Heine reaction

The Heine reaction is a name reaction in organic chemistry that was named after Harold W. Heine , who first described it in 1959. This reaction is the isomerization of an N- acyl aziridine to the corresponding oxazole .

Overview reaction

N- Acyl aziridine reacts with sodium iodide to form oxazolines :

mechanism

This reaction is a nucleophilic substitution (S _N 2 reaction). As a nucleophilic particle, the iodide attacks the carbon atom of the aziridine . The oxygen atom is negatively charged by shifting electrons . In the next reaction step this oxygen atom attacks the carbon atom as a nucleophilic particle , whereby the negatively charged iodide is split off again. This change in the atomic arrangement ( isomerization ) resulted in an oxazole .

The reaction takes place in the solvent acetone , 2-propanol or acetonitrile at room temperature. As nucleophile particles instead can sodium and potassium are used. The radical R ¹ is, for. B. an alkyl or aryl radical , an aryl radical for R ² and a CO ₂ -alkyl or CO ₂ -aryl radical for R ³ .

variants

Instead of the oxygen atom, sulfur or nitrogen can also be used. A sulfur atom creates a thiazoline and a nitrogen atom, as shown in the figure, creates an imidazoline .

In a further variant, an azo group occurs in the aziridine . A triazine is the product .

literature

• Harold W. Heine: The Isomerization of Aziridine Derivatives . In: Angewandte Chemie International Edition in English . tape 1 , no. October 10 , 1962, p. 528-532 , doi : 10.1002 / anie.196205281 .

Individual evidence

1. ↑ Harold W. Heine, Mary Emma Fetter, Elva Mae Nicholson: The Isomerization of Some 1-Aroylaziridines. II. In: J. Am. Chem. Soc. 81, No. 9, 1959, pp. 2202-2204, doi: 10.1021 / ja01518a048 .
2. ↑ László Kürti , Barbara Czakó: Strategic Applications Of Named Reactions In Organic Synthesis . Elsevier Academic Press, USA 2005, ISBN 978-0-12-429785-2 , pp. 198 .