InChI=1S/C19H20O8S/c1-11(2)3-7-14-16(21)9-12(10-17(14)22)4-5-13-6-8-15(20)19(18(13)23)27-28(24,25)26/h3-6,8-10,20-23H,7H2,1-2H3,(H,24,25,26)/b5-4+