InChI=1S/C16H16O6S/c1-21-16-11-14(17)8-7-13(16)4-2-3-12-5-9-15(10-6-12)22-23(18,19)20/h2-3,5-11,17H,4H2,1H3,(H,18,19,20)/b3-2+