Alloxan 5-hydrazones

S-Alkylthiosulfates s. S-Carb-amylmethylthiosulfates Allenes, diene synthesis with — 16, 733 Alloxan 5-hydrazones 16, 460... 

Hydrazine pyrosulfite in water added to alloxan monohydrate in water, and the resulting soln. warmed on a water bath alloxan-5-hydrazone (Y 93-95%) added slowly to a cooled mixture of 2 N NaOH and 30%-H2O2, then acidified with a few drops of coned. HCl 5-diazobarbituric acid (Y 86-88%). F. e. s. 

Hydrogen peroxide sodium hydroxide 5-Diazobarbituric acids from alloxan 5-hydrazones... 

Alloxan forms an oxime (1007) which is the same compound, violuric acid, as that formed by nitrosation of barbituric acid likewise, a hydrazone and semicarbazone. Reduction of alloxan gives first alloxantin, usually formulated as (1008), and then dialuric acid (1004 R = OH) the steps are reversible on oxidation. Vigorous oxidation with nitric acid and alkaline hydrolysis both give imidazole derivatives (parabanic acid and alloxanic acid, respectively) and thence aliphatic products. Alloxan and o-phenylenediamine give the benzopteridine, alloxazine (1009) (61MI21300). 

Uracil-5-azoisobarhiluric acid alloxan-6- uracil-5-)hydrazone), chocolate-brown powder, insoluble in water and organic solvents, soluble in alkalies to form a deep red solution which soon fades. It does not melt below 300 . 

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