InChI=1S/C19H17NO9S/c1-19(7-27-19)18-17(29-30(24,25)26)13-11(28-18)6-10(22)12-15(13)20(2)14-8(16(12)23)4-3-5-9(14)21/h3-6,17-18,21-22H,7H2,1-2H3,(H,24,25,26)