(E)-Methyl N'-(3-methoxy-benzyl-idene)hydrazinecarboxyl-ate.

The title compound, C(10)H(12)N(2)O(3), crystallizes with two independent mol-ecules in the asymmetric unit which differ in the orientation of the meth-oxy group. Each independent mol-ecule adopts a trans configuration with respect to the C=N bond. In the crystal structure, mol-ecules are linked into chains running along [001] by N-H⋯O and N-H⋯N hydrogen bonds. In addition, an inter-molecular C-H⋯π inter-action is observed.

The title compound, C 10 H 12 N 2 O 3 , crystallizes with two independent molecules in the asymmetric unit which differ in the orientation of the methoxy group. Each independent molecule adopts a trans configuration with respect to the C N bond. In the crystal structure, molecules are linked into chains running along [001] by N-HÁ Á ÁO and N-HÁ Á ÁN hydrogen bonds. In addition, an intermolecular C-HÁ Á Á interaction is observed.

Comment
Benzaldehydehydrazone derivatives have attracted much attention due to their pharmacological activity (Parashar et al., 1988) and their photochromic properties (Hadjoudis et al., 1987). They are important intermediates of 1,3,4-oxadiazoles, which have been reported to be versatile compounds with many interesting properties (Borg et al., 1999). Metal complexes based on Schiff bases have received considerable attention because they can be utilized as model compounds of active centres in various proteins and enzymes (Kahwa et al., 1986;Santos et al., 2001). We report here the crystal structure of the title compound (Fig. 1).
In the crystal structure, molecules are linked into chains running along the [001] by N-H···O and N-H···N hydrogen bonds. In addition, an intermolecular C-H···π interaction is observed (Table 1).
Experimental 3-Methoxybenzaldehyde (1.36 g, 0.01 mol) and methyl hydrazinecarboxylate (0.90 g, 0.01 mol) were dissolved in stirred methanol (20 ml) and left for 2.5 h at room temperature. The resulting solid was filtered off and recrystallized from ethanol to give the title compound in 95% yield. Single crystals suitable for X-ray analysis were obtained by slow evaporation of an ethanol solution at room temperature (m.p. 436-438 K).

Refinement
H atoms were positioned geometrically (N-H = 0.86 Å and C-H = 0.93 or 0.96 Å) and refined using a riding model, with U iso (H) = 1.2U eq (C,N) and 1.5U eq (C methyl ). A rotating group model was used for the methyl groups.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq O1 0.68188 (7