InChI=1S/C19H20O8S/c1-19(2,23)8-7-14-16(21)9-13(10-17(14)22)4-3-12-5-6-15(20)18(11-12)27-28(24,25)26/h3-11,20-23H,1-2H3,(H,24,25,26)/b4-3+,8-7+