1872.] Dr. A. W. Hofmann on Aromatic Monamines. 53 



potash and chloroform, into the powerfully smelling isonitriles, may also 

 with advantage be resorted to. 



The liquid boiling between 217° and 230° was separated by distillation 

 into four fractions, each of which was then converted into a magnificently 

 crystalline chlorhydrate. These several salts, after recrystallization, were 

 all found to contain 



[C e H 2 (CH 3 ) 3 ]H 3 N.HCl j 

 and to yield platinum salt of the composition 



2[[C 6 H 2 (CH 3 )JH 2 N . H CI] . Pt Cl 4 . 

 I was thus led to believe that the fraction boiling between 217° and 

 230° consisted of several isomeric cumidines ; but on separating the bases 

 from the several chlorhydrates, it was found that they all exhibited very 

 nearly the same boiling-point. The liquid thus obtained boiled between 

 225° and 227°, and had the vol. w. 0*9633 ; it did not solidify when ex- 

 posed to a temperature of —10°. I am therefore inclined to assume that 

 only one cumidine is formed by the action of heat on trimethylated 

 phenylammonium iodide, and that the irregularities in the boiling-point 

 of the original fraction must be due to the presence of small quantities of 

 impurities. 



It deserves to be noticed that cumidine obtained from aniline, when 

 heated with corrosive sublimate, yields no trace of red colouring-matter, 

 whilst a splendid crimson is at once produced if a mixture of this base 

 with pure aniline be treated. I reserve for a future communication the 

 study of the colouring-matter thus obtained. 



Taking into consideration the general observations recorded in the pre- 

 ceding paragraphs, the compound here designated as cumidine was natu- 

 rally assumed to be a primary monamine. Little doubt as this conception 

 appeared to present, it had nevertheless to be proved by experiment ; 

 for this purpose the base was submitted to methylation. Cumidine is 

 readily acted upon by methylic iodide at the common temperature. Since 

 it was only necessary to establish the degree of substitution, the first 

 product of methylation was at once submitted to a second treatment ; 

 this second methylation likewise commenced at the common temperature, 

 but had to be finished in the water-bath. The dimethylated base thus 

 obtained had the vol. w. 0*9076 : it boiled between 213° and 214°; hence, 

 in this case also, the insertion of two methyl groups had lowered the 

 boiling-point. Dimethylcumidine may be cooled to — 10° without solidi- 

 fying : like all tertiary monamines, it forms very soluble salts, but gives a 

 very beautiful platinum salt, containing 



2[[C 6 H 2 (CH 8 )J (OH,), N . H 01] . Pt Cl 4 . 

 Remarkably enough, dimethylated cumidine exhibits the same reluctance 

 to form a quartary compound with methyl iodide that has already been 

 pointed out as a peculiarity of the tertiary xylidine. But whilst in the case 

 of dimethylxylidine, though difficultly and sparingly, combination after 



