Oxazolone is a chemical compound and

functional group In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the re ...

, with the molecular formula C₃H₃NO₂. It was named in-line with the

Hantzsch–Widman nomenclature In organic chemistry, Hantzsch–Widman nomenclature, also called the extended Hantzsch–Widman system (named for Arthur Rudolf Hantzsch and ), is a type of systematic chemical nomenclature used for naming heterocyclic parent hydrides having no ...

and is part of a large family of

oxazole Oxazole is the parent compound for a vast class of heterocyclic aromatic organic compounds. These are azoles with an oxygen and a nitrogen separated by one carbon. Oxazoles are aromatic compounds but less so than the thiazoles. Oxazole is a weak ...

based compounds. There are a total of 5 structural isomers of oxazolone; 3 according to the location of the carbonyl group and 2 more according to the location of the double bound C=X (with X= N or C): *2-(3''H'')oxazolone *2-(5''H'')oxazolone *4-(5''H'')-oxazolone *5-(2''H'')-oxazolone *5-(4''H'')-oxazolone Oxazolones

The 4-oxazolone motif, which is also formally a lactam, is present in a number of drugs (

fenozolone Fenozolone (Ordinator) was developed by Laboratoires Dausse in the 1960s and is a psychostimulant related to pemoline. See also * 4-Methylaminorex * Aminorex * Clominorex * Cyclazodone * Fluminorex * Pemoline * Thozalinone Thozalinone ( US ...

thozalinone Thozalinone (USAN) (brand name Stimsen; former developmental code name CL-39808) is a psychostimulant that has been used as an antidepressant in Europe. It has also been trialed as an anorectic. Thozalinone is described as a " dopaminergic sti ...

cyclazodone Cyclazodone is a centrally acting stimulant drug developed by American Cyanamid Company in the 1960s. The drug is related to other drugs such as pemoline and thozalinone. It displayed a favorable therapeutic index and margin of safety in compari ...

, reclazepam etc.). Substituted 5-oxazolones may also be regarded as the cyclization products of ''N''-

acyl In chemistry, an acyl group is a moiety derived by the removal of one or more hydroxyl groups from an oxoacid, including inorganic acids. It contains a double-bonded oxygen atom and an alkyl group (). In organic chemistry, the acyl group (IUPAC ...

α-

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha a ...

s, making them

lactones Lactones are cyclic carboxylic esters, containing a 1-oxacycloalkan-2-one structure (), or analogues having unsaturation or heteroatoms replacing one or more carbon atoms of the ring. Lactones are formed by intramolecular esterification of the c ...

, and are sometimes referred to as azlactones.

References

{{reflist Oxazolones