1885.] The Chemical Constitution of lsatin. 197 



separating ; from nitrogen-benzoyl carboxylic acid there thus results 

 amidophenyl carboxylic acid. 



Action of Water on Isatoic Acid. 



As already mentioned, isatoic acid undergoes decomposition by pro- 

 longed boiling with water, carbonic acid being evolved. The dark- 

 coloured powder which separated out on cooling, yielded, after 

 crystallisation from alcohol of 50 per cent., beautiful needles of 

 anthranilic acid (melting point 145°), from which, by solution in 

 hydrochloric acid, the characteristic compound of the latter with 

 anthranilic acid, melting at 191°, was obtained. 



Behaviour of Isatoic Acid toiuards Mineral Acids. 



If isatoic acid be gently warmed with ordinary strong hydrochloric 

 acid, decomposition with foaming (evolution of carbonic acid) ensues ; 

 the crystalline mass obtained on evaporation is again dissolved in 

 hydrochloric acid, in order to destroy all the isatoic acid. The residue, 

 after solution in water, yields, on cooling, colourless prisms of the 

 hydrochloric-anthranilic acid, containing one molecule of water. 



0*392 gram of the compound dried in an exsiccator over sulphuric 

 acid, gave 0*630 gram C0 2 , and 0*188 gram H 2 0=43*9 per cent. C, and 

 5'3 per cent. H. 



1*152 gram of the same compound, precipitated by nitrate of silver, 

 &c, gave 0*863 gram AgCl, corresponding to 18*5 per cent. CI. 



Calculated for 

 C 6 H 4 NH 2 ,COOH.HCl + H 2 0: 



i * \ 



C 7 84 43'9 



H 10 10 5-2 



N 14 — 



3 48 - 



CI 35-5 18*5 



From this hydrochloric acid compound anthranilic acid itself was 

 precipitated in the usual way by the addition of ammonia and then 

 of glacial acetic acid. From the hot aqueous solution, which has 

 been treated with animal charcoal, it crystallised in colourless prisms 

 an inch long, which, according to the analysis, had the proper com- 

 position, and were also recognised as o-amidobenzoic acid through its 

 transformation, by means of nitrous acid, into salicylic acid. 



0*3475 gram gave 0*159 gram H 3 0, and 0*780 gram 000=5*1 per 

 cent. H, and 61*2 per cent. C. 



Found. 



43 *9 

 5-3 



18 -5 



