InChI=1S/C20H20O11/c21-10-4-3-8(1-2-9-5-11(22)14(24)12(23)6-9)7-13(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+