200 PROCEEDINGS OP THE AMERICAN ACADEMY 



and extracted with ether. The ether left on evaporation a white 

 crystalline acid, which softened somewhat at 120° and melted com- 

 pletely at 165°. After two recrystallizations from water the acid 

 melted sharply at 176-177°, and was therefore monobromfumaric acid. 

 The oxidation took place according to the following equation: — 



C.H 3 BrS0 6 + 3 Br 2 + 4 H 2 = C 4 H 3 Br0 4 + C0 2 + H 2 S0 4 + 6 HBr. 



Action of Nitric Acid. 



We have made no experiments concerning the action of dilute nitric 

 acid upon /3-brom-S-sulphopyromucic acid, since it could safely be as- 

 sumed that oxidation would ensue as with the 8-sulphopyromucic acid, 

 and that monobromfumaric acid would be formed. It seemed to us, 

 however, of decided interest to act upon the acid with fuming nitric 

 acid, since a bromnitropyromucic acid should then result. Dry /3- 

 brom-S-sulphopyromucic acid was slowly added to three times its 

 weight of fuming nitric acid. The reaction progressed slowly in the 

 cold, more rapidly on warming, and without any considerable oxida- 

 tion. After the reaction was completed, the greater part of the nitric 

 acid was expelled by gentle heat, the crystalline acid left was dissolved 

 in a dilute solution of sodic carbonate, and the alkaline solution then 

 extracted with ether. Upon evaporation of the ether a small quan- 

 tity of a neutral oil was left, which gradually solidified. The quantity 

 of the product which we thus obtained was so minute that further in- 

 vestigation was out of the question. The alkaline solution when acidi- 

 fied and again extracted with ether yielded in abundance a crystalline 

 acid which proved to be /3-brom-S-nitropyromucic acid. It was readily 

 soluble in alcohol, ether, or hot benzol, more sparingly in cold benzol. 

 It dissolved freely in hot water, and as the solution cooled it was de- 

 posited in long clustered flattened needles, which contained one mole- 

 cule of water. The anhydrous acid melted at 159-160°. At 100° 

 the acid appeared to sublime slowly. 



I. 1.2492 grm. of the acid crystallized from water lost, at 60°, 



0.0911 grm. H 2 0* 

 II. 0.9980 grm. of the acid crystallized from water lost, at 78°, 

 0.0740 grm. H 2 0. 



Calculated for Found. 



C 5 H 2 Br(N0 2 )0 3 . H 2 0. I. II. 



H 2 7.09 7.29 7.42 



* A slight mechanical loss renders the result of this determination uncertain 

 in the second decimal place. 



