A carboxylic acid derivative is an organic compound that, upon reacting with water under appropriate conditions, affords a carboxylic acid as the only product or one of the products.
Most carboxylic acid derivatives are carbonyl compounds with the following general structural formula.
R = H, alkyl group, aryl group
G = a ligand bonded to the carbonyl carbon by a heteroatom
Nitriles are the most common class of carboxylic acid derivatives that are not carbonyl compounds.