tert-Butyl N′-[4-(2-pyridyl)benzylidene]hydrazinecarboxylate

In the molecule of the title compound, C17H19N3O2, the aromatic rings are oriented at a dihedral angle of 3.68 (3)°. In the crystal structure, intermolecular N—H⋯O hydrogen bonds link the molecules into chains along the a axis. A weak C—H⋯π interaction is also present.

In the molecule of the title compound, C 17 H 19 N 3 O 2 , the aromatic rings are oriented at a dihedral angle of 3.68 (3) . In the crystal structure, intermolecular N-HÁ Á ÁO hydrogen bonds link the molecules into chains along the a axis. A weak C-HÁ Á Á interaction is also present.

Comment
The title compound is an important intermediate in the syntheses of medicines. We report herein its crystal structure.
In the molecule of the title compound (Fig 1), the bond lengths (Allen et al., 1987) and angles are within normal ranges.
In the crystal structure, intermolecular N-H···O hydrogen bonds (Table 1) link the molecules into chains along the a axis, in which they may be effective in the stabilization of the structure. There also exists a weak C-H···π interaction (Table 1).

Experimental
The title compound was prepared according to a literature method (Sugi et al., 2002). Crystals suitable for X-ray analysis were obtained by dissolving the title compound (1.5 g) in methanol (25 ml) and evaporating the solvent slowly at room temperature for about 5 d.

Refinement
H atoms were positioned geometrically, with N-H = 0.86 Å (for NH) and C-H = 0.93 and 0.96 Å for aromatic and methyl H, respectively, and constrained to ride on their parent atoms, with U iso (H) = xU eq (C,N), where x = 1.5 for methyl H and x = 1.2 for all other H atoms. The absolute structure could not be determined reliably, and 338 Friedel pairs were averaged before the last cycle of refinement. Fig. 1. The molecular structure of the title molecule, with the atom-numbering scheme.

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 Rfactors(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.