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Wenker synthesis

The Wenker synthesis is an organic reaction converting a beta amino alcohol to an aziridine with the aid of sulfuric acid.^[1]

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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.^[2]

Starting from cyclooctene oxide, trans-2-Aminocyclooctanol gives a mixture of Cycloöctenimine and of cyclooctanone as a result of competing Hofmann elimination.^[3]

References

^ The Preparation of Ethylene Imine from Monoethanolamine Henry Wenker J. Am. Chem. Soc.; 1935; 57(11) pp 2328 - 2328. (doi:10.1021/ja01314a504)
^ 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)
^ 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)