Studies towards DIAD promoted N-demethylation of N,N-dimethylanilines

• The demethylation of N , N -dimethylanilines mediated by diisopropyl azodicarboxylate (DIAD) was achieved. • The reaction mechanism was investigated experimentally and further verified by theoretical calculations. • The applications on the metabolic study was demonstrated. The demethylation of N , N -dimethylanilines promoted by diisopropyl azodicarboxylate (DIAD) to provide N -methylanilines was achieved in this paper. This protocol featured with mild reaction condition, simple operation and moderate to good yield. The intermediates were isolated and identified by means of spectroscopy methods. The reaction mechanism was investigated experimentally and further verified by theoretical calculations. This method could be applied to the study of the metabolites of medicines containing N , N -dimethylaniline fragments.