InChI=1S/C20H18O7/c1-8(21)20(27)6-5-9-11(7-20)18(25)14-15(16(9)23)19(26)13-10(17(14)24)3-2-4-12(13)22/h2-4,8,21-23,25,27H,5-7H2,1H3/t8?,20-/m1/s1