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

In the title compounds, C27H28N2O3, (I), and C28H30N2O3, (II), the conformation about the C=N bond is E. The piperidine rings adopt chair conformations with the attached phenyl rings almost normal to their mean planes, the dihedral angles being 85.82 (8) and 85.84 (7)° in (I), and 87.98 (12) and 86.42 (13)° in (II). The phenyl rings are inclined to one another by 52.87 (8)° in (I) and by 60.51 (14)° in (II). The main difference in the conformation of the two compounds is the angle of inclination of the phenoxycarbonyl ring to the piperidine ring mean plane. In (I), these two planes are almost coplanar, with a dihedral angle of 2.05 (8)°, while in (II), this angle is 45.24 (13)°. In the crystal of (I), molecules are linked by C—H...O hydrogen bonds, forming inversion dimers with R22(14) loops. The dimers are linked via C—H...π interactions forming a three-dimensional network. In the crystal of (II), there are no significant intermolecular interactions present