X-ray crystal structure and conformational flexibility study of a N-substituted 2,6-diphenylpiperidine derivative

Piperidine is one of the basic skeletons in many of pharmacological active compounds derived from natural or synthetic medicaments. Substitution of various groups in the piperidine ring regulates conformational flexibility due to the nature of the substituent on the nitrogen atom. One of the N-substituted piperidine derivatives, PMDPM , phenyl(3-methyl-2,6-diphenylpiperidin-1-yl)methanone, was crystallized and analysed by X-ray crystallography. The crystallographic data are: C 23 H 25 NO, M = 355.46, triclinic, space group P 1̅, a = 8.2543(7), b = 10.5543(8), c = 12.6184(6) Å, α = 77.901(7), β = 71.270(2)°, γ = 70.390(5)°; V = 974.3(1) Å 3 , Z = 2, d cal = 1.212 Mg/m 3 , λ(Mo K α ) = 0.71073 Å. The core piperidine ring of PMDPM shows a positional disorder and adopts dual conformations as chair and twisted boat . The phenyl rings are oriented axially to the piperidine ring with the dihedral angle of 22.0(1)° between them. The packing is stabilized by C–H⋯O intra molecular interactions including few C–H⋯π and π⋯π weak interactions.