InChI=1S/C18H19NO7S/c1-25-16-9-5-14(6-10-16)17(26-27(22,23)24)12-19-18(21)11-4-13-2-7-15(20)8-3-13/h2-11,17,20H,12H2,1H3,(H,19,21)(H,22,23,24)/b11-4+