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Acetyl
IUPAC name	ethanoyl
Other names	Acetyl cation Acetylium ion
Identifiers
CAS number
PubChem	644096
SMILES	C[C+]=O
Properties
Molecular formula	C2H3O+
Molar mass	43.04 g/mol
Exact mass	43.01839
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

In organic chemistry, acetyl is a functional group, the acyl with chemical formula COCH₃. It is sometimes abbreviated as Ac (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. The acetyl moiety is a component of many organic compounds, including the neurotransmitter acetylcholine, acetyl-CoA, and the analgesics acetaminophen, 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 to coenzyme A (CoA) and from acetyl-CoA. Acetyl-CoA is an intermediate both in the biological synthesis and in the breakdown of many organic molecules. In synthetic organic chemistry,

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. Conversely, removal of the acetyl group by histone deacetylases (HDACs) condenses DNA structure, thereby preventing transcription.^[1]

Synthetic organic and pharmaceutical chemistry

Acetylation can be achieved using a variety of methods, most commonly by 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 acetylglycine:^[2]

H₂NCH₂CO₂H + (CH₃CO)₂O → CH₃C(O)NHCH₂CO₂H + CH₃CO₂H

Pharmacology

Acetylated organic molecules exhibit increased ability to cross the blood-brain barrier. 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. The acetyl group in acetylsalicylic acid (aspirin) enhances its effectiveness relative to the natural anti-inflammatant salicylic acid. Similarly, acetylation converts the natural painkiller morphine into the far more potent heroin (diacetylmorphine).

Most recently, the supplement industry touts acetyl-L-carnitine as being more effective than other preparations of carnitine. Acetylation of resveratrol holds promise as one of the first anti-radiation medicines for human populations.

References

1. ^ Nelson, D. L.; Cox, M. M. "Lehninger, Principles of Biochemistry" 3rd Ed. Worth Publishing: New York, 2000. ISBN 1-57259-153-6.
2. ^ R. M. Herbst and D. Shemin (1943), "Acetylglycine", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV2P0011  ; Coll. Vol. 2: 11  

See also

• Acetoxy group
• Histone acetylation and deacetylation
• Polyoxymethylene plastic, a.k.a. acetal resin, a thermoplastic