Japp–Klingemann reaction

In the Japp - Klingemann reaction is a reaction names in organic chemistry, which was named after their discoverers Francis Japp and Klingemann Felix. It is a chemical reaction that is used to prepare β -keto esters or arylhydrazones of acids and aryldiazonium salts.

Overview reaction

In the Japp - Klingemann reaction, an aryldiazonium salt and a β -keto ester and an aryl hydrazone react to form a carboxylate.

Mechanism

In the first step of the β -keto ester is deprotonated by a hydroxide ion. This produces a nucleophilic addition of the enolate to the aryl diazonium salt azo compound. The intermediate was isolated in a few cases. Usually, however, the basic hydrolysis of the azo compound converted in situ to a tetrahedral intermediate that decomposes to a carboxylic acid and a hydrazone anion. The last step is caused by proton transfer the desired product arylhydrazone.

Use

By heating the products with strong acid arise analogous to the Fischer indole synthesis.