Oxomalonic acid

When dihydroxyacetone is heated in aqueous solution with cupric acetate, the product is chiefly oxomalonic acid. Evans and Waring, J. Am. Chem. Soc. 48, 2680 (1926). 

Alloxane can act as a source of oxomalonic acid under certain conditions,97,98 and 1,3-dimcthyl-substituted alloxane can act as a source of the monomethylamide of oxomalonic acid.96 4-Isobutyl-2-rrilluoromethyl-l,3-oxazol-5(2/7)-one (8) acts as a source of isopropyl-substituted pyruvic acid.99... 

Calcium Mesoxalate, Mcsorslir acid caldum salt calcium ketomalonate calcium oxomalonate ketomalonic acid calcium salt oxomalonic acid calcium salt Mesoxan. CjCaOs mol wt 156.11. C 23,08%, Ca 25.677°, O 51.257°. Prepn Scheiber, Hopfer, Ber. 53, 908 (1920) Kobayashi, Japan, pat. 4157( 52), CA, 48, 5212a (1954) Yanagisawa, Japan, pat. 7463( 60), C.A. 55, 5880a (1961). 

This reaction was initially reported by Martinet in 1913. It is a synthesis of dioxindole derivatives by alkali treatment of the condensation products from substituted anilines and ethyl or methyl ester of oxomalonic acid in the absence of oxygen. Thus it is known as the Martinet reaction. In the presence of oxygen, the dioxindoles are further oxidized into isatins. This reaction has been extended to the preparation of a- and -naphthisatins." ... 

When an aromatic ring is treated with diethyl oxomalonate, (Et00C)2C=0, the product is an arylmalonic acid derivative, ArC(OH)(COOEt)2, which can be converted to an arylmalonic acid, ArCH(COOEt)2. This is therefore a way of applying the malonic ester synthesis (10-104) to an aryl group (see also 13-12). Of course, the opposite mechanism applies here The aryl species is the nucleophile. 

The best carbonyl components for these reactions are highly electrophilic compounds such as glyocylate, pyruvate, and oxomalonate esters, as well as chlorinated and fluorinated aldehydes. Most synthetic applications of the carbonyl-ene reaction utilize Lewis acids. Although such reactions may be stepwise in character, the stereochemical outcome is often consistent with a cyclic TS. It was found, for example, that steric effects of trimethylsilyl groups provide a strong stereochemical influence.28... 

The hypothesis ofWindaus and Ullrich48 that imidazole-4(5)-carbox-ylic acid (31) is formed after oxidation of D-glucose to 2-oxomalon-aldehydic acid, 0CH-C0-C02H, needs revision. As the reaction mixture was kept for three years, it is far more probable that a 4(5)-(hydroxyalkyl)imidazole was first formed, and that this was subsequently oxidized by the copper hydroxide in the reaction mixture to imidazole-4(5)-carboxylic acid. 

Allylic carboxylation. Diethyl oxomalonate (1) undergoes a thermal ene reaction with mono-, di-, and trisubstituted alkenes at 145 180°. The reaction is also subject to catalysis with Lewis acids, which can lead to a different ene product. The products are a-hydroxymalonic esters. The corresponding malonic acids are converted to carboxylic acids by bisdecarboxylation with NaI04 and a trace of pyridine- or with ceric ammonium nitrate (CAN). Diethyl oxomalonate then functions as an cnophilic equivalent of C02. 

Bromomandelic acid has been prepared by the bromination of -bromoacetophenone followed by alkaline hydrolysis 3 by the alkaline hydrolysis of the product formed by the addition of chloral to -bromophenylmagnesium bromide 4 and by the condensation of bromobenzene and ethyl oxomalonate in the presence of stannic chloride followed by hydrolysis and decarboxylation.5 />-Bromomandelic acid is a valuable reagent in the analyses of zirconium and hafnium.6... 

The Martinet procedure for the synthesis of indole-2,3-diones involves the reaction of an aminoaromatic compound and either an oxomalonate ester or its hydrate in the presence of an acid to yield a 3-(3-hydroxy-2-oxindole)carboxylic acid derivative which after oxidative decarboxylation yields the respective isatin. This method was applied with success for the synthesis of 5,6-dimethoxyisatin from 4-aminoveratrole whereas the use of 2,4-dimethoxyaniline was less successful40 (Scheme 9). 

Thermal and Lewis acid catalyzed ene reactions of electron-deficient ketones proceed in good yield. Dialkyl oxomalonate esters " and pyruvate esters have been most extensively studied. 1,2,3-Tri-ketones, methyl phenylglyoxylate, carbonyl sulfide, carbonyl cyanide, hexafluoroacetone, hexafluorocyclobutanone and 1,1,1-trifluoromethyl ketones have also been developed as enophiles. 

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. 

The Cu(n)-catalyzed reaction of silyl enol ethers with oxomalonic esters in the presence of a bis(oxazoline) ligand constitutes the first step of an access to chiral p-hydroxy acids. Enantioselective Mukaiyama aldol reaction performed in the presence of 52, and that in aqueous ethanol has been accomplished to a certain degree of success (32-85% ee). ... 

The traditional synthesis of 1,2,3-trihydroxybenzene by decartx)xylation of gallic acid from natural sources has been superseded by the use of acyclic precursors. Dimethyl oxomalonate and dimethyl glutarate undergo cyclodehydration and tautomerism to give a diester product which uponhydrolysis decarboxylates to pyrogallol in about 65% yield (ref.3). 

CTarbazoles can be derived from the acid-catalyzed intramolecular addition of the ketones (117) derived from gramine and oxomalonate systems (116) <88TL6505> (Scheme 33). Treatment of the ketone (118) with one equivalent of n-butyllithium followed by one equivalent of methyllithium and then borohydride reduction of the intermediate diol gave the pyridocarbazole (119). The transformation involves intramo<< ular trapping of the intermediate ddehyde at C-3 (Equation (30)) <83TL3831>. 

The removal of modified trityl and of pixyl groups has been carried out by the use of an acidic species generated by the reaction of diethyl oxomalonate with methanol, thought to be the hemiacetal formed by addition of methanol to the ketonic carbonyl. In the case of 2 -deoxy-purine nucleosides depurination occurred competitively. 99 silver ion has been found to have a pronounced effect on the regioselectivity of tritylation of nucleosidic hydroxyl groups.390... 

Thermal or Lewis acid-catalysed ene reactions between olefins and diethyl oxomalonate followed by oxidative bis-decarboxylation using ceric ammonium nitrate lead to /3,y-unsaturated acids in good yield (Scheme 2). ... 

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