Azirine
Chemical compound
From Wikipedia, the free encyclopedia
Azirine is three-membered heterocyclic unsaturated (i.e. it contain a double bond) compound containing a nitrogen atom and related to the saturated analogue aziridine.[1] Azirines are highly reactive yet have been reported in a few natural products such as Dysidazirine. There are two isomers of azirine: 1H-Azirines with a carbon-carbon double bond are not stable and rearrange to the tautomeric 2H-azirine, a compound with a carbon-nitrogen double bond. 2H-Azirines can be considered strained imines and are isolable.
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| Names | |
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| IUPAC name
2H-Azirine | |
| Identifiers | |
3D model (JSmol) |
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| 1633516 | |
| ChEBI | |
| ChemSpider | |
PubChem CID |
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| Properties | |
| C2H3N | |
| Molar mass | 41.053 g·mol−1 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Preparation
2H-Azirine is most often obtained by the thermolysis of vinyl azides.[2] During this reaction, a nitrene is formed as an intermediate. Alternatively, they can be obtained by oxidation of the corresponding aziridine. Azirine can be generated during photolysis of isoxazole.[3] Due to the weak N-O bond, the isoxazole ring tends to collapse under UV irradiation, rearranging to azirine.[4]
Substituted azirines can be produced via the Neber rearrangement.
Reactions
Photolysis of azirines (under 300 nm) is a very efficient way to generate nitrile ylides. These nitrile ylides are dipolar compounds and can be trapped by a variety of dipolarophiles to yield heterocyclic compounds, e.g. pyrrolines.
The strained ring system also undergoes reactions that favor ring opening and can act as a nucleophile or an electrophile.
Azirines readily hydrolyse to give aminoketones which are themselves susceptible to self-condensation.
See also
- Dysidazirine, one of only a few naturally occurring azirines