202 



Professor Kolbe. 



[Mar. 12, 



Addition of water to the solution of the acid in alcohol, or in the 

 mixture of alcohol and acetone, precipitates it. 



The chemical behaviour* of nitro-isatoic acid corresponds generally 

 with that of isatoic acid, the former being however more stable towards 

 water, acids, &c, than the latter. Just as isatoic acid yields with those 

 reagents anthranilic acid, so does the nitro- derivative give a nitro- 

 anthranilic acid, which corresponds with one of the two known com- 

 pounds of this composition, and therefore explains the function of the 

 nitroxyl in the original nitro-isatoic acid. 



If the latter be evaporated along with aqueous hydrochloric acid, 

 carbonic acid is evolved ; the residue (which contains no hydrochloric 

 acid in chemical combination) yields, upon recrystallisation from 

 alcohol, a strong acid which forms yellow needles, is difficultly soluble 

 in water, easily in alcohol and ether, and not at all in chloroform and 

 benzol ; it melts between 265° and 270° with decomposition. 



The same acid is formed, although more slowly, by the continued 

 boiling of a mixture of water and nitro-isatoic acid. As is shown by 

 the properties of the product — as given above — but especially by the 

 composition of the baryta salt prepared from it (see the analysis of 

 the same below), we have here to do with the nitro- anthranilic acid 

 already obtained in a different way by Hiibnerf and by Griess,"f the 

 so-called m-nitro-o-amidobenzoic acid or (e-nitro-amidobenzoic acid). 



The barium salt prepared from the above by means of baryta 

 water, precipitation of the excess of barium by carbonic acid, and 

 evaporation of the filtrate, crystallises in sharp reddish-yellow needles. 

 According to the analysis, it is nitro-amidobenzoate of barium + 3 mol. 

 water of crystallisation. 



I. 0*2025 gram of the air-dried substance lost at 110° 0*020 gram 

 H 2 = 9 87 per cent. H 3 0. 



II. 0*165 of the same substance lost at 110° 0*015 gram H 2 0=9*~ 

 per cent. 



III. 0*1825 gram of the dehydrated substance gave 0*0854 gram 

 BaSO 4 =0*0502 gram Ba=27*50 per cent. Ba. 



Calculated for |c 6 Nb,lcoiooBa-|-3HoO : H = 9*76 per cent. 



\ nh;j / - 



The anhydrous salt contains Ba= 27*45 per cent. 

 If nitro-isatoic acid be suspended in a small quantity of warm 

 water, and ammonia added, it is quickly dissolved. The solution soli- 



* The chemical behaviour of nitro-isatoic acid towards water, hydrochloric acid, 

 and ammonia, and also towards reducing agents, has been investigated by Dr. Bell- 

 mann since the death of the author. 4 



f " Liebig's Ann. Chem.," Bd. 195, 21. 



X " Ber. Berl. Chem. aes.," Bd. 11, 1730. 



