Experimental

R factor = 0.047; wR factor = 0.124; data-to-parameter ratio = 16.5. In the title compound, C20H16N2O2, the condensed tricyclic fragment is near to planar, with an r.m.s. deviation of 0.0531 Å. The 1,4-dihydropyridine (1,4-DHP) ring adopts a slightly puckered boat-like conformation. The N and opposite C atoms deviate from the least-squares plane of the four other ring atoms by 0.039 (3) and 0.141 (3) Å, respectively. The C O group located at the tricyclic fragment is fixed in an s-trans orientation, while the second C O group adopts an s-cis orientation with respect to the double bonds of the 1,4-DHP ring. The pyridine ring has a pseudo-axial orientation with respect to the 1,4-DHP ring. The dihedral angle between the tricyclic system and the pyridine ring is 77.3 (3). In the crystal, the pyridine N atom accepts a hydrogen bond from the N—H group of the 1,4-DHP ring. The hydrogen bonds link the molecules into infinite C(8) chains along the b-axis direction. Related literature For general information on the relationship between 1,4-di-hydropyridine ring substituents and pharmaceutical effects, see: Christopher et al. (2010); Bisenieks et al. (1987, 1995); Ivanov et al. (1989). For the synthesis of 1,4-DHP-containing tricyclic derivatives, see: Bisenieks et al. (1982)