286 PROCEEDINGS OF THE AMERICAN ACADEMY 



the halogen derivatives of these two acids which we had at our dis- 

 posal showed precisely the same difference in behavior. The removal 

 of the sulpho group from the chlorsulphopyromucic acid in question 

 may therefore be taken as evidence that the sulpho group is in the 

 8 position. 



Action of Bromine. 



Like all the derivatives of S-sulphopyromucic acid which have thus 

 far been examined, /3-chlor-8-sulphopyromucic acid is at once oxidized 

 by bromine in aqueous solution, and sulphuric acid is formed. Bromine 

 was added in slight excess to a solution of the barium salt of the 

 acid, the baric sulphate removed by filtration, and the acid filtrate 

 extracted with ether. The acid thus obtained was very readily solu- 

 ble in water and practically insoluble in benzol. After recrystalliza- 

 tion from water it was dried and washed with benzol. The acid thus 

 purified melted at 188°, and with the quantity at our command we 

 found it impossible to raise this melting point. Although chlorfumaric 

 acid melts at 191°,* there can be no doubt that chlorfumaric acid had 

 been found in the reaction. 



Actio7i of Nitric Acid. 



Like the brom-8-sulphopyromucic acids, the /8-chlor-8-sulphopyro- 

 mucic acid is readily converted into the corresponding nitro-acid by 

 the action of fuming nitric acid. For its preparation we dissolved 

 the dry sulphonic acid in cold fuming nitric acid, warmed the solution 

 for some time upon the water bath, and finally evaporated the nitric 

 acid at a gentle heat. The crystalline product thus obtained was re- 

 crystallized first from water, then from benzol, and finally from water. 

 The /J-chlor-S-nitropyromucic acid is readily soluble in hot water, 

 sparingly soluble in cold water, and crystallizes in thick clustered nee- 

 dles. By the slow cooling of the hot solution, or by spontaneous evap- 

 oration of the solution, well formed monoclinic (?) prisms with bevelled 

 ends are obtained. The crystallized acid contains one molecule of 

 water, part of which at least it loses over sulphuric acid, and the 

 whole of which may be driven off at 75°. The anhydrous acid melts 

 at 140-141°. 



1.4274 grm. air-dried substance lost at 75° 0.1281 grm. HgO. 



Calculated for C5H,C1N05 . Ufl Found. 



H.O 8.59 8.97 



* Kauder, Journal fur prakt. Chemie, [2.] xxxi. 28. 



