Mattox-Kendall reaction
The Mattox-Kendall reaction - also called Kendall-Mattox reaction or Kendall synthesis - is a name reaction in organic chemistry that goes back to the chemists VR Mattox and EC Kendall (1886–1972). The reaction was first published in 1948 and is an important reaction in steroid chemistry , which describes the splitting off of hydrogen bromide (HBr) from α- bromo ketones to α , β- unsaturated ketones.
Overview reaction
In the Mattox-Kendall reaction, for. B. 2-Bromo-4-phenylcyclohexanone ( 1 ) converted to 4-phenylcylohex-2-an-1-one ( 2 ). In the process, hydrogen bromide (HBr) is eliminated. A new C = C double bond is thus formed :
Reaction mechanism
A possible reaction mechanism for the Mattox-Kendall reaction is described by Zerong Wang using the example of a steroid as follows:
The phenylhydrazine ( 1 ) reacts with the α- bromoketone ( 2 ) of a steroid, splitting off water and the bromide ion (Br−) to form the phenylhydrazone ( 3 ). The bromide ion reacts with the hydrogen atom of the 1-phenyldiazen-1-ium and leaves the reaction as hydrogen bromide (HBr). In the meantime, by adding 2-oxopropanoate, a proton is split off and double bonds / electron pairs migrate in the molecule ( 4 ). Protonation of the 2-phenyldiazane produces an α , β- unsaturated ketone ( 5 ) through working-up hydrolysis and cleavage of the phenylhydrazine (PhNHNH 2 ).
application
The Mattox-Kendall reaction is often used for the transformation of steroids .
See also
Individual evidence
- ↑ a b c d Zerong Wang: Comprehensive Organic Name Reactions and Reagents . tape 2 : H-Q . John Wiley, Hoboken (NJ) 2009, ISBN 978-0-470-28662-3 , pp. 1845-1848 .
- ^ A. Fischer, W. Müller, W. Pötsch Eds .: Lexicon of important chemists . 1st edition. tape 1 . Bibliographisches Institut, Leipzig 1998, ISBN 3-323-00185-0 , p. 233 .