Crystal structure and conformational analysis of N-formyl and N-nitroso derivatives of piperidinone

Single crystal X-ray studies for N-formyl-2,6-diortho chlorophenyl-3,5-dime thyl piperidin-4-one (FOCDMPO) and N-nitroso-2,6-di(3',4',5'-trimethoxyphen yl)-3,5-dimethyl piperidin-4-one (NTMPO) are reported. Crystals of FOCDMPO and NTMPO belong to the monoclinic space groups P2(1)/n and C2/c, respectiv ely. FOCDMPO: a = 9.147(2), b = 14.586(3), c = 13.665(5) Angstrom and beta = 101.68(2)degrees; NTMPO: a = 38.52(2), b = 13.727(5), c = 9.564(3) Angstr om and beta = 98.60(1)degrees. In both the structures, the piperidine ring adopts a boat conformation with slight distortion. In FOCDMPO, one of the p henyl and methyl groups are in axial positions while the other phenyl and m ethyl groups are in equatorial orientations. In NTMPO, the situation is rev ersed. The molecules are stabilized by weak intermolecular C-H ... O intera ctions in addition to van der Waals forces.