iPi^] The Reduction of !N"aphtazarin^e 101 



carbazine which is weakly basic and propose to follow with 

 semicarbazine which is not so weak a base. Con«clusive state- 

 ments can not jet be made as to the constitution of the yellow 

 and red forms but the question is being actively studied in our 

 laboratory. 



EXPERIMENTAL PART 



Purification of Naphtazamie 

 We were presented with one-half kilogram of naphtazarine 

 by the Badische Anilin u. Soda Fabrik in Ludwigshafen am 

 Ehein and wish to express here our sincere thanks for the same. 

 In order to bring the material to a higher state of purity 

 we tried to recrystallize it from various solvents but could find 

 no suitable solvent. So we resorted to the sublimation, process, 

 employing a large sublimation apparatus similar to one described 

 by Morey (Journ. Amer. Chem. Soc, 34,550 (1912)). The 

 copper or platinum vessel containing the substance rested upon 

 a resistance coil of ni chrome wire carrying 1.5 amperes of 

 current. This was placed upon a very tall inverted beaker which 

 stood in a large flat crystallizing dish. Over the whole was 

 inverted a bell jar and a still larger one over this. The whole 

 rested upon a metallic plate, the bottom of an old vacuum pump 

 with a hole in the center. This hole gave insertion to the tube 

 leading to the May-Xelson electric vacuum pumj). A vacuum 

 of 2 to 10 mm. was maintained 5 to 8 hours for each 15 gram lot. 

 One-third of the material was non-sublimable. The sublimed 

 product consists of glistening green needles which upon being 

 powdered formed a dark red mass. J^aphtazarine possesses no 

 melting point but sublimes above 140°. 



Reduction of Naphtazarine 

 The naphtazarine was reduced by suspending 20 grams in 

 95 per cent, alcohol, adding 100 grams stannous chloride dis- 

 solved in 50 cc. concentrated hydrochloric acid and boiling 

 the mixture on the water bath under a reflux condenser for 

 thirty minutes. This produced a clear greenish red solution 

 containing only a few insoluble particles. An odor of hydrogen 

 sulfide was quite pronounced. In order to isolate the product it 

 is very unsatisfactory merely to pour the solution into water or 



