Investigation of ring and nitrogen inversion in N-Methyl-1,2,3,4-tetrahydroisoquinoline by dynamic N.M.R. methods

Abstract

ΔG? for the overall ring and nitrogen inversion barriers in N-methyl-1,2,3,4-tetrahydroisoquinoline has been found to be 35.2 kJ/mol in vinyl chloride, and 50.2 kJ/mol in aqueous solution. Both measurements are believed to reflect the height of the nitrogen inversion barrier. The difference is attributed to hydrogen bonding in the aqueous solution. At low pH anomalous inversion rates were obtained.