Of dihydroxyfumaric acid

Fenton s reagent. To a solution of tartaric acid or a tartrate add 1 drop of freshly prepared ferrous sulphate solution, i drop of hydrogen peroxide solution and then excess of NaOH solution an intense violet coloration is produced, due to the ferric salt of dihydroxyfumaric acid, HOOC C(OH) C(OH)COOH. 

Biosyntheses of hexuronic acids and L-ascorbic acid in plants and animals are closely related. Hexuronic acids, L-ascorbic acid, and L-tartaric acid (a possible precursor of dihydroxyfumaric acid) commonly occur together in plants. If a rat is given chloretone (an antispasmodic), both L-ascorbic acid and D-glucuronic acid are excreted in increased quantity.244 Unlike humans, rats can synthesize their own vitamin C, and are therefore independent of outside sources. Here, D-glucose and D-galactose can be utilized, but not D-mannose. 

Fig. 6.5 FIRP catalyzed hydroxylation of L-tyrosine to L-Dopa in the presence of dihydroxyfumaric acid...

The nuclear hydroxylation of aromatics can be catalyzed by horseradish peroxidase, and with suitably activated substrates synthetically useful yields can be obtained.The reactions are usually carried out at 0 C in the presence of dihydroxyfumaric acid cofactor and a source of oxygen. Thus l-DOPA (102) has been prepared using this system. ... 

The third type of oxygen transfer reactions is the hydroxylation of aromatic compounds [88,89], Selective hydroxylations of aromatic compounds are very difficult in preparative organic chemistry because they are laborious, time-consuming and, most important, inefficient. However, hydroxylations of some aromatic compounds may be performed by class III plant peroxidases at the expense of molecular oxygen and in the presence of dihydroxyfumaric acid (XI) as propagator (Scheme VII). 

A stirred mixture of dihydroxyfumaric acid, Mg-sulfate, and methanol treated 4.5 hrs. at 0-5 with anhydrous HCl, and stored 3 days at room temp. -> dimethyl dihydroxyfumarate. Y 93.2% 45% without MgS04. E. E. Jaffe and H. Matrick, J. Org. Chem. 33, 4004 (1968). 

It yields a blue color in alkaline medium. The formation reaction of dihydroxyfumaric acid is complex. The development of a color is not surprising since a chelate of Fe + with the following structural moiety ... 

Tartaric add. (d) Make a saturated aqueous solution of ferrous sulphate (do not heat). Add one drop of it to the neutral solution of the compound, followed by two drops of 10 volume hydrogen peroxide and an excess of sodium hydroxide solution. An intense violet colour due to the ferric salt of dihydroxyfumaric acid, is a positive test (Fenton s test). 

In addition to activities ordinarily ascribed to them, peroxidase and catalase possess properties as oxygen transferases and mixed function oxidases. They may exist in functionally active ferrous forms which have, like hemc lobin and myoglobin, the property of combining with molecular oxygen. This oxygen may be transferred to substrate, or be reduced in steps. For purposes of the present review, mechanisms that have been proposed for peroxidatic and catalatic oxidations will be summarized and followed by discussion of dihydroxyfumaric acid oxidase, tryptophan oxidase, and indolyl-acetic oxidase and related oxidases, and indole oxidase. All of these have properties in common with peroxidase and catalase. 

There a number of cases other than those of dihydroxyfumaric acid oxidase and tryptophan oxidase in which peroxidases appear to play the part of oxidases. These include indolylacetic acid oxidase and the related indolylpropionic and indolylbutyric acid oxidases (285, 415,416,618,733,777), the oxidase of oxalic, oxalacetic, ketomalonic, and dihydroxytartaric acids (414), of phenylacetaldehyde (413) and saturated fatty acid oxidase (711). 

The study of dihydroxyfumaric acid oxidase thus appears to be the study of a chemical accident. But we are only able to see this as a result of our present understanding of the enzyme. The discrimination between the essential and the fortuitous is wholly dependent upon a prior knowledge of the true and the false. And such knowledge has been in part aggrandized by studying things later proven accidental. 

This reaction sequence is a general one for ene-diols. For example, in the same conditions, dihydroxyfumaric acid is oxidized by two moles of periodate, first to a diketone and then to two moles of oxalic acid (25,56). 

Selective hydroxylation of some aromatic compounds can be achieved using HRP C in the presence of oxygen and dihydroxyfumaric acid (270). This process afforded l-DOPA from L-tyrosine, D-(-)-3,4-dihydroxy-phenylglycine from D-(—)-4-hydroxyphenylglycine, and L-epinephrine (adrenalin) from L-(-)-phenylephrine in yields of up to 70%. 

Pasta P, Carrea G, Monzani E, Gaggero N, Colonna S (1999) Chloroperoxidase-Catalyzed Enantioselective Oxidation of Methyl Phenyl Sulfide with Dihydroxyfumaric Acid/Oxygen or Ascorbic Acid/Oxygen as Oxidants. Biotechnol Bioeng 62 489... 

Some of the earliest kinetic studies on metal ion-promoted reactions were carried out on metal ion-promoted decarboxylations of j8-oxo acids. The literature on this topic up to about 1974 has been reviewed. Much of the work has centred on oxaloacetic acid (HO2CCOCH2CO2H = H20xac) and its derivatives, a,a-dimethyl oxaloacetic acid and fluorooxaloacetic acid. Studies have also been made with acetonedicarboxylic acid (3-oxoglutaric acid), " dihydroxyfumaric acid, dihydroxytartaric acid, acetosuccinic acid, oxalosuccinic acid and 2-oxalopropionic acid (Figure 6). The decarboxylation of )3-oxo acids is of considerable biological importance, and in a number of cases metalloenzymes are involved. Similarities in the enzymatic and chemical processes stimulated early interest in these reactions as models for the enzymatic systems. 

An interesting application of this method is a convenient synthesis of the parent oxazole.124 186 It is prepared by oxidizing tartaric acid with hydrogen peroxide to dihydroxyfumaric acid (55), the methyl or ethyl ester of which is condensed with formamide in the presence of hydrogen chloride to give 4,5-dialkoxycarbonyloxazole (56, R = Me or Et), which is saponified with aqueous barium hydroxide or alcoholic sodium hydroxide. The anhydrous salt is then decarboxylated to oxazole, without isolation of the comparatively unstable 4,5-oxazoledicarboxylic acid, in 55-70% yield. 

If the reaction is incompatible with a peroxo species, molecular oxygen in presence of a chemical reductant (such as ascorbic or dihydroxyfumaric acid) may be used as oxidant [1353, 1354]. 

Dry urea added to a soln. of anhydrous dihydroxyfumaric acid in n-butanol, the resulting suspension cooled to 0°, satd. with dry HGl, more n-butanol added until a soln. results, and stored 3 days at room temp. di-n-butyl 2-imidazo-lone-4,5-dicarboxylate. Y 72%. F. e. s. P. H. Laursen and B. E. Christensen, J. Org. Chem. 27, 2500 (1962) method s. H. J. H. Fenton and W. A. R. Wilks, Soc. m, 1570 (1912). 

Aerobic hydroxylation catalyzed by peroxidase is evidently related to other (tatalytic effects ascribed to hemoproteins, to heme, and to ferrous iron in the presence of oxygen and electron donors (for example, 253,254,.383,476,774,775, the formation of bile pigments, and iron-catalyzed oxygen transfers). Relationships among amounts of oxygen consumed, dihydroxyfumaric acid oxidized, and aromatic substance hydroxylated are not yet known. Since under the conditions of reaction peroxidase has an oxyhemoglobin type of structure... 

In 1953, Kenten and Mann, during their survey of various donors active in the oxidatic reaction (see Section III), showed that p-cresol promotes the oxida tion of dihydroxyfumarate. Kenten later (1955) demonstrated that in the case of indoleacetic acid, some phenolic compounds (monophenols, resorcinol, etc.) are stimulatory while others are inhibitory (most polyphenols) despite the fact that all were substrates for peroxidase. Similar results have been obtained for pyridine nucleotides (Akazawa and Conn, 1958). Yamazaki analyzed the behavior of phenols and other hydrogen donors effective in the peroxidatic activity of the enzyme, and has shown that they fall into two classes, which he terms redogenic and oxidogenic. Table IV gives a list of the donors... 

The reaction of iodate with triose reductone is not only a function of the concentration of the reagents, it is also dependent on the pH of the solution. In solutions of triose reductone more dilute than 10"3M, iodine is set free from iodate, if the pH of the solution is lower than about 3 (55). Dihydroxyfumaric and L-ascorbic acids (26), which also have free ene-diol structures, behave similarly. 

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