Research on arylhydrazones of substituted glyoxylic acids

Reaction of the hydrazides and acetylhydrazides of cyanoacetic acid with aryldiazonium chlorides gives arylhydrazones of the hydrazide and acetylhydrazide of cyanoglyoxylic acid. 2-Acetyl-3-imino-4-arylpyrazol-5-ones and 3-imino-4-arylazopyrazol-5-ones are obtained by cyclizing the arylhydrazones.For Part IX see [1].