InChI=1S/C22H20O9/c1-8(2)6-11(23)14-10(4)17-20(16(25)19(14)29-5)31-22(28)13-9(3)7-12(24)15(21(26)27)18(13)30-17/h6-7,24-25H,1-5H3,(H,26,27)