Ethyl acetoacetate

The organic compound ethyl acetoacetate (EAA) is the ethyl ester of acetoacetic acid. It is a solvent, and is used as a chemical intermediate in the production of a wide variety of compounds, such as amino acids, analgesics, antibiotics, antimalarial agents, antipyrene and aminopyrene, and vitamin B1; and also in the manufacture of dyes, inks, lacquers, perfumes, plastics, and yellow paint pigments. Alone, it is used as a flavoring for food.

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Preparation

Ethyl acetoacetate may be prepared via the Claisen condensation of ethyl acetate. Two moles of ethyl acetate condense to form one mole each of ethyl acetoacetate and ethanol.

Another method is to use acetyl ketene and ethanol. They directly form ethyl acetoacetate, and the yield is good, so this method is widely used in industry, but acetyl ketene is very dangerous.

Chemistry

Ethyl acetoacetate is often used similar to diethyl malonate in the Malonic ester synthesis or the Knoevenagel condensation. The protons alpha to carbonyl groups are easily deprotonated and than the carbanion formed can undergo nucleophilic substitution. A subsequent thermal decarboxylation is also possible.

Analysis

Ethyl acetoacetate is an ester of a β-keto carbonic acid and therefore has a strong keto enol tautomery. The enolate forms purple complexes with iron(III) salts:

References

Carey, Francis A. (2006). Organic Chemistry, Sixth Edition, New York, NY: McGraw-Hill. ISBN 0-07-111562-5.