JACKSON AND KOCH. — DERIVATIVES OF ORTHOBENZOQUINONE. 217 



chine in presence of benzolsulj-hiuic acid, and we should expect that the 

 two bodies would be identical, but, strangely enough, they seem to be 

 isomeres, since Hiusberg and Hinimelschein's compound contains water 

 of crystallization, and melts in presence of this at 117° ; when dried in 

 the steam oven, at 143°-145° ; when previously fused in the air, at 

 164°; whereas our substance contains no water, and melts at 153°, 

 whether dried at ordinary temperatures or by previous fusion. We made 

 five attempts to prepare their body according to Hiusberg and Himmel- 

 schein, but did not succeed in finding the conditions under which it is 

 formed, which must lie within very narrow limits ; and, as in doing this 

 we had devoted more time to the subject than we could afford, we were 

 obliged to abandon our intention of making a comparative study of the 

 two compounds. 



Action of Aniline on the Solution of Orthobenzoquinone. 



The solution of orthoquinone in chloroform was heated with an excess 

 of aniline for five minutes on the steam-bath ; the chloroform was then 

 allowed to evaporate, and the residue, after having been freed from ani- 

 line by treatment with hydrochloric acid and washing with water, was 

 purified by recrystallization from a mixture of two parts of alcohol to one 

 of benzol, until it showed the constant melting point 203°, when it was 

 dried at 100°, and analyzed with the following result : — 



0.2909 gram of the substance gave 28.2 c.c. of nitrogen at a tempera- 

 ture of 22° and a pressure of 774 mm. 



Calculated for „ , 



CoH,(C„H5NU)„0„U5NO. *°"'°'^- 



Nitrogen 11.51 11.27 



The substance is therefore a dianilinoquinoneanil. When the aqueous 

 wash waters obtained in the preparation of this substance were extracted 

 with ether, pyrocatechine was obtained, recognized by its odor and 

 lead salt. 



Properties of the dianilinoquinoneanil, CgH2(C6H5NII).,C(5H5NO. — 

 Crystallized from alcohol and benzol it forms bronze-colored small 

 needles melting at 203°, although thev begin to draw totiether some- 

 what at 198°. The melting point of this substance is identical with that 

 (202°-203°) given by Zincke and Hageu * for the dianilinoquinoneanil 

 made from paraquinone by the action of aniline and glacial acetic acid, 



* Ber. d. cliem. C.es., XVIII. 787. 



