InChI=1S/C20H16O8/c1-8(21)16-10(4-13(23)7-15(25)26)2-9-3-11-5-12(22)6-14(24)17(11)20(28)18(9)19(16)27/h2,4-6,22-24,27H,3,7H2,1H3,(H,25,26)/b13-4-