34 Miss Thomas and Mr Jones, Active Nitrogen Compounds. 



lower temperature (132°) than the inactive iodide and crystallises 

 in quite a different form. 



The crystals of both iodides have been examined by Mr Dain, 

 of Clare College. The laevo iodide crystallises in the tetragonal 

 system, whereas the crystals of the inactive iodide belong to the 

 oblique system. The inactive iodide must therefore be a racemic 

 compound : the melting point of either iodide is however depressed 

 only very slightly by admixture with the other. 



The active iodide is stable in alcoholic solution and [M] D in 

 absolute alcohol = — 428°. It is however racemised in chloroform 

 solution, a solution with a molecular rotatory power [M ] D = — 508° 

 becoming completely inactive after two days. 



Phenyl-benzyl-isoamyl-methyl ammonium iodide was prepared 

 by treatment of methyl-isoamyl-aniline with the theoretical quan- 

 tity of benzyl iodide. After crystallising from alcohol it formed 

 small prisms which melted at 156° C. The d camphor-sulphonate 

 was prepared from it in the usual manner. The salt of the laevo 

 base is the less soluble in acetone, but many recrystallisations are 

 required before the separation of the d and I constituents is com- 

 plete. After twenty recrystallisations the salt melts at 178 — 

 8"5° C. and has [M] D = — 317°, and the rotation is not yet constant. 

 The value of [M] D for the eZ-camphor-sulphonic ion is 51"7° so 

 that the basic ion already has a molecular rotatory power of nearly 

 — 370°. The iodide recovered from the camphor-sulphonate melts 

 at the same temperature as the inactive, gives [M] D = — 478° in 

 alcohol, and racemises in chloroform solution. 



A comparison of these results with those obtained for the 

 corresponding ethyl and allyl compounds shows : 



(1) That substitution of the isopropyl or isoamyl for the ethyl 

 group causes a change in the molecular rotation of more than 

 370° and 350° respectively ([M] D for phenyl-benzyl-ethyl-methyl 

 ammonium ion = 19°). 



(2) Substitution of isopropyl or isoamyl for allyl increases 

 the molecular rotation to a great extent ([-MJd for phenyl-benzyl- 

 methyl-allyl ammonium ion = 166°). 



These results are striking, and several other compounds are in 

 process of resolution in the hope that some regularity in the effect 

 of the various radicals may be observed. It is noteworthy that 

 the effect of an unsaturated group in increasing the rotatory power, 

 which is so frequent in other series of compounds, is not shown in 

 this series. 



