Phenyl azide is an organic compound with the formula C
6H
5N
3. 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
In chemistry, azide (, ) is a linear, polyatomic anion with the formula and structure . It is the conjugate base of hydrazoic acid . Organic azides are organic compounds with the formula , containing the azide functional group. The dominant ...
substituent bound to a
phenyl group. The C−N=N angle is approximately 116°. It was discovered in 1864 by
Peter Griess by the reaction of ammonia and
phenyldiazonium
Benzenediazonium tetrafluoroborate is an organic compound with the chemical formula, formula 6H5N2F4. It is a salt of a diazonium compound, diazonium cation and tetrafluoroborate. It exists as a colourless solid that is soluble in polar solve ...
.
Preparation
Phenyl azide is prepared by the
diazotization of
phenylhydrazine with
nitrous acid:
:C
6H
5NHNH
2 + HNO
2 → C
6H
5N
3 + 2 H
2O
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):
:RC
6H
4I + NaN
3 → RC
6H
4N
3 + 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
A triazole is a heterocyclic compound featuring a five-membered ring of two carbon atoms and three nitrogen atoms with molecular formula C2H3N3. Triazoles exhibit substantial Isomer, isomerism, depending on the positioning of the nitrogen atoms w ...
.
Phenyl azide reacts with
triphenylphosphine to give the Staudinger reagent
triphenylphosphine phenylimide (C
6H
5NP(C
6H
5)
3).
Thermolysis induces loss of N
2 to give the highly reactive phenylnitrene C
6H
5N.
[W. H. Pearson, P. S. Ramamoorthy, H. Y. Lo in "Phenyl Azide", ''Encyclopedia of Reagents for Organic Synthesis'' (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. .]
Safety
As with many other azides, phenyl azide poses a risk of explosion,
[ 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."][ The pure substance may be stored in the dark, cold, and even then the shelf-life is only weeks.
]
References
{{reflist
Phenyl compounds
IARC Group 3 carcinogens
Organoazides