364 Mr. C. H. Browning and others. Relationshijjs between 



method of Hoffman and Konigs,* and converted into the nitroso compound, f 

 A mixture of 2 - 6 grm. nitroso N-methyl tetrahydroquinoline, 1*5 grm. of 

 p-dimethylamino o-toluidine, 15 c.c. of glacial acetic acid and 2 c.c. of cone, 

 hydrochloric acid were warmed gently on the water-bath. Heat was 

 developed and the liquid became a brilliant green which rapidly changed 

 through brown black, dull scarlet to magenta. The heating was continued 

 from 3 to 4 hours, when the product was dissolved in 50 c.c. of hot water, 

 filtered and the colouring matter precipitated with zinc chloride and brine. 

 It forms a green iridescent mass which is at first sticky, but rapidly hardens. 

 The substance dissolves in water with a magenta colour similar to that of 

 toluylene red methochloride (p. 360). On analysis the zinc salt gave 

 N = 14 - 5 per cent. ; CssH^NsC^Zn requires N = 14 - 1 per cent. The 

 formula of the hydrochloride is therefore 



CH 2 N 



^ q U\)\)\) s ^ rci - 



N N 

 CH 3 CH 3 CI 



[89.] 2.Dimetliyla'iaino-1 '.amino-3.6Aimethylphena.zine methochloride. — 16 

 parts of ^-arnino-dimethyl o-toluidine and 15 parts of wi-dimethylamino 

 p-toluidine were dissolved in 300 parts of water, 20 parts of cone, hjdro- 

 chloric acid and 30 parts of 50 per cent, acetic acid, and cooled to 10° with 

 stirring. Thirty parts of sodium dichr ornate in 400 parts of water were run 

 in during 3 hours. A bluish-red coloration develops immediately and 

 becomes more intense as the oxidising agent is added. The mixture was 

 finally warmed on the water-bath for an hour, filtered and salted out with 

 zinc chloride and sodium chloride. In this way the zinc chloride salt of 

 the colouring matter is obtained. It was purified by solution in water, 

 filtration and reprecipitation with salt solution. It could not be recrystal- 

 lised from alcohol or dilute hydrochloric acid. The substance by analogy 

 with the formation of tetramethyldiamino-phenazine (p. 361) has the 

 following structure : — 



ST 



(ch 3 ) 2 n[ x/ ' x/ I X/ Jnh 2 .hci. 



N 



CH 3 CI 



* ' Ber.,' vol. 16, p. 728 (1883). 



t Konigs and Freer, ' Ber.,' vol. 18, p. 2388 (1885). 



