Methanesulfonyl azide

Methanesulfonyl azide is the azide of methanesulfonic acid. It is used as a reagent for the production of diazo compounds.

Methanesulfonyl azide

Names
Other names Mesyl azide
Identifiers
CAS Number	1516-70-7
3D model (JSmol)	Interactive image
ChemSpider	483609
PubChem CID	556271
CompTox Dashboard (EPA)	DTXSID80339446
InChI InChI=1S/CH3N3O2S/c1-7(5,6)4-3-2/h1H3 Key: BHQIGUWUNPQBJY-UHFFFAOYSA-N
SMILES CS(=O)(=O)N=[N+]=[N-]
Properties
Chemical formula	CH3N3O2S
Molar mass	121.12 g·mol−1
Melting point	18 °C (64 °F; 291 K)
Boiling point	120 °C (248 °F; 393 K) decomposes
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Preparation

Methanesulfonyl azide can be prepared from methanesulfonyl chloride by reaction with sodium azide in ethanol or methanol, Preparation in situ is also possible, for example in acetonitrile, and is advantageous to avoid explosion hazards.

Properties

Methanesulfonyl azide melts at 18 °C and decomposes from 120 °C. Like many other azides, it is explosive. At low temperature, methanesulfonyl azide crystallizes in the triclinic crystal system in the space group P1 with the lattice parameters a = 5.6240 Å; b = 5.9498 Å, c = 7.6329 Å, α = 72.216°, β = 70.897°, and γ = 88.601°, and two molecules per unit cell.

Reactions

Methanesulfonyl azide is a suitable reagent for introducing diazo compounds into other compounds. Historically, tosylazide was mainly used for this purpose. However, nowadays, compounds that are less explosive and/or form an amide after diazo transfer, which can be easily separated from the reaction products, are often used. In addition to imidazole-1-sulfonyl azide and 4-acetamidobenzenesulfonyl azide, methanesulfonyl azide is also utilized. The advantages of methanesulfonyl azide are particularly its simple and inexpensive production and the straightforward purification of the reaction mixture. Starting from Ω-bromoacetophenone, by reaction with trimethylphosphite, and then with sodium hydride and methanesulfonyl azide, a diazo reagent can be produced, which can convert aldehydes into alkynes. This method works similarly to the reaction with the Ohira-Bestmann reagent but is significantly more expensive to produce.

The photolysis of methanesulfonyl azide in a matrix of argon or neon yields a short-lived nitrene. If methanesulfonyl azide is irradiated in the presence of a hydrocarbon, methanesulfonyl amide is formed, as well as N-substituted derivatives by reaction with the hydrocarbon.