InChI=1S/C17H17NO9/c19-11(20)4-2-8-5-7-1-3-9(6-10(7)18-8)26-17-14(23)12(21)13(22)15(27-17)16(24)25/h1-6,12-15,17-18,21-23H,(H,19,20)(H,24,25)/b4-2+