InChI=1S/C13H18N2O7S/c14-7-11(16)12(17)8-15-13(18)6-3-9-1-4-10(5-2-9)22-23(19,20)21/h1-6,11-12,16-17H,7-8,14H2,(H,15,18)(H,19,20,21)/b6-3+