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Ball-and-stick model of the trimethylsilyldiazomethane molecule
IUPAC name
Other names
3D model (JSmol)
ECHA InfoCard 100.131.243
MeSH Trimethylsilyldiazomethane
Molar mass 114.22 g·mol−1
Appearance greenish-yellow liquid[1][2]
Boiling point 96.0[1] °C (204.8 °F; 369.1 K)
Safety data sheet External MSDS
Harmful Xn Highly Flammable F Dangerous for the Environment (Nature) N
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Trimethylsilyldiazomethane, (CH3)3SiCHN2, is a diazo compound widely used as a less-explosive replacement for diazomethane.


Trimethylsilyldiazomethane may be prepared from reacting (trimethylsilyl)methylmagnesium chloride with diphenyl phosphorazidate.[3]


Trimethylsilyldiazomethane is a commercially available reagent used in organic chemistry as a methylating agent. It is a less explosive alternative to diazomethane for the methylidenation of carboxylic acids. It also reacts with alcohols to give methyl ethers, where diazomethane may not.[4]

It has also been employed widely in tandem with GC-MS for the analysis of various carboxylic compounds which are ubiquitous in nature. The fact that the reaction is rapid and occurs readily makes it attractive. However, it can form artifacts which complicate spectral interpretation. Such artifacts are usually the trimethylsilylmethyl esters, RCO2CH2SiMe3, formed when insufficient methanol is present. Acid-catalysed methanolysis is necessary to achieve near-quantitative yields of the desired methyl esters, RCO2Me.[5]

The compound is a reagent in the Doyle-Kirmse reaction with allyl sulfides and allyl amines.


Inhalation of trimethylsilyldiazomethane is potentially fatal and has been implicated in the death of at least two chemists, a pharmaceutical worker in Windsor, Nova Scotia, Canada and one in New Jersey.[6][7]

Although less likely to explode than diazomethane, trimethylsilyldiazomethane may be just as toxic. Inhalation of diazomethane is known to cause pulmonary edema; trimethylsilyldiazomethane is suspected to behave similarly.[8]

When used as a reagent in organic synthesis to convert carboxylic acids to their methyl esters, trimethylsilyldiazomethane undergoes acid-catalysed methanolysis, forming diazomethane in situ.[5] A similar hydrolysis reaction may take place when trimethylsilyldiazomethane comes into contact with water on the surface of a human lung.[8]


  1. ^ a b Seyferth, Dietmar.; Dow, Alan W.; Menzel, Horst.; Flood, Thomas C. (1968). "Trimethylsilyldiazomethane and trimethylsilylcarbene". J. Am. Chem. Soc. 90 (4): 1080–1082. doi:10.1021/ja01006a055. 
  2. ^ Seyferth, Dietmar; Menzel, Horst; Dow, Alan W.; Flood, Thomas C. (1972). "Trimethylsilyl-substituted diazoalkanes I. Trimethylsilyldiazomethane". J. Organomet. Chem. 44 (2): 279–290. doi:10.1016/S0022-328X(00)82916-2. 
  3. ^ Takayuki Shioiri, Toyohiko Aoyama, and Shigehiro Mori (1993). "Diazo(trimethylsilyl)methane". Organic Syntheses.  ; Collective Volume, 8, p. 612 
  4. ^ Armin Presser & Antje Hüfner (2004). "Diazo(trimethylsilyl)methane – A Mild and Efficient Reagent for the Methylation of Carboxylic Acids and Alcohols in Natural Products". Chemical Monthly. 135 (8). doi:10.1007/s00706-004-0188-4. 
  5. ^ a b Kühnel, E.; Laffan, D. D. P.; Lloyd-Jones, G. C.; Martínez del Campo, T.; Shepperson, I. R.; Slaughter, J. L. (2007). "Mechanism of Methyl Esterification of Carboxylic Acids by Trimethylsilyldiazomethane". Angew. Chem. Int. Ed. 46 (37): 7075–7078. doi:10.1002/anie.200702131. 
  6. ^ Family says N.S. pharmaceutical worker named chemical he used before death, The Amherst Daily News, October 20, 2008
  7. ^ N.S. probe into pharma worker's death finds vent hoods turned off in lab,, May 13th, 2009
  8. ^ a b Murphy, N. G.; Varney, S. M.; Tallon, J. M.; Thompson, J. R.; Blanc, P. D. (2009). "Fatal Occupational Exposure to Trimethylsilyl-Diazomethane". Clin. Toxicol. 47 (7): 712. doi:10.1080/15563650903076924.