Acetylation

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In organic chemistry, acetylation is the replacement of a hydrogen atom with an acetyl group . The exchange can take place at the functional groups −OH, −SH and −NH 2 , but also directly at a −C − H bond, whereby corresponding compounds, e.g. B. acetates or ketones arise. For example, the acetylation of morphine produces diacetylmorphine (heroin).

Acetylation in Organic Chemistry

Acetyl groups are widely used as protective groups in organic chemistry. The most common is the use of acetic anhydride , with which quantitative yields can be achieved at room temperature . Catalyzed reactions of a parent compound with acetyl chloride are also used.

Acetylation in Biochemistry

In biochemistry , the acetylation of a protein is usually catalyzed by acetyltransferases ( enzymes ) . The cleavage ( deacetylation , deacetylation [derived from the English]) of the acetyl group, i.e. the reverse of this reaction, is catalyzed by deacetylases ( deacetylases ).

The acetylation or deacetylation of a protein is a regulatory mechanism for the function of the protein.

The best-known example of proteins whose function is influenced in this way are the histone proteins, which are involved in the structure of chromatin . Here, the acetylated or deacetylated state of the histones means a signal for other proteins, which can recognize whether the gene expression of the genes in this region of the chromatin should be activated or repressed .

Drug synthesis

Salicylic acid (left) is acetylated to acetylsalicylic acid by acetic anhydride with elimination of acetic acid. The acetyl group in question, C 2 H 3 O, is marked in blue .

In the manufacturing process of acetylsalicylic acid , the acetylation of the phenolic hydroxyl group of salicylic acid is a key step. Many other drugs are made by acetylation, e.g. B. Acetylcysteine from cysteine . Other examples are acetylcholine , β-acetyldigoxin and oxaceprol .

See also

Individual evidence

  1. ↑ a b Otto-Albrecht Neumüller (Ed.): Römpps Chemie-Lexikon. Volume 1: A-Cl. 8th revised and expanded edition. Franckh'sche Verlagshandlung, Stuttgart 1979, ISBN 3-440-04511-0 , p. 47.
  2. ^ H. Büchi, HG Khorana: CV. Total synthesis of the structural gene for an alanine transfer ribonucleic acid from yeast. Chemical synthesis of an icosadeoxyribonucleotide corresponding to the nucleotide sequence 31 to 50. In: Journal of Molecular Biology. 72, 1972, pp. 251-288, doi : 10.1016 / 0022-2836 (72) 90148-9 .
  3. ↑ RI ZHDANOV, SM ZHENODAROVA: Chemical Methods of Oligonucleotide Synthesis. In: Synthesis. 1975, 1975, pp. 222-245, doi : 10.1055 / s-1975-23714 .
  4. ↑ Gilbert Stork, Takashi Takahashi, Isao Kawamoto, Toshio Suzuki: Total synthesis of prostaglandin F2.alpha. by chirality transfer from D-glucose. In: Journal of the American Chemical Society. 100, 1978, pp. 8272-8273, doi : 10.1021 / ja00494a045 .
  5. ↑ Alan C. Spivey, Stellios Arseniyadis: Nucleophilic Catalysis by 4- (dialkylamino) Pyridines Revisited The Search for Optimal Reactivity and Selectivity?. In: Angewandte Chemie International Edition. 43, 2004, pp. 5436-5441, doi : 10.1002 / anie.200460373 .
  6. ^ Axel Kleemann , Jürgen Engel, Bernd Kutscher and Dieter Reichert: Pharmaceutical Substances , Thieme-Verlag Stuttgart, 5th edition (2009), pp. 16-17, ISBN 978-3-13-558405-8 .
  7. ^ Axel Kleemann , Jürgen Engel, Bernd Kutscher and Dieter Reichert: Pharmaceutical Substances , Thieme-Verlag Stuttgart, 5th edition (2009), pp. 13-14, ISBN 978-3-13-558405-8 .