5-(4-Methoxyphenyl)-3-(pyridin-2-yl)-4,5-dihydro-1H-pyrazole-1-carbothioamide

In the title compound, C16H16N4OS, the dihedral angle between the pyridine and benzene rings is 81.08 (6)°. The pyrazole ring makes dihedral angles of 12.36 (7) and 87.96 (6)°, respectively, with the pyridine and benzene rings. In the crystal, molecules are linked by N—H⋯O and N—H⋯S hydrogen bonds and a weak C—H⋯S interaction into a layer parallel to the ab plane. Weak C—H⋯π and π–π interactions [centroid–centroid distances = 3.7043 (9) and 3.8120 (7) Å] are also observed.


Related literature
Cg3 is the centroid of the C9-C14 ring.  In the title molecule ( Fig. 1), C 16 H 16 N 4 OS, the dihedral angle between the pyridine and benzene ring is 81.08 (6)°, whereas the pyrazole ring makes dihedral angles of 12.36 (7) and 81.08 (6)° with the pyridine and benzene rings, respectively.
The reaction mixture was vigorously stirred and refluxed for 3 h. The pale-yellow solid of the title compound obtained after cooling off the reaction was then filtered off under vacuum. Pale yellow block-shaped single crystals of the title compound suitable for X-ray structure determination were recrystallized from methanol/ethanol (1:2 v/v) by slow evaporation of the solvent at room temperature after several days (m.p. 468-469 K).

Refinement
Amide H atoms were located in a difference maps and refined freely [N-H = 0.847 (18) and 0.84 (2) Å]. The remaining H atoms were positioned geometrically and allowed to ride on their parent atoms, with C-H = 0.93 Å for aromatic, 0.98 Å for CH, 0.97 Å for CH 2 and 0.96 Å for CH 3 . The U iso (H) values were constrained to be 1.5U eq (C) for methyl H atoms and 1.2U eq (C) for the remaining H atoms. A rotating group model was used for the methyl groups. Fig. 1. The molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atom-numbering scheme.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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.