Schmidt reaction

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The Schmidt reaction is a name reaction in organic chemistry that was named after its discoverer, the German chemist Karl-Friedrich Schmidt (1887–1971). By means of the Schmidt reaction, carboxylic acids can be broken down into primary amines and ketones can be broken down into carboxamides .

Schmidt reaction of the carboxylic acids

Overview reaction

In this Schmidt reaction, carboxylic acids react with strong mineral acids (mostly sulfuric acid ), with hydrazoic acid and with a subsequent hydrolysis to primary amines .

Overview of the Schmidt reaction of the carboxylic acids

mechanism

Here, the hydroxyl group of the carboxylic acid is first protonated by adding the strong acid ( sulfuric acid ) , so that a mesomeric-stabilized acylium ion is formed after the water has been split off . This is from the hydrogen azide nucleophilic attack. With the escape of nitrogen and with a 1,2-alkyl shift (rearrangement of the radical R), a carbenium ion is obtained. The primary amine is finally formed by hydrolysis and with elimination of a proton and carbon dioxide .

Mechanism of the Schmidt reaction of carboxylic acids

Schmidt reaction of the ketones

Overview reaction

In this Schmidt reaction, ketones react with strong mineral acids (mostly sulfuric acid ), with hydrazoic acid and with subsequent hydrolysis to form carboxamides .

Overview of the Schmidt reaction of the ketones

mechanism

In this reaction, the carboxy group of the ketone is first protonated by adding the strong acid ( sulfuric acid ) . Thereafter, the accesses hydrazoic acid the carbenium ion to nucleophilic, wherein water is then cleaved off. In the next reaction step, nitrogen is released and the remainder of R 1 is rearranged. This carbenium ion is hydrolyzed and, after deprotonation and tautomerization , the carboxamide is formed .

Mechanism of the Schmidt reaction of the ketones

The reaction proceeds in a similar way to the Curtius reaction or the Beckmann rearrangement . Optionally, the amide can be further hydrolyzed to an amine.

See also

literature

  • Author collective: Organikum , 22nd edition, Wiley-VCH, Weinheim, 2004, ISBN 3-527-31148-3
  • E. Breitmaier, G. Jung: Organische Chemie , 5th ed., 374ff., Thieme, Stuttgart, 2005

Individual evidence

  1. ↑ T. Laue, A. Plagens: Name and catchword reactions of organic chemistry . Teubner Verlag, 2006, ISBN 3-8351-0091-2 , p. 297-300 .
  2. ↑ T. Laue, A. Plagens: Name and catchword reactions of organic chemistry . Teubner Verlag, 2006, ISBN 3-8351-0091-2 , p. 297-300 .