Acetyl group

Acetyl group
Names
	IUPAC name Acetyl (preferred to ethanoyl)
	Systematic IUPAC name Methyloxidocarbon(•) (additive)
Identifiers
CAS Number	3170-69-2 ;
3D model (JSmol)	Interactive image ;
Abbreviations	Ac
Beilstein Reference	1697938
ChEBI	CHEBI:46887 ;
ChemSpider	121499 ;
Gmelin Reference	786
PubChem CID	137849 ;
	InChI InChI=1S/C2H3O/c1-2-3/h1H3 Key: TUCNEACPLKLKNU-UHFFFAOYSA-N ;
	SMILES C[C]=O;
Properties
Chemical formula	C2H3O
Molar mass	43.045 g·mol−1
Thermochemistry
Std enthalpy of; formation (ΔfH⦵298)	−15 to −9 kJ mol−1
Related compounds
Related compounds	Acetone ; Carbon monoxide ; Acetic acid
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Last updated May 14, 2024

In organic chemistry, acetyl is a functional group with the chemical formula −COCH₃ and the structure −C(=O)−CH₃. It is sometimes represented by the symbol Ac^[5]^[6] (not to be confused with the element actinium). In IUPAC nomenclature, acetyl is called ethanoyl.

Acetylation

In nature

The introduction of an acetyl group into a molecule is called acetylation. In biological organisms, acetyl groups are commonly transferred from acetyl-CoA to other organic molecules. Acetyl-CoA is an intermediate both 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.^[7]

Histones and other proteins are often modified by acetylation. For example, on the DNA level, histone acetylation by acetyltransferases (HATs) causes an expansion of chromatin architecture, allowing for genetic transcription to occur. However, removal of the acetyl group by histone deacetylases (HDACs) condenses DNA structure, thereby preventing transcription.^[8]

Synthetic organic and pharmaceutical chemistry

Acetylation can be achieved 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. A typical acetylation is the conversion of glycine to N-acetylglycine:^[9]

{\ce {H2NCH2CO2H + (CH3CO)2O -> CH3C(O)NHCH2CO2H + CH3CO2H}}

Pharmacology

Acetylated organic molecules exhibit increased ability to cross the selectively permeable blood–brain barrier.^{[ citation needed ]} 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 ]} 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).

There is some evidence that acetyl-L-carnitine may be more effective for some applications than L-carnitine.^[10] Acetylation of resveratrol holds promise as one of the first anti-radiation medicines for human populations.^[11]

Etymology

The term was coined by Justus von Liebig in 1839 to denote what he believed to be the radical of the acetic acid, and what we now call the vinyl group (coined in 1851). When it became a scientific consensus that his theory was wrong and the acid had a different radical, the name was carried over to the correct one, but the name of acetylene (coined in 1860) was retained.^[12]

Related Research Articles

Alanine (symbol Ala or A), or α-alanine, is an α-amino acid that is used in the biosynthesis of proteins. It contains an amine group and a carboxylic acid group, both attached to the central carbon atom which also carries a methyl group side chain. Consequently it is classified as a nonpolar, aliphatic α-amino acid. Under biological conditions, it exists in its zwitterionic form with its amine group protonated (as −NH₃⁺) and its carboxyl group deprotonated (as −CO₂⁻). It is non-essential to humans as it can be synthesized metabolically and does not need to be present in the diet. It is encoded by all codons starting with GC (GCU, GCC, GCA, and GCG).

Coenzyme A (CoA, SHCoA, CoASH) is a coenzyme, notable for its role in the synthesis and oxidation of fatty acids, and the oxidation of pyruvate in the citric acid cycle. All genomes sequenced to date encode enzymes that use coenzyme A as a substrate, and around 4% of cellular enzymes use it (or a thioester) as a substrate. In humans, CoA biosynthesis requires cysteine, pantothenate (vitamin B₅), and adenosine triphosphate (ATP).

In chemistry, an acyl group is a moiety derived by the removal of one or more hydroxyl groups from an oxoacid, including inorganic acids. It contains a double-bonded oxygen atom and an organyl group or hydrogen in the case of formyl group. In organic chemistry, the acyl group is usually derived from a carboxylic acid, in which case it has the formula R−C(=O)−, where R represents an organyl group or hydrogen. Although the term is almost always applied to organic compounds, acyl groups can in principle be derived from other types of acids such as sulfonic acids and phosphonic acids. In the most common arrangement, acyl groups are attached to a larger molecular fragment, in which case the carbon and oxygen atoms are linked by a double bond.

Pyruvic acid (IUPAC name: 2-oxopropanoic acid, also called acetoic acid) (CH₃COCOOH) is the simplest of the alpha-keto acids, with a carboxylic acid and a ketone functional group. Pyruvate, the conjugate base, CH₃COCOO⁻, is an intermediate in several metabolic pathways throughout the cell.

Acetyl-CoA is a molecule that participates in many biochemical reactions in protein, carbohydrate and lipid metabolism. Its main function is to deliver the acetyl group to the citric acid cycle to be oxidized for energy production.

<span class="mw-page-title-main">Acetate</span> Salt compound formed from acetic acid and a base

An acetate is a salt formed by the combination of acetic acid with a base. "Acetate" also describes the conjugate base or ion typically found in aqueous solution and written with the chemical formula C^₂H^₃O⁻
₂. The neutral molecules formed by the combination of the acetate ion and a positive ion are also commonly called "acetates". The simplest of these is hydrogen acetate with corresponding salts, esters, and the polyatomic anion CH^₃CO⁻
₂, or CH^₃COO⁻
.

In chemical nomenclature, the IUPAC nomenclature of organic chemistry is a method of naming organic chemical compounds as recommended by the International Union of Pure and Applied Chemistry (IUPAC). It is published in the Nomenclature of Organic Chemistry. Ideally, every possible organic compound should have a name from which an unambiguous structural formula can be created. There is also an IUPAC nomenclature of inorganic chemistry.

<span class="mw-page-title-main">Acyl halide</span> Oxoacid compound with an –OH group replaced by a halogen

In organic chemistry, an acyl halide is a chemical compound derived from an oxoacid by replacing a hydroxyl group with a halide group.

In chemistry, acetylation is an organic esterification reaction with acetic acid. It introduces an acetyl group into a chemical compound. Such compounds are termed acetate esters or simply acetates. Deacetylation is the opposite reaction, the removal of an acetyl group from a chemical compound.

Acetic anhydride, or ethanoic anhydride, is the chemical compound with the formula (CH₃CO)₂O. Commonly abbreviated Ac₂O, it is the simplest isolable anhydride of a carboxylic acid and is widely used as a reagent in organic synthesis. It is a colorless liquid that smells strongly of acetic acid, which is formed by its reaction with moisture in the air.

<span class="mw-page-title-main">Acetyl chloride</span> Organic compound (CH₃COCl)

Acetyl chloride is an acyl chloride derived from acetic acid. It belongs to the class of organic compounds called acid halides. It is a colorless, corrosive, volatile liquid. Its formula is commonly abbreviated to AcCl.

An organic acid anhydride is an acid anhydride that is also an organic compound. An acid anhydride is a compound that has two acyl groups bonded to the same oxygen atom. A common type of organic acid anhydride is a carboxylic anhydride, where the parent acid is a carboxylic acid, the formula of the anhydride being (RC(O))₂O. Symmetrical acid anhydrides of this type are named by replacing the word acid in the name of the parent carboxylic acid by the word anhydride. Thus, (CH₃CO)₂O is called acetic anhydride.Mixed (or unsymmetrical) acid anhydrides, such as acetic formic anhydride (see below), are known, whereby reaction occurs between two different carboxylic acids. Nomenclature of unsymmetrical acid anhydrides list the names of both of the reacted carboxylic acids before the word "anhydride" (for example, the dehydration reaction between benzoic acid and propanoic acid would yield "benzoic propanoic anhydride").

<span class="mw-page-title-main">Malonyl-CoA</span> Chemical compound

Malonyl-CoA is a coenzyme A derivative of malonic acid.

Chemical nomenclature is a set of rules to generate systematic names for chemical compounds. The nomenclature used most frequently worldwide is the one created and developed by the International Union of Pure and Applied Chemistry (IUPAC).

In organic chemistry, the acetoxy group, is a functional group with the formula −OCOCH₃ and the structure −O−C(=O)−CH₃. As the -oxy suffix implies, it differs from the acetyl group by the presence of an additional oxygen atom. The name acetoxy is the short form of acetyl-oxy.

Methylidyne, or (unsubstituted) carbyne, is an organic compound whose molecule consists of a single hydrogen atom bonded to a carbon atom. It is the parent compound of the carbynes, which can be seen as obtained from it by substitution of other functional groups for the hydrogen.

<span class="mw-page-title-main">Thioacetic acid</span> Organosulfur compound (CH3C(O)SH)

Thioacetic acid is an organosulfur compound with the molecular formula CH₃C(O)SH. It is a thioic acid: the sulfur analogue of acetic acid, as implied by the thio- prefix. It is a yellow liquid with a strong thiol-like odor. It is used in organic synthesis for the introduction of thiol groups in molecules.

Acetyl-CoA synthetase (ACS) or Acetate—CoA ligase is an enzyme involved in metabolism of acetate. It is in the ligase class of enzymes, meaning that it catalyzes the formation of a new chemical bond between two large molecules.

<span class="mw-page-title-main">Ethenone</span> Organic compound with the formula H2C=C=O

In organic chemistry, ethenone is the formal name for ketene, an organic compound with formula C₂H₂O or H₂C=C=O. It is the simplest member of the ketene class. It is an important reagent for acetylations.

Acetic acid, systematically named ethanoic acid, is an acidic, colourless liquid and organic compound with the chemical formula CH₃COOH. Vinegar is at least 4% acetic acid by volume, making acetic acid the main component of vinegar apart from water. It has been used, as a component of vinegar, throughout history from at least the third century BC.

References

↑ "List of Radical Names Beginning from "A"". Nomenclature of Organic Chemistry, Sections A, B, C, D, E, F, and H, Pergamon Press, Oxford, 1979. Copyright 1979 IUPAC.
↑ "R-5.7.1 Carboxylic acids, where acetyl appears as an example". IUPAC, Commission on Nomenclature of Organic Chemistry. A Guide to IUPAC Nomenclature of Organic Compounds (Recommendations 1993), 1993, Blackwell Scientific publications, Copyright 1993 IUPAC.
↑ IUPAC Chemical Nomenclature and Structure Representation Division (2013). "P-65.1.7.2.1". In Favre, Henri A.; Powell, Warren H. (eds.). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. IUPAC–RSC. ISBN 978-0-85404-182-4.
↑ "Acetyl". Chemical Entities of Biological Interest. UK: European Bioinformatics Institute.
↑ Banik, Gregory M.; Baysinger, Grace; Kamat, Prashant V.; Pienta, Norbert, eds. (January 2020). The ACS Guide to Scholarly Communication. Washington, DC: American Chemical Society. doi:10.1021/acsguide.50308. ISBN 978-0-8412-3586-1. S2CID 262269861.
↑ Hanson, James A. (2001). Functional group chemistry. Cambridge, Eng: Royal Society of Chemistry. p. 11. ISBN 0-85404-627-5.
↑ Patel, Mulchand (June 13, 2014). "The Pyruvate Dehydrogenase Complexes: Structure-based Function and Regulation". The Journal of Biological Chemistry. 289 (24): 16615–16623. doi: 10.1074/jbc.R114.563148 . PMC 4059105 . PMID 24798336.
↑ Nelson, David L.; Cox, Michael M. (2000). Lehninger principles of biochemistry (3rd ed.). New York: Worth Publishers. ISBN 1-57259-153-6.
↑ Herbst, R. M.; Shemin, D. (1943). "Acetylglycine". Organic Syntheses ; Collected Volumes, vol. 2, p. 11.
↑ Liu, J; Head, E; Kuratsune, H; Cotman, C. W.; Ames, B. N. (2004). "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". Annals of the New York Academy of Sciences. 1033 (1): 117–31. Bibcode:2004NYASA1033..117L. doi:10.1196/annals.1320.011. PMID 15591009. S2CID 24221474.
↑ Koide, Kazunori; Osman, Sami; Garner, Amanda L.; Song, Fengling; Dixon, Tracy; Greenberger, Joel S.; Epperly, Michael W. (14 April 2011). "The Use of 3,5,4′-Tri-acetylresveratrol as a Potential Prodrug for Resveratrol Protects Mice from γ-Irradiation-Induced Death". ACS Medicinal Chemistry Letters. 2 (4): 270–274. doi:10.1021/ml100159p. PMC 3151144 . PMID 21826253.
↑ Constable, Edwin C.; Housecroft, Catherine E. (2020-04-20). "Before Radicals Were Free – the Radical Particulier of de Morveau". Chemistry. 2 (2): 293–304. doi: 10.3390/chemistry2020019 . ISSN 2624-8549.

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[1] "List of Radical Names Beginning from "A"". Nomenclature of Organic Chemistry, Sections A, B, C, D, E, F, and H, Pergamon Press, Oxford, 1979. Copyright 1979 IUPAC.

[2] "R-5.7.1 Carboxylic acids, where acetyl appears as an example". IUPAC, Commission on Nomenclature of Organic Chemistry. A Guide to IUPAC Nomenclature of Organic Compounds (Recommendations 1993), 1993, Blackwell Scientific publications, Copyright 1993 IUPAC.

[3] IUPAC Chemical Nomenclature and Structure Representation Division (2013). "P-65.1.7.2.1". In Favre, Henri A.; Powell, Warren H. (eds.). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. IUPAC–RSC. ISBN 978-0-85404-182-4.

[4] "Acetyl". Chemical Entities of Biological Interest. UK: European Bioinformatics Institute.

[5] Banik, Gregory M.; Baysinger, Grace; Kamat, Prashant V.; Pienta, Norbert, eds. (January 2020). The ACS Guide to Scholarly Communication. Washington, DC: American Chemical Society. doi:10.1021/acsguide.50308. ISBN 978-0-8412-3586-1. S2CID 262269861.

[isbn0-85404-627-5-6] Hanson, James A. (2001). Functional group chemistry. Cambridge, Eng: Royal Society of Chemistry. p. 11. ISBN 0-85404-627-5.

[7] Patel, Mulchand (June 13, 2014). "The Pyruvate Dehydrogenase Complexes: Structure-based Function and Regulation". The Journal of Biological Chemistry. 289 (24): 16615–16623. doi: 10.1074/jbc.R114.563148 . PMC 4059105 . PMID 24798336.

[8] Nelson, David L.; Cox, Michael M. (2000). Lehninger principles of biochemistry (3rd ed.). New York: Worth Publishers. ISBN 1-57259-153-6.

[9] Herbst, R. M.; Shemin, D. (1943). "Acetylglycine". Organic Syntheses ; Collected Volumes, vol. 2, p. 11.

[10] Liu, J; Head, E; Kuratsune, H; Cotman, C. W.; Ames, B. N. (2004). "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". Annals of the New York Academy of Sciences. 1033 (1): 117–31. Bibcode:2004NYASA1033..117L. doi:10.1196/annals.1320.011. PMID 15591009. S2CID 24221474.

[11] Koide, Kazunori; Osman, Sami; Garner, Amanda L.; Song, Fengling; Dixon, Tracy; Greenberger, Joel S.; Epperly, Michael W. (14 April 2011). "The Use of 3,5,4′-Tri-acetylresveratrol as a Potential Prodrug for Resveratrol Protects Mice from γ-Irradiation-Induced Death". ACS Medicinal Chemistry Letters. 2 (4): 270–274. doi:10.1021/ml100159p. PMC 3151144 . PMID 21826253.

[12] Constable, Edwin C.; Housecroft, Catherine E. (2020-04-20). "Before Radicals Were Free – the Radical Particulier of de Morveau". Chemistry. 2 (2): 293–304. doi: 10.3390/chemistry2020019 . ISSN 2624-8549.

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