InChI=1S/C20H18O7/c1-3-7-14(22)26-19-13(25-2)10-12(21)15-16(23)17(24)18(27-20(15)19)11-8-5-4-6-9-11/h4-6,8-10,21,24H,3,7H2,1-2H3