5a-Butyl-1,3,8,10-tetrachloro-7,13-bis(4-nitrobenzoyl)-5a,6a,12a,12b-tetrahydro-7H,13H-thieno[2,3-b:4,5-b′]bis(1,4-benzoxazine)

The title compound, C34H24Cl4N4O8S, is a linear pentacyclic system formed of two substituted benzoxazinyl groups fused to 2-n-butyltetrahydrothiophene. The oxazine ring, which is fused to the n-butyl-substituted side of the thiophene ring, is in a boat conformation. The other fused oxazine ring and the tetrahydrothiene ring are each in an envelope conformation. The bridgehead C atom α to both the S and N atoms forms the flap of each envelope. This results in a twist of the pentacyclic system such that the dihedral angle between the terminal dichlorobenzene rings is 82.92 (8)°. In the crystal, inversion-related molecules form a weakly hydrogen-bonded dimer, with two C—H⋯O interactions between an H atom on the oxazine ring and an amide O atom. Additionally, C—H⋯O interactions occur between an H atom on a screw-related nitrobenzene ring and an O atom on the nitrobenzene ring of one molecule. One of the Cl atoms and the butyl group are disordered over two sets of sites with occupancy ratios of 0.94 (2):0.06 (2) and 0.624 (4):0.376 (4), respectively.

The title compound, C 34 H 24 Cl 4 N 4 O 8 S, is a linear pentacyclic system formed of two substituted benzoxazinyl groups fused to 2-n-butyltetrahydrothiophene. The oxazine ring, which is fused to the n-butyl-substituted side of the thiophene ring, is in a boat conformation. The other fused oxazine ring and the tetrahydrothiene ring are each in an envelope conformation. The bridgehead C atom to both the S and N atoms forms the flap of each envelope. This results in a twist of the pentacyclic system such that the dihedral angle between the terminal dichlorobenzene rings is 82.92 (8) . In the crystal, inversionrelated molecules form a weakly hydrogen-bonded dimer, with two C-HÁ Á ÁO interactions between an H atom on the oxazine ring and an amide O atom. Additionally, C-HÁ Á ÁO interactions occur between an H atom on a screw-related nitrobenzene ring and an O atom on the nitrobenzene ring of one molecule. One of the Cl atoms and the butyl group are disordered over two sets of sites with occupancy ratios of 0.94 (2):0.06 (2) and 0.624 (4):0.376 (4), respectively.

Experimental
(3) and 0.478 (3)  In the crystal two inversion-related molecules form a weakly hydrogen-bonded dimer with C2-H2 ···O2 interactions (Table 1 and Fig. 2) Additionally, C14-H14···O3 hydrogen bonding interactions form between an oxygen on the nitrobenzene ring of one molecule and a hydrogen on a screw related nitrobenzene ring.

Experimental
The title compound was synthesized by following a reported procedure (Heine et al., (1993). The crystals suitable for Xray crystallographic analysis were grown from a solution of acetonitrile by slow evaporation at room temperature.

Refinement
The H atoms were positioned geometrically and refined using a riding model, with C-H = 0.93, 0.96, 0.97 and 0.98 Å, for aryl, methyl, methylene and methyne H-atoms, respectively. The U iso (H) were allowed at 1.5U eq (C methyl) or 1.2U eq (C non-methyl).

Data collection
Siemens R3m/V diffractometer Radiation source: fine-focus sealed tube Graphite monochromator θ 2 θ scans 8579 measured reflections 8215 independent reflections 5039 reflections with I > 2σ(I) 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.
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )