New biscoumarin derivatives: synthesis, crystal structure, theoretical study and antibacterial activity against Staphylococcus aureus.

Five novel biscoumarins 1-5 were synthesized and characterized. In these compounds, two classical asymmetrical intramolecular O-H···O hydrogen bonds were used to stabilize the whole structures and the HB energies were performed with the density functional theory (DFT) [B3LYP/6-31G*] method. The five compounds were evaluated for their in vitro antibacterial activities 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) by the means of minimum inhibitory concentration and time-kill curves.