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