6-Amyl-α-pyrone, also 6-pentyl-2-pyrone or 6PP, is an unsaturated
lactone
Lactones are cyclic carboxylic esters. They are derived from the corresponding hydroxycarboxylic acids by esterification. They can be saturated or unsaturated.
Lactones are formed by lactonization, the intramolecular esterification of the corresp ...
molecule. It contains two
double bond
In chemistry, a double bond is a covalent bond between two atoms involving four bonding electrons as opposed to two in a single bond. Double bonds occur most commonly between two carbon atoms, for example in alkenes. Many double bonds exist betw ...
s in the ring and a
pentyl substituent at carbon adjacent to the ring oxygen. It is a colorless liquid which possesses characteristic coconut aroma, produced biologically by ''
Trichoderma
''Trichoderma'' is a genus of fungi in the family Hypocreaceae that is present in all soils, where they are the most prevalent culturable fungi. Many species in this genus can be characterized as opportunistic avirulent plant symbionts. This re ...
'' species. It is found in animal foods, peach (''
Prunus persica
The peach (''Prunus persica'') is a deciduous tree first domesticated and cultivated in China. It bears edible juicy fruits with various characteristics, most called peaches and the glossy-skinned, non-fuzzy varieties called nectarines. Peach ...
''), and heated beef.
Reactivity
Chemically, 6PP is converted into a linear ketone via
ring opening and
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 ...
in presence of water, which subsequently undergoes solid base catalyzed
aldol condensation
An aldol condensation is a condensation reaction in organic chemistry in which two carbonyl moieties (of aldehydes or ketones) react to form a β-hydroxyaldehyde or β-hydroxyketone (an aldol reaction), and this is then followed by dehydration t ...
reaction into C14/C15 hydrocarbon precursor. Upon heating in presence of Pd/C catalyst with formic acid, the double bonds of the 6PP get reduced to yield the flavoring compound
δ-decalactone
δ-Decalactone (DDL) is a chemical compound, classified as a lactone, that naturally occurs in fruit and milk products in traces. It can be obtained from both chemical and biological sources. Chemically, it is produced from Baeyer–Villiger oxid ...
. In presence of strong reducing agent like lithium aluminium hydride, the double bonds of the ring get saturated and transformed into 1,5-decanediol via sequential hydrogenation steps.
References
External links
Safety Data Sheet
{{DEFAULTSORT:Amyl-α-pyrone, 6-
2-Pyrones