196 PROCEEDINGS OP THE AMERICAN ACADEMY 



pyromucic acid. The same substance was formed in somewhat larger 

 quantity when we attempted to prepare nitropyromucic acid without 

 isolating the sulphonic acid by the addition of nitric acid to a solution 

 of pyromucic acid in fuming sulphuric acid. The substance dissolved 

 sparingly in boiling water, and crystallized on cooling in clustered 

 prisms which melted at 100-101°. On warming with sodic hydrate a 

 bright yellow color was developed. A filter paper moistened with its 

 alcoholic solution and exposed to the vapors of amnionic sulphide 

 turned yellow at first, then salmon-red. This behavior corresponds 

 closely with that observed by V. Meyer* and Otto Stadler in the case 

 of nitro derivatives of thiophen. Although from lack of material we 

 have as yet made no analyses of this substance, we shall describe later 

 a dibromdinitrofurfuran,f which was obtained under similar conditions 

 from the /3y-dibrom-8-sulphopyromucic acid, whose formation leaves 

 no doubt that this substance is in fact aa-dinitrofurfuran. It will be 

 further studied in the future in this Laboratory. 



Fusing potassic hydrate converts the 8-sulphopyromucic acid into 

 succinic acid, and at the same time more or less oxalic acid is formed. 

 Although we have also made certain experiments concerning the action 

 of fusing sodic formiate, we have as yet reached no satisfactory con- 

 clusion, and must therefore postpone all consideration of our results 

 until we have made further investigations. 



o 



/3-Brom-S-Sulphopyromucic Acid. 



Although we have not succeeded in preparing substitution products 

 directly from S-sulphopyromucic acid, they may readily be made by 

 the action of fuming sulphuric acid upon substituted pyromucic acids. 

 If 0-brompyrornucic acid is dissolved in three times its weight of fum- 

 ing sulphuric acid (Sp. Gr. 1.95), no carbonization takes place at or- 

 dinary temperatures, and from the diluted solution may be isolated by 

 neutralization with baric carbonate the barium salt of /?-brom-3-sul- 

 phopyromucic acid. The free acid is extremely soluble even in cold 

 water, and crystallizes in radiating needles which deliquesce rapidly 

 in moist air. 



Baric ft-Brom-8-Sulphopyromucate, BaC 5 HBrSO, ; . 4 H 2 0. — This 

 salt is readily soluble in hot water, more sparingly soluble in cold 

 water, and crystallizes in flat clustered prisms. It is precipitated in 

 the form of fine needles on the addition of alcohol to its aqueous solu- 



* Berichte d. deutsch. chem. Gesellsch., xvii. 2779. t Page 205. 



