Bis(trimethylsilyl)acetamide

Bis(trimethylsilyl)acetamide (BSA) is an organosilicon compound with the formula MeC(OSiMe3)NSiMe3 (Me = CH3). It is a colorless liquid that is soluble in diverse organic solvents, but reacts rapidly with moisture and solvents containing OH and NH groups. It is used in analytical chemistry to increase the volatility of analytes, e.g., for gas chromatography. It is also used to introduce the trimethylsilyl protecting group in organic synthesis. A related reagent is N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA).

Synthesis and reactions
BSA is prepared by treating acetamide with trimethylsilyl chloride in the presence of a base (Me = CH3, Et = C2H5):
 * MeC(O)NH2 + 2 SiMe3Cl  +  2 Et3N→ MeC(OSiMe3)NSiMe3  +  2 Et3NHCl

The reaction of BSA with alcohols gives the corresponding trimethylsilyl ether, together with acetamide as a byproduct (Me = CH3):
 * 2 ROH + MeC(OSiMe3)NSiMe3 → MeC(O)NH2  +  2 ROSiMe3