204 PROCEEDINGS OF THE AMERICAN ACADEMY 



in the aromatic series. Moreover, those hodies which contain the 

 halogen in the side-chain are extremely susceptible to double de- 

 composition, and are even decomposed by heating for a short time 

 with water. The halogen in the main ring, on the other hand, is 

 held quite as persistently as that in the corresponding derivatives 

 of pyromucic acid. The study of these bodies presented at first 

 many difficulties, the solution of which cost us so much time and 

 labor that we have been unable to carry our researches as far as we 

 had hoped. Since one of us must now relinquish the work, we 

 shall present the results we have obtained, although they are in 

 many respects incomplete. Further researches upon the subject 

 will be made in this Laboratory. We are especially sorry that we 

 have been unable to determine with precision the place in which 

 the bromine enters the furfuran ring ; while we have obtained by 

 oxidation of the brommethylpyromucic acid in question an acid 

 which is doubtless a bromacetacrylic acid, we have not yet been able 

 to establish its structure and thus make it available in determining 

 the constitution of the brommethylpyromucic acid from which it is 

 formed. There can be little doubt, however, that the bromine in 

 this case enters the /3 position, as it does with pyromucic acid it- 

 self as soon as the 8 hydrogen atom is replaced by bromine. 



/3(?)-Brommethylpyromucic Acid. 



When dry bromine acts at ordinary temperatures upon methyl- 

 pyromucic acid, hydrobromic acid is at once evolved, and brom- 

 methylpyromucic acid is formed. The reaction is most readily 

 controlled by the use of a solvent, and we have found glacial acetic 

 acid most convenient for the purpose. We have found it necessary 

 to add decidedly more than one molecule of bromine, and the best 

 results were obtained by using three atoms. The methylpyromucic 

 acid is dissolved in one and a half times its weight of glacial acetic 

 acid (99.5 per cent), and the necessary amount of bromine care- 

 fully added, taking care that the temperature does not rise above 

 17°. After standing for some time at ordinary temperatures, the 

 greater part of the hydrobromic acid is expelled in vacuo over 

 lime, the residue poured into water, and the acid extracted with 

 ether. The crude acid left on the distillation of the ether we have 

 found it most advantageous to convert into the sodium salt with 

 alcoholic sodic hydrate. The sodium salt is easily collected 

 upon a filter, and the acid is then reprecipitated from its aqueous 



