3-(4-Chlorophenyl)-2,1-benzisoxazole-5-carbonyl chloride

The molecule of the title compound, C14H7Cl2NO2, is not planar; the dihedral angle between the mean planes of the chlorophenyl and benzisoxazole rings is 20.32 (7)°. The carbonyl chloride group is twisted with respect to the benzisoxazole ring by 2.5 (1)°. The molecular conformation is stabilized by an intramolecular C—H⋯Cl hydrogen bond. In the crystal packing, adjacent molecules are linked into dimers by intermolecular C—H⋯O hydrogen bonds. The dimers are further stacked into columns along the unique axis direction by π–π stacking interactions, with a centroid⋯centroid distance of 3.828 (5) Å. Other weak intermolecular C—H⋯O and C—H⋯Cl interactions are also present.

The molecule of the title compound, C 14 H 7 Cl 2 NO 2 , is not planar; the dihedral angle between the mean planes of the chlorophenyl and benzisoxazole rings is 20.32 (7) . The carbonyl chloride group is twisted with respect to the benzisoxazole ring by 2.5 (1) . The molecular conformation is stabilized by an intramolecular C-HÁ Á ÁCl hydrogen bond. In the crystal packing, adjacent molecules are linked into dimers by intermolecular C-HÁ Á ÁO hydrogen bonds. The dimers are further stacked into columns along the unique axis direction bystacking interactions, with a centroidÁ Á Ácentroid distance of 3.828 (5) Å . Other weak intermolecular C-HÁ Á ÁO and C-HÁ Á ÁCl interactions are also present.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: RZ2265).

Comment
Our interest in benzo [c]isoxazoles is concerned with their biological activity and their application as precursors of the variety of bioactive compounds (Angibaud et al., 2003;Walsh et al., 1990;Hester et al., 1989;McEvoy et al., 1968). The title compound will be used in our further investigations as a building block for modifications by nucleophiles.
The asymmetric unit of the title compound is shown in Figure 1. The planarity of the molecule is disturbed by intramolecular attractive and repulsive interactions of the C-H···Cl, C-H···O and C-H···H-C types. The dihedral angle between the least-square mean planes of the chlorophenyl and benzisoxazole rings is 20.32 (7)°. The carbonyl chloride group is rotated by 2.5 (1)° with respect to the benzisoxazole ring. An intramolecular C-H···Cl hydrogen bonding interactions is observed (Table 1). The crystal packing ( Fig. 2) is governed by intermolecular interactions of the C-H..O type and by π-π stacking interactions. The C-H···O type hydrogen bonds connect adjacent molecules into dimers, forming ten-membered rings of graph set motif R 2 2 (10) (Bernstein et al., 1995). The dimers are further linked along the unique axis direction by π-π stacking interactions: Cg1···Cg1 i = Cg2···Cg2 i = 3.828 (5) Å (Cg1 and Cg2 are the centroids of the C1/C2/C4-C7 and C8-C13 aromatic rings, respectively; symmetry code: (i) x, 1+y, z); the corresponding perpendicular interplanar distances are 3.429 (4) and 3.475 (4) Å, respectively, and the centroid-centroid offsets are 1.702 (4) and 1.605 (3) Å, respectively. Additionally, two weak C-H···O and C-H···Cl interactions are present in the structure (shown as dotted lines in Figure 2).

Experimental
To 40 ml of an ethanol solution of potassium hydroxide (4 g, 0.1 mol) p-nitrobenzoic acid (1.67 g, 10 mmol) was added with stirring. Then 5 ml of an ethanol solution of 4-chlorophenylacetonitrile (1.82 g, 12 mmol) was added to the reaction mixture. The suspension was stirred for 4 h at 323 K and left overnight at room temperature. The reaction mixture was poured into 150 ml of water and acidified with hydrochloric acid. The precipitate was isolated by filtration, washed with water and dried. Crude acid was added to a solution of thionyl chloride (1.19 ml, 20 mmol) in benzene (15 ml) and heated under reflux until a clear solution was obtained. Yellow needles of the title compound were obtained by slow cooling of the reaction solution (m.p. 453-454 K; 2 g, yield 70%).

Refinement
All H atoms were found in difference-Fourier maps. In the final refinement cycles, H atoms were positioned geometrically and treated as riding atoms, with C-H = 0.95 Å and with U iso (H) = 1.2 U eq (C).
supplementary materials sup-2 Figures   Fig. 1. The molecular structure of the title compound with the atom labeling scheme. Displacement ellipsoids are drawn at the 50% probability level.  Table 1.