InChI=1S/C22H20O12/c1-31-19-12(33-22-17(28)15(26)16(27)20(34-22)21(29)30)5-3-9-14(25)13(32-18(9)19)7-8-2-4-10(23)11(24)6-8/h2-7,15-17,20,22-24,26-28H,1H3,(H,29,30)/b13-7+