Trimethylsilyl azide
{{chembox
| Watchedfields = changed
| verifiedrevid = 470615689
| ImageFileL1 =Trimethylsilyl azide.png
| ImageSizeL1 = 130
| ImageAltL1 = Skeletal formula of Trimethylsilyl azide
| ImageFileR1 =Trimethylsilyl-azide-3D-spacefill.png
| ImageSizeR1 = 130
| ImageAltR1 = Ball-and-stick model of the trimethylsilyl azide molecule
| PIN =Azidotri(methyl)silane
| OtherNames =
|Section1={{Chembox Identifiers
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 70747
| InChI = 1/C3H9N3Si/c1-7(2,3)6-5-4/h1-3H3
| InChIKey = SEDZOYHHAIAQIW-UHFFFAOYAJ
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C3H9N3Si/c1-7(2,3)6-5-4/h1-3H3
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = SEDZOYHHAIAQIW-UHFFFAOYSA-N
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo =4648-54-8
| PubChem =78378
| Beilstein = 1903730
| EINECS =225-078-5
| SMILES = [N-]=[N+]=N[Si](C)(C)C
}}
|Section2={{Chembox Properties
| C=3 | H=9 | N=3 | Si=1
| Appearance = colorless liquid
| Odour = Odourless;{{cite web |title=SAFETY DATA SHEET |url=https://www.fishersci.com/store/msds?partNumber=AAL00173&productDescription=keyword&vendorId=VN00024248&countryCode=US&language=en |website=ThermoFisher Scientific |date=16 Feb 2015}} pungent{{cite web |title=TRIMETHYLSILYL AZIDE, 96% Safety Data Sheet |url=https://www.gelest.com/wp-content/uploads/SIT8580.0_TRIMETHYLSILYL-AZIDE-96_GHS-US_English-US.pdf |publisher=Gelest |access-date=17 January 2025 |date=15 July 2015}}
| Density =0.8763 g/cm3 (20 °C)
| MeltingPtC = -95
| BoilingPtC = 52 to 53
| BoilingPt_notes = at 175 mmHg (92 to 95 °C at 760 mmHg)
| Solubility =reacts to form dangerous hydrazoic acid
}}
|Section7={{Chembox Hazards
| ExternalSDS =
| MainHazards =
| NFPA-H = 4
| NFPA-F = 3
| NFPA-R = 0
| NFPA-S =
| GHSPictograms = {{GHS02}}{{GHS06}}{{GHS09}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|225|301|311|331|410}}
| PPhrases = {{P-phrases|210|233|240|241|242|243|261|264|270|271|273|280|301+310|302+352|303+361+353|304+340|311|312|321|322|330|361|363|370+378|391|403+233|403+235|405|501}}
| FlashPtC = 6
| AutoignitionPt = >
| AutoignitionPtC = 300
| ExploLimits =
| LD50 = {{ubl|100 mg/kg (Oral, expert judgement)|315.8 mg/kg (dermal)}}
| PEL =
}}
}}
Trimethylsilyl azide is the organosilicon compound with the formula {{chem2|(CH3)3SiN3}}. A colorless liquid, it is a reagent in organic chemistry, serving as the equivalent of hydrazoic acid.{{cite book |doi=10.1002/047084289X.ra117.pub3 |chapter=Azidotrimethylsilane |title=Encyclopedia of Reagents for Organic Synthesis |year=2016 |last1=Nishiyama |first1=Kozaburo |last2=Wang |first2=Cheng |last3=Lebel |first3=Hélène |pages=1–16 |isbn=9780470842898 }}
Preparation
Trimethylsilyl azide is commercially available. It may be prepared by the reaction of trimethylsilyl chloride and sodium azide:{{OrgSynth | author = L. Birkofer and P. Wegner | title = Trimethylsilyl azide | volume = 50 | page = 107 | year = 1970 | doi = 10.15227/orgsyn.050.0107}}
: {{chem2|(CH3)3Si\sCl + NaN3 → (CH3)3Si\sN3 + NaCl}}
Reactions
The compound hydrolyzes to hydrazoic acid:{{cite journal | doi = 10.1055/s-2007-984895 | title = Trimethylsilyl Azide (TMSN3): A Versatile Reagent in Organic Synthesis | year = 2007 | author = Jafarzadeh, Mohammad | journal = Synlett | volume = 2007 | issue = 13 | pages = 2144–2145| doi-access = free }}
: {{chem2|(CH3)3SiN3 + H2O → (CH3)3SiOH + HN3}}
The compound adds to ketones and aldehydes to give the siloxy azides and subsequently tetrazoles:
: {{chem2|(CH3)3SiN3 + R2CO → R2C(N3)OSi(CH3)3}}
It ring-opens epoxides to give azido alcohols.
It has been used in the Oseltamivir total synthesis.
Safety
Trimethylsilyl azide is incompatible with moisture, strong oxidizing agents, and strong acids. Azides are often explosive, as illustrated by their use in air bags.