InChI=1S/C21H20O10/c1-28-15-6-10(4-12(23)17(15)25)20-16(5-9-2-3-11(22)7-14(9)30-20)31-21-19(27)18(26)13(24)8-29-21/h2-7,13,18-19,21,24,26-27H,8H2,1H3,(H2-,22,23,25)/p+1