InChI=1S/C24H20O8/c25-15-10-17(26)16-12-21(31-22(29)7-6-13-4-2-1-3-5-13)24(32-20(16)11-15)14-8-18(27)23(30)19(28)9-14/h1-11,21,24-28,30H,12H2/b7-6+/t21-,24-/m1/s1