Synthesis and structure of (3aRS,10SR,10aSR)-2-(4-chloro-phen-yl)-5-[(4-methyl-phen-yl)sulfon-yl]-1-oxo-1,2,3,3a,4,5,10,10a-octa-hydro-pyrrolo-[3,4-b]carbazole-10-carb-oxy-lic acid with an unknown solvent.

The title compound, C28H23ClN2O5S, crystallizes with two independent mol-ecules (A and B) in the asymmetric unit. In the central fused ring systems, the pyrrolidine rings adopt envelope conformations and the cyclo-hexene rings adopt distorted-half chair conformations. In mol-ecules A and B, the least-squares mean planes of the sixteen-membered central ring systems form dihedral angles of 81.5 (1) and 84.0 (1)°, respectively, with the benzene rings attached to the sulfanyl groups, while they make dihedral angles of 18.6 (1) and 7.7 (1)°, respectively, with the chloro-benzene rings. In the crystal, O-H⋯O hydrogen bonds and weak C-H⋯O and C-H⋯Cl inter-actions link the mol-ecules, forming a three-dimensional network. The contribution of some disordered solvent to the scattering was removed using the SQUEEZE routine [Spek (2015 ▸). Acta Cryst. C71, 9-18] in PLATON. The solvent contribution was not included in the reported mol-ecular weight and density. A Hirshfeld surface analysis indicates that H⋯H (36.8% for mol-ecule A; 29.8% for mol-ecule B), O⋯H/H⋯O (22.1% for A and 27.3% for B), C⋯H/H⋯C (22.1% for A and 20.2% for B) and Cl⋯H/H⋯Cl (9.7% for A and 13.2% for B) inter-actions are the most important contributors to the crystal packing.