InChI=1S/C17H17NO7S/c19-14(11-12-7-3-1-4-8-12)18-15(17(20)21)16(25-26(22,23)24)13-9-5-2-6-10-13/h1-10,15-16H,11H2,(H,18,19)(H,20,21)(H,22,23,24)