InChI=1S/C20H20O11/c21-10-6-9(3-1-8-2-4-11-12(5-8)29-7-28-11)30-20(27)13(10)17-15(23)14(22)16(24)18(31-17)19(25)26/h1-5,9,13-18,22-24H,6-7H2,(H,25,26)/b3-1+