InChI=1S/C20H20O11/c21-10-5-8(1-2-9-3-4-12(22)14(24)13(9)23)6-11(7-10)30-20-17(27)15(25)16(26)18(31-20)19(28)29/h1-7,15-18,20-27H,(H,28,29)/b2-1+