(Z)-3-[(2-Aminobenzyl)amino]-1-phenylbut-2-en-1-one

In the title compound, C17H18N2O, the aromatic rings are almost normal to one another, making a dihedral angle of 89.00 (8)°. There is an intramolecular N—H⋯O hydrogen bond in the molecule enclosing an S(6) ring motif. In the crystal, molecules are linked by N—H⋯O hydrogen bonds, forming chains along [010].


Comment
Chalcones are a major class of natural products with widespread distribution in fruits, vegetables, spices, tea and soy based foodstuff and have recently been the subject of great interest for their interesting pharmacological activities (Di Carlo et al., 1999). Chalcones and flavonoids have been reported to be active anti-tuberculosis agents (Lin et al.,2002).
Against this background and in order to obtain detailed information on molecular conformation in the solid state, an Xray study of the title compound was carried out.
In the crystal, molecules are linked by N-H···O hydrogen bonds forming chains along the b axis direction (Table 1 and

Experimental
To a warm ethanolic solution (25 ml) of 2-aminobenzylamine (0.25 g, 0.2 mmol), an ethanolic solution of benzylacetone (0.3 g, 0.2 mmol) was added dropwise and the resulting solution was refluxed for 3 h. The solution was then filtered hot and allowed to stand at room temperature. After slow evaporation of the solvent at 298 K, block-like colourless crystals of the title compound were obtained. They were filtered off, washed with cold methanol and dried [Yield 0.45 g, 83%].

Refinement
Hydrogen atoms were placed in calculated positions and refined as riding atoms: N-H = 0.86 Å, C-H = 0.93-0.97 Å, with Uiso(H) = 1.5Ueq(C-methyl) and = 1.2Ueq(N,C) for other H atoms.  The molecular structure of the title compound, with atom labelling. Displacement ellipsoids are drawn at the 30% probability level. The intramolecular N-H···O hydrogen bond is shown as a dashed line (see Table 1 for details).

Figure 2
A partial view along the a axis of the crystal packing of the title compound. The hydrogen bonds are shown as dashed lines (see Table 1 for details).

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.