InChI=1S/C13H18N2O6S/c14-8-7-11(16)9-15-13(17)6-3-10-1-4-12(5-2-10)21-22(18,19)20/h1-6,11,16H,7-9,14H2,(H,15,17)(H,18,19,20)/b6-3+