Crystal structure of 5-amino-5′-chloro-6-(4-chloro­benzo­yl)-8-nitro-2,3-di­hydro-1H-spiro­[imidazo[1,2-a]pyridine-7,3′-indolin]-2′-one including an unknown solvent mol­ecule

The asymmetric unit of the title compound, C(21)H(15)Cl(2)N(5)O(4), contains two independent mol­ecules (A and B) having similar conformations. The amine (NH(2)) group forms an intra­molecular hydrogen bond with the benzoyl group, giving an S(6) ring motif in both mol­ecules. The central six-membered rings adopt sofa conformations and the imidazole rings are planar (r.m.s deviations = 0.0150 and 0.0166 Å). The pyridine and imidazole rings are inclined to one another by 3.54 (1) and 3.03 (1)° in mol­ecules A and B, respectively. In the crystal, mol­ecules are linked by N—H⋯O hydrogen bonds, forming chains along the a axis which enclose R (2) (2)(16) ring motifs. The rings are linked by weak N—H⋯O and C—H⋯O hydrogen bonds and C—H⋯π inter­actions forming sheets lying parallel to (001). A region of disordered electron density, most probably disordered solvent mol­ecules, occupying voids of ca 753 Å(3) for an electron count of 260, was treated using the SQUEEZE routine in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148–155]. Their formula mass and unit-cell characteristics were not taken into account during refinement.