Hydroxymalonic acid

Oxidative bisdecarboxylation.1 A new route to lactones is based on the ability of CAN to effect oxidative decarboxylation of a-hydroxymalonic acids to carboxylic acids (11, 143-144) and of a-alkoxymalonic acids to lactones. 

Photolysis of pentobarbitone (pentobarbital, 285) was achieved on a solution buffered to pH 11 with a low-pressure mercury lamp over 10 h. At this pH the mono anion was the main species present. The products identified were the dealkylated ethyl barbitone (286), the amide (294) and both diastereoisomers of the ureide (295). On more prolonged irradiation, there also appeared ethylhydroxybarbitone (287) and an unidentified dimeric compound. When ethylbarbitone (286) was photolysed in the same way, it gave (287) and 2-ethyl-2-hydroxymalonic acid. Finally, pentobarbitone was irradiated in molar sodium hydroxide solution, where the dianion would be the main form present, to give (295) with a small amount of (294) [175]. 

Schuchmann MN, Schuchmann H-P, von Sonntag C (1995) Oxidation of hydroxymalonic acid by OH radicals in the presence and in the absence of molecular oxygen. A pulse radiolysis and product study. J Phys Chem 99 9122-9129... 

At higher temperatures, carbon dioxide, formic acid, oxalic acid, glycolic acid, hydroxymalonic acid, glyceric acid, and other acids were shown to be formed. The formation of carbon dioxide is ascribed to decarboxylation of 38 oxalic acid and D-erythronic acid arise from cleavage of the C-2-C-3 bond compound 39 is cleaved to glyoxylic acid plus D-erythronic acid. Compound 40 is oxidized further to D-g7ycero-2,3-pentodiulosonic acid and is subsequently cleaved to oxalic and glyceric acids. 

The presence of additional hydroxide groups at the dicarboxylic acid, as in malic and tartaric acid, increases the acidic character and, thus, the retention (Table 3-21). A corresponding chromatogram is shown in Fig. 3-88. However, a separation of malic acid (monohydroxysuccinic acid) and malonic acid is not possible under these conditions, while tartronic acid (hydroxymalonic acid) exhibits a significantly higher retention. 

Calcium carbonate in suspension in glycerol and hydrogen peroxide causes a considerable structural alteration, with the appearance of formaldehyde, formic acid, glyceric acid, and hydroxymalonic acid. Under identical conditions, D-glucose gives formaldehyde, formic acid, acetic acid, oxalic acid, D-glucaric acid, and other, unidentified, hydroxy acids. ... 

Oxidation of the hydroxymalonic acid ene adducts with cerium(IV) ammonium nitrate in aqueous acetonitrile or sodium periodate results in oxidative didecarboxylation to give an allylcarboxylic acid. The two step process ene reaction with diethyl oxomalonate and oxidative didecarboxylation provides a general procedure for the conversion of alkenes to allylcarboxylic acids. 

Hydroxymalonic acids from a-acoxymalonic acid esters... 

Tartronic acid, HOOC—CH(OH)—COOH, or hydroxymalonic acid, may be considered as the simplest of the aldaric acids. It has been obtained by the oxidation of glucose or fructose with hydrogen peroxide and ferrous sulfate 40), It is also formed by the cyanohydrin synthesis from glyoxylic acid (41). The oxidation of glycerol gives only small amounts of this acid. 

Without additional reagents a-Ketocarboxylic acids from y -cfaloro-a-hydroxymalonic acids... 

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