Ethyl acetoacetate is subject to
keto-enol tautomerism. In the neat liquid at 33 °C, the enol consists of 8% of the total. The enol is moderately acidic. Thus ethyl acetoacetate behaves similarly to
acetylacetone: The dianion of ethyl acetoacetate is also a useful building block, except that the electrophile adds to the terminal carbon. The strategy can be depicted in the following simplified form: : (Bu =
butyl) Reduction of ethyl acetoacetate gives ethyl 3-hydroxybutyrate. Ethyl acetoacetate transesterifies to give benzyl acetoacetate via a mechanism involving acetylketene. Ethyl (and other) acetoacetates nitrosate readily with equimolar sodium nitrite in acetic acid, to afford the corresponding oximinoacetoacetate esters. A dissolving-zinc reduction of these in acetic acid in the presence of ketoesters or beta-diketones constitute the
Knorr pyrrole synthesis, useful for the preparation of
porphyrins. Another similarity to
acetylacetone, ethyl acetoacetate forms chelate complexes, such as and the Fe(III) derivative. ==See also==