InChI=1S/C19H20O6S/c20-17(12-10-15-6-2-1-3-7-15)9-5-4-8-16-11-13-18(21)19(14-16)25-26(22,23)24/h1-3,5-7,9,11,13-14,21H,4,8,10,12H2,(H,22,23,24)/b9-5+