174 



Mr. P. Griess on some 



[Feb. 15, 



cultly so in hot ; they dissolve readily in hot alcohol, but scarcely at all 

 in ether. The barium salt forms yellowish- red needles, which are very 

 readily soluble in water even in the cold. Dried between filter-paper they 

 were found to have the composition (C 7 H. N 2 4 ) 2 , Ba + 3H 2 0. 



(j nitroamidobenzoic acid is the name by which I have designated the 

 acid obtained from /3 dinitrouramidobenzoic acid by the above-mentioned 

 reaction. It is only very slightly soluble in hot water, but rather easily 

 so in boiling alcohol, from which it crystallizes on cooling in clusters of 

 yellowish-red glistening needles or small plates. The dry acid, when gently 

 heated, sublimes in shining rhombic plates without previously melting. Its 

 barium salt forms bright yellowish-red prisms, often well defined, which are 

 slightly soluble even in boiling water. Dried between filter-paper they 

 have the composition (C 7 H 5 N 2 4 ) 2 , Ba + 2H 2 0, the water of crystalliza- 

 tion not being entirely expelled below 190° C. 



The y nitroamidobenzoic acid obtained from the y dinitrouramidoben- 

 zoic acid, by boiling its aqueous solution, is easily distinguished from its 

 two before-mentioned isomerides, in being very readily soluble not only 

 in hot water, but also in alcohol and ether, even in the cold. It crystal- 

 lizes in yellow prisms, which melt, when heated, to a brownish oil ; at a 

 higher temperature it decomposes with slight explosion and evolution of 

 yellowish vapours. Its barium salt forms reddish-yellow needles, which 

 are very easily soluble even in cold water, and when dried between folds 

 of bibulous paper have the composition (C 7 H 5 N 2 4 ) 2 , Ba-r-7H 2 0. 



Action of Tin and Hydrochloric Acid on the Isomeric Nitroamido- 

 benzoic Acids. 



If the isomeric nitroamidobenzoic acids are gently warmed with tin and 

 hydrochloric acid, they are reduced to the corresponding diamido-acids in 

 the following manner : — 



C 7 H 4 (N0 2 )(NH 2 )0 2 + H 6 = C 7 H 4 (NH 2 ) 2 2 + 2H 2 0. 



V ¥ — - N , " 



) nitroamidobenzoic %' \ diamidobenzoic 



| acids. I acids. 



These diamido-acids are separated from the tin chloride, formed at the 

 same time, by the ordinary methods. 



a diamidobenzoic acid, C 7 H 4 (NH 2 ) 2 2 , crystallizes from its solution 

 in boiling water, in which it is sparingly soluble, in minute but well-de- 

 fined short prisms, which have a greyish tinge. It is remarkable for the 

 extremely sparing solubility of its sulphate, 7 H 8 N 2 2 , SH 2 4 , a com- 

 pound crystallizing in white needles. 



{3 diamidobenzoic acid crystallizes in pale yellow-coloured plates, which 

 are very difficultly soluble in cold water, but rather readily so when it is 

 hot. Its sulphate has the formula [C 7 H 4 (NH 2 ) 2 OJ 2 , SH 2 4 , and is 

 very sparingly soluble in hot water, although not so much so as the cor- 



