2-Chloro-3-(4-chlorobenzamido)-1,4-naphthoquinone

The naphthoquinone ring is almost perpendicular [dihedral angle 71.02 (3)°] to the phenyl group of the title compound, C17H9Cl2NO3, while the dihedral angle between the amide group and the 4-chlorophenyl ring is 21.9 (2)°. The conformation of the N—H and C=O bonds are anti to each other. N—H⋯Cl hydrogen bonds link the molecules into chains in the a-axis direction. In addition, these chains are linked by weak intermolecular C—H⋯O interactions.

The naphthoquinone ring is almost perpendicular [dihedral angle 71.02 (3) ] to the phenyl group of the title compound, C 17 H 9 Cl 2 NO 3 , while the dihedral angle between the amide group and the 4-chlorophenyl ring is 21.9 (2) . The conformation of the N-H and C O bonds are anti to each other. N-HÁ Á ÁCl hydrogen bonds link the molecules into chains in the aaxis direction. In addition, these chains are linked by weak intermolecular C-HÁ Á ÁO interactions.

D-HÁ
RJB acknowledges the Laboratory for the Structure of Matter at the Naval Research Laboratory for access to their diffractometers.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: AT2690).
The naphthoquinone ring is almost perpendicular to the phenyl group of the title compound C 17 H 9 Cl 2 NO 3 , while the dihedral angle betwen the amide group and the 4-chlorophenyl ring is 21.9 (2)° ( Fig. 1). The conformation of the N-H and C=O bonds are anti to each other . N-H···Cl hydrogen bonds link the molecules into chains in the a direction. In addition, these chains are linked by weak intermolecular Ar-H···O interactions ( Fig. 2, Table 1).

Experimental
A mixture of 2-amino-3-chloro-1,4-naphthoquinone (213 mg, 1.03 mmol) and 4-chloro-benzoylchloride (2 ml) was refluxed for 2 1/2 h (powerstat setting at 70). The reaction mixture was cooled to room temperature. The precipitate was isolated by vacuum filtration and the yellow-grey solid was washed with diethyl ether. The crude was recrystallized from ethanol (20 ml) to obtain a yellow solid (67 mg, 18.8%). Crystals for x-ray study were obtained by recrystallization from methanol.