DERIVATIVES OF URIC ACID. 237 



soluble in concentrated sulphuric acid without decom- 

 position; is reprecipitated by water; is resolved, by 

 boiling with water, into oxalic acid, urea, and am- 

 monia. 



If methylamine, ethylamine, or analogous bases are 

 employed instead of ammonia in the preparation of 

 oxaluramide, crystalline precipitates, similar to oxalu- 

 ramide, consisting of methyl- or ethyl-oxaluramide, are 

 formed. 



Oxalantine, C 6 HW 4 5 + H 2 0. Parabanic acid, in 

 contact with zinc and hydrochloric acid, yields a 

 crystalline powder, containing zinc, which dissolves 

 with great difficulty in boiling water. If water is 

 added to it, and it is then treated with sulphuretted 

 hydrogen, zinc sulphide is precipitated, and the aqueous 

 solution contains oxalantine, which it deposits in crys- 

 tals on being evaporated. It is produced, together 

 with other substances, by boiling a concentrated solu- 

 tion of alloxanic acid. White, crystalline crusts, diffi- 

 cultly soluble in water, is not decomposed by hot con- 

 centrated nitric acid ; but it reduces the metals from 

 silver or mercury salts after an addition of ammonia. 



Alloxantine, C 8 H 4 N 4 7 + 3H 2 0. Is produced by 

 spontaneous decomposition of alloxan, when left to 

 itself; by the action of dilute nitric acid on uric acid ; 

 or of reducing agents on alloxan. It is prepared most 

 readily by dissolving uric acid in warm dilute nitric 

 acid (1 part nitric acid of specific gravity 1.42 and 

 8-10 parts of water of 60-70), and adding carefully 

 a solution of tin chloride, containing concentrated 

 hydrochloric acid. It is obtained from alloxan by 

 conducting concentrated hydrogen into the aqueous 

 solution of the latter. It is hereby thrown down 

 mixed with sulphur, from which it may be separated 

 by dissolving in boiling water. Small, colorless, hard 

 prisms; becomes red and purple in an ammoniacal 

 atmosphere ; is very difficultly soluble in cold water, 

 easily in hot. The solution gives, with baryta water, 

 a beautiful violet precipitate, which, when heated, 



