187:2.] 



Derivatives of Uramidobenzoic Acid. 



169 



formation takes place in the manner indicated in the following equation : — 

 C 10 H 12 N 2 O 3 + H 2 = Cells N 2 3 + CJB^O. 



Basic compound. Water. Uramidoben- Alcohol. 



zoic acid. 



Since then I have shown * that this acid is also formed when urea and 

 amidobenzoic acid are cautiously melted together : — 



C 7 H 7 N0 2 + COH 4 N 2 = C^a^O. + NH 3 



Urea. Uramidoben- Ammonia, 



^oic acid. 



A third and more advantageous process of preparing uramidobenzoic acid, 

 that of Menschutkin f, depends on the mutual decomposition which takes 

 place when aqueous solutions of potassium cyanate and amidobenzoic-acid 

 hydrochloride are mixed : — 



C 7 H 7 N0 2 ,HC1 + CNOK = C 8 H 8 N 2 3 + KaCl. 



Amidobenzoic Potassium Uramidoben- 



acid hydro- cyanate. zoic acid, 



chloride. 



Menschutkin has described this acid under the name of oxybenzuramic 

 acid ; but I have satisfied myself that it is identical with the uramidobenzoic 

 acid obtained by the two first-mentioned processes. 



I will not here recapitulate the properties of this acid, which are described 

 in my former papers on the subject, and in that of Menschutkin, who has 

 also considered the constitution of the compound. The uramidobenzoic 

 acid is particularly remarkable for the great number of derivatives it is 

 capable of yielding, being surpassed by but few organic compounds in this 

 respect. It is my intention in this communication to describe several of 

 these derivatives. 



Action of strong Nitric Acid on Uramidobenzoic Acid. 



When uramidobenzoic acid, deprived of its water of crystallization, is 

 gradually introduced into well-cooled fuming nitric acid that has been freed 

 from nitrous acid, it is dissolved in large quantities, and without any evo- 

 lution of gas. The solution, when nearly saturated, is allowed to stand for 

 about one hour, and then poured into a large quantity of water, taking care 

 to avoid rise of temperature. By this means an abundant yellowish-white 

 crystalline precipitate is obtained, having strongly marked acid proper- 

 ties. It is soluble in alcohol, and easily so in ether, even in the cold, crys- 

 tallizing therefrom in yellowish-white needles which have the composition 

 C 8 H 6 N 4 0_. In spite of their appearance, however, they are by no means 

 homogeneous, consisting, as I have ascertained, of three different acids, all 



* Deut. Chem. Ges. Ber. 1869, p. 47. 



t Ann. Chem. und Pharm. vol. cliii. p. 83. 



o2 



