Azirine

Names
IUPAC name

2H-Azirine

Identifiers

CAS Number

* 157-16-4

3D model (JSmol)

* Interactive image

Beilstein Reference

| 1633516
ChEBI |

* CHEBI:30971

ChemSpider |

* 119750

PubChem CID

* 135972

InChI

* InChI=1S/C2H3N/c1-2-3-1/h1H,2H2

Key: NTJMGOWFGQXUDY-UHFFFAOYSA-N

SMILES

* C1C=N1

Properties

Chemical formula

| 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).

Infobox references

Chemical compound

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.

## Preparation

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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

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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

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* Dysidazirine, one of only a few naturally-occurring azirines

## References

[edit]

1. ^ Teresa M. V. D. Pinho e Melo and Antonio M. d’A. Rocha Gonsalves (2004). "Exploiting 2-Halo-2H-Azirine Chemistry". Current Organic Synthesis. 1 (3): 275–292\. doi:10.2174/1570179043366729. Archived from the original on 2006-09-28.
2. ^ Palacios F, Ochoa de Retana AM, Martinez de Marigorta E, de los Santos JM (2001). "2H-Azirines as synthetic tools in organic chemistry". Eur. J. Org. Chem. 2001 (13): 2401–2414\. doi:10.1002/1099-0690(200107)2001:13<2401::AID-EJOC2401>3.0.CO;2-U.
3. ^ Edwin F. Ullman (1966). "Photochemical Transposition of Ring Atoms in Five-Membered Heterocycles. The Photorearrangement of 3,5-Diphenylisoxazole". J. Am. Chem. Soc. 88 (8): 1844–1845\. Bibcode:1966JAChS..88.1844U. doi:10.1021/ja00960a066.
4. ^ Cheng, K.; Qi, J.; Ren, X.; Zhang, J.; Li, H.; Xiao, H.; Wang, R.; Liu, Z.; Meng, L; Ma, N.; Sun, H. (2022). "Developing Isoxazole as a Native Photo-Cross-Linker for Photoaffinity Labeling and Chemoproteomics". Angew. Chem. Int. Ed. 61 (47): e202209947. doi:10.1002/anie.202209947. PMID 36151600.

*[CID]: Compound ID