The conformational analysis of saturated heterocycles. Part XV. 1-t-Butyl-3-methyl- and 1-t-butyl-3,5-dimethyl-4-piperidone and the corresponding 3-ethyl and 3,5-diethyl derivatives

Abstract

The conformational equilibria of 1-t-butyl-3-methyl- and 1-t-butyl-3,5-dimethyl-4-piperidone and the corresponding 3-ethyl and 3,5-diethyl derivatives in carbon tetrachloride were elucidated by n.m.r. spectral studies after simultaneous base-catalysed equilibration and deuteriation. The results are compared with those for the corresponding cyclohexanones and demonstrate the smaller steric requirements of a lone electron pair compared to those of a hydrogen atom.