Phenylhydrazone of ethyl pyruvate

The phenylhydrazone of ethyl pyruvate on heating with sulfuric acid in acetic acid forms indole-2-carboxyIic acid (58%). When the phenylhydrazone has nuclear substituents like alkyl, halo, or nitro groups, the corresponding 4-, 5-, 6-, or 7-substituted indoles are obtained. When pbenylhydrazine is added to a boiling mixture of cyclohexanone and... [Pg.427]

In 1887, in an attempt to prepare the azo ester 4 by coupling benzenediazonium chloride 2 with ethyl 2-methylacetoacetate 1, Japp and Klingemann obtained a product which was recognized as the phenylhydrazone of ethyl pyruvate 3.1"4... [Pg.630]

Japp and Klingemann found that benzenediazonium salt 2 coupled with ethyl methylacetoacetate 1 in alkaline solution to give the phenylhydrazone of ethyl pyruvate 3 with elimination of acetic acid. However, if the ketonic ester was first hydrolyzed with alkali and then coupled, the product was monophenylhydrazone 10, with carbon dioxide being eliminated rather than acetic acid.6... [Pg.631]

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