Crystal structures of two new 3-(2-chloro­eth­yl)-r(2),c(6)-diarylpiperidin-4-ones

The syntheses and crystal structures of 3-(2-chloro­eth­yl)-r-2,c-6-di­phenyl­piperidin-4-one, C19H20ClNO, (I), and 3-(2-chloro­eth­yl)-r-2,c-6-bis­(4-fluoro­phen­yl)piperidin-4-one, C19H18ClF2NO, (II), are described. The piperidone ring adopts a chair conformation in (I), whereas a slightly distorted chair conformation is formed in (II). The dihedral angle between the mean plane of the phenyl rings is 59.1 (1)° in (I) and 76.1 (1)° in (II). The crystal packing features weak inter­molecular N—H⋯O hydrogen bonds in each structure.