InChI=1S/C21H28O11/c1-7-4-12-14(9(3)20(29)30-12)13(5-8(2)11(23)6-10(7)22)31-21-17(26)15(24)16(25)18(32-21)19(27)28/h4,10-18,21-26H,2-3,5-6H2,1H3,(H,27,28)/b7-4+