InChI=1S/C18H19NO7S/c1-25-15-8-6-14(7-9-15)17(20)12-19-18(21)10-5-13-3-2-4-16(11-13)26-27(22,23)24/h2-11,17,20H,12H2,1H3,(H,19,21)(H,22,23,24)/b10-5+