Use of debenzylation of quaternary benzylammonium salts in the synthesis of α-deuteriated tertiary amines

Abstract

Simple syntheses are described of two deuteriated tertiary amines, namely NN-dimethyl-p-nitro[α-²H₂]benzylamine and tri([1-²H₂]ethyl)amine. The deuteriation step in the preparation of the former amine involves a selective exchange of the benzyl protons in dimethylbis-(p-nitrobenzyl)ammonium bromide by treatment with alkaline deuterium oxide. The second preparation requires [1-²H₂]ethyl iodide, which is converted into benzyltri([1-²H₂]ethyl)ammonium iodide. The final, key step common to both syntheses is the debenzylation of the quaternary ammonium ion.