Polyene
In organic chemistry, polyenes are polyunsaturated organic compounds that contain multiple carbon–carbon double bonds (C=C).[1][2] Some sources consider dienes to be polyenes,[3] whereas others require polyenes to contain at least three carbon–carbon double bonds.[4]
Conjugated polyenes contain a conjugated system of alternating single and double carbon–carbon bonds, with characteristic optical properties.
The following polyenes are used as antimycotics for humans: amphotericin B, nystatin, candicidin, pimaricin, methyl partricin, and trichomycin.[5]
Optical properties
[edit]Some polyenes are brightly colored, an otherwise rare property for a hydrocarbon. Normally alkenes absorb in the ultraviolet region of a spectrum, but the absorption energy state of polyenes with numerous conjugated double bonds can be lowered such that they enter the visible region of the spectrum, resulting in compounds which are coloured (because they contain a chromophore). Thus many natural dyes contain linear polyenes.
Chemical and electrical properties
[edit]Polyenes tend to be more reactive than simpler alkenes. For example, polyene-containing triglycerides degrade in atmospheric oxygen via the process of rancidification and drying. Polyacetylene exhibits high electrical conductivity in air.. Most conductive polymers are polyenes, and many have conjugated structures.
Occurrence
[edit]A few fatty acids are polyenes. Another class of important polyenes are polyene antimycotics.[6]
- Representative polyenes
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![Amphotericin B is an example of a polyene antifungal (antimycotic) agent.[7]](//upload.wikimedia.org/wikipedia/commons/thumb/4/49/Amphotericin_B_new.svg/250px-Amphotericin_B_new.svg.png)
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Leukotriene A4 is a regulator of the immune response. -
![Polyacetylenes are a synthetic polymer of theoretical interest because they exhibit metallic properties upon oxidation.[8]](//upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Trans-Polyacetylene.svg/250px-Trans-Polyacetylene.svg.png)
Polyacetylenes are a synthetic polymer of theoretical interest because they exhibit metallic properties upon oxidation.[8]
![Amphotericin B is an example of a polyene antifungal (antimycotic) agent.[7]](/wiki/File:Amphotericin_B_new.svg)
![Polyacetylenes are a synthetic polymer of theoretical interest because they exhibit metallic properties upon oxidation.[8]](/wiki/File:Trans-Polyacetylene.svg){kind=small}
See also
[edit]References
[edit]- ^ Sharp, DWA, ed. (1990). The Penguin Dictionary of Chemistry (2nd ed.). London, England ; New York, N.Y., USA: Penguin Books. p. 320. ISBN 9780140512328.
- ^ Oxford Dictionary of English (2nd, rev ed.). Oxford ; New York: Oxford University Press. 2005. p. 1364. ISBN 9780198610571.
- ^ Oxford Dictionary of Biochemistry and Molecular Biology (1st, rev ed.). Oxford: Oxford University Press. 1997. p. 520. ISBN 9780198506737.
- ^ Benet‐Buchholz, Jordi; Boese, Roland; Haumann, Thomas; Traetteberg, Marit (15 March 1997). "Structural Chemistry of Dienes and Polyenes". The Chemistry of Dienes and Polyenes. pp. 25–65. doi:10.1002/0470857218.ch2.
- ^ Zotchev, Sergey B. (2003). "Polyene macrolide antibiotics and their applications in human therapy". Current Medicinal Chemistry. 10 (3): 211–223. doi:10.2174/0929867033368448. PMID 12570708.
- ^ NCBI Bookshelf (1996). "Polyene Antifungal Drugs". The University of Texas Medical Branch at Galveston. Retrieved 29 January 2010.
- ^ Torrado, J. J.; Espada, R.; Ballesteros, M. P.; Torrado-Santiago, S. "Amphotericin B formulations and drug targeting", Journal of Pharmaceutical Sciences, 2008, volume 97, pp. 2405–2425. doi:10.1002/jps.21179.
- ^ Lam, Jacky W. Y.; Tang, Ben Zhong. "Functional Polyacetylenes", Accounts of Chemical Research, 2005, volume 38, pp. 745–754. doi:10.1021/ar040012f.
