InChI=1S/C21H22O11S/c1-5-11(2)20(24)31-18-16-13(8-6-12-7-9-14(22)30-17(12)16)29-19(18)21(3,4)32-15(23)10-28-33(25,26)27/h5-9,18-19H,10H2,1-4H3,(H,25,26,27)/b11-5+