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United States Department of Agriculture

Agricultural Research Service


item Isbell, Terry

Submitted to: Elsevier
Publication Type: Book / Chapter
Publication Acceptance Date: 2/25/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The chemistry of fatty acids containing Delta5 unsaturated is heavily influenced by the close proximity of the carboxylic acid functionality with respect to the olefin. The carboxyl group stabilizes developing cations at the Delta5 and Delta4 positions and provides a lower energy pathway for chemistry that would otherwise be difficult. Utilization of the carboxyl stabilized cation has resulted in delta-lactones. The delta-lactone can undergo facile ring opening with nucleophiles to yield novel 5-hydroxy-amides, 5-hydroxy-esters and 5-alkoxy-esters. Isolation and quantitation of polyunsaturated fatty acids commonly found in fish oils (containing the Delta5-double bond) is accomplished through iodolactonization methods that can chemically differentiate Delta4 and Delta5-polyunsaturated fatty acids (PUFAs) from other PUFAs. Iodolactonization along with fractional crystallization of the iodolactone provides a physical separation method which yields highly enriched Delta4 or Delta5 PUFAs. These Delta5-PUFAs play a significant role in the biochemistry of humans and animals. Lastly, Delta5- unsaturation has also been shown to be the most oxidatively stable olefin position of fatty acids studied thus far.

Last Modified: 05/26/2017
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