Autumn angel transamination

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The Herbst-Engel transamination is a name reaction in organic chemistry that was first described in 1934 by its discoverers Robert M. Herbst and LL Engel.

Overview reaction

An α-amino acid is made to react with an α-keto acid . The transamination is a process in which the amino group is transmitted an amino acid to a keto acid, wherein a new amino acid, and an aldehyde is formed.

Overview reaction of the Herbst-Engel transamination

Reaction mechanism

The following mechanism is suggested by Zerong Wang . In the first step, the α-amino acid 1 is reacted with the α-keto acid 2 . By intramolecular protonation of the alkoxide 3 arises connection 4 .

Reaction mechanism of the Herbst-Engel transamination, a

It is assumed that the subsequent elimination of water from 4 produces the imine 5 .

Reaction mechanism of the Herbst-Engel transamination, b

An elimination of carbon dioxide , with a simultaneous hydrogen shift, causes the formation of a new imine 6 . Finally, carried addition of water. Cleavage of the resulting amino alcohol 7 produces the new α-amino acid 8 and the aldehyde 9 . It's a slow response.

literature

  • Zerong Wang: Comprehensive Organic Name Reactions and Reagents , Vol 2. John Wiley & Sons, Hoboken, New Jersey 2009, pp. 1388-1391, ISBN 978-0-471-70450-8 .

Individual evidence

  1. Robert M. Herbst, LL Engel: A reaction between α-ketonic acids and α-amino acids , Journal of Biological Chemistry 1934, 107 , 505-512, http://www.jbc.org/content/107/2/ 505.short .
  2. Robert M. Herbst: The Reaction between α-Ketonic Acids and α-Amino Acids , Journal of the American Chemical Society 1936, 58 , 2239-2243, doi: 10.1021 / ja01302a046 .
  3. Robert M. Herbst, D. Rittenberg: The transamination reaction. The mechanism of the reaction between alpha keto acids and alpha amino acids , J. Am. Chem. Soc. 1943, 380-389, doi: 10.1021 / jo01192a012 .
  4. DE Metzler, Joanne Olivard, Esmond E. Snell : Transamination of Pyridoxamine and Amino Acids with Glyoxylic Acid , J. Am. Chem. Soc. 1953, 76 , 644-648, doi: 10.1021 / ja01632a003 .