54 



Dr. A. W. Hofmann on the 



[Dec. 5, 



all took place ; all attempts with dimethylated cumidine have hitherto 

 failed. The base was heated with methylic iodide for days in the water- 

 bath, and ultimately even to 150° without any result. This inability of 

 forming quartary compounds must, in one way or another, depend upon 

 the arrangement of the material within the molecule. At all events, it 

 deserves to be noticed that there are dimethylated xylidines and cumi- 

 dines which readily combine with methyl iodide. The dimethylated 

 bases existing in the less volatile fractions of commercial dimethylaniline 

 all form quartary compounds without difficulty, and must therefore cor- 

 respond to xylidines and cumidines which differ from those derived 

 from trimethylated phenylammonium iodide. 



In what relation stands the cumidine above described to the cumidines 

 already known? Of the several purely methylic cumidines which are 

 possible, two only are somewhat accurately known ; these are the two bases 

 which are derived, the one from so-called pseudocumol (obtained by treating 

 xylylic bromide and methylic iodide with sodium), the other from mesitylol. 

 The former cumidine is a solid fusing at 62°, and need not therefore be 

 further considered here. Most probably the cumidine above described 

 will prove identical with the primary monamine corresponding to mesi- 

 tylol. Unfortunately mesitylamine has been hitherto so little studied, 

 that even its boiling-point is not known. I hope next winter to exa min e 

 more minutely this group of compounds. 



In conclusion, I have great pleasure in expressing my best thanks to 

 Mr. E. Mylius, Assistant in the Berlin Laboratory, for the zeal and care 

 with which he has furthered the progress of these researches. 



II. " Transformation of Aniline into Toluidine.^ By A. W. Hof- 

 mann, M.D., Ph.D., F.R.S. Received August 22, 1872. 



Whilst engaged with the experiments described in the previous paper, 

 I have made some observations which I may be allowed briefly to mention 

 to the Society, since the coming autumnal vacation will suspend work 

 for a time. 



In reviewing the experience collected as to the action of high tempe- 

 ratures upon trimethylated phenylammonium iodide, the question 

 naturally suggested itself whether the transposition of methyl groups, 

 such as it occurs in the quartary compound, would take place also on 

 heating tertiary or secondary ammonium salts. Experiment has answered 

 this question in the affirmative. 



G-enerally speaking the phenomena are exactly what, from the results 

 of former observations, might have been expected. It is my intention to 

 study next winter more soundly the reactions here sketched out ; for the 

 present I may be permitted just to allude to the happy solution of a 

 problem with which during the last few years I had repeatedly, but 

 always unsuccessfully, been engaged. 



