Phenyl azide
{{Chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 411095002
| Name = Phenyl azide
| ImageFile1 = Phenyl azide Structural Formula V1.svg
| ImageSize1 = 170px
| ImageName1 = Skeletal formula
| ImageFileL2 = Phenyl-azide-from-xtal-3D-bs-17.png
| ImageNameL2 = Ball-and-stick model
| ImageSizeL2 =
| ImageFileR2 = Phenyl-azide-from-xtal-3D-sf.png
| ImageNameR2 = Space-filling model
| ImageSizeR2 =
| PIN = Azidobenzene{{cite book | title = Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book) | publisher = The Royal Society of Chemistry | date = 2014 | location = Cambridge | pages = 66, 1119 | doi = 10.1039/9781849733069-FP001 | isbn = 978-0-85404-182-4}}
|Section1={{Chembox Identifiers
| SMILES = [N-]=[N+]=NC1=CC=CC=C1
| CASNo_Ref = {{cascite|correct|??}}
| CASNo = 622-37-7
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 2G0EH7N6YB
| RTECS =
| EINECS = 210-730-3
| PubChem = 69319
| ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}}
| ChemSpiderID = 62529
| InChI = 1/C6H5N3/c7-9-8-6-4-2-1-3-5-6/h1-5H
| InChIKey = CTRLRINCMYICJO-UHFFFAOYAH
| StdInChI_Ref = {{stdinchicite|changed|chemspider}}
| StdInChI = 1S/C6H5N3/c7-9-8-6-4-2-1-3-5-6/h1-5H
| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}
| StdInChIKey = CTRLRINCMYICJO-UHFFFAOYSA-N
| MeSHName = C014747
}}
|Section2={{Chembox Properties
| C=6 | H=5 | N=3
| Appearance = Pale yellow, oily liquid
| Density =
| Solubility = not appreciable
| MeltingPt =
| BoilingPtC = 49 to 50
| BoilingPt_notes = at 5 mmHg
| Viscosity =
}}
|Section7={{Chembox Hazards
| ExternalSDS =
| MainHazards = explosive
| FlashPt =
| HPhrases =
| PPhrases =
| GHS_ref =
}}
|Section8={{Chembox Related
| OtherFunction_label = compounds
| OtherFunction = Aniline
Nitrobenzene
Nitrosobenzene
Phenylhydrazine
Phenylhydroxylamine
Diazonium cation
}}
}}
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 116°. It was discovered in 1864 by Peter Griess by the reaction of ammonia and phenyldiazonium.{{Cite journal|last1=Griess|first1=John Peter|last2=Hofmann|first2=August Wilhelm Von|date=1864-01-01|title=XX. On a new class of compounds in which nitrogen is substituted for hydrogen|journal=Proceedings of the Royal Society of London|volume=13|pages=375–384|doi=10.1098/rspl.1863.0082|s2cid=94746575|doi-access=free}}{{Cite journal|last=Griess|first=Peter|date=1866|title=Ueber eine neue Klasse organischer Verbindungen, in denen Wasserstoff durch Stickstoff vertreten ist|url=https://onlinelibrary.wiley.com/doi/10.1002/jlac.18661370105|journal=Annalen der Chemie und Pharmacie|language=de|volume=137|issue=1|pages=39–91|doi=10.1002/jlac.18661370105}}
Preparation
Phenyl azide is prepared by the diazotization of phenylhydrazine with nitrous acid:{{OrgSynth | title = Phenyl azide | author = R. O. Lindsay and C. F. H. Allen | volume = 22 | pages = 96 | year = 1942 | doi = 10.15227/orgsyn.022.0096}}
: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):{{Cite journal|last=Andersen|first=Jacob|last2=Madsen|first2=Ulf|last3=Björkling|first3=Fredrik|last4=Liang|first4=Xifu|date=2005|title=Rapid Synthesis of Aryl Azides from Aryl Halides under Mild Conditions|url=http://www.thieme-connect.de/DOI/DOI?10.1055/s-2005-872248|journal=Synlett|language=en|volume=2005|issue=14|pages=2209–2213|doi=10.1055/s-2005-872248|issn=0936-5214}}
: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.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. {{doi|10.1002/047084289X.rp049.pub2}}.
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.