InChI=1S/C20H14O8/c1-23-18-16-9(2-3-24-16)4-10-17(18)28-15-7-25-12-6-14-13(26-8-27-14)5-11(12)20(15,22)19(10)21/h2-6,15,22H,7-8H2,1H3