204 PROCEEDINGS OF THE AMERICAN ACADEMY. 



none, and of hydrochloric acid at 160° to 175° on the red pyrocatechine 

 ether. There seems no doubt, therefore, that it is formed from the red 

 body by the conversion of two orthoquinone oxygen atoms into hydroxyl 

 groups ; in other words, tliat it is the pyrocatechine corresponding to the 

 red orthoquinone ; and this view is coufirmed by the oxidation of the 

 brown substance to the red by nitric acid. The reaction of the hydro- 

 chloric acid is especially instructive in regard to the constitution of these 

 two bodies, as it is the familiar conversion of a quinone to a hydroqui- 

 none by this reagent. The red color of the original substance also points 

 to the presence of orthoquino oxygen in it, whereas the lighter color 

 of the reduction product (brown when crystallized, but {purplish white 

 when amorphous) confirms the view that it is the hydroxy compound. 

 We therefore assign the following formulas and names to these sub- 

 stances, — red compound, Br4C6=02='CeBr202, hexabromorthoquinopyro- 

 catechine ether; the brown reduction product, Br4C6=02=C6Br2(OH)2, 

 hexabromdiorthoxypyrocatechine ether. The only observed fact not in 

 accordance with this last formula is that the substance does not dissolve 

 in a solution of sodic hydrate, as we should expect it to do considering 

 that it contains two phenol hydroxyls ; this may, however, be explained 

 by the very slight solubility of the substance (soluble only in warm 

 nitrobenzol), which might prevent the solution of sodic hydrate from 

 coming into sufficiently close contact with it to react. 



The hexabromorthoquinopyrocatechine ether was formed when acetic 

 acid or alcohol was used as the solvent, but none of it was obtained 

 when the tetrabromorthoquinone and tetrabrompyrocatechine were mixed 

 in solution in chloroform or ether. In this latter case the residue left 

 after the evaporation of the solvent was a reddish white mass, apparently 

 a mixture of the unaltered reagents, which contained none of the hexa- 

 bromorthoquinopyrocatechitie ether. This is strange, as Zincke by mix- 

 ing the two substances in ethereal solution obtained a black crystalline 

 substance. An attempt will be made in this laboratory next year to find 

 the conditions under which this black compound is formed. 



"We have succeeded also in obtaining a reaction similar to that just 

 described from tribromresorcine and tetrabromorthoquinone. The other 

 phenols tried acted simply as reducing agents. The product proved to 

 be a ditribrommetoxyphenyldibromorthoquinophenylene ether, 



(C6HBr30HO)2C6Br202. 



This substance melts at 217°, and like the reduction product just de- 

 scribed, does not dissolve in a solution of sodic hydrate, in spite of the two 



