InChI=1S/C21H21NO9S/c1-26-13-8-11-12(9-14(13)27-2)18(31-32(23,24)25)17-15-10(6-7-22-17)19(28-3)21(30-5)20(29-4)16(11)15/h6-9,18H,1-5H3,(H,23,24,25)