InChI=1S/C21H19NO4/c1-14-17(13-21(24)25)18-12-16(26-2)9-10-19(18)22(14)20(23)11-8-15-6-4-3-5-7-15/h3-12H,13H2,1-2H3,(H,24,25)/b11-8+