Isanic acid
Chemical compound
From Wikipedia, the free encyclopedia
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]
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| Names | |
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| IUPAC name
octadec-17-en-9,11-diynoic acid | |
| Other names
Erythrogenic acid | |
| 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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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
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
The synthesis of isanic acid is possible starting from 10-undecynoic acid.[5]
Physical properties
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.[citation needed][clarification needed]
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]