2,6-Difluoro-N-(prop-2-ynyl)benzamide

In the molecule of the title difluorobenzamide derivative, C10H7F2NO, the angle formed by the least-squares mean line through the prop-2-ynyl group [maximum deviation = 0.011 (3) Å] and the normal to the benzene ring is 59.03 (7)°. In the crystal, molecules are linked via N—H⋯O and C—H⋯F hydrogen bonds into layers parallel to the ac plane.

In the molecule of the title difluorobenzamide derivative, C 10 H 7 F 2 NO, the angle formed by the least-squares mean line through the prop-2-ynyl group [maximum deviation = 0.011 (3) Å ] and the normal to the benzene ring is 59.03 (7) . In the crystal, molecules are linked via N-HÁ Á ÁO and C-HÁ Á ÁF hydrogen bonds into layers parallel to the ac plane.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: RZ5082). Some difluorobenzamide derivatives are known to have excellent antiviral and antiproliferation activities (Chang et al., 2002). They are also well known for their anti-diabetic (Kees et al., 1989), anti-fungal (Carmellino et al., 1994), antibacterial (Ragavan et al., 2010) and anti-cancer (Rauko et al., 2001) properties.
The structure of the title fluorinated benzamide derivative ( Fig. 1) is distinctly similar to that of the previously reported compound N-(4-cyanophenyl)-2,6-difluorobenzamide (Fun et al., 2010), with the difference that the N-(4-cyanophenyl) moiety is replaced by a prop-2-ynyl chain (C8-C10). The observed distance for the C9-C10 acetylene bond is 1.162 (3) Å. The angle between the least-squares mean line through the prop-2-ynyl group (maximum deviation 0.011 (3) Å for atom C9) and the normal to the benzene ring is 59.03 (7)°. The molecule has no prominent intramolecular non-covalent interactions. In the crystal, molecules are linked via C-H···F (Fig. 2) and N-H···O hydrogen bonds (Table 1) to form layers parallel to the ac plane. No π···π stacking interactions are observed.

Experimental
Prop-2-yn-1-amine (36.3 mmol, 1.0 eq) was dissolved in dichloromethane (20 mL) in a round bottom flask and kept at 0 °C. Diisopropylethylamine (DIPEA) (145 mmol, 4.0 eq) and 2,6-diflurobenzoyl chloride (54.4 mmol, 1.5 eq) were then added and the mixture stirred for 1.5 h. Progress of the reaction was monitored by thin layer chromatography. On completion of the reaction the mixture was dissolved in water and extracted with diethyl ether (2 × 25 mL). The organic layer was dried with anhydrous Na 2 SO 4 and concentrated to obtain a crude gummy product. The crude product was finally purified by flash column chromatography by using EtOAc/hexane (3:7 v/v) as eluent to afford the title compound in 77% yield. Crystals suitable for X-ray analysis were obtained by slow evaporation of an ethanol solution.

Refinement
The amide and acetylenic H atoms were located in a difference Fourier map and refined freely. All other H atoms were placed at calculated positions and refined as riding, with C-H = 0.93-0.97 Å and with U iso (H) = 1.2U eq (C).

Computing details
Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); 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: SHELXTL (Sheldrick, 2008).  The molecular structure of the title compound, showing displacement ellipsoids at the 50% probability level. 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.