Ethyl 5-amino-3-(pyridin-4-yl)-1-(2,4,6-trichlorophenyl)-1H-pyrazole-4-carboxylate dimethyl sulfoxide hemisolvate

The asymmetric unit of the title compound, C17H13Cl3N4O2·0.5C2H6OS, contains two almost identical molecules and one dimethyl sulfoxide (DMSO-d 6) solvent molecule. The pyrazole ring forms dihedral angles of 54.6 (4) and 80.0 (4)° in one molecule, and dihedral angles of 54.2 (4) and 81.2 (4)° in the other molecule, with the directly attached pyridine and trichlorophenyl rings, respectively. The dihedral angles of the pyridine and trichlorophenyl rings are 51.2 (4) and 52.0 (4)°, respectively. The crystal packing is characterized by intra- and intermolecular 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 molecule and the S atom of DMSO are disordered over two sites.

The asymmetric unit of the title compound, C 17 H 13 Cl 3 N 4 O 2 Á-0.5C 2 H 6 OS, contains two almost identical molecules and one dimethyl sulfoxide (DMSO-d 6 ) solvent molecule. The pyrazole ring forms dihedral angles of 54.6 (4) and 80.0 (4) in one molecule, and dihedral angles of 54.2 (4) and 81.2 (4) in the other molecule, with the directly attached pyridine and trichlorophenyl rings, respectively. The dihedral angles of the pyridine and trichlorophenyl rings are 51.2 (4) and 52.0 (4) , respectively. The crystal packing is characterized by intra-and intermolecular 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 molecule and the S atom of DMSO are disordered over two sites.  BAT thanks the Alexander von Humboldt Foundation for funding.
The asymmetric unit of the title compound contains two almost identical molecules and DMSO-d6 ( Fig. 1). In molecule A the pyrazole ring forms dihedral angles of 54.6 (4)° and 80.0 (4)° with the directly attached pyridine and trichlorophenyl rings, respectively. In molecule B the pyrazole ring forms dihedral angels of 54.2 (4)° and 81.2 (4)° with the pyridine and trichlorophenyl rings, respectively. The dihedral angle of the pyridine and trichlorophenyl rings in molecules A and B are 51.1 (4)° and 52.0 (4)°, respectively.
The crystal packing (Fig. 2) shows that the amino function (N12) acts as a hydrogen bond donor forming an intramolecular hydrogen bond to the oxygen atom (O15) and two intermolecular hydrogen bonds to the nitrogen atom of was added dropwise and the reaction was stirred over night. The precipitate was filtered from the reaction mixture, washed with water and recrystallized from hot ethanol. Yield: 56%. Suitable crystals for X-ray were taken from the NMR-tube in DMSO-d 6 .

Refinement
Hydrogen atoms attached to carbons were placed at calculated positions with C-H = 0.95 Å (aromatic) or 0.98-0.99 Å (sp 3 C-atom). All H atoms were refined in the riding-model approximation with isotropic displacement parameters (set at 1.2-1.5 times of the U eq of the parent atom). Obtained crystals were twinned. Using the twin matrix -1 0 0, 0 -1 0, -.4 0 1 with BSAF 0.488 (2) the structure refinement was successful. The solvent molecule and the ethyl group are disorderd with site occupation factors of 0.55 and 0.737 (6) for the major occupied site. The displacement ellipsoids of the atoms C17A, C17C and C2B were restrained to an isotropic behaviour with an effective esd of 0.01 for C17A and C17C and 0.005 for C2B.   Crystal structure of the title compound with view along the a-axis. Hydrogen bonding is shown with dashed lines.
Molecule A coloured in black, B in red and DMSO in green.   (10) Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.