Orientation of the unshared electron pair of the nitrogen atom in N-substituted 2,5-dimethyl-4-piperidinones

The axial orientation of the unshared electron pair of the nitrogen atom in cis isomers of N-substituted R=H, CH₃, CH₂C₆H₅, or C(CH₃)₃] 2,5-dimethyl-4-piperidinones was proven by using the stereospecificity of the direct ¹³C-¹³C spin-spin coupling constants, vicinal ¹³C-¹H spin-spin coupling constants, and two-dimensional nuclear-Overhauser-effect spectroscopy (NOESY).Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 512–513, April, 1989.