InChI=1S/C21H21N3O4S/c1-15-20(6-4-5-16-7-9-17(10-8-16)23(2)3)21(25)24(22-15)18-11-13-19(14-12-18)29(26,27)28/h4-14H,1-3H3,(H,26,27,28)/b5-4+,20-6-