InChI=1S/C21H22O9S/c1-28-20-11-14(5-9-18(20)24)3-7-16(22)13-17(23)8-4-15-6-10-19(21(12-15)29-2)30-31(25,26)27/h4-6,8-13,22,24H,3,7H2,1-2H3,(H,25,26,27)/b8-4+,16-13-