Whiskey Lactone CAS 39212-23-2

Cis – 3-Methyl-4-octanolide, also known as cis- β- methyl- γ- Octalactone or 5-butyldihydro-4-methylfuran-2 (3 H) – one, a compound of lactone family, chemical formula C9H16O2. It exists as two optical isomers: 3 R, 4 R (“+”) and 3 S, 4 S (“-“).

3S, 4S isomers, commonly known as whisky lactone or oak lactone, are important components in the aroma of whisky (first discovered by Suomalainen and Nyk ä nen in 1970) and other alcoholic beverages aged in oak barrels. It is sometimes added to wine as a flavoring. It has the aroma of coconut, celery or fresh wood, and can be detected by human body when the concentration in the air is 1 microgram/l. The mixture of cis and trans isomers can repel mosquitoes and flies.

3S, 4S isomers are extracted from some precursors in oak by alcoholic beverages. It can be synthesized from cyclopentane derivatives.

Whisky lactone, as its cis and trans isomers, exists in whisky and oak volatiles; Cis isomers are more important in sensory aspects. It is a transparent, almost colorless liquid with a strong, warm, sweet and coumarin like smell.

The cis trans mixture can be prepared by the free radical addition reaction of valeraldehyde and crotonic acid, and then the oxyacid obtained by the reduction cyclization with sodium borohydride/sulfuric acid. It is used in aromatic compositions, such as beverages. It is reported to exist in cognac, rum, Irish malt, bourbon whisky, scotch whisky, sherry, port and wine.