Oxaloacetic acid tautomerism

The simplest member of the series of aliphatic a-keto acids is pyruvic acid. It is conveniently prepared by the distillation of tartaric acid with a dehydrating agent such as postassium hydrogen sulphate (Expt 5.173). The reaction probably involves dehydration to the tautomeric oxaloacetic acid (13) intermediate, which then decarboxylates by virtue of its constitution as a / -keto acid. 

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