InChI=1S/C20H20O10/c21-11-4-3-10(14(23)8-11)2-1-9-5-12(22)7-13(6-9)29-20-17(26)15(24)16(25)18(30-20)19(27)28/h1-8,15-18,20-26H,(H,27,28)/b2-1+