4-Pyrone (γ-pyrone or pyran-4-one) is an
unsaturated cyclic chemical compound with the molecular formula C
5H
4O
2.It is
isomer
In chemistry, isomers are molecules or polyatomic ions with identical molecular formula – that is, the same number of atoms of each element (chemistry), element – but distinct arrangements of atoms in space. ''Isomerism'' refers to the exi ...
ic with
2-pyrone
2-Pyrone (α-pyrone or pyran-2-one) is an Saturated and unsaturated compounds, unsaturated cyclic chemical compound with the molecule, molecular formula C5H4O2. It is isomeric with 4-pyrone.
2-Pyrone is used in organic synthesis as a building blo ...
.
Preparation
4-Pyrone is prepared via the thermal
decarboxylation
Decarboxylation is a chemical reaction that removes a carboxyl group and releases carbon dioxide (CO2). Usually, decarboxylation refers to a reaction of carboxylic acids, removing a carbon atom from a carbon chain. The reverse process, which is ...
of
chelidonic acid
Chelidonic acid is a heterocyclic organic acid with a pyran skeleton.
Preparation
Chelidonic acid can be prepared in two steps from diethyl oxalate and acetone:
:
Uses
Chelidonic acid is used to Organic synthesis, synthesize 4-Pyrone, 4-pyrone ...
.
Reactions
4-Pyrone and its
derivatives react with
amine
In chemistry, amines (, ) are organic compounds that contain carbon-nitrogen bonds. Amines are formed when one or more hydrogen atoms in ammonia are replaced by alkyl or aryl groups. The nitrogen atom in an amine possesses a lone pair of elec ...
s in
protic solvent
In chemistry, a protic solvent is a solvent that has a hydrogen atom bound to an oxygen (as in a hydroxyl group ), a nitrogen (as in an amine group or ), or fluoride (as in hydrogen fluoride). In general terms, any solvent that contains a labi ...
s to form
4-Pyridone
4-Pyridone is an organic compound with the formula . It is a colorless solid.
Preparation
4-Pyridone, and its derivatives, are prepared from 4-pyrone and amines in protic solvents.
:
Tautomerism
4-Pyridone exists a keto-enol tautomerism with ...
s.
Derivatives
4-Pyrone forms the central core of several natural chemical compounds,
including
maltol
Maltol is a naturally occurring organic compound that is used primarily as a flavor enhancer. It is found in nature in the bark of larch trees and in the needles of pine trees, and is produced during the roasting of malt (from which it gets its n ...
,
meconic acid,
kojic acid
Kojic acid is an organic compound with the formula . It is a derivative of 4-Pyrone, 4-pyrone that functions in nature as a chelation agent produced by several species of fungus, especially ''Aspergillus oryzae'', which has the Japanese common na ...
, and of the important class of the
Flavones
Flavones (from Latin ''flavus'' "yellow") are a class of flavonoids based on the backbone of 2-phenylchromen-4-one (2-phenyl-1-benzopyran-4-one) (as shown in the first image of this article).
Flavones are common in foods, mainly from spices, and ...
.
:
See also
*
Pyrone
Pyrones or pyranones are a class of heterocyclic chemical compounds. They contain an unsaturated six-membered ring, which has one oxygen atom and a carbonyl functional group. There are two isomers, denoted as 2-pyrone and 4-pyrone. The 2-pyrone ...
*
4-Pyridone
4-Pyridone is an organic compound with the formula . It is a colorless solid.
Preparation
4-Pyridone, and its derivatives, are prepared from 4-pyrone and amines in protic solvents.
:
Tautomerism
4-Pyridone exists a keto-enol tautomerism with ...
*
Dehydroacetic acid
References
{{DEFAULTSORT:Pyrone, 4-