InChI=1S/C21H20O11/c22-10-7-13(25)15(12(24)6-5-9-3-1-2-4-11(9)23)14(8-10)31-21-18(28)16(26)17(27)19(32-21)20(29)30/h1-8,16-19,21-23,25-28H,(H,29,30)/b6-5+