Active ester

Activation can be imparted by modifications of the acyl or the alkoxy components of a normal ester, say ethyl acetate.

Active esters are employed in both synthetic and biological chemistry.

Of great interest is the enhanced reactivity of active esters toward amines to give amides.

[3] In synthetic chemistry, active esters include derivatives of nitrophenols and pentafluorophenol.

[1] Active esters of acrylic acid are precursors to polymers with reactive side chains.