N.m.r. Studies of rate processes and conformations. Part VI. Ring inversion in hexahydro-1,3,5-triazines

Abstract

The energy barriers to chair–chair interconversion in tri-N-methyl-, -ethyl-, -isopropyl-, and -t-butyl-hexahydrotriazine have been measured by the study of the temperature-dependence of their nuclear magnetic resonance spectra. The free enegies of activation vary with the substituent upon the nitrogen atoms, and the rate of ring inversion is increased by substituents that facilitate nitrogen inversion. Solvent effects confirm that the observed rate process is ring inversion and not hindered nitrogen inversion.