:Salicylic acid is acetylated to form aspirin<unk>  is an organic esterification reaction with acetic acid. It introduces an acetyl functional group into a chemical compound. Such compounds are termed acetate esters or acetates. Deacetylation is the opposite reaction, the removal of an acetyl group from a chemical compound.
Acetylation
Hydroxylation
Demethylation
Hydrolysis
Saponification
Flagging 
Glucuronidation
Chelation