Lactones

Lactones are heterocyclic compounds which contain an ester bond within the molecule, i.e. an oxygen bridge (- O -) directly on the same carbon atom with a carboxyl group (= O). They are formed as an ester bond between a hydroxyl and a carboxyl group in the same molecule. This reaction forms a ring compound. Lactones can thus also be described as intramolecular ester compounds of hydroxycarboxylic acids. A typical representative of lactones is coumarin.

If the name lactone is used, the ring size - the number of additional carbon atoms to the COO group - is indicated. Alpha-lactone is a three-ring, beta-lactone a four-ring, gamma-lactone a five-ring, etc.