Bis(trimethylsilyl)acetamide (BSA) is an

organosilicon compound Organosilicon compounds are organometallic compounds containing carbon–silicon bonds. Organosilicon chemistry is the corresponding science of their preparation and properties. Most organosilicon compounds are similar to the ordinary organic c ...

with the formula Me₃SiNC(OSiMe₃)Me (Me = CH₃). It is a colorless liquid that is soluble in diverse organic solvents, but reacts rapidly with compounds, including solvents and moisture, containing OH and NH functional groups. It is used in

analytical chemistry Analytical chemistry studies and uses instruments and methods to separate, identify, and quantify matter. In practice, separation, identification or quantification may constitute the entire analysis or be combined with another method. Separati ...

for the derivatisation of compounds in analysis to increase their volatility, e.g. for gas chromatography. It is also used to introduce the

trimethylsilyl A trimethylsilyl group (abbreviated TMS) is a functional group in organic chemistry. This group consists of three methyl groups bonded to a silicon atom minus;Si(CH3)3 which is in turn bonded to the rest of a molecule. This structural group is ch ...

protecting group in organic synthesis.Harry Heaney, Jian Cui, “N,O-Bis(trimethylsilyl)acetamide” Encyclopedia of Reagents for Organic Synthesis Copyright © 2007 John Wiley & Sons. . A related reagent is N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA).

Synthesis and reactions

BSA is prepared by treating acetamide with

trimethylsilyl chloride Trimethylsilyl chloride, also known as chlorotrimethylsilane is an organosilicon compound (silyl halide), with the formula (CH3)3SiCl, often abbreviated Me3SiCl or TMSCl. It is a colourless volatile liquid that is stable in the absence of water. I ...

in the presence of a base: : 2 Me₃SiCl + H₂NC(O)Me + 2 Et₃N → Me₃SiNC(OSiMe₃)Me + 2 Et₃NHCl The reaction of BSA with alcohols gives the corresponding trimethyl silyl ether, together with N-(trimethylsilyl)acetamide as a byproduct: :ROH + Me₃SiNC(OSiMe₃)Me → Me₃SiN(H)C(O)Me + ROSiMe₃

References

{{reflist Reagents for organic chemistry Trimethylsilyl compounds