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Acetyl group

Names
IUPAC name Acetyl (preferred to ethanoyl)[1][2][3]
Systematic IUPAC name Methyloxidocarbon(•)[4] (additive)
Identifiers
CAS Number	3170-69-2 N
3D model (JSmol)	Interactive image
Abbreviations	Ac
Beilstein Reference	1697938
ChEBI	CHEBI:46887 Y
ChemSpider	121499 Y
Gmelin Reference	786
PubChem CID	137849
InChI InChI=1S/C2H3O/c1-2-3/h1H3 Y Key: TUCNEACPLKLKNU-UHFFFAOYSA-N Y
SMILES C[C]=O
Properties
Chemical formula	C2H3O
Molar mass	43.05 g·mol−1
Thermochemistry
Std enthalpy of formation (ΔfHo298)	−15 to −9 kJ mol−1
Related compounds
Related compounds	Acetone Carbon monoxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

In organic chemistry, acetyl is a moiety, the acyl with chemical formula CH₃CO. It is sometimes represented by the symbol Ac^[5] (not to be confused with the element actinium). The acetyl group contains a methyl group single-bonded to a carbonyl. The carbonyl center of an acyl radical has one nonbonded electron with which it forms a chemical bond to the remainder R of the molecule. In IUPAC nomenclature, acetyl is called ethanoyl, although this term is rarely heard.^{[citation needed]} The acetyl moiety is a component of many organic compounds, including acetic acid, the neurotransmitter acetylcholine, acetyl-CoA, acetylcysteine, acetaminophen (also known as paracetamol), and acetylsalicylic acid (better known as aspirin).

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 synthetase and in the breakdown of many organic molecules. Acetyl-CoA is also created during the second stage of cellular respiration, the Krebs Cycle, by the action of pyruvate dehydrogenase on pyruvic acid.

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.^[6] In addition to HDACs, Methyl group additions are able to bind DNA resulting in DNA methylation, and this is another common way to block DNA acetylation and inhibit gene transcription.^{[citation needed]}

Synthetic organic and pharmaceutical chemistry

Acetylation can be achieved using a variety of methods, the most common one being via 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:^[7]

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.^[8] Acetylation of resveratrol holds promise as one of the first anti-radiation medicines for human populations.^[9]

See also

• Acetaldehyde


• Acetoxy group


• Histone acetylation and deacetylation


• 
  Polyoxymethylene plastic, a.k.a. acetal resin, a thermoplastic

References