A study of the nitrogen inversion process in the bicyclic oxazine, N-methyl-2-oxa-3- azabicyclo [2, 2, 2] octane, by 13C NMR spectrocopy reveals a free energy of activation of 14.9 kcal mole-1. Detailed examination of the kinetics of the process observed in the 1H spectra of N-methyl tetrahydro-1, 2-oxazine shows ΔH≠ 15.1±0.4 kcal mole-1 and ΔS≠ 2.3±1.5 cal mol-1K-1. It is concluded from the similarity in the activation parameters that ...