( 273.2) 
VII.—On some New Bases of the Leucoline Series. Part Il].—The Action of 
Lodide of Methyl on Tetracoline, Pentacoline, Hexacoline, Heptacoline, 
and Octacoline. By G. Carr Rostnson, F.R.S.E., and W. L. Goopwin. 
(Read 16th June 1879.) 
In the first paper read before this Society “On some New Bases of the 
Leucoline Series,” and published in the Society’s “ Transactions,”* it was stated 
that amongst other methods proposed for separating the members of the series 
and identifying the higher bases, was the process of converting the mixed bases 
into methyl-iodide compounds by digesting them with the iodide at a high 
temperature, and separating by fractional crystallisation the bodies so produced. 
It was found, however, that repeated crystallisation of these bodies could not 
be effected without great risk of their decomposition. This process was, there- 
fore, abandoned in favour of fractional distillation. 
Subsequent investigation of these bases by the latter process—that of frac- 
tional distillation—yielded five new members of the series, viz. :—Tetracoline, 
C,,H,,N ; Pentacoline, C,,H,,N ; Hexacoline, C,,H,,N ; Heptacoline, 
C,,;H,,N; and Octacoline, C,,H,,N. These bases, as was shown by the 
analyses of their platinum salts, being obtained in a state of great purity. 
We are now enabled to lay before the Society the results arrived at by the 
study of the action of methyl-iodide on the pure bases. 
This inquiry has shown that these bases combine readily with methyl- 
iodide, that the bodies so produced can readily be obtained in a state of great 
purity, and that, owing to this circumstance, they can be examined more easily 
and expeditiously than the platinum salts of the bases. 
With Tetracoline, C,,.H,,N, and Pentacoline, C,,H,.N, iodide of methyl 
unites at ordinary temperatures. On dissolving the base in the iodide and 
agitating the solution, yellow crystals of the iodide of methyl-tetracoline and of 
methyl-pentacoline appear in a few minutes. With Hexacoline, C,,H,,N, and 
the higher members, iodide of methyl only combines when digested for some 
time with the base at 100° C. 
When these bases are digested with iodide of methyl on the water-bath in 
a flask fitted with an inverted condenser, the methyl compound is quickly 
thrown down in a fine powdery condition and always of a green colour. By 
heating the solution of the base in methyl-iodide in sealed tubes, the salt is 
obtained in well-defined crystals, the yield is larger, and the colour of the salt 
varies with the different bases ; ¢.g., the iodide of methyl-tetracoline so obtained 
* “Transactions of Royal Society of Edinburgh,” vol, xxviii. part ii. 
VOL. XXIX. PART I. 4A 
