(E)-N′-[1-(4-Aminophenyl)ethylidene]benzohydrazide

Crystals of the title compound, C15H15N3O, were obtained from a condensation reaction of benzohydrazide and 1-(4-aminophenyl)ethanone. The molecule assumes an E configuration with the aminophenyl and benzohydrazide units located on opposite sites of the C=N double bond. In the crystal structure, the benzene rings of the molecule are slightly twisted with respect to the central hydrazide, the dihedral angles being 18.22 (12) and 27.62 (12)°. The crystal structure contains intermolecular N—H⋯O and weak C—H⋯N hydrogen bonding.

Crystals of the title compound, C 15 H 15 N 3 O, were obtained from a condensation reaction of benzohydrazide and 1-(4aminophenyl)ethanone. The molecule assumes an E configuration with the aminophenyl and benzohydrazide units located on opposite sites of the C N double bond. In the crystal structure, the benzene rings of the molecule are slightly twisted with respect to the central hydrazide, the dihedral angles being 18.22 (12) and 27.62 (12) . The crystal structure contains intermolecular N-HÁ Á ÁO and weak C-HÁ Á ÁN hydrogen bonding.

Comment
Since some hydrazone derivatives have shown to be potential DNA damaging and mutagenic agents (Okabe et al., 1993), a series of new hydrazone derivatives have been prepared in our laboratory (Shan et al., 2003). As part of the ongoing investigation, the title compound has recently been prepared and its crystal structure is reported here.
The molecular structure of the title compound is shown in Fig. 1. The N2-C8 bond distance of 1.292 (2) Å indicates a typical C═N double bond. The aminophenyl and benzohydrazide moieties located on the opposite sites of the C═N bond, the molecule assumes an E configuration, similat to that found in a related compound, (E)-acetylpyrazine 4-nitrophenylhydrazone (Shan et al., 2008). The terminal benzene rings are slightly twisted to the central hydrazide (O1/C7/N1/N2), with dihedral angles of 18.22 (12)° between C1-benzene and hydrazide planes and 27.62 (12)° between aminophenylethylidene and hydrazide planes, indicating the approximately co-planar molecular structure except for methyl H atoms.
The crystal structure contains molecular classic N-H···O hydrogen bonding and weak C-H···N hydrogen bonding (Table 1).

Experimental
Benzohydrazide (0.27 g, 2 mmol) was dissolved in ethanol (10 ml), then acetic acid (0.1 ml) was added to the ethanol solution with stirring. The solution was heated at 333 K for several minutes until the solution cleared. 1-(4-aminophenyl)ethanone (0.27 g, 2 mmol) was then added slowly into the solution, and the mixture was kept at 333 K with continuous stirring for 6 h. After the solution had cooled to room temperature yellow powder crystals appeared. The powder crystals were separated and washed with water three times. Recrystallization from an absolute ethanol yielded well shaped single crystals of the title compound.

Refinement
Methyl H atoms were placed in calculated positions with C-H = 0.96 Å and the torsion angle was refined to fit the electron density, U iso (H) = 1.5U eq (C). Other H atoms were placed in calculated positions with C-H = 0.93 and N-H = 0.86 Å, and refined in riding mode with U iso (H) = 1.2U eq (C,N). Fig. 1. The molecular structure of the title compound with 50% probability displacement ellipsoids for non-H atoms.