Mr Reilly, The resolution of, ete. 177 
The resolution of asymmetric quinquevalent nitrogen com- 
pounds. By Jos. Rettty (M.A., M.Se., 1851 Exhibition Scholar), 
Emmanuel College. (Communicated by Professor Pope.) 
[Read 25 October 1915.] 
Many peculiarities have been recorded with regard to the 
varying facilities with which different optically active acids can 
be utilised to effect the separation of asymmetric quinquevalent 
nitrogen compounds into their optically active constituents. In 
the first successful resolution of a compound of this class, namely 
benzylphenylallylmethylammonium iodide, Pope and Peachey 
(Trans. Chem. Soc. 1899, Lxxv. 1127) fractionally crystallised 
the compound obtained by replacing the iodine by the d- or 
[-@-camphorsulphonate radical, yet Wedekind (Ber. 1899, xxx11. 
517) previously had failed to obtain the two modifications by 
repeated crystallisation of the d-tartrate or d-camphoric acid 
derivative. Later, Jones failed to separate dextro- and laevo- 
phenylmethylethylallylammonium d-@-camphorsulphonate into 
its two constituents even after repeated crystallisation from 
various solvents, while he found that the dextro- or laevo-a-bromo- 
camphor-7-sulphonate salt of the inactive base could readily be 
resolved by fractional crystallisation. 
It might therefore be considered that the stronger the 
optically active acid employed to effect the resolution the more 
easily would such a result be achieved. This, however, is not 
always the case as the following results show. Wedekind (Zeit. 
physikal Chem. 1903, XLV. 235), aware of the previous work of 
Pope and his pupils, attempted to resolve p-tolylbenzylmethylallyl- 
ammonium lodide into its two antipodes by the aid of d-8-camphor- 
sulphonic acid, but failed, yet Jones (Trans. Chem. Soc. 1908, Xcut. 
1790, cf. Homer, Proc. Camb. Phil. Soc. 1907, X1v. 11. 196) succeeded 
by fractional crystallisation of the hydrogen d-tartrate. Several 
other instances have been recorded in which resolution 1s brought 
about by the aid of the comparatively weak acids, d- or /-tartaric 
or d- or l-camphoric, where the much stronger acids such as d- 
or J/-8-camphor-sulphonic, or d- or /-a-bromocamphor-7-sulphonic 
have been unsuccessful. 
Racemisation effects have been advanced as the cause of 
non-resolution in many cases. A similar explanation has been 
put forward to explain the failure to separate into dextro- and 
