Synthesis, antibacterial activities, and theoretical studies of dicoumarols†
Four dicoumarols (DC, 2-PyDC, 3-PyDC and 4-PyDC) were synthesized and characterized via IR, 1H NMR, HRMS, and single crystal X-ray crystallography. Two classical intramolecular O–H⋯O hydrogen bonds (HBs) stabilized their structures. The total HB energies in DC, 2-PyDC, 3-PyDC and 4-PyDC were calculated with the density functional theory (DFT) [B3LYP/6-31G*] method. The in vitro antibacterial activity of DC, 2-PyDC, 3-PyDC and 4-PyDC 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) was evaluated by observing the minimum inhibitory concentration and time–kill curves. The results showed that among all the compounds, 2-PyDC exhibited the most potent antibacterial activity.