Dimethylmalonic acid

Dimethylmalonic acid [595-46-0] M 132.1, m 192-193 pK 3.03, pK 5.73. Crystd from benzene/pet ether and sublimed in a vacuum with slight decomposition. 

The 2 1 reaction of 9-BBN with a series of dicarboxylic acids, namely oxalic acid, malonic acid, 2,2-dimethylmalonic acid, and succinic acid, in dimeth-oxyethane gives in some cases dimeric and in other cases macrocyclic (acyloxy)diorganoboranes. This has been proved by IR spectroscopy (all C = O groups are bidentate), B-NMR 5 = 10 ppm) and X-ray crystallography [47]. With oxalic acid two structures are possible (IV and V), of which the first with a five-membered boron heterocycle instead of a four-membered one is the more probable formulation (Fig. 13). 

Fig. 13. Possible structures for (acyloxy)boranes formed from the reaction of 9-BBN with oxalic acid and solid state structure of the complex with 2,2-dimethylmalonic acid 30...

The electrochemical results suggested to explore the possibility of creating a C-C bond between the electrogenerated a-carbanion fi and carbon nucleophiles. Results of practical importance have hitherto been obtained upon electroreduction of 2-bromoisobutyramides in acetonitrile at Hg or Pt cathodes, in the presence of carbon dioxide and an alkylating agent. The enolate-amide fi undergoes quantitative carboxy-alkylation, to yield ester amides of 2,2-dimethylmalonic acid (ref. 16). 

Diimidazolides of dicarboxylic acids react with hydrazines in a 1 1 molar ratio to form cyclic hydrazides e.g., the diimidazolide of 2,2-dimethylmalonic acid and phenyl-hydrazine affords 1-phenyl-4,4-dimethyl-3,5-dioxopyrazolidine in 67% yield ... 

The recent development of the Sharpless ami-nohydroxylation [2] makes it possible to synthesize an amino alcohol in both optical antipodes (Fig. 2). For example, starting from 2-vinyl-naphthalene (5), the amino alcohol 6 is readily synthesized by the aminohydroxylation protocol [3]. After deprotection, the free amino alcohol 8 was coupled with dimethylmalonic acid di-... 

A. Just had earlier shown that 2-methylpropanoic acid (LVI) can be produced by the oxidation of l,3-dihydroxy-2,2-dimethylpropane (LIV), dimethylmalonic acid (LV) being a probable intermediate. Glattfeld and... 

Kimura and coworkers tried to shorten the extended reaction times required for these cyclization reactions by using more reactive derivatives of malonic acid. They reacted the diazide derivative of a,a-dimethylmalonic acid with l,9-diamino-3,7-diazanonane in chloroform for 12 hr at 0°C to give the dimethyl-[14]N4 macrocycle in a 23% yield (Kimura et al., 1989a). This method will probably not be widely accepted because diazides are not safe... 

Finally, the preparation of dimethylmalonic acid by heating trimethylacetic acid with alkaline permanganate solution is worth mention.408... 

Dimethylketene Acetic anhydride (25 g), dimethylmalonic acid (6.5 g), and concentrated sulfuric acid (1 drop) are placed in a dry Claisen flask dissolution occurs when the mixture is shaken. The solution is set aside at room temperature for 2 days, then a little powdered barium carbonate is added and the acetic acid and anhydride are removed by gentle heating in a vacuum. A new receiver is then attached and this is cooled in ice. The temperature is then gradually raised to about 100°, whereupon the dimethylmalonic anhydride decomposes with evolution of carbon dioxide and distillation of the dimethylketene produced. The yield is 65% (2.3 g) and the b.p. 34°. 

Dimethylmalonic acid Dimethylproparredioc acid CsHsO, 696-46-0 132.116 pr (bz/peth) 192.6 subI s hot HjO ... 

Methylcorrinoids are competent for the efficient methylation of alkyl radicals. Thermolysis of 2 -bis(ethoxycarbonyl)propylcobalamin and methylcobalamin at 70 °C led to formation of cob(II)alamin and the organic products 2-ethyl-2-methylmalonic acid diethyl ester and 2,2-dimethylmalonic acid diethyl ester. The former product was generated with quantitative deuterium incorporation from CDsCobjllljalamin. The proposed mechanism involves homolytic substitution on methylcob(III)alamin by the 2 -bis(ethoxycarbonyl)propyl radical, resulting in net methyl-radical abstraction, a process calculated to be highly exothermic (A7/ -201 kJmoK ). The stereochemical course of the reaction should result in net inversion at the methyl carbon, although this has not been demonstrated. The reaction may serve as a precedent for several biosynthetic methylations, such as the antibiotic thienamycin synthesis. ... 

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