2G0 PROCEEDINGS OF THE AMERICAN ACADEMY 



Monopotassic dimethylurate. 

 KC 5 H(CH 3 ) 2 N 4 3 .HH 2 0. 



Potassic carbonate, in slight excess of the theoretical amount, is 

 added to the acid suspended in boiling water. The solution is boiled 

 for some time, and the salt precipitated by adding about ten volumes of 

 alcohol. It is then filtered, washed with alcohol, and dried in vacuo 

 over sulphuric acid. The salt crystallizes in branching needles, which 

 are quite soluble in water. 



0.2540 gr. salt dried in vacuo gave 0.0278 gr. H 2 = 10.94% 



Calculated for KC 5 H(CH 3 ) 2 N 4 3 . 1£ H 2 . " . 10.35% 



0.218O gr. anhydrous salt gave 0.0702 gr. KC1 . K = 1 6.88% 



Calculated for KC 5 H(CIL) 2 N 4 3 16.70% 



Dlsodic dimethylurate. 



Na 2 C 6 (CH 3 ) 2 N 4 O s . 4^ H 2 0. 



This salt is precipitated from a sodic hydrate solution of the acid 

 by alcohol in the same way as the dipotassic salt. It crystallizes in 

 needles much larger than those of the corresponding potassic salt. 



0.3064 gr. salt dried in vacuo gave 0.0780 gr. H.,0 = 25.46% 



Calculated for Na 2 C 5 (ClL) 2 N 4 0, . 4J H 2 . " . 25.23% 



0.2234 gr. anhydrous salt gave 0.1 074 gr. NaCl . Na = 18.91 % 



Calculated for Na 2 C 5 (CH 3 ) 2 N 4 3 ..... 19.17% 



Monosodic dimethylurate. 

 NaC 5 H(CIL) L ,K 4 3 . 2 H 2 0. • 



This salt was made in the same way as the monopotassic salt. It 

 forms microscopic needles which are more soluble in water than the 

 potassic salt. 



0.5327 gr. salt dried in vacuo gave 0798 gr. H 2 = 14.98% 



Calculated for NaCT4(CH 3 ) 2 N 4 3 . 2 H 2 0. . " . 14.18% 



0.3069 gr. anhydrous salt gave 0.0638 gr. NaCl . Na = 10.1 7 % 



Calculated for NaC, I I(CII.,) 2 N 4 ;{ 10.54% 



Di baric dimethylurate. 



BaC a (CH 8 ) 2 N 4 8 . 3 II 2 0. 



Dimethyluric acid was dissolved in as little boiling water as possi- 

 ble, a solution of baric hydrate added in slight excess of the amount 



