Editing Polyene

{{Short description|1=Organic compound with ≥3 C=C bonds}}
{{about|the class of chemical compounds|polyenes in antifungal therapy|Polyene antimycotic|the ancient Macedonian writer|Polyaenus}}

In [[organic chemistry]], '''polyenes''' are [[Saturated and unsaturated compounds|polyunsaturated]] [[organic compound]]s that contain multiple [[carbon–carbon bond|carbon–carbon]] [[double bond]]s ({{chem2|C\dC}}).<ref name=Penguin2ed>{{cite book |editor-last1=Sharp |editor-first1=DWA |title=The Penguin Dictionary of Chemistry |date=1990 |publisher=Penguin Books |location=London, England ; New York, N.Y., USA |isbn=9780140512328 |edition=2nd |page=320 |url=https://archive.org/details/penguindictionar00shar/page/320/mode/2up?q=polyenes}}</ref><ref name=OED2rev>{{cite book |title=Oxford Dictionary of English |date=2005 |publisher=Oxford University Press |location=Oxford ; New York |isbn=9780198610571 |edition=2nd, rev |page=1364 |url=https://archive.org/details/oxforddictionary0000unse_z0z2/page/1364/mode/1up?q=polyene}}</ref> Some sources consider [[diene]]s to be polyenes,<ref>{{cite book |title=Oxford Dictionary of Biochemistry and Molecular Biology |date=1997 |publisher=Oxford University Press |location=Oxford |isbn=9780198506737 |edition=1st, rev |page=520 |url=https://archive.org/details/isbn_9780198506737/page/n530/mode/1up?q=polyene}}</ref> whereas others require polyenes to contain at least three carbon–carbon double bonds.<ref name=StructChem>{{cite book |last1=Benet‐Buchholz |first1=Jordi |last2=Boese |first2=Roland |last3=Haumann |first3=Thomas |last4=Traetteberg |first4=Marit |title=The Chemistry of Dienes and Polyenes |chapter=Structural Chemistry of Dienes and Polyenes |date=15 March 1997 |pages=25–65 |doi=10.1002/0470857218.ch2}}</ref> 

'''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]].<ref>{{cite journal|title=Polyene macrolide antibiotics and their applications in human therapy |author=Zotchev, Sergey B.|journal=Current Medicinal Chemistry|year=2003|volume=10|issue=3 |pages=211–223|doi=10.2174/0929867033368448|pmid=12570708 }}</ref>

==Optical properties==
Some polyenes are brightly colored, an otherwise rare property for a hydrocarbon.  Normally alkenes absorb in the [[ultraviolet]] region of a [[Ultraviolet-visible spectroscopy|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 [[dye]]s contain linear polyenes.

== Chemical and electrical properties ==
Polyenes tend to be more reactive than simpler alkenes. For example, polyene-containing [[triglyceride]]s are reactive towards atmospheric oxygen. [[Polyacetylene]], which partially oxidized or reduced, exhibits high electrical conductivity. Most [[conductive polymer]]s are polyenes, and many have [[conjugated system|conjugated]] structures. Poly(aza)acetylenes are readily prepared from [[pyridine]] precursors without the necessity of a controlled atmosphere, simply by [[ultraviolet]] irradiation of a mixture of pyridine and poly(4-vinyl) pyridine.{{citation needed|date=February 2024}} Recent research at the [[Weizmann Institute of Science|Weizmann Institute]] and [[Aix-Marseille University]] showed a clear transition between ionic and electronic conductivity with increasing UV dose over 30 hours.<ref>{{Cite journal |last1=Vaganova |first1=Evgenia |last2=Eliaz |first2=Dror |last3=Shimanovich |first3=Ulyana |last4=Leitus |first4=Gregory |last5=Aqad |first5=Emad |last6=Lokshin |first6=Vladimir |last7=Khodorkovsky |first7=Vladimir |date=January 2021 |title=Light-Induced Reactions within Poly(4-vinyl pyridine)/Pyridine Gels: The 1,6-Polyazaacetylene Oligomers Formation |journal=Molecules |language=en |volume=26 |issue=22 |pages=6925 |doi=10.3390/molecules26226925 |pmid=34834017 |pmc=8621047 |issn=1420-3049|doi-access=free }}</ref>

==Occurrence==
A few [[fatty acid]]s are polyenes.  Another class of important polyenes are [[polyene antimycotic]]s.<ref name="ncbi">{{cite web |url=https://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=mmed&part=A4050 |title=Polyene Antifungal Drugs |last=NCBI Bookshelf |date=1996 |publisher=The University of Texas Medical Branch at Galveston |access-date=29 January 2010}}</ref>

<gallery caption="Representative polyenes" widths="170px" heights="112px">
File:Amphotericin B new.svg|[[Amphotericin B]] is an example of a [[polyene antimycotic|polyene antifungal (antimycotic)]] agent.<ref>Torrado, J. J.; Espada, R.; Ballesteros, M. P.; Torrado-Santiago, S. "Amphotericin B formulations and drug targeting", Journal of Pharmaceutical Sciences, 2008, volume&nbsp;97, pp.&nbsp;2405–2425. {{doi|10.1002/jps.21179}}.</ref>
File:Leukotriene A4.svg|[[Leukotriene]] A4 is a regulator of the immune response.
File:Trans-Polyacetylene.svg|[[Polyacetylene]]s are a synthetic polymer of theoretical interest because they exhibit metallic properties upon oxidation.<ref>Lam, Jacky W. Y.; Tang, Ben Zhong. "Functional Polyacetylenes", Accounts of Chemical Research, 2005, volume&nbsp;38, pp.&nbsp;745–754. {{doi|10.1021/ar040012f}}.</ref>
</gallery>

==References==
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[[Category:Polyenes| ]]
[[Category:Conjugated hydrocarbons]]