2-{4-Methyl-N-[(2,3,4,9-tetrahydro-1H-carbazol-3-yl)methyl]benzenesulfonamido}ethyl 4-methylbenzenesulfonate

In the title compound, C29H32N2O5S2, the indole ring system is nearly planar, with a maximum deviation of 0.013 (2) Å, and the cyclohexenone ring has an envelope conformation with the methine C atom as the flap. The two methylbenzene rings are approximately perpendicular to each other, making a dihedral angle of 89.09 (8)°. In the crystal, N—H⋯O hydrogen bonds link the molecules into a chain running along the a-axis direction, and weak C—H⋯O hydrogen bonds and C—H⋯π interactions are observed between the chains.

In the title compound, C 29 H 32 N 2 O 5 S 2 , the indole ring system is nearly planar, with a maximum deviation of 0.013 (2) Å , and the cyclohexenone ring has an envelope conformation with the methine C atom as the flap. The two methylbenzene rings are approximately perpendicular to each other, making a dihedral angle of 89.09 (8) . In the crystal, N-HÁ Á ÁO hydrogen bonds link the molecules into a chain running along the a-axis direction, and weak C-HÁ Á ÁO hydrogen bonds and C-HÁ Á Á interactions are observed between the chains.

Related literature
For tetrahydrocarbazole systems present in the framework of a number of indole-type alkaloids of biological interest, see: Saxton (1983). For related structures, see: Hö kelek et al.  (2011). For the use of tetrahydrocarbazolone in the synthesis of central-nervous-system-active drugs, see: Romeo et al. (2006). For the syntheses of tetrahydrocarbazolonebased antitumor-active compounds from tetrahydrocarbazoles, see: Chen et al. (2009). For the syntheses of aminotetrahydrocarbazoles as central nervous system agents, see: Mooradian et al. (1977). For bond-length data, see: Allen et al. (1987).  Table 1 Hydrogen-bond geometry (Å , ).

Comment
Tetrahydrocarbazole systems are present in the framework of a number of indole-type alkaloids of biological interest (Saxton, 1983). The structures of tricyclic, tetracyclic and pentacyclic ring systems with dithiolane and other substituents of the tetrahydrocarbazole core, have been reported previously. Tetrahydrocarbazoles have been increasingly important intermediates in the syntheses of indole or carbazole alkaloids and various biologically active heterocyclic compounds because of their unique structures. For instance, tetrahydrocarbazole was used in the syntheses of central nervous system active drugs (Romeo et al., 2006). Tetrahydrocarbazolone based antitumor active compounds were synthesized from tetrahydrocarbazoles (Chen et al., 2009). Aminotetrahydrocarbazoles were also synthesized as central nervous system agents (Mooradian et al., 1977). The present study was undertaken to ascertain the crystal structure of the title compound.
The molecule of the title compound contains a carbazole skeleton with methyl phenylsulfonamide and ethyl methyl benzenesulfonate groups, (Fig. 1), where the bond lengths are close to standard values (Allen et al., 1987) and generally agree with those in the previously reported compounds. In all structures atom N9 is substituted.
In the crystal, intermolecular N-H···O and C-H···O hydrogen bonds link the molecules into infinite chains along the a-axis (Table 1 and Fig. 2). π···π contacts between the benzene rings, Cg4-Cg4 i [symmetry code: where Cg4 is the centroid of the ring D (C13-C18)] may further stabilize the structure, with centroid-centroid distance of 3.955 (1) Å. There also exist two weak C-H···π interactions (Table 1).

Refinement
The H9 atom is located in a difference Fourier synthesis and refined isotropically. The remaining C-bound H-atoms were positioned geometrically with C-H = 0.95, 1.00, 0.99 and 0.98 Å, for aromatic, methine, methylene and methyl Hatoms, respectively, and constrained to ride on their parent atoms, with U iso (H) = k × U eq (C), where k = 1.5 for methyl Hatoms and k = 1.2 for all other H-atoms.   Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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.