JACKSON AND KOCH. — DERIVATIVES OF ORTHOBENZOQUINONE. 223 



The oxidation was then repeated in the same way, and the dried product 

 was found to weigh three grams ; the conversion from the chocolate- 

 colored substance to the red body, therefore, takes place quantitatively. 

 The red product was recrystallized from warm nitrobenzol, freed from 

 the excess of nitrobenzol with alcohol, dried at 100°, and analyzed with 

 the following result : — 



0.1317 gram of the substance gave by the method of Carius 0.2140 gram 

 of argentic bromide. 



Calculated for ^ • 



CioBrA- ^°"°*- 



Bromine 69.76 69.15 



There can be no doubt that this substance is the hexabromorthoquin- 

 opyrocatechine ether described above. 



As to the formula of the chocolate-colored product of the reduction 

 there is a certain amount of doubt. Our analysis shows only that its 

 composition does not differ to a marked extent from that of the red 

 mother substance. Its formation by reduction and its conversion to 

 the original body by nitric acid would indicate that it was the hydroxyl 

 compound corresponding to the red quinone, but, on the other hand, its 

 insolubility in sodic hydrate is hard to reconcile with this view. As 

 this may be due, however, to the very slight solubility of the substance 

 in all solvents, which might prevent the sodic hydrate from coming 

 sufficiently in contact with it to react, we are inclined to consider that it 

 is the hexabromorthodioxypyrocatechine ether, and to assign it provision- 

 ally the formula Ci2Br602(OH)2. We hope that the study of this sub- 

 stance may be finished in this Laboratory in the near future. 



Our attempts to decompose the hexabromorthoquinopyrocatechine 

 ether with sulphuric acid led to no result, as no action was observed 

 even after boiling it for several hours with sulphuric acid of 1.44 or 

 even 1.6 specific gravity; but hydrochloric acid reacted upon it, as is 

 shown by the following experiment : 5 grams of the red body were 

 sealed in a tube with 25 c.c. of strong hydrochloric acid, and heated 

 from 160°-175° for five hours ; the product, after washing with water 

 and alcohol, showed a strong resemblance to the purplish white body 

 obtained by the reduction with sodium amalgam. On treating it with 

 fuming nitric acid diluted with glacial acetic acid it turned red at 

 once, so that there can be little doubt of the identity of the two 

 substances. This observation can be satisfactorily explained on the 

 theory already adopted, that the purplish white substance is the dihy- 



