5-Amino-6-benzoyl-8-nitro-2,3-di­hydro-1H-spiro­[imidazo[1,2-a]pyridine-7,3′-indolin]-2′-one dimethyl sulfoxide monosolvate

In the title compound C₂₁H₁₇N₅O₄·C₂H₆OS, the central six-membered ring derived from 1,4-di­hydro­pyridine adopts a distorted boat conformation with a small puckering amplitude of 0.127 (3) Å. The sums of bond angles around the pyridine N atom [358.7 (2)°] and the other imidazolidine N atom [60 (2)°] indicate that these atoms are in sp² hybridization, leading to an essentially planar imidazolidine ring. The last heterocycle, an oxindole moiety, is also nearly planar with an r.m.s. deviation of 0.0185 (1) Å. The amine NH₂ group forms an intra­molecular hydrogen bond with the benzoyl group, giving a S(6) motif. In the crystal, N—H...O hydrogen bonds lead to the formation of chains along the c-axis direction. Within the chains there are further N—H...O and C—H...O hydrogen bonds enclosing R²₂(14) ring motifs. The chains are linked via N—H...O and C—H...O hydrogen bonds involving the dimethyl sulfoxide solvent mol­ecule which acts as both an acceptor and a donor..

5-Amino-5′-bromo-6-(4-methyl­benzo­yl)-8-nitro-2,3-di­hydro-1H-spiro­[imidazo[1,2-a]pyridine-7,3′-indolin]-2′-one including an unknown solvate

In the title compound, C₂₂H₁₈BrN₅O₄, the central six-membered ring, derived from 1,4-di­hydro­pyridine, adopts a distorted boat conformation with a puckering amplitude of 0.197 (3) Å, the imidazole ring adopts a twisted conformation with a puckering amplitude of 0.113 (3) Å, and the oxindole moiety is planar with an r.m.s. deviation of 0.0125 Å. Two intra­molecular N—H...O hydrogen bonds are formed, each closing an S(6) loop. In the crystal, strong N—H...O hydrogen bonds lead to the formation of zigzag chains along the c axis. These are consolidated in the three-dimensional crystal packing by weak N—H...O hydrogen bonding, as well as by C—H...O, C—H...Br and C—H...π inter­actions. A small region of electron density well removed from the main mol­ecule was removed with the SQUEEZE procedure in PLATON [Spek (2009). Acta Cryst. D65, 148–155] following unsuccessful attempts to model it as a plausible solvent mol­ecule. The unit-cell characteristics do not take into account this feature of the structure.