- lactone
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—lactonic /lak ton"ik/, adj./lak"tohn/, n. Chem.any of a group of internal esters derived from hydroxy acids.[1840-50; LACT- + -ONE]
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any of a class of cyclic organic esters (ester), usually formed by reaction of a carboxylic acid group with a hydroxyl group or halogen (halogen element) atom present in the same molecule. Commercially important lactones include diketene and β-propanolactone used in the synthesis of acetoacetic acid derivatives and β-substituted propanoic (propionic) acids, respectively; the perfume ingredients pentadecanolide and ambrettolide; vitamin C; and the antibiotics (antibiotic) methymycin, erythromycin, and carbomycin.The γ- and δ-lactones, containing five- and six-membered rings, respectively, are the most common. They are formed by loss of water from the corresponding hydroxy acids, a process that often occurs spontaneously even in aqueous solution. Diketene and β-propanolactone are made by the reaction of ketene with itself or with formaldehyde, respectively. Lactones with 7 to 24 atoms in the ring are prepared by slow distillation of the appropriate hydroxy acids under greatly reduced pressure.William H. Brown* * *
Universalium. 2010.
