Illustrated Glossary of Organic Chemistry

Macrolactone: A lactone contained within a large ring, usually consisting of eight or more atoms. Several important antibiotics such as erythromycin are macrolactones.

A macrolactone in a twelve-membered ring.
The lactone is shown in red.
Molecular structure of erythromycin, a macrolactone
antibiotic. The fourteen-membered macrolactone ring is shown in red.


- H2O

Seco acid

Macrolactone product
A seco acid is the starting material used to produce a macrolactone. The seco acid has an alcohol on one end and a carboxylic acid on the other. The reaction in which the alcohol and carboxyl group are joined to form the macrolactone is a type of esterification called macrolactonization.