N-Benzoyl-N-(1,4-dioxonaphthalen-2-yl)benzamide

The title molecule, C24H15NO4, crystallizes with two molecules in the asymmetric unit (Z′ = 2). For both molecules, the two amide groups are not coplanar, as the dihedral angles of the respective NCO groups are similar at 50.37 (14) and 51.22 (13)°. However, the orientations of the substituent phenyl rings with the central naphthalene system are significantly different for the two molecules; for one molecule, these dihedral angles are 80.29 (3) and 80.95 (4)°, while for the second molecule they are 86.63 (3) and 72.82 (4)°. The crystal packing shows the molecules to be linked by weak C—H⋯O interactions.

The title molecule, C 24 H 15 NO 4 , crystallizes with two molecules in the asymmetric unit (Z 0 = 2). For both molecules, the two amide groups are not coplanar, as the dihedral angles of the respective NCO groups are similar at 50.37 (14) and 51.22 (13) . However, the orientations of the substituent phenyl rings with the central naphthalene system are significantly different for the two molecules; for one molecule, these dihedral angles are 80.29 (3) and 80.95 (4) , while for the second molecule they are 86.63 (3) and 72.82 (4) . The crystal packing shows the molecules to be linked by weak C-HÁ Á ÁO interactions.  Table 1 Hydrogen-bond geometry (Å , ). Symmetry codes: (i) x; y þ 1; z; (ii) x; y À 1; z; (iii) Àx þ 1; Ày þ 1; Àz þ 2.
RJB wishes to acknowledge the NSF-MRI program (grant No. CHE-0619278) for funds to purchase the diffractometer. We also acknowledge the MRI grant No. CHE-1126533 from the National Science Foundation for the purchase of a TOF LC/MS system used in this study, which was also funded in part by grant No. 5-U54-CA914-31 (Howard University/Johns Hopkins Cancer Center Partnership).
In the structure of the title compound there are two molecules in the asymmetric unit (Z′ = 2). For both molecules the two amide moieties are not coplanar as the dihedral angles of the respective NCO groups are similar at 50.37 (14) Experimental 2-Amino-1,4-naphthoquinone (318 mg, 1.83 mmol) was dissolved in freshly distilled THF (15 ml). NaH (115 mg, 4.78 mmol) was added and the mixture was stirred at room temperature for 15 min. The appropriate benzoyl chloride (0.55 ml, 4.74 mmol) was added, drop wise, and the mixture was stirred for 24 h. THF was evaporated under vacuum and the mixture was washed with ice-water (10 g ice in 10 ml water). The aqueous mixture was extracted with CH 2 Cl 2 (30 ml, 20 ml consecutively) and the combined organic phase washed with water (3 x 20 ml), saturated NaCl solution (20 ml), then dried over anhydrous MgSO 4 . The crude was purified via tirturating in ethanol (2 ml) and column chromatography with an eluent mixture of ethyl acetate and hexane to furnish the imide(70 mg, 10%).

Refinement
H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms with a C-H distance of 0.95 and U iso (H) = 1.2U eq (C). The structure was a non-merohedral twin and was refined with a BASF (batch supplementary materials sup-2 Acta Cryst. (2012). E68, o2379 scale factor) value of 0.4084 (7) and a twin law for the two components of -1 0 0, 0 -1 0, 0 0 1.   The molecular packing for C 24 H 15 NO 4 viewed along the a axis. The C-H···O interactions are shown by dashed lines.

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.