InChI=1S/C20H20O10/c21-11-5-2-9(3-6-11)1-4-10-7-12(22)8-13(14(10)23)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+