(Z)-Ethyl 3-(4-chlorophenyl)-2-cyano-3-(2,6-difluorobenzamido)acrylate

The title compound, C19H13ClF2N2O3, was prepared by the reaction of (Z)-ethyl 3-amino-3-(4-chlorophenyl)-2-cyanoacrylate and 2,6-difluorobenzoyl chloride. The dihedral angle between the chlorobenzene and fluorobenzene rings is 37.0 (1)°. The ethyl group is disordered over two positions [occupancies = 0.52 (2):0.48 (2)]. In addition to intramolecular N—H⋯O and N—H⋯F hydrogen bonds, the crystal packing shows the molecules to be connected by intermolecular C—H⋯O and C—H⋯N hydrogen bonds.


S1. Comment
Recently, 2-cyanoacrylates have been in widespread used as agrochemicals because of their unique mechanism of action and good environmental profiles. The title compound is useful as an inhibitor of Pyricularia oryzae, Rhizoctonia solani, Botrytis cinerea and Gibberella zeae (Heller et al., 2004;Creagh & Hubbell, 1992;Ibers & Hamilton, 1964).
In the title compound( Fig.1),all bond lengths and angles are unexceptional.The planar chlorobenzene ring is approximately perpendicular to the fluorobenzene ring with a dihedral angle of 37.0 (1)°. The ethyl group is disordered over two positions occupancies (0.52 (2):0.48 (2)).The molecular conformation is stabilized by C-H···O and N-H···O hydrogen bonds (Table 1). The crystal packing is governed by additional N-H···O and N-H···F Interactions (Fig. 2).

S2. Experimental
To a solution of (Z)-ethyl 3-amino-3-(4-chlorophenyl)-2-cyanoacrylate (1.25 g,0.0050 mol) in CH 2 Cl 2 (18 ml), 2,6-difluorobenzoyl chloride (2.65 g,0.015 mol) was added. Subsequently, Et 3 N(1.52 g,0.015 mol) waa dropped into the solution under stirring. Then, the reaction mixture was heated to reflux and stirred for 4 h and then cooled to room temperature. The reaction solution was filtered off and some white solid was separated. The organic phase was washed with water and then dried over Na 2 SO 4 . After removal of the solvent, a brown dope was obtained. After column chromatography using ethylacetate/light petroleum (1:6) as the eluent. Small single crystals were grown from a solution of ethyl acetate/petroleum ether(3:1) after 45 days,at room temperature.

S3. 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, with UU iso (H)=1.5UU eq (C). Other H atoms were placed in calculated positions with C-H =0.96 Å(methylene) and 0.93 Å(aromatic C-H), and refined in riding mode, with U iso (H)=1.2U eq (C). In the absence of significant anomalous scattering, Friedel pairs were merged.   The packing of the title compound, viewed down the c axis.  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. (