( fiOfi ) 



principally ; but even with the amide of dimethyl malonic acid and 

 formaldehyde we have not arrived at the desired result. Methylene- 

 malonamide is of importance for this reason, that the CH 2 -group of 

 malonic acid might give a nitroderivative, whilst this may be equally 

 expected from the two NH-sroups. 



CH 2 — NH— CH 2 



A sixth isomer is the already quoted of which one 



CO — NH- CO 

 iminodiaceticimide 

 might expect that it should yield with nitric acid only a nitrate, 

 but not a nitro-derivative. 



On heating the diamide of iminodiacetic acid in vacuo, Mr. Jongkees 

 obtained a substance which sublimes and has the composition of 

 the imide. This, however, does not behave as was expected, but 

 when evaporated with nitric acid, seems to give a nitro-derivative, 

 whose properties are, however, somewhat different from the usual 

 ones of nitramines or nitramides. 



The last isomer of some signilicance for the problem under con- 

 sideration, for the preparation of which no experiments have, as yet, 



CO— NH — CH 2 

 been made, w r ould be | , in which one NH-group between 



CO— CH 2 — NH 

 CO and CH 3 renders probable a nitro-compound, whereas the second, 

 placed between tw r o CH 2 , could only yield a nitrate. 



The other four are derivatives of hydrazine, and are of no importance 

 for our problem, because the two NH-groups contained therein are 



CH— CO— NH 

 in a state of combination. One of those has been pre- 



CH 2 — CO— NH 

 pared by Dr. Friedmann and, when it was brought in contact with 

 nitric acid a violent evolution of red vapours was noticed, evidently 

 caused by oxidation. 



The details of these researches which of course, are being continued 

 will appear in the "Recueil des Travaux chimiques des Pays-Bas." 



But it is evident that the second rule will have to be altered, 

 namely in that sense that the direct nitration (if any) of the hetero- 

 cyclic compounds, which contain NH placed between CO and C^,, 

 depends also on the manner in which the groups, between which 

 the group NH is placed, are combined ; therefore it is the same as 

 has been noticed with acyclic compounds. In how far the cycle itself 

 plays a role has not yet been satisfactorily made out but we may 

 point, provisionally, to one peculiarity, namely, that the three com- 

 pounds which do not seem to conform to the previously established 

 rule contain the NH-gronps in the para position in regard to each other. 



