InChI=1S/C19H18O7S/c1-11(2)3-4-12-7-13(5-6-17(12)26-27(22,23)24)18-19(25-18)14-8-15(20)10-16(21)9-14/h3-10,18-21H,1H2,2H3,(H,22,23,24)/b4-3+