N,O-Bis(trimethylsilyl)acetamide (BSA) is a silylating agent used in organic chemistry, particularly for introducing trimethylsilyl (TMS) groups to molecules. It's a colorless, moisture-sensitive liquid, and a powerful reagent for protecting functional groups like amides, amines, alcohols, carboxylic acids, enols, and phenols. BSA is also used as a base precursor in certain reactions.