Dibromomalonic acid

Dibutyl tellurium induced cyclopropanation of a,/ -unsaturated esters, ketones, and nitriles with dibromomalonic acid derivatives. Bis[4-methoxyphenyl] tellurium hardly promoted these reaction even at 150°3. 

The Belousov-Zhabotinsky reaction demonstrated here is set in train by the reduction of potassium bromate to elemental bromine by malonic acid and manganese(II) sulfate this is shown by the orange coloration. The reaction of the bromine with malonic acid to give mono or dibromomalonic acid leads to decolorisation. At the same time more bromine is formed in the initial redox process, and this again replaces one or two hydrogen atoms of the malonic acid. The process is repeated many times the start reaction is inhibited by complexa-tion of the brominated malonic acid by Mn(ll) ions, so that the oscillation slowly comes to an end. ... 

Laboratory prepn From dibromomalonic acid Conrad. Reinbach, Ber. 35, 1819(1902) from malonic ester and N203 Curtiss, Am. Chem. J. 35, 477 (1906)... 

When bromine (1 mole) is added to a suspension of malonic acid in ether, the acid dissolves whilst it is converted into bromomalonic acid 575,576 use of 2 moles of bromine in formic acid leads to dibromomalonic acid, particularly rapidly if the mixture is irradiated.578 If bromine is added to a dry ethereal solution of an alkyl- or arylalkyl-malonic acid at such a rate that the mixture... 

This must not be confused with the behavior of dibromomalonic acid.22 Here the inductive effect of the bromine substituents predominates, so that in aqueous solution, where the acid exists mainly as univalent anion, decarboxylation occurs even at room temperature, whereas the acid is stable for months if its dissociation is strongly repressed. 

Ionization of dicarboxylic acids has been shown to have a profound effect on the decarboxylation rate. The disodium salt of malonic acid (NaOOCCH2COONa) was found to be relatively stable with respect to decarboxylation (Fairclough 1938) up to temperatures of 125 °C, whereas the monosodium salt decomposed by a first-order reaction. Rates for the decarboxylation of both malonic and oxalic acids were slower in polar solvents in which a high degree of ionization was expected (Richardson and O Neal 1972). Similarly, the rate of decomposition of dibromomalonic acid was found to be proportional to the concentration of the undissociated acid molecule in solution (Muus 1935). 

Moore JW, Pearson RG (1981) Kinetics and mechanism. Wiley, New York, 455 pp Mosher WA, Kehr CL (1953) The decomposition of organic acids in the presence of lead tetraacetate. J Am Chem Soc 75 3172-3176 Muus J (1935) Carbon dioxide cleavage from dibromomalonic acid. J Phys Chem 39 343-353... 

Ethyl ethylenetetracarboxylate has been prepared from monochloro- and monobromomalonic ester through removal of halogen acid with sodium,1 sodium ethylate,2 potassium acetate,3 potassium carbonate,4 sodium urethane, sodium formanilide and sodium acetanilide.6 It has also been prepared by treating the disodium derivative of ethyl ethane-1,1,2,2-tetracarboxylate with bromine,7 or iodine 8 by treating dibromomalonic ester with sodium,9 or sodium ethylate 10 and by treating the disodium derivative of malonic ester with iodine.11... 

Bromination of a polyunsaturated carboxylic acid. Bromination of an acid of this type by the method of Rathke and Lindert (4, 306) proved unsatisfactory owing to low yields, but was accomplished by conversion of 1 into the a-anion with lithium N-isopropylcyclohexylamide, bromination with diethyl dibromomalonate at — 78°, and removal of the ester group. The pure acid 3 is fairly stable. ... 

An enantioselective dibromination of cinnamic alcohols (9) has been developed, which involves a combination of dibromomalonate as the bromonium source, a titanium bromide species as the bromide source, and a tartaric acid-derived diol (20 mol%). Ligand acceleration has been observed in this transformation, which affords the dibromides (11) with <85% ee transition state (10) has been proposed. ... 

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