Methyl (E)-2-({2-[(E)-(hydroxyimino)methyl]phenoxy}methyl)-3-(4-methylphenyl)acrylate

In the title compound, C19H19NO4, the dihedral angle between the mean planes through the benzene rings is 82.18 (7)°. The C=N double bond is trans-configured. The molecules are linked into centrosymmetric dimers via pairs of O—H⋯N hydrogen bonds with the motif R 2 2(6). The crystal packing also features C—H⋯O interactions. The methyl group attached to one of the aromatic rings is disordered over two almost equally occupied positions [occpancy ratio = 0.51 (4):0.49 (4)].

In the title compound, C 19 H 19 NO 4 , the dihedral angle between the mean planes through the benzene rings is 82.18 (7) . The C N double bond is trans-configured. The molecules are linked into centrosymmetric dimers via pairs of O-HÁ Á ÁN hydrogen bonds with the motif R 2 2 (6). The crystal packing also features C-HÁ Á ÁO interactions. The methyl group attached to one of the aromatic rings is disordered over two almost equally occupied positions [occpancy ratio = 0.51 (4):0.49 (4)].

Related literature
For information on oximes, see: Chaudhuri (2003 Table 1 Hydrogen-bond geometry (Å , ).  Oximes are a classical type of chelating ligands which are widely used in coordination and analytical chemistry (Chaudhuri, 2003). Against this background, and in order to obtain detailed information on molecular conformations in the solid state, an X-ray study of the title compound was carried out.
X-Ray analysis confirms the molecular structure and atom connectivity as illustrated in Fig. 1. The bond lengths and angles in (Fig. 1) agree with those observed in other acrylate derivatives (SakthiMurugesan et al., 2011). the whole molecule is not planar as the dihedral angle between the two phenyl rings is 82.18 (7)°, it shows that both the rings are almost perpendicular to each other. The methoxybutene group connects the two phenyl rings, results in twisting the rings and placed those rings in perpendicular direction. The oxime group having the C═N forming an E configuration. The atom C19 is deviated by -0.037 (2) Å from the least squares plane of the C13-C18 ring. The hydroxyethanimine group is essentially coplanar with the benzene ring, the largest deviation from the mean plane being -0.008 (1) Å for the C2 atom.
The enoate group assumes an extended conformation as can be seen from torsion angles C8-C9-C10-O3

Experimental
To a stirred solution of (E)-methyl 2-((2-formylphenoxy)methyl)-3 -p-tolyacrylate (4 mmol) in 10 ml of EtOH/H 2 O mixture(1:1) was added NH 2 OH.HCl(6 mmol) in the presence of 50% NaOH at room temperature. Then the reaction mixture was allowed to stir at room temperature For 1.5 h. After completion of the reaction, solvent was removed and crude mass was diluted with water (15 ml) and extracted with ethyl acetate (3x15ml). The combined organic layer was washed with brine (2x10ml) and dried over anhydrous Na 2 SO 4 and then evaporated under reduced pressure to obtain(E)methyl 2-((2-((E)-(hydroxyimino) methyl)phenoxy) methyl)-3-p-tolylacrylate as a colourless solid. Single crystals suitable for X-ray diffraction were obtained by slow evaporation of a solution of the title compound in acetone at room temperature.

Refinement
All H atoms were fixed geometrically and allowed to ride on their parent atoms, with C-H distances in the range 0.93-0.97 Å and an O-H distance of 0.82 Å and with U iso (H) = 1.5U eq (C methyl , O) or 1.2U eq (C) for other H atoms.   The crystal structure showing the centrosymmetric hydrogen bond motif R 2 2 (6). For the sake of clarity, the H atoms not involved in the motif have been omitted. The atoms marked with an asterisk (*) are at the symmetry position (2 -x, -y, 1z). The dashed lines indicate the hydrogen bonds.

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > σ(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 Occ. (