Structural Investigation of 2,6-Di-2-furyl-3,5-dimethyl-4-piperidinone and Its N-Nitroso Derivative in Solution and the Solid State-Influence of the Nitroso Moiety on the Conformation of the Piperidine Ring and Orientation of Its Substituents

Abstract The structures of the title compounds, 2,6-di-2-furyl-3,5-dimethyl-4-piperidinone (DFMP) and its N-nitroso derivative (DFMPNO), have been investigated in solution and the solid state by NMR and X-ray methods, respectively. Both of the structures were solved by direct methods of X-ray analysis and were refined to an R-factor of 0.059 and 0.057, respectively. The piperidine ring adopts a chair conformation in DFMP and a boat conformation in DFMPNO. Both of the furan rings are in an equatorial orientation in DFMP, whereas in DFMPNO one ring is in the axial position and the other ring is in the equatorial position. The nitroso group is in the perpendicular orientation in DFMPNO. The angle between the best plane of the piperidine ring and the nitroso group is 142.1(4)°. The interaction between the molecules are van der Waals in nature in both structures.