InChI=1S/C20H20O11/c1-28-13-6-9(3-5-12(13)21)2-4-10-7-11(8-14(22)29-10)30-20-17(25)15(23)16(24)18(31-20)19(26)27/h2-8,15-18,20-21,23-25H,1H3,(H,26,27)/b4-2+