Observation of an infrequent enantiomer/conformer substitutional disorder in ethyl 13-ethyl-4-oxo-8,13-dihydro-4H-benzo[5,6]azepino[3,2,1-ij]quinoline-5-carboxylate heptane hemisolvate.

Considering the importance of quinolones due to their broad spectrum of biological activities, the crystal structure of the title compound, C22H21NO3·0.5C7H16, has been determined. Two enantiomers of the benzazepinoquinoline molecule and one molecule of heptane form the asymmetric unit of this centrosymmetric triclinic (P-1) crystal. All the molecules in the crystal present disorder. Substitutional disorder is observed for the benzazepine molecules, where a minority conformer of the R enantiomer replaces the main conformer of the S enantiomer and vice versa. Positional disorder is found for the heptane solvent molecule, which occupies a void left by the independent enantiomers of both conformers.