773 



with evolution of gas, has the empirical composition of methyhiitro- 

 iirea and yet on purifying with ammonia, wc obtain only about 

 half the weight of r<,/;-metliylnitro-urea. Hence the j>resumplion that 

 the admixture consists of the isomere, c/,rif-methyliülro-urea. 



As a matter of fact, on treating this crude product with alkalis 

 or ammonia, methylnitramine is formed which I was able to show 

 by the melting point and other properlies. On decomposing with 

 baryta water a quantity of methylnitramine was obtained, pointing 

 to the presence of 40''/n a, cz-methylnitro-urea. 



The quantity of nitrous oxide formed on iieating with potassium 

 hydroxide indicated 55''/„ of rt,6-compound in the mixture. 



Summary of the results. 



1. On nitrating methylurea in sulphuric acid solution a mixture 

 is formed of the two isomeric mononitro-derivatives. 



2. On treating this mixture with cold ammonia solution, the a, a- 

 methylnitro-urea is decomposed, whilst the a, ('^-compound is converted 

 into its ammonium salt and is obtained in a pure condition by 

 addition of an acid. 



The structure of this a, 6-metliylnitro-urea is proved : 



a. by reduction: hydrazino-formic-methylamide NH.^-NH-CO-NH-CH, 



is formed, the composition of which is proved analytically (formation 



of hydrazine on heating with alkalis) and synthetically (preparation 



from N,H, and CONCH,). 



h. by the decomposition with alkalis and ammonia, which agrees 



in all respects with the formula of the a, 6-cora pound and is opposed 



to the formula of the a, cz-compound. 



3. The mixture of the isomers found in one of the nitration 

 experiments contained about 55 7o of ^he a, i-niethylnitro-urea and, 

 as appears from the decomposition with bases, fully 40 7» of the 

 a, a-compound. 



4. The essential difference in the behaviour of methylurea and 

 ethylurea towards nitration agents, as accepted up to the present, 

 is herewith annulled. 



The experimental details and the new compounds obtained in 

 this study will be described elsewhere. 



