InChI=1S/C21H20O11/c22-10-7-13(24)15(14(25)8-10)12(23)5-4-9-2-1-3-11(6-9)31-21-18(28)16(26)17(27)19(32-21)20(29)30/h1-8,16-19,21-22,24-28H,(H,29,30)/b5-4+