by single-crystal X-ray crystallography. All target compounds were evaluated for their in vitro antibacterial activity against Staphylococcus aureus (S. aureus ATCC 29213), methicillin-resistant S. aureus (MRSA XJ 75302), vancomycin-intermediate S. aureus (Mu50 ATCC 700699), and USA 300 (Los Angeles County clone, LAC). The minimum inhibitory concentration and time-kill curves were obtained for the test compounds and antibiotics. Among the tested compounds, 3-MBH showed the most potent antibacterial activities.