Uric Add, and their derivatives. 193 



hydantoiue is neutral, and allanturic acid a mono-basic acid, 

 while barbituric and dialuric acids are di-basic and mono-basic 

 respectively. The formulae proposed in this paper furnish an 

 explanation of the difference. 



Any formula I have seen for bromo-barbituric acid, C4H3 

 BrNg O3, would lead one to expect for it exactly the same degree 

 of basicity as that of barbituric acid. But the following (No. 

 1) with the urea residue oppositely attached) will show how 

 the former acid is mono-basic, while the latter is di-basic. 



1. Bromo-barbituric 2. Brom-alloxan or di-bromo- 3. Tri-brom-acetyl- 



acid (mono-basic), barbituric acid (non-acid). urea (neutral). 



c-c-d 



Br 



I-O-C 



C—C— 6 Br— G—b 



Br Br 



A further replacement of hydrogen by bromine gives us 

 what has been called di-bromo-barbituric acid, C^HaBr^NaOa, 

 a body which is, however, really devoid of acid character, not 

 forming salts. With the formula now proposed (No. 2, above), 

 this non-acid character becomes intelligible, and the name 

 brom-alloxan, originally employed by Baeyer, becomes fully 

 justified on comparison with alloxan as represented further on. 

 The conversion of this body into dialuric acid by the action of 

 hydro-sulphuric acid in the presence of water is explained by 

 the formula for dialuric acid given further on. 



On pushing the action of bromine still further, brom-alloxan 

 is converted, with separation of carbon dioxide, into tri-brom- 

 acetyl-urea, CjHgBrgNgOa (^o"^ ^^^ 2-carbon acid residue), 

 the formula of which (No. 3, above) is very simply derived 

 from No. 2, and brings us back to that of acetyl-urea as 

 already given. 



From mesoxalic acid, CjH^O, (No. 1), we get the acid mon- 

 ureide dialuric acid, C^H.N/O, (No. 2), 



1. Mesoxalic acid (di-basic). 2. Dialuric acid (mono-basic). 



C— C-0 O N 



HA 



