Phenyl azide

Phenyl azide is an organic compound with the formula C₆H₅N₃. It is one of the prototypical organic azides. It is a pale yellow oily liquid with a pungent odor. The structure consists of a linear azide substituent bound to a phenyl group. The C−N=N angle is approximately 120°. It was discovered in 1864 by Peter Griess by the reaction of ammonia and phenyldiazonium.^[2][3]

Phenyl azide

Ball-and-stick model Space-filling model
Names
Preferred IUPAC name Azidobenzene[1]
Other names Phenyl azide[1]
Identifiers
CAS Number	622-37-7 Y
3D model (JSmol)	Interactive image
ChemSpider	62529 N
ECHA InfoCard	100.009.756
EC Number	210-730-3
MeSH	C014747
PubChem CID	69319
UNII	2G0EH7N6YB Y
CompTox Dashboard (EPA)	DTXSID30878870
InChI InChI=1S/C6H5N3/c7-9-8-6-4-2-1-3-5-6/h1-5H N Key: CTRLRINCMYICJO-UHFFFAOYSA-N N InChI=1/C6H5N3/c7-9-8-6-4-2-1-3-5-6/h1-5H Key: CTRLRINCMYICJO-UHFFFAOYAH
SMILES [N-]=[N+]=NC1=CC=CC=C1
Properties
Chemical formula	C6H5N3
Molar mass	119.127 g·mol−1
Appearance	Pale yellow, oily liquid
Boiling point	49 to 50 °C (120 to 122 °F; 322 to 323 K) at 5 mmHg
Solubility in water	not appreciable
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	explosive
Related compounds
Related compounds	Aniline Nitrobenzene Nitrosobenzene Phenylhydrazine Phenylhydroxylamine Diazonium cation
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Preparation

Phenyl azide is prepared by the diazotization of phenylhydrazine with nitrous acid:^[4]

C₆H₅NHNH₂ + HNO₂ → C₆H₅N₃ + 2 H₂O

Aryl iodides bearing electron-withdrawing substituents undergo metathesis with sodium azide in the presence of Cu(I), sodium ascorbate, and N,N'-dimethylethane-1,2-diamine (DMEDA):^[5]

RC₆H₄I + NaN₃ → RC₆H₄N₃ + NaI

It can also be prepared by condensation of benzenediazonium salt with toluenesulfonamide, followed by hydrolysis.

Chemical reactions

Phenyl azide cycloadds to alkenes and especially alkynes, particularly those bearing electronegative substituents. In a classic example of click chemistry, phenyl azide and phenylacetylene react to give diphenyl triazole.

Phenyl azide reacts with triphenylphosphine to give the Staudinger reagent triphenylphosphine phenylimide (C₆H₅NP(C₆H₅)₃).

Thermolysis induces loss of N₂ to give the highly reactive phenylnitrene C₆H₅N.^[6]

Safety

As with many other azides, phenyl azide poses a risk of explosion,^[4] so a protective blast shield is recommended during purification and handling. Distillations are hazardous. Organic Syntheses recommends a vacuum of 5mm Hg to give a boiling point of "66–68 °C/21 mm. with a bath temperature of 70–75 °C."^[4] The pure substance may be stored in the dark, cold, and even then the shelf-life is only weeks.

References

1. Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. pp. 66, 1119. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4.
2. Griess, John Peter; Hofmann, August Wilhelm Von (1864-01-01). "XX. On a new class of compounds in which nitrogen is substituted for hydrogen". Proceedings of the Royal Society of London. 13: 375–384. doi:10.1098/rspl.1863.0082. S2CID 94746575.
3. Griess, Peter (1866). "Ueber eine neue Klasse organischer Verbindungen, in denen Wasserstoff durch Stickstoff vertreten ist". Annalen der Chemie und Pharmacie (in German). 137 (1): 39–91. doi:10.1002/jlac.18661370105.
4. R. O. Lindsay and C. F. H. Allen (1942). "Phenyl azide". Organic Syntheses. 22: 96. doi:10.15227/orgsyn.022.0096.
5. Andersen, Jacob; Madsen, Ulf; Björkling, Fredrik; Liang, Xifu (2005). "Rapid Synthesis of Aryl Azides from Aryl Halides under Mild Conditions". Synlett. 2005 (14): 2209–2213. doi:10.1055/s-2005-872248. ISSN 0936-5214.
6. W. H. Pearson, P. S. Ramamoorthyin "Phenyl Azide" Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. doi:10.1002/047084289X.