N′-(3,4-Dimethoxybenzylidene)acetohydrazide

The asymmetric unit of the title compound, C11H14N2O3, contains two independent molecules with close conformations; the C=N—N—C torsion angle is 176.4 (1)° in both molecules. In the crystal, intermolecular N—H⋯O and C—H⋯O hydrogen bonds link the molecules into chains running along the [01] direction.

The title compound ( Fig. 1) crystallizes with two independent molecules in the asymmetric unit. The side chains in the two independent molecules have the same orientations, with the C═N-N-C torsion angle being 176.4 (1)° in both molecules.
In the crystal structure, the molecules are linked into chains running along the [01-1] by N-H···O and C-H···O hydrogen bonds (Table 1).
Experimental 3,4-Methoxybenzaldehyde (1.66 g, 0.01 mol) and acetohydrazide (0.74 g, 0.01 mol) were dissolved in stirred methanol (25 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 85% yield. Single crystals suitable for X-ray analysis were obtained by slow evaporation of an ethanol solution at room temperature (m.p. 468-470 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 ). In the absence of significant anomalous scatterers, 1140 Friedel pairs were averaged.
supplementary materials sup-2 Figures Fig. 1. The content of asymmetric unit of the title compound. Displacement ellipsoids are drawn at the 30% probability level.

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.