Crystal structures of (E)-(3-ethyl-1-methyl-2,6-di­phenyl­piperidin-4-yl­idene)amino phenyl carbonate and (E)-(3-isopropyl-1-methyl-2,6-di­phenyl­piperidin-4-yl­idene)amino phenyl carbonate

The title compounds are the 3-ethyl, (I), and 3-isopropyl, (II), derivatives of (1-methyl-2,6-diphenylpiperidin-4-ylidene)amino phenyl carbonate. The main difference in the conformation of the two compounds is the angle of inclination of the phenoxycarbonyl ring with respect to the piperidine ring mean plane, with a dihedral angle of 2.05 (8)° in (I) and 45.24 (13)° in (II).

Methyl 1-phenyl-3-p-tolyl-1,9b-di­hydro-3H-chromeno[4,3-c]isoxazole-3a(4H)-carboxyl­ate

In the title compound, C₂₅H₂₃NO₄, the pyran ring of the chroman moiety has an envelope conformation with the methyl­ene C atom as the flap. The isoxazole ring has a twist conformation on the O—C bond. The dihedral angle between their mean planes is 57.87 (9)°. The attached phenyl and benzene rings are twisted away from its mean plane by 56.19 (10) and 50.57 (10)°, respectively. These two rings are normal to each other, subtending a dihedral angle of 89.2 (1)°. In the crystal, there are no classical hydrogen bonds; the mol­ecules are linked via C—H...π inter­actions, forming a two-dimensional network lying parallel to (10-1).

(E)-1,3-Dimethyl-2,6-di­phenyl­piperidin-4-one O-(phen­oxy­carbon­yl)oxime

The title piperidine derivative, C₂₆H₂₆N₂O₃, has an E conformation about the N=C bond. The piperidine ring has a chair conformation and its mean plane is almost perpendicular to the attached phenyl rings, making dihedral angles of 87.47 (9) and 87.34 (8)°. The planes of these two phenyl rings are inclined to one another by 60.38 (9)°. The plane of the terminal phenyl ring is tilted at an angle of 32.79 (9)° to the mean plane of the piperidine ring. The mol­ecular conformation is stabilized by two intra­molecular C—H...O contacts. There are no significant inter­molecular inter­actions in the crystal.