InChI=1S/C21H22O12/c1-29-11-7-10(31-14(22)8-11)4-3-9-5-12(30-2)15(23)13(6-9)32-21-18(26)16(24)17(25)19(33-21)20(27)28/h3-8,16-19,21,23-26H,1-2H3,(H,27,28)/b4-3+