InChI=1S/C20H19NO9S/c1-20(9-29-31(25,26)27)7-6-10-14(30-20)8-12-15(17(10)23)18(24)11-4-5-13(22)19(28-3)16(11)21(12)2/h4-8,22-23H,9H2,1-3H3,(H,25,26,27)