(E)-N′-Benzylidene-5-methylisoxazole-4-carbohydrazide

The molecule of the title compound, C12H11N3O2, is approximately planar with an r.m.s. deviation of 0.0814 Å from the plane through all the non-H atoms. The dihedral angle formed by the benzene and isoxazole rings is 6.88 (16)°. The molecular conformation is stabilized by an intramolecular C—H⋯N hydrogen bond, forming an S(6) ring, and the molecule displays an E configuration with respect to the C=N double bond. In the crystal structure, intermolecular N—H⋯O hydrogen bonds form centrosymmetric dimers which are further linked by weak C—H⋯N interactions augmented by very weak C—H⋯π contacts, forming layers parallel to (120).

The molecule of the title compound, C 12 H 11 N 3 O 2 , is approximately planar with an r.m.s. deviation of 0.0814 Å from the plane through all the non-H atoms. The dihedral angle formed by the benzene and isoxazole rings is 6.88 (16) . The molecular conformation is stabilized by an intramolecular C-HÁ Á ÁN hydrogen bond, forming an S(6) ring, and the molecule displays an E configuration with respect to the C N double bond. In the crystal structure, intermolecular N-HÁ Á ÁO hydrogen bonds form centrosymmetric dimers which are further linked by weak C-HÁ Á ÁN interactions augmented by very weak C-HÁ Á Á contacts, forming layers parallel to (120).

Experimental
Cg1 is the centroid of the C7-C12 ring.
Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97.  (Fun et al. 2008;Wei et al. 2009;Khaledi et al. 2008) and their biological activity (Molina et al. 1994;Khattab 2005) and coordination ability (Reiter et al.1985) have also been noted. Isoxazole compounds have also attracted much interest as they exhibit some fungicidal, plant-growth regulating and antibacterial activity (Stevens et al.1984). In order to study the properties of a new compound containing both the hydrazine and isoxazole groups, we synthesized the title compound and report its crystal structure here, Fig 1. The title compound C 12 H 11 N 3 O 2 , is approximately planar (rms deviation 0.0814 from the plane through all non-hydrogen atoms)with a dihedral angle of 6.88 (16)°. between the C7···C12 benzene and C2···C4,N1,O1 isoxazole rings. The molecule displays an E configuration with respect to the C6═N3 double bond, with a C7-C6-N3-N2 torsion angle of -179.3 (3)°. The dihedral angle formed by the benzene and isoxazole rings is 2.457 (114)°. An intramolecular C-H···N hydrogen bond generates an S6 ring motif (Bernstein et al. 1997) and locks the molecule into a planar configuration. Bond lengths (Allen et al.,1987) and angles are unexceptional and similar to those found in related stuctures (Fun et al., 2008;Wei et al., 2009;Khaledi et al., 2008).

Experimental
Benzaldehyde (4.6 g,0.02 mol) and 5-methylisoxazole-4-carbonyl hydrazine (2.8 g, 0.02 mol) was mixed with glacial acetic acid (50 ml). The mixture was heated at 65° C for 3 h, the precipitate collected by filtration and washed with water, chloroform and ethanol. The product was recrystallized from ethanol, then dried under reduced pressure to give the title compound in 85% yield. Colourless, block-shaped crystals were obtained by slow evaporation of a dimethylformamide solution.

Refinement
The H atom bound to N2 was located in a difference Fourier map and refined freely with the N-H distance restrained to 0.90 Å. All other H atoms were positioned geometrically and allowed to ride on their parent atoms, with C-H = 0.93-0.96 Å, and with U iso = 1.2 U iso (C) or 1.5 U iso (C) for methyl groups.