# Ionone

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> Markdown URL: https://mediated.wiki/source/Ionone.md
> Source: https://en.wikipedia.org/wiki/Ionone
> Source revision: 1350688963
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

{{Short description|Group of isomers}}
{{Chembox
| Verifiedfields = changed
| verifiedrevid = 443878506
| Name = Ionones
| ImageFileL1 = alpha-ionone-label.png
| ImageNameL1 =
| ImageSizeL1 = 

| ImageFileR1 = Alpha-Ionone 3D ball.png
| ImageSizeR1 = 
| ImageAltR1  = Ball-and-stick model of the alpha-ionone molecule
| ImageCaptionLR1 = alpha-ionone

| ImageFileL2 = beta-ionone-label.png
| ImageCaptionLR2 = beta-ionone
| ImageSizeL2 = 

| ImageFileR2 = Beta-Ionone 3D ball.png
| ImageSizeR2 = 
| ImageAltR2  = 
| ImageNameR2 = Ball-and-stick model of the beta-ionone molecule

| ImageFileL3 = gamma-ionone-label.png
| ImageNameL3 =
| ImageSizeL3 = 

| ImageFileR3 = Gamma-Ionone 3D ball.png
| ImageSizeR3 = 
| ImageCaptionLR3 = gamma-ionone
| ImageAltR3 = Ball-and-stick model of the gamma-ionone molecule
| IUPACName = α: (3''E'')-4-(2,6,6-Trimethylcyclohex-2-en-1-yl)but-3-en-2-one<br />β: (3''E'')-4-(2,6,6-Trimethylcyclohex-1-en-1-yl)but-3-en-2-one<br />γ: (3''E'')-4-(2,2-Dimethyl-6-methylenecyclohexyl)but-3-en-2-one
| OtherNames = Cyclocitrylideneacetone, irisone, jonon
| Section1 = {{Chembox Identifiers
| CASNo_Ref = {{cascite|changed|??}}
| CASNo = 127-41-3
| CASNo_Comment = α
| CASNo2_Ref = {{cascite|changed|??}}
| CASNo2 = 79-77-6
| CASNo2_Comment  = β
| CASNo3_Ref = {{cascite|changed|??}}
| CASNo3 = 79-76-5
| CASNo3_Comment  = γ
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C13H20O/c1-10-6-5-9-13(3,4)12(10)8-7-11(2)14/h7-8,12H,1,5-6,9H2,2-4H3/b8-7+
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = SFEOKXHPFMOVRM-BQYQJAHWSA-N
| InChIKey = SFEOKXHPFMOVRM-BQYQJAHWBW
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 4516050
| PubChem = 5363741
| InChI = 1/C13H20O/c1-10-6-5-9-13(3,4)12(10)8-7-11(2)14/h7-8,12H,1,5-6,9H2,2-4H3/b8-7+
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = QP734LIN1K
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 49250
| SMILES = O=C(\C=C\C1\C(=C)CCCC1(C)C)C
}}
| Section2 = {{Chembox Properties
| Formula = C<sub>13</sub>H<sub>20</sub>O
| MolarMass = 192.30 g/mol
| Density = α: 0.933 g/cm<sup>3</sup><br />β: 0.945 g/cm<sup>3</sup>
| MeltingPt = β:
| MeltingPtC = −49
| BoilingPt = β:
| BoilingPtC = 126 to 128
| BoilingPt_notes = at 12&nbsp;mmHg
}}
}}
The '''ionones''', from greek ἴον ion "violet",<ref>{{Cite book |last=Genaust |first=Helmut |date=1976 |title=Etymologisches Wörterbuch der botanischen Pflanzennamen |url=http://dx.doi.org/10.1007/978-3-0348-7650-6 |doi=10.1007/978-3-0348-7650-6|isbn=978-3-0348-7651-3 }}</ref> are a series of closely related [chemical substance](/source/chemical_substance)s that are part of a group of compounds known as [rose](/source/rose) [ketone](/source/ketone)s, which also includes [damascone](/source/damascone)s and [damascenone](/source/damascenone)s.  Ionones are [aroma compound](/source/aroma_compound)s found in a variety of [essential oil](/source/essential_oil)s, including [rose oil](/source/rose_oil). β-Ionone is a significant contributor to the aroma of roses, despite its relatively low concentration, and is an important [fragrance](/source/fragrance) chemical used in [perfume](/source/perfume)ry.<ref name="Leff2005">
{{cite web |url=http://www.leffingwell.com/rose.htm|title=Rose (Rosa damascena)|last=Leffingwell|first=JC|date=3 February 2005|website=Aroma from Carotenoids - Rose|publisher=Leffingwell & Associates|access-date=14 January 2014}}</ref> The ionones are derived from the degradation of [carotenoid](/source/carotenoid)s.

The combination of [α](/source/Alpha_and_beta_carbon)-ionone and β-ionone is characteristic of the scent of [violet](/source/Violet_(plant))s and used with other components in perfumery and [flavouring](/source/flavouring) to recreate their scent.<ref>{{cite book |last1=Curtis |first1=T |last2=Williams |first2=DG |title=Introduction to Perfumery|edition=2nd|location=Fort Washington, New York|publisher=Micelle Press|year=2001|isbn=9781870228244}}</ref><ref name="Jens2010">{{cite web |url=http://www.bojensen.net/EssentialOilsEng/EssentialOils31/EssentialOils31.htm#Violet |title=Violet |last=Jensen |first=B |date=6 February 2010 |website=Essential Oils |access-date=14 January 2014}}</ref>

The [carotene](/source/carotene)s [α-carotene](/source/alpha-carotene), [β-carotene](/source/beta-carotene), [γ-carotene](/source/gamma-carotene), and the [xanthophyll](/source/xanthophyll) β-[cryptoxanthin](/source/cryptoxanthin), can all be metabolized to β-ionone, and thus have [vitamin A](/source/vitamin_A) activity because they can be converted by plant-eating animals to [retinol](/source/retinol) and [retinal](/source/retinal). Carotenoids that do not contain the β-ionone [moiety](/source/moiety_(chemistry)) cannot be converted to retinol, and thus have no vitamin A activity.

Ionones are classified as apocarotenoids (specifically C₁₃-norisoprenoids), formed by oxidative cleavage of larger carotenoid molecules, which places them within the broader family of terpenoid-derived natural products. This structural origin explains both their occurrence in plants and their characteristic fragrance properties.<ref>{{Cite web |title=Иононы: химическая природа, получение и применение |url=https://iononeinfo.ru/ |access-date=2026-04-16 |website=iononeinfo.ru |language=ru}}</ref>

==Biosynthesis==
Carotenoids are the precursors of important fragrance compounds in several flowers. For example, a 2010 study of ionones in ''[Osmanthus fragrans](/source/Osmanthus_fragrans)'' Lour. var. ''aurantiacus'' determined its essential oil contained the highest diversity of carotenoid-derived volatiles among the flowering plants investigated. A [cDNA](/source/cDNA) encoding a carotenoid cleavage enzyme, OfCCD1, was identified from [transcripts](/source/Transcription_(genetics)) isolated from flowers of ''O. fragrans'' Lour. The recombinant enzymes cleaved carotenes to produce α-ionone and β-ionone in ''in vitro'' assays.<ref name="Bald2010">{{cite journal |last1=Baldermann |first=S |last2=Kato |first2=M |last3=Kurosawa |first3=M| last4=Kurobayashi |first4=Y |last5=Fujita |first5=A |last6=Fleischmann |first6=P |last7=Watanabe |first7=N| title=Functional characterization of a carotenoid cleavage dioxygenase 1 and its relation to the carotenoid accumulation and volatile emission during the floral development of ''Osmanthus fragrans'' Lour |journal=Journal of Experimental Botany |volume=61 |issue=11 |pages= 2967–2977 |year=2010 |doi=10.1093/jxb/erq123 |pmid=20478967 |doi-access=free |hdl=10297/6189 |hdl-access=free }}</ref>

The same study also discovered that carotenoid content, volatile emissions, and OfCCD1 transcript levels are subject to [photorhythm](/source/photorhythm)ic changes, and principally increased during daylight hours. At the times when OfCCD1 transcript levels reached their maxima, the carotenoid content remained low or slightly decreased. The emission of ionones was also higher during the day; however, emissions decreased at a lower rate than the transcript levels. Moreover, carotenoid content increased from the first to the second day, whereas the volatile release decreased, and the OfCCD1 transcript levels displayed steady-state oscillations, suggesting that the [substrate](/source/Enzyme_substrate_(biology)) availability in the cellular compartments is changing or other regulatory factors are involved in volatile [norisoprenoid](/source/Terpene) formation. The formation of ionones proceeds by a process mediated by the [carotenoid dioxygenase](/source/carotenoid_dioxygenase)s.<ref name="Bald2010" />

thumb|center|500px|Biosynthesis of the ionones

==Organic synthesis==

Ionone can be [synthesised](/source/organic_synthesis) from [citral](/source/citral) and [acetone](/source/acetone) with [calcium oxide](/source/calcium_oxide) as a basic [heterogeneous catalyst](/source/heterogeneous_catalysis) and serves as an example of an [aldol condensation](/source/aldol_condensation) followed by a [rearrangement reaction](/source/rearrangement_reaction).<ref>{{cite journal | last1=Noda | first1=C | last2=Alt | first2=GP | last3=Werneck | first3=RM | last4=Henriques | first4=C. A. |last5=Monteiro |first5=JLF |title=Aldol condensation of citral with acetone on basic solid catalysts |journal=Brazilian Journal Chemical Engineering |year=1998 |volume=15 |issue=2 | pages=120–125 |doi=10.1590/S0104-66321998000200004| doi-access=free }}</ref><ref>{{cite journal| title= Pseudoionone |last1=Russell | first1=A |last2=Kenyon |first2=RL |journal=[Organic Syntheses](/source/Organic_Syntheses) |volume=23 |pages=78 |url=http://www.orgsyn.org/demo.aspx?prep=cv3p0747|doi=10.15227/orgsyn.023.0078 |year=1943 |url-access=subscription }}</ref>

The [nucleophilic addition](/source/nucleophilic_addition) of the [carbanion](/source/carbanion) '''3''' of acetone '''1''' to the [carbonyl](/source/carbonyl) group on citral '''4''' is [base](/source/base_(chemistry)) [catalysed](/source/catalysis). The aldol condensation product '''5''' [eliminates](/source/elimination_reaction) water through the [enolate ion](/source/enolate_ion) '''6''' to form pseudoionone '''7'''.

:Image:ionone3.svg

The reaction proceeds by [acid](/source/acid) catalysis where the [double bond](/source/double_bond) in '''7''' opens to form the [carbocation](/source/carbocation) '''8'''. A rearrangement reaction of the carbocation follows with ring closure to '''9'''. Finally a hydrogen atom can be abstracted from '''9''' by an acceptor molecule ('''Y''') to form either '''10''' (extended  [conjugated system](/source/conjugated_system)) or '''11'''.

:Image:ionone4.svg

==Genetic differences in odor perception==
A [single-nucleotide polymorphism](/source/single-nucleotide_polymorphism) in the [OR5A1](/source/OR5A1) receptor (rs6591536<ref>{{cite web|url=https://www.snpedia.com/index.php/Rs6591536|title=rs6591536|website=SNPedia}}</ref>) causes very significant differences in the odor perception of beta-ionone, both in sensitivity and also in subjective quality. Individuals who contain at least one G [allele](/source/allele) are sensitive to beta-ionone and perceive a pleasant floral scent, while individuals who are [homozygous](/source/homozygous) AA are ~100 times less sensitive and at higher concentrations perceive a pungent sour/vinegar odor instead.<ref name="McRae2013">{{cite journal |vauthors=Jaeger SR, McRae JF, Bava CM, Beresford MK, Hunter D, Jia Y, Chheang SL, Jin D, Peng M, Gamble JC, Atkinson KR, Axten LG, Paisley AG, Tooman L, Pineau B, Rouse SA, Newcomb RD | title = A Mendelian Trait for Olfactory Sensitivity Affects Odor Experience and Food Selection | journal = Current Biology | volume = 23 | issue = 16 | pages = 1601–1605 | year = 2013 | pmid = 23910657 | doi = 10.1016/j.cub.2013.07.030 | doi-access = free }}</ref>

==See also==
* [Irone](/source/Irone)s, a group of related chemical compounds
* [α-Isomethyl ionone](/source/%CE%B1-Isomethyl_ionone), a type of ionone

==References==
{{reflist}}

Category:Perfume ingredients
Category:Flavors
Category:Enones
Category:Sesquiterpenes
Category:Apocarotenoids
Category:Cyclohexenes

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Adapted from the Wikipedia article [Ionone](https://en.wikipedia.org/wiki/Ionone) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Ionone?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.