Isanic acid

Isanic acid
Names
IUPAC name
octadec-17-en-9,11-diynoic acid
Other names
Erythrogenic acid
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
UNII
  • InChI=1S/C18H26O2/c1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-18(19)20/h2H,1,3-6,11-17H2,(H,19,20)
    Key: OASRDXXKKGHDJZ-UHFFFAOYSA-N
  • OC(=O)CCCCCCCC#CC#CCCCCC=C
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).
Infobox references

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

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.

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

  1. ^ "NCATS Inxight Drugs — ISANIC ACID". drugs.ncats.io. Retrieved 10 April 2025.
  2. ^ 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.
  3. ^ Vegetable oils. PROTA. 2007. p. 128. ISBN 978-90-5782-191-2. Retrieved 25 April 2025.
  4. ^ 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.
  5. ^ 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.
  6. ^ 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.
  7. ^ Journal of the Chemical Society. Chemical Society. 1896. p. 638. Retrieved 10 April 2025.
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