InChI=1S/C20H18O7/c1-20(2)15(23)6-10-5-9(3-4-13(10)27-20)19-18(25)17(24)16-12(22)7-11(21)8-14(16)26-19/h3-5,7-8,15,21-23,25H,6H2,1-2H3