ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS, vol.61, 2005 (SCI-Expanded)
The title compounds, C20H21F2NO3 and C21H23F2NO3, respectively, belong to a class of 1,4-dihydropyridines whose members sometimes display calcium modulatory properties. The 1,4-dihydropyridine rings have the usual shallow boat conformation. In each structure, the 2,3-difluorophenyl ring is oriented such that the fluoro substituents are in a synperiplanar orientation with respect to the 1,4-dihydropyridine ring plane and the oxocyclohexene ring has a slightly distorted envelope conformation. Both structures exhibit the same intermolecular N - H center dot center dot center dot O hydrogen-bonding motif, in which the molecules are linked into chains by interactions involving the carbonyl O atom of the oxocyclohexene ring.