191 Ii\ The Reduction of Naphtazarine 103 



dish witli water and heated upon a water bath until the odor of 

 ammonia could no longer be detected. The product was impure 

 and remained so after extraction with ether. It was therefore 

 converted into its hydrochloride by adding 5 parts of alcohol 

 and 5 parts of concentrated hydrochloric acid. The result- 

 ing emulsion- was filtered with suction and washed with 

 very little water. The residue was dissolved in 5 parts of 

 water, filtered from slight impurities and finally neutralized 

 with pure sodium hydroxide. The resulting solution 

 was allowed to crystallize slowly. The product obtained 

 thus was pure, melting at 122°. This is a very efficient addi- 

 tion to the purification process of Curtius and Burkhardt. 

 The formula is NHoNH.CO.NHCeH^. The melting point of 

 the hydrochloride is 216°. 



Action of Phenylsemicarhazine on Tetrahydroxynaphthalene 

 The action of phenylsemicarhazine on the yellow and the red 

 forms of tetrahydroxynaphthalene was studied simultaneously. 

 The amoun.ts used were in the proportion of one molecule to one 

 molecule. Saturated solutions of each were mixed and two 

 series were carried out, one in alcohol solution, the other in 

 chloroform solution. The solutions were kept in beakers placed 

 in desiccators. In the alcoholic solutions precipitation began 

 about the fourth day and gradually increased, a slow evaporation, 

 of the solvent taking place simultaneously. The precipitates 

 were dark colored, the solutions being dark red. Recrystallized 

 from alcohol the products became lighter brown and behaved 

 similarly on heating in a capillary tube, darkening at 205° and 

 decomposing at 214°. 



In the chloroform series the yellow form made a yellow solu- 

 tion, and the red form a red solution. On the third day the 

 precipitation began in the yellow solution but none took j)lace in 

 the red solution until the seventh day. Precipitation continued 

 in each case until the weight of the precipitate was equal to 

 55 per cent, of the total weight of the reacting substances. The 

 crystals in both cases were light yellow in color and behaved 

 upon heating like the products from the alcoholic solutions. The 

 analytical work was interrupted before entirely satisfactory 



