Simonis Chromone Synthesis

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The Simonis Chromon Synthesis is a name reaction in organic chemistry. It was discovered in 1913 by chemists Ernst Petschek and Hugo Simonis . It is used for the synthesis of chromone from phenol and a β- keto ester.

Overview reaction

In this P 2 O 5 -catalyzed reaction, phenol and a β-ketoester are cyclized to form chromone:

Simonis Chromon Synthesis - Overview Reaction

The reaction can also take place with substituted phenols and other β-ketoesters.

mechanism

The complex mechanism of the Simonis chromone synthesis is still discussed in the literature.

Simonis Chromone Synthesis - Reaction Mechanism

It is assumed that phenol 1 initially attacks oxonium ion 2 from the underside . This leads to the formation of transition state 3 . In a double elimination reaction, water is first split off, creating molecule 4 . After the subsequent elimination of ethanol , 2-methylchromone 5 is formed .

application

Chromone (1,4-benzopyron) forms the basic skeleton of the flavones (2-phenylchromones) and isoflavones (3-phenylchromones). Isoflavones occur as a yellow dye in some plants and their flowers. The Simonis Chromon Synthesis is used in the production of flavones. Phenol reacts with ethyl benzoylacetate ( enol tautomer) under catalysis by P 2 O 5 to form the natural polymethine dye flavone. In addition, the Simonis chromone synthesis can be used to produce the natural product Visnagin, which is found in some fruits.

  • Flavone

  • Isoflavone

  • Visnagin

See also

Individual evidence

  1. ^ Organic chemistry . In: Journal of the Chemical Society, Abstracts . tape 104 , no. 0 , 1913, p. i813-i921 (890) , doi : 10.1039 / CA9130400813 .
  2. ↑ Ernst Petschek, H. Simonis: A new chromone synthesis . In: Reports of the German Chemical Society . tape 46 , no. 2 , 1913, pp. 2014–2020 , doi : 10.1002 / cber.191304602117 .
  3. ↑ a b c d Eberhard Breitmaier, Günther Jung: Organic Chemistry: Fundamentals, Compound Classes, Reactions, Concepts, Molecular Structure, Natural Products, Synthesis Planning, Sustainability Vol. 7. Georg Thieme Verlag, Stuttgart, 2012, ISBN 978-3-13-541507- 9 , pp. 695-696.
  4. ↑ a b c d e f Jie Jack Lie, EJ Corey: Name Reactions in Heterocyclic Chemistry II. John Wiley & Sons, Inc., Hoboken, NJ, 2011, ISBN 9780470085080 , pp. 479-486, doi 10.1002 / 9781118092828.
  5. ↑ Martha Windholz, Susan Budavari, Lorraine Y. Stroumtos, Margaret Noether Done: The Merck Index An Encyclopedia of Chemicals and Drugs Vol. 9, Merck & Co., INC., Rahway, NJ, 1976, ISBN 0-911910-26- 3 , p. ONR-82.