Oxaluric acid

Ethyladenine - parabanic acid - oxaluric acid monohyd-476... 

Ursaure, /. a urelde of acid character, as barbi turic or oxaluric acid, a -uric acid. 

Oxalur ic acid, ABL9 Oxalylurea, AB29 Oxine, A08l... 

Sp is also a major (final) product in the oxidation of dGuo by triplet states (Luo et al. 2001a Adam et al. 2002a,b for an earlier study see Adam et al. 1996). Further reported oxidation products of 8-oxo-G are oxaluric acid (by 02( Ag) Duarte et al. 2000), cyanuric acid, iminoallantoin, parabanic acid and 1,3,5-triazepane-2,4,6,7-tetrone (Hickerson et al. 1999). Oxaluric and parabanic acids may also be formed upon the reaction of the 8-oxo-G radical with 02- (Misiaszek et al. 2005 Chap. 12.3). 

The unstable dication (261) is hydrolyzed and some products are oxidized further. From the electrolyzed solution, urea, parabanic acid (262), oxaluric acid (263), ammonia, 4-aminopurpuric acid (264), and possibly allantoin (265) were isolated. 

The isolation of allantoin (7), after lead peroxide oxidation of uric acid was followed by the recognition of other oxidation products, the main product of which are oxonic acid (8), allantoxaidine (9) and oxaluric acid (HjNOCHNCOCOjH). Their structures have been clarified by comprehensive studies using isotopically labeled compounds. ... 

Figure 4.8 Formation of oxaluric acid lesions via the combination reaction of 8-oxo-G(-H) with Or radicals.

The combination of 0 with 8-oxo-G(-H)" radicals in double- and single-stranded DNA occurs with the rate constant of (1.0-1.3) x 108M 1s 1 [30]. The major end products of this reaction are the dehydroguanidinohydantoin lesions (Gh x) derived from the addition of 0 to the C5 position of 8-oxo-G(-H) , followed by the decomposition of the 5-HOO-8-oxo-G(-H) hydroperoxide (Figure 4.8). The Ghox lesions are unstable and slowly hydrolyze to oxaluric acid. 

It is a white, sparingly soluble powder, which is converted into urea and oxalic acid when boiled with water or alkalies. Its ammonium salt crystallizes in white, glistening, sparingly soluble needles. Its ready conversion into urea and oxalic acid and its formation from oxalylurea, itself a product of oxidation of uric acid, render it probable that oxaluric acid is one of the many intermediate products of the oxidation of the nitrogenous constituents of the body. 

The acid formed is called oxaluric acid. It resembles oxamic acid in structure,—... 

Fig. 32. Characterization of the dehydro-guanidinohydantoin derivative by its hydrolysis into an oxaluric acid derivative or its reduction into a mixture of two diastereoisomers of a guanidinohydantoin derivative on a dinucleotide. Numbering of carbon atoms corresponds to that of guanine.

These (except those for guanine and adenine) are the same as the formulae proposed by Medicus (see p. 778), Fischer s colleague in Wurzburg. Fischer synthesised theobromine, and in 1898 purine, the basic substance of the whole series.2 Parabanic, oxaluric, and barbituric acids were synthesised by Pono-mareff and by Grimaux. Important syntheses in the group were also carried out by Wilhelm Traube, assistant professor in Berlin. ... 

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