Lactone

Lactone are a family of compounds that ciontain several different arranges of cyclic compounds that contain an oxygen atmon on the core ring as well as a double bonded oxygen atom.

Lactones are usually named according to the precursor acid molecule (aceto = 2 carbon atoms, propio = 3, butyro = 4, valero = 5, capro = 6, etc.), with a -lactone suffix and a Greek letter prefix that specifies the number of carbon atoms in the heterocycle — that is, the distance between the relevant -OH and the -COOH groups along said backbone. The first carbon atom after the carbon in the -COOH group on the parent compound is labelled α, the second will be labeled β, and so forth. Therefore, the prefixes also indicate the size of the lactone ring: α-lactone = 3-membered ring, β-lactone = 4-membered, γ-lactone = 5-membered, etc.

Relevnt members of this clsss are only γ-butyrolactione (GBL) and γ-Hydroxyvaleric acid (GHV, 4-Methyl-GHB).

Some other axamples include:

Lactone nomenclature: α-acetolactone, β-propiolactone,
γ-butyrolactone, and δ-valerolactone