Editing Acetyl group

{{Short description|1=Chemical group, –C(=O)CH₃}}
{{Distinguish|Acetal}}
{{Chembox
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| Watchedfields  = changed
| verifiedrevid  = 4772398727
| ImageFile      = Acetyl group.svg
| ImageFile_Ref  = {{chemboximage|correct|??}}
| ImageSize      = 121
| ImageName      = Skeletal formula of acetyl with all implicit hydrogens shown
| IUPACName      = Acetyl (preferred to ethanoyl)<ref>{{Cite web|url = http://www.acdlabs.com/iupac/nomenclature/79/r79_1037.htm|title = List of Radical Names Beginning from "A" |work = Nomenclature of Organic Chemistry, Sections A, B, C, D, E, F, and H, Pergamon Press, Oxford, 1979. Copyright 1979 IUPAC}}</ref><ref>{{Cite web|url = http://www.acdlabs.com/iupac/nomenclature/93/r93_480.htm|title = R-5.7.1 Carboxylic acids, where acetyl appears as an example |work = IUPAC, Commission on Nomenclature of Organic Chemistry. A Guide to IUPAC Nomenclature of Organic Compounds (Recommendations 1993), 1993, Blackwell Scientific publications, Copyright 1993 IUPAC }}</ref><ref>{{BlueBook2013|rec=65.1.7.2.1}}</ref>
| SystematicName = Methyloxidocarbon(•)<ref>{{Cite web|url = https://www.ebi.ac.uk/chebi/searchId.do?chebiId=46887|title = Acetyl|work = Chemical Entities of Biological Interest|location = UK|publisher = European Bioinformatics Institute}}</ref> (additive)
| Section1       = {{Chembox Identifiers
| Abbreviations = Ac
| CASNo_Ref = {{cascite|changed|??}}
| CASNo = 3170-69-2
| PubChem = 137849
| ChemSpiderID = 121499
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 46887
| Beilstein = 1697938
| Gmelin = 786
| SMILES = C[C]=O
| StdInChI = 1S/C2H3O/c1-2-3/h1H3
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = TUCNEACPLKLKNU-UHFFFAOYSA-N
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
}}
| Section2       = {{Chembox Properties
| C=2 | H=3 | O=1
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| Section3       = {{Chembox Thermochemistry
| DeltaHf = −15 to −9 kJ mol<sup>−1</sup>
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| Section4       = {{Chembox Related
| OtherCompounds = [[Acetone]]<br>[[Carbon monoxide]]<br>[[Acetic acid]]
}}
}}

In [[organic chemistry]], an '''acetyl group''' is a [[functional group]] denoted by the [[chemical formula]] {{chem2|\sCOCH3}} and the [[Chemical structure|structure]] {{chem2|\sC(\dO)\sCH3}}. It is [[Skeletal formula#Pseudoelement symbols|sometimes represented]] by the symbol '''Ac'''<ref>{{Cite book |url=https://pubs.acs.org/doi/book/10.1021/acsguide |title=The ACS Guide to Scholarly Communication |date=January 2020 |publisher=American Chemical Society |isbn=978-0-8412-3586-1 |editor-last=Banik |editor-first=Gregory M. |location=Washington, DC |language=en |doi=10.1021/acsguide.50308 |s2cid=262269861 |editor-last2=Baysinger |editor-first2=Grace |editor-last3=Kamat |editor-first3=Prashant V. |editor-last4=Pienta |editor-first4=Norbert}}</ref><ref name="isbn0-85404-627-5">{{cite book |author=Hanson, James A. |title=Functional group chemistry |publisher=Royal Society of Chemistry |location=Cambridge, Eng |year=2001 |pages=11 |isbn=0-85404-627-5 }}</ref> (not to be confused with the element [[actinium]]). In [[IUPAC nomenclature of chemistry|IUPAC nomenclature]], an acetyl group is called an '''ethanoyl''' '''group'''.

An acetyl group contains a [[methyl]] group ({{chem2|\sCH3}}) that is [[single-bond]]ed to a [[carbonyl]] ({{chem2|C\dO}}), making it an [[acyl group]]. The carbonyl center of an acyl [[Radical (chemistry)|radical]] has one non-bonded [[electron]] with which it forms a [[chemical bond]] to the remainder (denoted with the letter ''R'') of the molecule.

The acetyl [[Moiety (chemistry)|moiety]] is a component of many [[organic compound]]s, including [[acetic acid]], the [[neurotransmitter]] [[acetylcholine]], [[acetyl-CoA]], [[acetylcysteine]], [[acetaminophen]] (also known as paracetamol), and acetylsalicylic acid (also known as [[aspirin]]).

==Acetylation==
Acetylation is the chemical reaction known as "ethanoylation" in the IUPAC nomenclature. It depicts a reactionary process that injects an acetyl functional group into a chemical compound. The opposite reaction is called "'''de'''acetylation", and this is the '''removal''' of the acetyl group.  Therefore, the process of adding an acetyl group into a molecule is called [[acetylation]]. An example of an acetylation reaction is the conversion of [[glycine]] to [[N-acetylglycine|''N''-acetylglycine]]:<ref>{{OrgSynth|first1=R. M.|last1=Herbst|first2=D.|last2=Shemin|title=Acetylglycine|collvol=2|collvolpages=11|year=1943|prep=CV2P0011}}</ref>
:{{chem2 | H2NCH2CO2H  +  (CH3CO)2O -> CH3C(O)NHCH2CO2H  +  CH3CO2H }}

=== In biology ===
[[Enzyme]]s which perform acetylation on proteins or other biomolecules are known as [[acetyltransferase]]s. In biological organisms, acetyl groups are commonly transferred from [[acetyl-CoA]] to other organic molecules. Acetyl-CoA is an intermediate in the biological synthesis and in the breakdown of many organic molecules. Acetyl-CoA is also created during the second stage of cellular respiration ([[pyruvate decarboxylation]]) by the action of [[pyruvate dehydrogenase]] on [[pyruvic acid]].<ref>{{Cite journal |last=Patel |first=Mulchand |date=June 13, 2014 |title=The Pyruvate Dehydrogenase Complexes: Structure-based Function and Regulation |journal=The Journal of Biological Chemistry |volume=289 |issue=24 |pages=16615–16623 |doi=10.1074/jbc.R114.563148 |doi-access=free |pmid=24798336 |pmc=4059105 }}</ref>

[[Protein]]s are often modified via acetylation, for various purposes. For example, acetylation of [[histone]]s by [[Histone acetyltransferase|histone acetyltransferases (HATs)]] results in an expansion of local [[chromatin]] structure, allowing [[Transcription (genetics)|transcription]] to occur by enabling [[RNA polymerase]] to access [[DNA]]. However, removal of the acetyl group by [[histone deacetylase]]s (HDACs) condenses the local chromatin structure, thereby preventing transcription.<ref>{{cite book|first1=David L.|last1=Nelson |first2=Michael M.|last2=Cox|title=Lehninger principles of biochemistry|date=2000|publisher=Worth Publishers|location=New York|isbn=1-57259-153-6|edition=3rd|url-access=registration|url=https://archive.org/details/lehningerprincip01lehn}}</ref>

===In synthetic organic and pharmaceutical chemistry===
[[Acetylation]] can be achieved by chemists using a variety of methods, most commonly with the use of [[acetic anhydride]] or [[acetyl chloride]], often in the presence of a tertiary or aromatic [[amine]] [[base (chemistry)|base]].

==Pharmacology==
Acetylated organic molecules exhibit increased ability to cross the selectively permeable [[blood–brain barrier]].<ref name=":0">{{Cite journal |last=Pardridge |first=William M |date=2012-08-29 |title=Drug Transport across the Blood–Brain Barrier |url=https://pmc.ncbi.nlm.nih.gov/articles/PMC3494002/ |journal=Journal of Cerebral Blood Flow &amp; Metabolism |language=en |volume=32 |issue=11 |pages=1959–1972 |doi=10.1038/jcbfm.2012.126 |issn=0271-678X |archive-url=http://web.archive.org/web/20250101201559/https://pmc.ncbi.nlm.nih.gov/articles/PMC3494002/ |archive-date=2025-01-01|pmc=3494002 }}</ref> Acetylation helps a given drug reach the brain more quickly, making the drug's effects more intense and increasing the effectiveness of a given dose.{{Citation needed|date=January 2016}} The acetyl group in [[acetylsalicylic acid]] (aspirin) enhances its effectiveness relative to the natural [[anti-inflammatant]] [[salicylic acid]]. In similar manner, acetylation converts the natural painkiller [[morphine]] into the far more potent [[heroin]] (diacetylmorphine).<ref name=":0" />

There is some evidence that [[Acetylcarnitine|acetyl-<small>L</small>-carnitine]] may be more effective for some applications than [[L-carnitine|<small>L</small>-carnitine]].<ref>{{Cite journal
 | pmid = 15591009
| year = 2004
| last1 = Liu
| first1 = J
| title = Comparison of the effects of L-carnitine and acetyl-L-carnitine on carnitine levels, ambulatory activity, and oxidative stress biomarkers in the brain of old rats
| journal = Annals of the New York Academy of Sciences
| volume = 1033
| issue = 1
| pages = 117–31
| last2 = Head
| first2 = E
| last3 = Kuratsune
| first3 = H
| last4 = Cotman
| first4 = C. W.
| last5 = Ames
| first5 = B. N.
| s2cid = 24221474
| doi = 10.1196/annals.1320.011
| bibcode = 2004NYASA1033..117L
}}</ref> Acetylation of [[resveratrol]] holds promise as one of the first anti-radiation medicines for human populations.<ref>{{cite journal|last1=Koide|first1=Kazunori|last2=Osman|first2=Sami|last3=Garner|first3=Amanda L.|last4=Song|first4=Fengling|last5=Dixon|first5=Tracy|last6=Greenberger|first6=Joel S.|last7=Epperly|first7=Michael W.|title=The Use of 3,5,4′-Tri-acetylresveratrol as a Potential Prodrug for Resveratrol Protects Mice from γ-Irradiation-Induced Death|journal=ACS Medicinal Chemistry Letters|date=14 April 2011|volume=2|issue=4|pages=270–274|doi=10.1021/ml100159p|pmid=21826253|pmc=3151144}}</ref>

== Etymology ==
The term "acetyl" was coined by the German chemist [[Justus von Liebig]] in 1839 to describe what he incorrectly believed to be the radical of [[acetic acid]] (the main component of [[vinegar]], aside from water), which is now known as the [[vinyl group]] (coined in 1851); "acetyl" is derived from the Latin ''acētum,'' meaning "vinegar." When it was shown that Liebig's theory was wrong and acetic acid had a different radical, his name was carried over to the correct one, but the name of [[acetylene]] (coined in 1860) was retained.<ref>{{Cite journal |last1=Constable |first1=Edwin C. |last2=Housecroft |first2=Catherine E. |date=2020-04-20 |title=Before Radicals Were Free – the Radical Particulier of de Morveau |journal=Chemistry |language=en |volume=2 |issue=2 |pages=293–304 |doi=10.3390/chemistry2020019 |issn=2624-8549 |doi-access=free}}</ref>
{{expand section|date=January 2023}}

==See also==
* [[Acetaldehyde]]
* [[Acetoxy group]]
* [[Histone acetylation and deacetylation]]
* [[Polyoxymethylene plastic]] (acetal resin), a thermoplastic

==References==
{{Reflist}}

{{Functional group}}

[[Category:Acyl groups]]