DERIVATIVES OF URIC ACID. 245 



( N(CH S ).CH? 

 Methylhydantoine, C 4 H 6 ]S T2 2 = CO { ^ ^ 



is produced by prolonged heating of creatinine (p. 249) 

 with baryta water to 100. Colorless crystals, easily 

 soluble in water and alcohol. Fuses at 145, and when 

 carefully heated sublimes at 145 in small lustrous 

 crystalline flakes. When boiled with silver or mercury 

 oxides, it yields salts. 



Ethylhydantoine, C 3 IP(C 2 H 5 )^ 2 2 , is formed by 

 heating ethylglycocol (p. 86) with urea to 120-125. 

 Large, colorless rhombic prisms, appearing of a plate 

 form, easily soluble in water and alcohol, in ether more 

 difficultly soluble. Fuses below 100. 



Hydantoic acid (Glycoluric acid), C 3 II 6 ]S T2 3 



C0 | Nil 2 CO OH is formcd b y ^oi\ing allantoine, hy- 

 dantoine or glycolurile with barium hydroxide ; and by 

 heating glycocol with urea. Large rhombic prisms, 

 easily soluble in hot water, rather difficultly soluble in 

 cold water. Monobasic acid. The barium salt is pre 

 cipitated from an aqueous solution by means of alcohol, 

 as an amorphous, flocky, or syrupy mass. It is soluble 

 in water in all proportions, and does not crystallize. 

 Heated with concentrated hydriodic acid, hydantoic 

 acid is resolved into glycocol, ammonia, and carbonic 

 anhydride. It bears the same relation to hydantoine 

 as alloxanic acid to alloxan, and oxaluric acid to para- 

 banic acid. 



Allanturic acid (Glyoxylurea ?), C 3 H 4 N 2 3 . Is pro 

 duced at first, together with urea, by boiling allantoine 

 with baryta water, and by treating allantoine with lead 

 peroxide or nitric acid. Non-crystalline, deliquescent 

 acid. But slightly known. Is resolved, by further 

 action of baryta water, into hydantoic and parabanic 

 acids, and the latter acid (oxalylurea) is immediately 

 decomposed, forming oxalic acid, carbonic anhydride, 

 and ammonia. Hence hydantoic acid, oxalic acid, car- 



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