1872.] 



Derivatives of Uramidobenzoic Acid. 



177 



Decomposition of the Isomeric Diamidohenzoic Acids at a high 

 temperature. 



When either of the diamidohenzoic acids is submitted to dry distillation 

 in a retort, it splits up into carbonic acid, which is evolved, and a yellow 

 oil, which crystallizes in the neck of the retort, thus : — 



C 7 H„N 2 a = C H 8 N 2 + CO, 

 The compound C 6 H 8 N 2 , obtained in this manner from the a diamido- 

 henzoic acid, is moderately soluble in hot water, and crystallizes therefrom 

 in reddish-coloured scales, melting at 140° C. It exhibits the character of 

 a base, and forms crystalline salts with the mineral acids. It can readily 

 be seen that the composition of this base is the same as that of the pheny- 

 lene diamines described by Dr. Hofmann*, C 6 H 8 N 2 =C 6 H 4 (N H 2 ) 2 ♦ and 

 its properties leave no doubt that it is identical with one of the latter, 

 namely, that formed by the action of reducing agents on the nitraniline 

 prepared from substituted anilides. 



The compound C 6 H 8 N 2 , obtained by the dry distillation of /3 diamido- 

 henzoic acid, differs not only from the base just described, but also from 

 the phenylene diamine which Dr. Hofmann obtained by the reduction of 

 dinitrobenzol. It is easily soluble in hot water, and crystallizes therefrom 

 in white rectangular four-sided tables or plates, which usually have a 

 reddish tinge. It melts at 99° C, and boils at about 252° C. It is like- 

 wise possessed of basic properties, and must be regarded as a new isomeric 

 modification of phenylene diamine. The sulphate of this base crystallizes 

 in pearly scales, the composition of which corresponds to the formula 

 C 6 H 4 (N H 2 ),, SH 2 4 + l^H, O, and which readily part with their water 

 of crystallization at a temperature a little above 100° C. Its platinum-salt 

 is precipitated in the form of brownish-red needles. When ferric chloride 

 is added to a solution of this base in hydrochloric acid, ruby-red needles 

 immediately form, consisting of the hydrochloride of a new base. In a 

 free state the latter forms bright yellow microscopic needles, which are 

 almost insoluble in all neutral solvents. I have reason to believe that 

 it has the formula C 12 H 10 N 4 , and that its method of formation is as 

 follows : — 



2(C 6 H 8 N 2 ) + 3 = C 12 H 10 N 4 + 3H 2 0. 



ISew phenylene New base. Water, 



diamine. 



As one or other of the phenylene diamines just mentioned is obtained 

 when the a or (3 diamidohenzoic acid is submitted to dry distillation, I 

 fully expected that the y diamidohenzoic acid, under the same circum- 

 stances, would give rise to a third phenylene diamine, and that this would 

 be identical with that derived from dinitrobenzol. Strange to say, this is 

 not the case, the phenylene diamine obtained by the dry distillation of y 



* Proc. Koy. Soc. vol. xii. p. G39. 



