InChI=1S/C20H20O8/c1-6-8-9-10(13(22)12(6)21)14(23)16(27-5)15(24)11(9)17(25)20(26)18(8)28-7(2)19(20,3)4/h7,21,23-24,26H,1-5H3/t7-,20+/m0/s1