InChI=1S/C21H18O6/c1-10(2)4-6-12-14(23)9-16-18(19(12)25-3)20-17(21(24)27-16)13-7-5-11(22)8-15(13)26-20/h4-5,7-9,22-23H,6H2,1-3H3