9,10,11,12-Tetra­chloro-12b-hydr­oxy-12c-phenyl-1,2,3,3a,5,6,12b,12c-octa­hydro-8 H-cyclo­penta­[6,7][1,4]oxazepino[5,4- a]isoindol-8-one.

The medium-sized heterocyclic title compound, C21H17Cl4NO3, crystallizes with two crystallographically independent mol­ecules in the asymmetric unit. The cyclo­pentane rings adopt half-chair conformations. Symmetry-related mol­ecules are linked via O—H⋯O hydrogen bonds to form dimers, which are arranged into one-dimensional chains along the [100] direction. C—H⋯π and π–π inter­actions were also observed in the crystal structure. [ABSTRACT FROM AUTHOR]