Alloxane hydrate

The reaction of alloxane hydrate (342) and 46a,c gives 100% yield of the products 343a,c upon milling at room temperature [104]. The solid-state reaction of 2-oxoglutaric acid (344) and 46a similarly gives a quantitative yield of the quinoxalinone 345 in the solid state upon heating of coground mixtures for 30 min to 120-125 °C [104]. 

Oxidation of 5-substituted barbimric acids 258 with concomitant ring contraction has been shown to afford 2,4-oxazolidinediones 260 (Scheme 6.58). Similarly, examples of 5-aryl- and 5-heteroaryl-2,4-oxazolidinediones, for example, 231 and 233-240 (Table 6.8 and Fig. 6.19) have been prepared from alloxan hydrate 261. Thus, conversion of 261 to the dilauric acid intermediates 262 and reaction with sodium hydroxide gave the target compounds.Swiss chemists isolated 265 as a side product (12% yield) from the oxidation of the thymidine base in 263 during their preparation of 264 (Scheme 6.58). 

Crystalline o-plienylendiamine la (108 mg, 1.00 mmol) and alloxane hydrate 2 (160 mg, 1.00 mmol) were ball-milled at room temperature for 1 h to give 232 mg (100%) of pure 3a. 

The ene reaction has also been used alloxan hydrate and terminally unsaturated 1-octadecene (2) as illustrated in Eq. 2 ... 

When the ene synthesis was performed using alloxan hydrate with internally unsaturated l-hydroxyl-9-octadecene (3) two products were isolated as illustrated in Eq. 3 ... 

Uric acid, a purine derivative found mainly in the excrement of snakes and birds, has the molecular formula CsHnNiiOa- On nitric acid oxidation it breaks down to urea and a hydrated compound called alloxan of formula CijRaNaOit HaO. Alloxan is readily obtained by oxidation of barbituric acid. What is the probable structure of alloxan and uric acid Why is alloxan hydrated ... 

Alloxan (233)235 gives in acid solution a kinetically controlled polarographic wave the rate-controlling process involved may be the dehydration of the hydrated carbonyl at C-5. The reduction product, dialuric acid (234), can be anodic reoxidized to alloxan or, between pH 4.6 and 6.6, reduced further, probably to barbituric acid (235). 

SYNS ALLOXAN MONOHYDRATE DMESOXALYU CARBAMIDE MONOHYDRATE 2,4,5,6(1H,3H)-PYRIMI-DINETETRONE HYDRATE 2,4,5,6-TETRAOXOHEXA-HYDROPYRIMIDINE HYDRATE... 

An efficient one-pot synthesis of 3-(2-oxo)-chromen-3-yl)-6//-8//-pyiimido[4,5-cjpyridazine 5,7-diones 101 by reaction of 3-acetylcoumarins 99 with alloxan monohydrate 100 in acetic acid followed by hydrazine hydrate has been reported <05JHC1223>. 

We are told that oxidation of barbituric acid yields alloxan, which is the hydrated form of the tetraketone, CitHuNaOi,. By comparing the molecular formulas of barbituric acid and the tetraketone, we see that two hydrogens have been lost, and one oxygen added. Oxidation must therefore have occurred at the methylene carbon, forming the ketone, as shown below ... 

Synonyms Alloxane monohydrate Mesoxalylcarbamide monohydrate Mesoxalylurea monohydrate 5-Oxobarblturic acid monohydrate Pyrimidinetetrone hydrate 2,4,5,6(1 H,3H)-Pyrimidinetetrone hydrate 2,4,5,6-Tetraoxohexahydropyrimldlne hydrate Empirical C4H2N2O4 H2O Properties Wh. gran, solid turns pink on exposure to air sol. in water, DMSO sol. 5-10 mg/ml in 95% ethanol, acetone m.w. 160.09 m.p. 240 C (dec.) b.p. subl. (vacuum)... 

H,3H)-Pyrimidinedione, 5-chloro-3-(1,1-dimethylethyl)-6-methyl-. See Terbacil 5-Pyrimidinemethanol, a-(2-chlorophenyl)-a-(4-chlorophenyl)-. See Fenarimol Pyrimidine phosphate. See Pirimiphos-methyl, Pyrimidinetetrone hydrate 2,4,5,6(1H,3H)-Pyrimidinetetrone hydrate. See Alloxan monohydrate... 

Tetraoxohexahydropyrimidine hydrate. See Alloxan monohydrate Tetraphene. See 1,2-Benzanthracene Tetraphenylboron sodium. See Sodium tetraphenylboron... 

After the research of Wohler and Liebig (1838, see p. 333), uric acid and its derivatives were investigated by Schlieper. The latter showed that uric acid on reduction by hydriodic acid forms glycocoll and the decomposition products of urea (NH3 and CO2). Gerhardt formulated alloxan as the mesoxalyl, and parabanic acid as the oxalyl, derivatives of urea, which he then regarded as hydrate d oxyde de cyanammonium , giving complicated formulae, which were simplified by Kekule as ... 

The synthesis of riboflavin begins (Scheme 12.115) with the formation of barbituric acid by the condensation of diethyl malonate [(CH3CH202C)2CH2] with urea [(NH2)2C=0] in ethanolic sodium ethoxide. Then, the barbituric acid can either (a) be oxidized directly to the hydrate of alloxan or (b) first be converted to the ben-zylidine adduct and then oxidized to the same compound. Both oxidations are... 

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