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.

	Macrolactonization - 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.