Illustrated Glossary of Organic Chemistry

Ester: A molecule or functional group derived by condensation of an alcohol and an acid with simultaneous loss of water. The most common type of ester is carboxylic ester (also called a carboxylate ester; frequently just called an ester), derived from a carboxylic acid. A carboxylic ester is sometimes abbreviated as RCOOR or RCO2R.


Carboxylic acid


General carboxylate ester structure.

Representative Carboxylate Esters

Ethyl acetate, a common solvent.   
Methyl salicylate (oil of wintergreen).   
Nepetalactone, the active substance in catnip.



Sulfuric acid

Dimethyl sulfate, a sulfate ester.
Condensation of an alcohol with sulfuric acid produces a sulfate ester. In this example, sulfuric acid condenses with two equivalents of methanol to produce dimethyl sulfate.


 A nucleoside

Phosphoric acid

A nucleotide
Condensation of an alcohol with a phosphoric acid produces a phosphate ester. In this example, phosphoric acid condenses with a nucleoside to produce a nucleotide.