InChI=1S/C20H20O11S/c1-28-15-6-3-12(9-14(15)21)5-8-19(22)30-18(20(23)24)11-13-4-7-16(29-2)17(10-13)31-32(25,26)27/h3-10,18,21H,11H2,1-2H3,(H,23,24)(H,25,26,27)/b8-5+/t18-/m0/s1