Isanic acid
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| Names | |
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| IUPAC name
octadec-17-en-9,11-diynoic acid
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| Other names
Erythrogenic acid
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| Identifiers | |
3D model (JSmol)
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| ChEBI | |
| ChemSpider | |
PubChem CID
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| UNII | |
CompTox Dashboard (EPA)
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| Properties | |
| C18H26O2 | |
| Molar mass | 274.404 g·mol−1 |
| Appearance | crystalline platelets or prisms, light-sensitive; turns red |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Isanic acid or erythrogenic acid is a linear fatty acid composed of 18 carbon atoms, with two triple bonds in the positions 9≡10 and 11≡12 and a double bond in the position 17=18. This is one of the rare polyacetylenic acids with conjugated triple bonds. Its delta notation is 18:3Δ9a,11a,17. Its structural formula is CH2=CH-(CH2)4–C≡C–C≡C–(CH2)7–COOH.[1]
Exocarpic acid is isomeric to isanic acid. The related isanolic acid, unlike isanic acid, contains an additional hydroxyl group. The oxygenated isanic acid is called ketoisanic acid.
Discovery
[edit]Isanic acid was initially isolated in 1937 by researchers A. Steger and J. van Loon[2] in the oil of the seeds of Ongokea gore or Ongokea klaineana, a plant from equatorial Africa, called in the native language "boleka" or "isane", hence the common name of isanic acid.[3][4] The oil seeds contain about 60% lipids.[5] Various analyses have revealed the concentration of isanic acid in isane oil from 32% to 51%.
Synthesis
[edit]The synthesis of isanic acid is possible starting from 10-undecynoic acid.[5]
Physical properties
[edit]Isanic acid can be detected together with its isomers with the double bond in position 13=14: boletic acid and exocarpic acid, and hydroxylated fatty acids, such as isanolic acid.
The high degree of unsaturation suggests that oils with a high content of these conjugated acetylenic fatty acids are drying. Isanic acid polymerizes easily,[6] turning a bright red color when exposed to light. Because of this characteristic the alternative name of erythrogenic acid was proposed by Castille in 1940.[5]
Insoluble in ether.[7]
References
[edit]- ^ "NCATS Inxight Drugs — ISANIC ACID". drugs.ncats.io. Retrieved 10 April 2025.
- ^ Steger, A.; van Loon, J. (1937). "Das fette Oel der Samen von Onguekoa Gore Engler". Fette und Seifen. 44 (6): 243–246. doi:10.1002/lipi.19370440608. ISSN 1521-4133. Retrieved 10 April 2025.
- ^ Vegetable oils. PROTA. 2007. p. 128. ISBN 978-90-5782-191-2. Retrieved 25 April 2025.
- ^ St, Oil and Colour Chemists Association of Australia (9 March 2013). Surface Coatings: Vol I-Raw Materials and Their Usage. Springer Science & Business Media. p. 24. ISBN 978-94-011-6940-0. Retrieved 25 April 2025.
- ^ a b c Black, H. K.; Weedon, B. C. L. (1 January 1953). "368. Unsaturated fatty acids. Part I. The synthesis of erythrogenic (isanic) and other acetylenic acids". Journal of the Chemical Society (Resumed): 1785–1793. doi:10.1039/JR9530001785. ISSN 0368-1769. Retrieved 10 April 2025.
- ^ Surface Coatings: Vol I-Raw Materials and Their Usage. Springer Science & Business Media. 9 March 2013. p. 24. ISBN 978-94-011-6940-0. Retrieved 10 April 2025.
- ^ Journal of the Chemical Society. Chemical Society. 1896. p. 638. Retrieved 10 April 2025.