Acetoacetic ester decomposition

Methylsuccinic acid has been prepared by the pyrolysis of tartaric acid from 1,2-dibromopropane or allyl halides by the action of potassium cyanide followed by hydrolysis by reduction of itaconic, citraconic, and mesaconic acids by hydrolysis of ketovalerolactonecarboxylic acid by decarboxylation of 1,1,2-propane tricarboxylic acid by oxidation of /3-methylcyclo-hexanone by fusion of gamboge with alkali by hydrog. nation and condensation of sodium lactate over nickel oxide from acetoacetic ester by successive alkylation with a methyl halide and a monohaloacetic ester by hydrolysis of oi-methyl-o -oxalosuccinic ester or a-methyl-a -acetosuccinic ester by action of hot, concentrated potassium hydroxide upon methyl-succinaldehyde dioxime from the ammonium salt of a-methyl-butyric acid by oxidation with. hydrogen peroxide from /9-methyllevulinic acid by oxidation with dilute nitric acid or hypobromite from /J-methyladipic acid and from the decomposition products of glyceric acid and pyruvic acid. The method described above is a modification of that of Higginbotham and Lapworth. ... 

The synthetic capabilities of this compound arc not yet exhausted. Acetoacetic ester and its alk d derivatives undergo decomposition in two wajs, accoidiiig to whether dilute alkalis and acids or, on the other hand, strong alkalis are employed. 

The distillate is rendered alkaline to remove any acids formed by the acid decomposition of the substituted acetoacetic ester or unreacted ethyl acetoacetate. 

It is not possible to perform the acid hydrolysis without some ketonic hydrolysis occurring. This reaction and the preceding one are important in many syntheses of aliphatic ketones and acids. They might have been included equally well in the decomposition section (p. 411) in fact they are often referred to as the ketonic and acid decomposition of acetoacetic ester. The malonic ester synthesis of fatty acids may be compared with the present reaction (p. 135). 

A history of ether and etherification is a welcome, and now rare, focus on an individual compound.72 It covers work by Berzelius, Gerhardt, Hennell, Kolbe, Liebig, and of course Williamson. Acetoacetic ester has received detailed historical notice in a biography,73 as have salicylic acid and the salicylates.74 Apart from natural products, few heterocyclic substances have been recently the subject of historical enquiry. An impressive exception is that of pyrrole, a simple molecule explored by Dippel, Reichenbach, Runge and others, and manufactured by Du Pont.75 There is also an account of the structural problems posed by piperidine.76 Accounts have been given of the discovery of aniline from crystallin (a product of the thermal decomposition of indigo),77 of the history of phenol over the last two centuries,78 and of organic nitrates and their uses in medicine.79... 

The ester so obtained,uniijce most acetoacetic ester derlvatires,may be hydrolyzed to the free acid without decomposition. Their general behavior is like that of the 1,1 diacid,the same reactivity of the ring being characteristic of both the benzoyl and acetyl compounds. The ester when treated with cold hydro-bromic acid gives y-bromethylacetacetic esterif the acid is used,carbon dioxide is evolved andy -brom-propyl jcetone results ... 

The distillate contains mostly C-acyl ester with a little of 0-acyl ester. Separation of these two esters by means of a carbonate solution in which only the C-acyl ester is soluble is possible. This separation is unnecessary in the present procedure for the 0-acyl derivative gives rise to ethyl acetoacetate during decomposition with ammonia. This low-boiling ester is removed during the distillation of diethyl -ketopimelate. 

Eight-membered N,0,S-containing ring systems 680 have become accessible via Rh2(OAc)4-catalyzed decomposition of diazomalonic or diazo-acetoacetic esters in the presence of penicillin derivatives 681. The reaction is mediated by sulfonium ylide 682 and proceeds stereoselectively but in moderate yields. The stereochemical migration control in the ylide occurs... 

Acetoacetic Ester Synthesis.—The hydrolysis of acetoacetic ester and its derivatives presents many points of interest, on account of the fact that the acid and its substitution-products, which are formed by the hydrolysis, are unstable and yield important decomposition-products. When the saponification of acetoacetic ester is effected by boiling it with a dilute aqueous solution of an acid or a base, it is probable that alcohol and acetoacetic acid are first formed —... 

The derivatives of acetoacetic ester undergo decompositions similar to those of the ester itself. As many substitution-products of acetoacetic ester can be prepared, we have, thus, a means of synthesizing substitution-products of acetone and of acetic acid. 

The reactions of acetoacetic ester represent a somewhat more complex case, but can be treated in the same way. Acetoacetic ester may decompose in two ways on treatment with dilute alkali (boiling) or with dilute sulfuric acid, it undergoes the ketonic decomposition with the formation of a ketone, an alcohol, and carbon dioxide treatment with concentrated alcoholic alkali results in the "acid decomposition and formation of acid and alcohol. These transformations may be formulated as follows ... 

The patent describes the formation of complex metal chelates by treatment of the ketoester simultaneously with an alcohol and a metal to effect trans-esterification and chelate formation by distilling out the by-product ethanol [1], This process was being applied to produce the zinc chelate of 2-tris(bromomethyl)ethyl acetoacetate, and when 80% of the ethanol had been distilled out (and the internal temperature had increased considerably), a violent decomposition occurred [2], This presumably involved interaction of a bromine substituent with excess zinc to form a Grignard-type reagent, and subsequent exothermic reaction of this with one or more of the bromo or ester functions present. 

Keto esters, such as methyl acetoacetate and methyl benzoylacetate, have been converted to carbethoxyketenes by nitrosation, reduction, diazotization, and finally decomposition of the intermediate diazoketo... 

The hydrolysis of alkyl and aryl acetoacetates (HS) possesses pH-independent rate constants (Table 1) corresponding to the decomposition of the conjugate base of the ester (CH3CO-CH"-CO2Ar). Comment on the hydrolysis mechanism considering that the value of PLg for the alkaline hydrolysis of aryl acetates is -0.26. 

ACETOACETIC ACID, METHYL ESTER (105-45-3) Combustible liquid (flash point 170°F/77°C). Moisture may cause decomposition. Incompatible with oxidizers, strong acids, nitrates. 

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