Crystal structure and activities of three biscoumarin derivatives against Staphylococcus aureus

Three new biscoumarin derivatives, namely, 3,3′-[(4-nitrophenyl)methylene]bis(4-hydroxy-2H-chromen-2-one) (NBH), 3,3′-[(4-methoxyphenyl)methylene]bis(4-hydroxy-2H-chromen-2-one) (MBH) and 3,3′-[(4-chloromethylphenyl)methylene]bis(4-hydroxy-2H-chromen-2-one) (CBH) were successfully synthesized and their structures were verified by single crystal X-ray crystallography. In their structures, there are two intramolecular H-bonds and the corresponding H-bond energies were calculated by DFT method. The antibacterial activities of NBH, MBH and CBH in vitro against drug-sensitive Staphylococcus aureus (ATCC 29213) and methicillin-resistant S. aureus (isolated MRSA strains) were further investigated.