InChI=1S/C19H20O8S/c1-11(2)3-7-14-16(21)10-13(18(22)19(14)23)6-4-12-5-8-15(20)17(9-12)27-28(24,25)26/h3-11,20-23H,1-2H3,(H,24,25,26)/b6-4+,7-3+