Relative substituent orientation in the structure of cis-3-chloro-1,3-dimethyl-N-(4-nitrophenyl)-2-oxocyclopentane-1-carboxamide

The structure of the title compound, C14H15ClN2O4, prepared by reaction of a methacryloyl dimer with nitroaniline, was determined to establish the relative substituent orientation on the cyclopentanone ring. In agreement with an earlier proposed reaction mechanism, the amide group and the methyl group adjacent to the chloro substituent adopt equatorial positions and relative cis orientation, whereas the Cl substituent itself and the methyl group adjacent to the amide have axial orientations relative to the mean plane of the five-membered ring. The conformation of the molecule is stabilized by one classical N—H...O (2.18 Å) and one non-classical C—H...O (2.23 Å) hydrogen bond, each possessing an S(6) graph-set motif. The crystal packing is defined by several non-classical intramolecular hydrogen bonds, as well as by partial stacking of the aromatic rings