N-[4-(Azetidin-1-ylsulfonyl)phenyl]-N-(2,4-difluorobenzyl)acetamide

In the title molecule, C18H18F2N2O3S, the dihedral angle between the benzene rings is 79.40 (11)°. The 2,4-difluorobenzyl and azetidine fragments adopt a trans arrangement relative to the central benzene ring. In the crystal, weak C—H⋯O hydrogen bonds connect molecules into a two-dimensional network parallel to (001).


N-[4-(Azetidin-1-ylsulfonyl)phenyl]-N-(2,4-difluorobenzyl)acetamide
Jian-Mei Lin, Jia-Wen Li and Jing-Song Lv Comment Sulfonamides were extensively employed as effective antimicrobial agents for the prevention and cure of bacterial infections in humanbiological systems as early as 70 years ago, and recently have aroused considerable interest in biology and medicine for their diversified pharmacological activities including antibacterial, antifungal, antiviral, antitumor, antiinflammatory and as carbonic anhydrase inhibitors (Song, et al., 2007;Wang, Wang et al., 2010). Our interest is to develop novel sulfonamide derivatives as antimicrobial agents and some structrally related sulfonamides have been reported as bioactive agents (Wang, Wan & Zhou, 2010;Wang & Gan et al., 2010). Herein, we report the crystal structure of the title compound (I).
In the molecule of (I) (Fig. 1) the dihedral angle between the two benzene rings is 79.40 (11)°. The 2,4-difluorobenzyl and azetidine fragments adopt a trans arrangement relative to the central benzene ring. In the crystal, weak C-H···O hydrogen bonds connect molecules into a two-dimensional network (Fig. 2) parallel to (001).

Experimental
A suspension of N-(4-(azetidin-1-ylsulfonyl)phenyl)acetamide (0.8 g, 3.0 mmol) and potassium carbonate (0.5 g, 3.6 mmol) was stirred in acetonitrile (30 mL) at 343 K. After half an hour, 1-(bromomethyl)-2,4-difluorobenzene (0.6 g, 3.0 mmol) was added, and the progress of the reaction was monitored by TLC. Upon completion, the reaction was extracted with chloroform (3 × 20 mL). The filtrate was concentrated and then directly purified by chromatographic column (petroleum ether/ethyl acetate) to afford the title compound (I). A crystal suitable for X-ray analysis was grown from a solution of (I) in a mixture of acetone and ethyl acetate by slow evaporation at room temperature.

Refinement
H atoms were placed at calculated position with C-H = 0.93 Å (aromatic), 0.97Å (methylene) 0.96 Å (methyl). The U iso (H) value was set equal to 1.2U eq (C) or 1.5U eq (C methyl ).  The molecular structure of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

Figure 2
Part of the crystal structure with hydrogen bonds shown as dashed lines.  (2) 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.