(3′R)-3′-Benzyl-2′,3′-dihydro-1H-spiro[indole-3,1′-naphtho[2,3-c]pyrrole]-2,4′,9′-trione

In the title compound, C26H18N2O3, the maximum deviations from planarity for the tetrahydro-1H-naphtho[2,3-c]pyrrole and indoline rings systems are 0.091 (1) and 0.012 (2) Å, respectively. These ring systems make a dihedral angle of 89.95 (6)° with each other and they make dihedral angles of 73.42 (8) and 71.28 (9)°, respectively, with the benzene ring. In the crystal, inversion dimers linked by pairs of N—H⋯O hydrogen bonds generate R 2 2(8) loops and C—H⋯O interactions connect the dimers into corrugated sheets lying parallel to the bc plane.

In the title compound, C 26 H 18 N 2 O 3 , the maximum deviations from planarity for the tetrahydro-1H-naphtho[2,3-c]pyrrole and indoline rings systems are 0.091 (1) and 0.012 (2) Å , respectively. These ring systems make a dihedral angle of 89.95 (6) with each other and they make dihedral angles of 73.42 (8) and 71.28 (9) , respectively, with the benzene ring. In the crystal, inversion dimers linked by pairs of N-HÁ Á ÁO hydrogen bonds generate R 2 2 (8) loops and C-HÁ Á ÁO interactions connect the dimers into corrugated sheets lying parallel to the bc plane.

Related literature
For a related structure, see: Sharma et al. (2012). For the biological activity of naphthoquinones, see: Babula et al. (2007). For 1,3-cycloaddition reactions involving naphthoquinones, see: Chen et al. (2011). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 Table 1 Hydrogen-bond geometry (Å , ). This is a continuation of our recently published work (Sharma et al., 2012). Naphthoquinones are known to possess various biological properties (Babula et al., 2007). Recently, there also have been a few efforts to conduct 1, 3-cycloaddition involving naphthoquinones (Chen et al., 2011).
After leaving the resultant concoction to stand for 1 h, the reaction solid was washed with cool water (3 × 2.5 ml) and cool ethanol (3 × 0.5 ml). The crude reaction solid was re-crystallized from hot methanol to afford the pure product (80% yield) as yellow plates.

Refinement
N bound H atom were located from a difference Fourier map and freely refined. The remaining H atoms were positioned geometrically and refined using a riding model with C-H = 0.95-1.00 Å and U iso (H) = 1.2U eq (C).  The molecular structure of (I), showing 50% probability displacement ellipsoids.

Figure 2
The crystal packing of (I). Dashed lines indicate hydrogen bonds. H atoms not involved in the hydrogen bond interactions have been omitted for clarity.   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.