InChI=1S/C20H20O8/c21-13(11-7-3-1-4-8-11)17(12-9-5-2-6-10-12)27-20-16(24)14(22)15(23)18(28-20)19(25)26/h1-10,14-18,20,22-24H,(H,25,26)