Abstract:
All β -keto-acids are unstable in aqueous solution and spontaneously lose carbon dioxide. Usually both the undissociated acid and its anion decompose at relative rates which vary widely for different β-keto-acids. Brown, B. R., Quart. Revs., 131 (1951).
Many β -keto-acids can enolise and decarboxylation could take place through the keto or enol form. Pedersen, K. J., J. Am. Chem. Soc., 51, 2098 (1929). investigated the decomposition of αα-dimethyl acetoacetic acid, which cannot enolise, and compared his results with those for acetoacetic acid.(Steinberger, R., and Westheimer, F. H., J. Am. Chem. Soc., 58, 240 (1936). have found that dimethyl oxaloacetic acid, which also only exists in the keto form, decarboxylates readily).
Pedersen, K. J., J. Am. Chem. Soc., 58, 240 (1936). therefore concluded that in the decarboxylation of β-keto-acids the keto form of the acid or anion decomposes spontaneously into carbon dioxide and an enol or enolate ion, which is then transformed into a stable ketone.
