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Acetoacetic ester synthesis is a chemical reaction where ethyl acetoacetate is alkylated at the α-carbon to both carbonyl groups and then converted into a ketone, or more specifically an α-substituted acetone. This is very similar to malonic ester synthesis. Acetoacetic ester synthesis equation
At large scale, ethyl acetoacetate is industrially produced by treatment of diketene with ethanol. [2] The small scale preparation of ethyl acetoacetate is a classic laboratory procedure. [3] It involves Claisen condensation of ethyl acetate. Two moles of ethyl acetate condense to form one mole each of ethyl acetoacetate and ethanol. [4]
The reaction has been demonstrated to proceed in water as reaction solvent and with direct aromatization by ferric chloride, manganese dioxide or potassium permanganate in a one-pot synthesis. [4] Hantzsch reaction with ammonium acetate, ethyl acetoacetate, formaldehyde and ferric chloride
The original Knorr synthesis employed two equivalents of ethyl acetoacetate, one of which was converted to ethyl 2-oximinoacetoacetate by dissolving it in glacial acetic acid, and slowly adding one equivalent of saturated aqueous sodium nitrite, under external cooling. Zinc dust was then stirred in, reducing the oxime group to the amine. This ...
The reaction mechanism of the Biginelli reaction is a series of bimolecular reactions leading to the desired dihydropyrimidinone. [14]According to a mechanism proposed by Sweet in 1973 the aldol condensation of ethylacetoacetate 1 and the aryl aldehyde is the rate-limiting step leading to the carbenium ion 2.
Ethyl acetoacetate, an important starting material in organic synthesis, can be prepared using a diketene in reaction with ethanol. They directly form ethyl acetoacetate, and the yield is high when carried out under controlled circumstances; this method is therefore used industrially.
Hantzsch ester refers to an organic compound with the formula HN(MeC=C(CO 2 Et)) 2 CH 2 where Me = methyl (CH 3) and Et = ethyl (C 2 H 5). It is a light yellow solid. The compound is an example of a 1,4-dihydropyridine. It is named after Arthur Rudolf Hantzsch who described its synthesis in 1881.
Acetoacetic esters are used for the acetoacetylation reaction, which is widely used in the production of arylide yellows and diarylide dyes. [3] Although the esters can be used in this reaction, diketene also reacts with alcohols and amines to the corresponding acetoacetic acid derivatives in a process called acetoacetylation.