Wenker synthesis

The Wenker synthesis is an organic reaction converting a beta amino alcohol to an aziridine with the aid of sulfuric acid. [cite journal
title = The Preparation of Ethylene Imine from Monoethanolamine
author = Henry Wenker
journal = Journal of the American Chemical Society
year = 1935
volume = 57
issue = 1
pages = 2328–2328
doi = 10.1021/ja01314a504]

The original Wenker synthesis of aziridine itself takes place in two steps. In the first step ethanolamine is reacted with sulfuric acid at high temperatures (250°C) to the sulfonate salt, This salt is then reacted with sodium hydroxide in the second step forming azirine. The base abstracts an amine proton enabling it to displace the sulfonate group. A modification of this reaction involving lower reaction temperatures (140 - 180°C) and therefore reduced charring increases the yield of the intermediate. ["A Modification of Wenker's Method of Preparing Ethyleneimine" Philip A. Leighton, William A. Perkins, and Melvin L. Renquist J. Am. Chem. Soc.; 1947; 69(6) pp 1540 - 1540. (DOI|10.1021/ja01198a512)]

Starting from cyclooctene oxide, "trans-2-Aminocyclooctanol" gives a mixture of Cycloöctenimine and of cyclooctanone as a result of competing Hofmann elimination. ["Chemistry of Ethylenimine. VII. Cycloöctenimine or 9-Azabicyclo [6.1.0] nonane" D. V. Kashelikar, Paul E. Fanta J. Am. Chem. Soc.; 1960; 82(18); 4927-4930. (DOI|10.1021/ja01503a044)]

References