204 



Professor Kolbe. 



[Mar. 12, 



parent prisms, and has, after drying over sulphuric acid, the composi- 

 tion given above. 



0"163 gram substance gave on precipitation with chloride of barium 

 0*153 gram BaS0 4 , corresponding to 32*2 per cent. S0 3 ; calculated 

 32-00 per cent. 



0-324 gram of the salt gave 316 c.c. N at 13° and 735 mm. 

 pressure= 11-13 per cent. N"; calculated 11*20 per cent. N". 



Attempts to isolate the free diamidobenzoic acid from the above 

 salts were unsuccessful ; the solutions of the latter became, on addition 

 of ammonia, of a deep indigo-blue colour. We have here in all 

 probability before us, in the above compounds, salts of the a-diamido- 

 benzoic acid described by Griess,* whose sulphuric acid compound 

 crystallises free of water, and which is also obtained direct from the 

 above described e-nitro-amidobenzoic acid by reduction. 



Action of Nitrous Acid on Isatoic Acid. 



Into water containing finely-powdered isatoic acid in suspension, and 

 kept at about 70°, nitrous acid was led ; carbonic acid and nitrogen 

 were evolved with foaming. From the hot filtered solution long felt- 

 like needles separated out on cooling, and these, at first yellowish, 

 were finally obtained colourless by several recrystallisations from hot 

 water to which animal charcoal had been added. This compound, a 

 strong acid, is almost insoluble in cold water, tolerably soluble in hot, 

 and very readily in alcohol, ether, and chloroform ; it melts at 228°, 

 and can be sublimed if cautiously heated. Its water solution is 

 coloured blood-red by addition of chloride of iron. According to 

 analysis, it has the composition C 7 H 5 N"0 5 . 



0-1804 gram substance gave 0-3037 gram C0 2 (0-0828 gram C), and 

 0-0491 gram H 2 (0-0055 gram H). 



0-1894 gram substance gave at 13° and 753 mm. pressure, 12*3 c.c. 

 1ST=0-0144 gram N". 



Found. 



45 -91 p. c. 



3'02 „ 



7-60 „ 





Calculated. 





c 7 ... 



, 84 



45 -90 



H 3 . 



... 5 



2-73 



N 



14 



7 -65 



5 ... 



80 



43 -72 





183 



100 -oo 



The melting point and other properties of the compound leave no 

 doubt that it is the carefully investigated «-nitrosalicylic acid of 

 Hiibner— C 6 H 3 (N0 2 )(OH)COOH. Its ethyl ether, prepared by 

 means of hydrochloric acid and alcohol, crystallises in long colourless 

 needles which melt at 95° and, according to the analysis, have the 

 * Journ. fur Prakt. Cliem," [2] 5, 237. 



