Ethyl 5-amino-3-(pyridin-4-yl)-1-(2,4,6-tri-chloro-phen-yl)-1H-pyrazole-4-carb-oxyl-ate dimethyl sulfoxide hemisolvate.

The asymmetric unit of the title compound, C(17)H(13)Cl(3)N(4)O(2)·0.5C(2)H(6)OS, contains two almost identical mol-ecules and one dimethyl sulfoxide (DMSO-d(6)) solvent mol-ecule. The pyrazole ring forms dihedral angles of 54.6 (4) and 80.0 (4)° in one mol-ecule, and dihedral angles of 54.2 (4) and 81.2 (4)° in the other mol-ecule, with the directly attached pyridine and trichloro-phenyl rings, respectively. The dihedral angles of the pyridine and trichloro-phenyl rings are 51.2 (4) and 52.0 (4)°, respectively. The crystal packing is characterized by intra- and inter-molecular hydrogen bonds. The crystal is a nonmerohedral twin with a contribution of 0.488 (1) for the minor twin component. The terminal ethyl group of one mol-ecule and the S atom of DMSO are disordered over two sites.