InChI=1S/C20H20O10/c21-11-7-10(14(23)13(22)8-11)4-1-9-2-5-12(6-3-9)29-20-17(26)15(24)16(25)18(30-20)19(27)28/h1-8,15-18,20-26H,(H,27,28)/b4-1+