Isodialuric acid

Isodialuric acid See Dialuric acid (probably the same)... 

Tanner,from infrared spectral work, tentatively concluded that 4,6- and 4,5-dihydroxy- and 4,5,6-trihydroxy-pyrimidines exist in the monooxo forms 117, 118 (X = H), and 118 (X — OH), respectively these conclusions are supported by ultraviolet spectral data and chemical evidence. " 2,4,5,6-Tetrahydroxypyrimidine has been isolated in two forms—dialuric acid and isodialuric acid, usually formulated as 119 and 120, respectively, on the basis of rather convincing chemical evidence [for a review see reference 109(f) cf. reference 178]. Isodialuric acid is converted into dialuric acid by base as would be expected if structures 119 and 120 are correct. On the basis of its infrared spectrum, dialuric acid has been concluded to exist in the tetrahydroxy form, but the correctness of this conclusion appears very doubtful. 

The dCyd oxidation products 5-hydroxy-dCyd and 5-hydoxy-dUrd have low oxidation potentials (Wagner et al. 2004) and are hence likely to be oxidized further. For this reason the oxidation of 4-hydroxy-dUrd has been studied (Riviere et al. 2004). Using Br2 or Na2IrBr6 but also menadione plus UV as oxidants, the main oxidation products were the isodialuric acid, dialuric acid and hydantoin derivatives. 

Riviere J, Bergeron F, Tremblay S, Gasparutto D, Cadet J, Wagner JR (2004) Oxidation of 5-hydroxy-2 -deoxyuridine into isodialuric acid, dialuric acid and hydantoin products. J Am Chem Soc 126 6548-6549... 

Only a few examples have been recorded using ureas as the imidazole nitrogen source. Thus isodialuric acid and urea afforded uric acid when heated in dilute acid and this is one of the earliest recorded preparations of this compound (l889LA(25i)235>. Af-Methyl and N,N-dimethylureas similarly gave low (10%) yields of 7-methyl- and 7,9-dimethyl-uric acid, respectively (25LA(44l)203). 

The application of pyrimidine-4,5-diols in Traube synthesis is less common. Isodialuric acid and urea can be condensed in sulfuric acid to form uric acid... 

The tautomeric properties of isodialuric acid (6-hydroxy-2,4,5-trioxopyrimidine) were characterized by the ab initio calculations based on 6-311G full geometry optimization (99JST(459)1). Of 10 possible tautomers, the trioxo form was found to be the most stable. The higher stability of 2-oxo-4-hydroxy tautomers compared to 2-hydroxy-4-oxo tautomers has also been predicted. 

Zastawny TH, Doetsch PW, Dizdaroglu M. A novel activity of E. coli uracU DNA V-glycosylase excision of isodialuric acid (5,6-dihydroxyuradl), a major product of oxidative DNA damage, from DNA. FEBS Lett 1995 364 255-258. 

Decomp, on heating. Reduces AgNOg in cold. Br —>- isodialuric acid. 

Isocytosine, 374 Isodialuric acid, 377 Isonieotinic acid, 333 Isoquinoline hydroxy-, 352, 355, 384 1-hydro xy-2- 2,4-dinitrophenyl) -1,2-dihydro, 179... 

Azopyrimidines of Type 4.—Of the known 5-keto-6-hydroxy-5,6-di-hydrouracils, two have been of particular interest. These are isodialuric acid (XVIII)and 6-methylisodialuric acid (XXI). 

Concerning the action of phenylhydrazine on these derivatives, Behrend and his students found that 6-methylisodialuric add gave a phenylhydrazine salt when treated in aqueous solution with phenylhydrazine. Levene found that isodialtuic acid was converted into 5,6-di-phenyl-hydrazinouracil (XX) by the action of a hot acetic acid solution of phenylhydrazine. This result becomes tmderstandable when we recall that Behrend, Koch, and von Vogd noticed that in hot acetic acid even bases like guanidine and thiourea isomerized isodialuric acid into dialuric acid (XIX). 

By employing phenylhydrazine hydrochloride, we have been able to avoid this isomerization and to obtain a direct condensation between isodialuric acid and phenylhydrazine. The reaction proceeds further, however, with the elimination of a second molecule of water, the ultimate product being the orange-brown uracil-5-azobenzene (XXII). Below is given a hypothesis for the mechanism of this reaction ... 

Condensation of hydrazine salts with isodialuric acid types 4 and 5). To a solution of 0.01 mol of isodialuric acid in 15 cc. of water was added a solution of 0.01 mol of the hydrazine salt containing a drop of hydrochloric acid. The mixture turned orange at once and a precipitate began to form. The reaction was complete within 24 hours. The product was filtered, washed with water, and dried at 100°. 

Uracil-5sodium sulfonate, light brown needles, by salting out the reaction product of phenylhydrazine-/)-sulfonic acid on isodialuric acid, soluble in water, dyes wool orange. 

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