Crystal structure of 4,5,6,7,8,8-hexachloro-2-(3,4-dimethoxyphenethyl)-3a,4,7,7a-tetrahydro-1H-4,7-methanoisoindole-1,3(2H)-dione [+solvent]

In the title compound, the pyrrolidine ring makes a dihedral angle of 14.83 (12)° with the 3,4-dimethoxyphenyl ring, which are attached to each other by an extended N—CH2—CH2—Car bridge.

In the title compound, C 19 H 15 Cl 6 NO 4 [+solvent], the six-membered ring of the norbornene moiety adopts a boat conformation and the two five-membered rings have envelope conformations. The pyrrolidine ring makes a dihedral angle of 14.83 (12) with the 3,4-dimethoxyphenyl ring, which are attached to each other by an extended N-CH 2 -CH 2 -C ar bridge. In the crystal, the structure features C-HÁ Á ÁO intermolecular hydrogen bonds, an offsetinteraction [intercentroid distance = 3.564 (1) Å ] and a C-ClÁ Á Á interaction. The contribution of some disordered solvent to the scattering was removed using the SQUEEZE routine [Spek (2015). Acta Cryst. C71, 9-18] of PLATON. The solvent contribution was not included in the reported molecular weight and density.
In all 17 structures, the five-membered ring has envelope conformations and the six-membered ring a boat conformation. The bond lengths and bond angles are very similar to those reported here for the title compound. For example, the Csp 2 -Cl bond lengths are shorter than the Csp 3 -Cl bond lengths; the former vary from ca 1.681 to 1.717 Å , while the latter vary from ca 1.725 to 1.798 Å . In the title compound these bond lengths are 1.691 (2)-1.692 (2) Å and 1.744 (2)-1.768 (2) Å , respectively.

Figure 2
A view along the c axis of the crystal packing of the title compound. The C-HÁ Á ÁO hydrogen bonds (thin black lines; Table 1) generate an R 4 4 (48) ring motif. The offsetinteraction is shown as a thin red line. For clarity, H atoms not involved in hydrogen bonding have been omitted.

Figure 1
The molecular structure of the title compound, with the atom labelling. Displacement ellipsoids are drawn at 30% probability level.
dride (1 equiv.) were stirred at room temperature in dry ethyl acetate for 30 min. The ethyl acetate was removed under reduced pressure and the resulting residue was dissolved in toluene. To this reaction mixture was added acetyl chloride (5 equiv.) and refluxed for 1 h. The reaction mixture was brought to room temperature and washed with aqueous Na 2 CO 3 and dried over anhydrous Na 2 SO 4 . It was then filtered and the filtrate was concentrated under reduced pressure followed by silica gel column purification to afford the title compound in 82% yield. Colourless block-shaped crystals were obtained by slow evaporation of a solution in ethanol.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2. The hydrogen atoms were placed in calculated positions and refined using a riding model: C-H = 0.93-0.98 Å with U iso (H) = 1.5U eq (C-methyl) and 1.2U eq (C) for other H atoms. The contribution of the disordered solvent to the scattering was removed using the SQUEEZE routine of PLATON (Spek, 2015). The solvent contribution was not included in the reported molecular weight and density. Further details are given in the archived CIF.

Funding information
RM thanks the UGC, Government of India for an SRF fellowship.