Dialkylmalonic acids

Thus, decarboxylation of dialkylmalonic acid is a more complicated reaction compared to that of phenylmalonate and requires ATP and recycling of coenzyme... 

Dialkylmalonic acids. Dianions of carboxylic acids have been prepared using LDA in THF-HMPT (4,301-302). Krapcho reports that trianions (2) of monosubstituted malonic acids (1) can be prepared with 3 equiv. of n-butyl-lithium in THF at 0°. These can be alkylated by primary halides to give dialkylmalonic acids (3). Alkylation cannot be achieved with secondary halides. This procedure is not applicable to malonic acid itself. 

Step 3 The mono- or dialkylmalonic ester can then be hydrolyzed to a mono- or dialkylmalonic acid, and substituted malonic acids decarboxylate readily. Decarboxylation gives a mono- or disubstituted acetic acid ... 

The results summarised in Table 4 show clearly that good yields of the 1 1 Michael adducts can be obtained in cathodically initiated reactions. It is not clear, however, why the reaction should fail for acrylonitrile even if dimerisation of the initially formed radical-anion is much faster thaq,protonation the resulting dimeric dianion should still be sufficiently basic to deprotonate dialkylmalonate esters. A feature of especial significance is the usefulness of esters of ethenetetracarboxylic acid. Apart from their use in EGB catalysed reactions they have been much used in stoichiometric amount. 

The monosubstituted malonie ester still possesses an activated hydrogen atom in its CH group it can be converted into a sodio derivative (the anion is likewise mesomeric) and this caused to react with an alkyl halide to give a C-disubstituted malonie ester. The procedure may accordingly be employed for the synthesis of dialkylmalonic and dialkylacetic acids ... 

Certain dialkylmalonates may be partially saponified to the acid esters, which decarboxylate to esters upon heating, Decarbethoxylation of dialkylmalonic esters may also be effected by heating at 220-230° with sodium ethoxide,... 

The acidity of malonic ester thus permits the preparation of substituted malonic esters containing one or two alkyl groups. How can these substituted malonic esters be used to make carboxylic acids When heated above its melting point, malonic acid readily loses carbon dioxide to form acetic acid in a similar way substituted malonic acids readily lose carbon dioxide to form substituted acetic acids. The monoalkyl- and dialkylmalonic esters we have prepared are readily converted into monocarboxylic acids by hydrolysis, acidification, and heat ... 

Carboxamides containing alkylamine arms like (34), synthesized from dialkylmalonate and ethylene-diamine, act as chelating dianionic N4-donors,44,45 whereas the geometric isomer (35) was prepared from 1,3-diaminopropane and chloroacetyl chloride.46 The hexadentate bis(pyrazine)-carboxamides (36) and (37) can be obtained by the addition of 1,3-propanediamine to the appropriate carboxylic acid.47 Compound (36), in the dianionic form, can be used to obtain homo- and hetero-metal bridged complexes, whereas (37) has been shown to yield tetranuclear copper(II) complexes involving opened-up dianionic ligand molecules.47... 

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