Acetoacetone is a
beta-diketone (1,3-diketone) which two ketones are separated only by one carbon. The
beta-ketone is stable as a conjugated enol rather than alpha-diketone due to the
delocalization which makes the counterion more stable and less likely to regain
the proton. Ascorbic acid is an example of enol compound. Enol compounds form
complexes with many transition metal ions. These compounds are readily soluble
in organic solvents. They are widely used as chelating agents, ligands, and
catalyst precursors.
Acetoacetic acid and its esters contain active
methylene groups which have relatively acidic alpha-protons due to H atom
adjacent to two carbonyl groups. The reactivity of its methylene group provide
the sequence of reactions of alkylation, hydrolysis of the esters and
decarboxylation resulting in substituted ketones. The methylene group can be
reacted to form amino-carbonyl compounds.
Acetoacetates
are important aliphatic parts adjoining azo dyes and pigments. Acetoacetic acid is unstable and
decompose to acetone and carbon dioxide at room temperature.
Aacetoacetate is one
of ketone bodies which are the end-products of rapid or excessive fatty acid
breakdown in the human body.
Methyl
acetoacetate has
a reactive hydrogen atom on the carbon alpha to
both carbonyl groups. It undergoes Knoevenagel condensation reaction as a reactant
to forms a large class of target products including
amino acids, drugs, colorants, lacquers,
perfumes, and plastics. Alone, it is used as a flavoring agent and a solvent.
Knoevenagel condensation is a nucleophilic addition of a
reactive
hydrogen atom at 1,3-diketone compounds to a carbonyl
group, followed by an dehydration reaction. 1,3-Diketone compounds (beta-ketones)
include malonic
acid, diethyl malonate,
Meldrum's acid,
and acetoacetic acid derivatives. |