224 PROCEEDINGS OF THE AMERICAN ACADEMY. 



droxy derivative from the red orthoquinone body, as then this action is 

 the familiar reduction of quinone oxygen by hydrochloric acid. This 

 theory is still further supported by the reduction of tetrabromortho- 

 quinone to the purplish white body by tribrompyrogallol described in the 

 next section. 



Behavior of Tetrabromorthoquinone loith Trihromresorcine. 



After we had found, as just described, that tetrabromorthoquinone 

 reacted with tetrabrompyrocatechine, it became of interest to try the 

 action of the tetrabromorthoquinone with other diatomic phenols, and, 

 as we found that unsubstituted phenols of this chass reduced the quinone, 

 — pyrocatechine, for instance, reducing it completely to tetrabrompyro- 

 catechine, — we turned our attention to the brompheuols. Of these, 

 tetrabromhydroquinone in alcoholic solution acted only as a reducing 

 agent, giving bromanil and tetrabrompyrocatechine. Tribrompyrogallol 

 also acted only as a reducing agent, giving tetrabrompyrocatechine, which 

 combined with unreduced tetrabromorthoquinone to give the hexabrom- 

 orthoquinopyrocatechine ether, and this was converted by further action 

 of the tribrompyrogallol into its purplish white reduction product. With 

 trihromresorcine, on the other hand, a new compound was obtained. 



8.4 grams of tetrabromorthoquinone and 7 grams * of trihromresor- 

 cine t were dissolved with the aid of heat in 600 c.c. of glacial acetic 

 acid mixed with 400 c.c. of water, and allowed to stand for twenty-four 

 hours. At the end of this time a dingy pink precipitate had formed, 

 which was filtered out, washed, and recrystallized from benzol, until 

 it showed the constant melting point 217°, when it was dried at 100°, 

 and analyzed with the following results : — 



I. 0.1389 gram of the substance gave by the method of Carius 0.2173 

 gram of argentic bromide. 

 II. 0.1370 gram of the substance gave by the method of Carius 0.2144 

 gram of argentic bromide. 



Bromine 



* The two reagents were used in the proportion of equal molecules, whereas 

 the analj'sis of tlie product sliowed that two molecules of the resorcine should 

 have been taken for each molecule of the quinone. 



t The trihromresorcine was prepared by the method of Benedikt (Monatsh. f. 

 Chem. IV. 227.) by mixing the calculated amount of bromine witli resorcine dis- 

 solved in glacial acetic acid. The product was purified by crystallization from 

 benzol and iigroin. 



