Experimental and theoretical rearrangement of N-acyl-2,2- dimethylaziridines in acidic medium

Abstract

The acid isomerization of N-acyl-2,2-dimethylaziridines 1 in concentrated sulfuric acid at room temperature leads to oxazolines 2 but the neutral hydrolysis of 1 in pure water at room temperature leads to amidoalcohols 3. However, the use of aqueous solutions of H2SO4 at different concentrations at room temperature leads to a mixture of oxazolines 2, amidoalcohols 3 and allylamides 4 with yields depending on the acidity of the medium and the nature of the acyl group. A mechanism has been suggested to explain the formation of these three products. DFT calculations employing the Gaussian 09 program with DFT/B3LYP methods and 6-311++G(2d,2p) basis set were carried out which gave the most stable geometry as well as their atomic charge distributions of compounds 1-4. The acidic aqueous solutions of the N-acyl-2,2-dimethylaziridines 1 lead to a mixture of oxazolines 2, amidoalcohols 3 and methallylamides 4. The mechanism proposed to explain the formation of products 2-4 have been confirmed by the quantum chemical calculations using the DFT/B3LYP method and 6-311++G(2d,2p) basis set.