InChI=1S/C21H20O11/c1-7-16(26)18(28)19(29)21(30-7)32-15-6-10-11(23)4-9(22)5-14(10)31-20(15)8-2-12(24)17(27)13(25)3-8/h2-7,16,18-19,21,26,28-29H,1H3,(H4-,22,23,24,25,27)/p+1