Japp–Klingemann reaction
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The Japp–Klingemann reaction is a chemical reaction used to synthesize hydrazones from β-keto-acids (or β-keto-esters) and aryl diazonium salts.[1][2][3][4][5][6] The reaction is named after the chemists Francis Robert Japp and Felix Klingemann.
Japp–Klingemann reaction | |
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Named after | Francis Robert Japp Felix Klingemann |
Reaction type | Coupling reaction |
Identifiers | |
RSC ontology ID | RXNO:0000158 |
The hydrazone products of the Japp–Klingemann reaction are most often used as intermediates in syntheses of more complex organic molecules. For example, a phenylhydrazone product can be heated in the presence of strong acid to produce an indole via the Fischer indole synthesis.[7][8]
If there is a leaving group elsewhere in the Japp–Klingemann product, the hydrazone instead can cyclize at that site via a substitution reaction to give a pyrazole. This process is a key part of the synthesis of pyraclofos [de] and related compounds:[9]