Pyrones or pyranones are a class of cyclic chemical compounds. They contain an unsaturated

Saturation (chemistry)

In chemistry, saturation has six different meanings, all based on reaching a maximum capacity...

 six membered ring containing one oxygen atom and a ketone

Ketone

In organic chemistry, a ketone is an organic compound with the structure RCR', where R and R' can be a variety of atoms and groups of atoms. It features a carbonyl group bonded to two other carbon atoms. Many ketones are known and many are of great importance in industry and in biology...

 functional group

Functional group

In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of...

. There are two isomers denoted as 2-pyrone

2-Pyrone

2-Pyrone is an unsaturated cyclic chemical compound with the molecular formula C5H4O2. It is isomeric with 4-pyrone....

 and 4-pyrone

4-Pyrone

4-Pyrone is an unsaturated cyclic chemical compound with the molecular formula C5H4O2. It is isomeric with 2-pyrone....

. The 2-pyrone (or α-pyrone) structure is found in nature as part of the coumarin

Coumarin

Coumarin is a fragrant chemical compound in the benzopyrone chemical class, found in many plants, notably in high concentration in the tonka bean , vanilla grass , sweet woodruff , mullein , sweet grass , cassia cinnamon and sweet clover...

 ring system. 4-Pyrone (or γ-pyrone) is found in some natural chemical compounds such as chromone

Chromone

Chromone is a derivative of benzopyran with a substituted keto group on the pyran ring. It is an isomer of coumarin.Derivatives of chromone are collectively known as chromones...

, maltol

Maltol

Maltol is a naturally occurring organic compound that is used primarily as a flavor enhancer. It is found in the bark of larch tree, in pine needles, and in roasted malt . It is a white crystalline powder that is soluble in hot water, chloroform, and other polar solvents...

 and kojic acid

Kojic acid

Kojic acid is a chelation agent produced by several species of fungi, especially Aspergillus oryzae, which has the Japanese common name koji. Kojic acid is a by-product in the fermentation process of malting rice, for use in the manufacturing of sake, the Japanese rice wine...

.