1-(1-Benzofuran-2-yl)ethanone O-(2,6-difluorobenzyl)oxime

In the title compound, C17H13F2NO2, the 2,2-difluorobenzyloxy residue assumes an E configuration with respect to the benzofuran system. The benzene ring makes a dihedral angle of 61.70 (4)° with the fused ring system (r.m.s. deviation = 0.008 Å). In the crystal, molecules are connected by weak C—H⋯F hydrogen bonds into chains extending parallel to the b-axis direction.

In the title compound, C 17 H 13 F 2 NO 2 , the 2,2-difluorobenzyloxy residue assumes an E configuration with respect to the benzofuran system. The benzene ring makes a dihedral angle of 61.70 (4) with the fused ring system (r.m.s. deviation = 0.008 Å ). In the crystal, molecules are connected by weak C-HÁ Á ÁF hydrogen bonds into chains extending parallel to the baxis direction.   Table 1 Hydrogen-bond geometry (Å , ).

Comment
The increase in fungal infections and the gained resistance to the currently used drugs in recent years directed the studies on obtaining new antifungal drugs (Benedetti & Bani, 1999). After the discovery of oxiconazole (Sheehan et al., 1999), ether oximes became of interest and a number of oximes were synthesized and found to be active against fungi (Attia et al., 2013;De Luca, 2006;Emami et al., 2004;Karakurt et al., 2001;Massolini et al., 1993;Mixich & Thiele, 1985). The crystal structure investigation of the title compound was undertaken to confirm the E configuration of the molecule, proposed on the basis of spectroscopic data.
The molecular structure of the title compound and the atom-labelling scheme is illustrated in Fig. 1. In this compound, the nine-membered benzofuran system is planar with an r.m.s. deviation of 0.0083 Å. The 2,6-difluorobenzyloxy moiety is in the E configuration with respect to the benzofuran system [torsion angle C2-C10-N12-O13: 178.89 (9) The molecular packing in the crystal lattice is stabilized by possible C7-H7···F22 i non-classical intermolecular hydrogen bonds (Table 1) which link molecules into chains lying parallel to the b axis (Fig. 2).

Refinement
All H atoms were placed in idealized positions and were refined within the riding model approximation: C methyl -H = 0.96 Å, C methylene -H = 0.97 Å, C(sp 2 )-H = 0.93 Å; U iso (H) = 1.2U eq (C) or 1.5U eq (C) for methyl H. The methyl group was refined as a rigid group which was allowed to rotate.  The molecular structure of the title compound showing the atom labelling scheme. Non-H atoms are drawn as 30% probability displacement ellipsoids and H atoms are shown as small spheres of arbitrary radius.

Figure 2
The hydrogen bonding (dotted lines) in the title structure. For symmetry code (i), see Table 1. H atoms not involved in hydrogen-bonding have been omitted for clarity.

1-(1-Benzofuran-2-yl)ethanone O-(2,6-difluorobenzyl)oxime
Crystal data C 17 H 13 F 2 NO 2 M r = 301.28 Monoclinic, P2 1 /n Hall symbol: -P 2yn a = 7.36652 (17)  Special details Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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.