N,N-DIACETYLAMINES AS BY-PRODUCTS FROM THE ACETYLATION OF AMINES

Abstract

Acetylation of five alicyclic amines and isopropylamine with a large excess of acetic anhydride for 1 hour under reflux led to formation of appreciable yields (23–35%) of N,N-diacetylamines in addition to the anticipated N-acetylamines, except in the case of cis-2-aminocyclohexanol, which gave only the O,N-diacetyl derivative. The N-acetyl derivatives show an acetamido methyl proton resonance in their nuclear magnetic resonance spectra at 8.04–8.09 τ, whereas the N,N-diacetylamines show no absorption in this region but instead a resonance equivalent to six protons at 7.63–7.69 τ due to the N,N-diacetyl group. The infrared spectra of these compounds are consistent with the structures assigned on the basis of their n.m.r. spectra. Splitting of the amide carbonyl band was not generally observed in these compounds although two of the substances exhibited a minor band on the low frequency side of the main band which might be attributed to this cause.