In the title compound, C19H14FN3O3, the central pyran ring adopts a boat conformation with the O atom and the quaternary C atom diagonally opposite displaced by 0.068 (1) and 0.075 (1) Å, respectively, above the mean plane defined by the other four ring atoms. The co-planar atoms of the pyran ring and the fluoro­phenyl ring are nearly perpendicular, as evidenced by the dihedral angle of 87.11 (1)°. The amine group forms an intra­molecular N—H⋯O(nitro) hydrogen bond. In the crystal, mol­ecules are linked into parallel chains along [100] by weak N—H⋯N and C—H⋯N(nitro) hydrogen bonds, generating C(8) and C(9) graph-set motifs, respectively.

In the title compound, C24H14BrN3S, the dihedral angles between the planes of the pyridine ring and the pendant thio­phene ring, the indole ring system (r.m.s. deviation = 0.022 Å) and the bromo­benzene ring are 9.37 (17), 21.90 (12) and 69.01 (15)°, respectively. The approximate coplanarity of the central ring and the indole ring system is supported by two intra­molecular C—H⋯N inter­actions. In the crystal, inversion dimers linked by pairs of N—H⋯N hydrogen bonds generate R 2 2(16) loops and the dimers are linked by C—H⋯π and aromatic π–π stacking [shortest centroid–centroid separation = 3.729 (3) Å] into a three-dimensional network.

In the title compound, C37H34N2O4S, the piperidine ring adopts a half-chair conformation. The thia­zole ring adopts a slightly twisted envelope conformation and the pyrrole ring adopts an envelope conformation; in each case, the C atom linking the rings is the flap atom. An intra­molecular C—H⋯O inter­action is noted. The crystal structure is stabilized by C—H⋯O and C—H⋯π inter­actions.

In the title compound, C20H22N2O2, the central pyridine ring forms a dihedral angle of 76.32 (8)° with the pseudo-axial benzene ring. The cyclo­octane ring adopts a twisted boat chair conformation. In the crystal, weak inter­molecular C—H⋯π inter­actions between inversion-related mol­ecules result in the formation of linear double chains along the b-axis direction.

In the title compound, C26H16ClN3, the dihedral angles between the central pyridine ring and the pendant phenyl, chlorobenzene and indole rings are 18.52 (12), 48.97 (11) and 21.20 (10)°, respectively. An intramolecular C—H...Nc(c = cyanide) hydrogen bond occurs. In the crystal, inversion dimers linked by pairs of N—H...Nchydrogen bonds generateR22(16) loops.