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