The conformational analysis of saturated heterocycles. Part XXXII. 1-t-Butylpiperidine-4-spiro-4′- and -5′-oxazolines and -4′- and -5′- thiazolines

Abstract

Compounds of the type mentioned in the title have been prepared and their dipole moments and low-temperature n.m.r. spectra investigated to provide evidence on the position of the conformational equilibria of type (1a)⇌(1b) and hence of the relative steric interactions involving sp²-hybridised nitrogen, and of oxygen and sulphur attached to sp²-carbon, compared in each case with a methylene group.