Mr Jones, The Absence of Isomerism, Sc. 169 



The Absence of Isomerism in substituted Ammonium Com- 

 pounds. By H. O. Jones, M.A., Clare College. 



[Received 15 July 1905.] 



Recent work on quinquevalent nitrogen compounds has shown 

 that no stable isomerides, other than optical isomerides, exist 

 except in the case of the a and ft phenyl-benzyl-methyl-allyl- 

 ammonium compounds discovered by Wedekind. The a compound 

 is formed in two ways by the addition of benzyl or allyl iodide 

 to the corresponding tertiary amine, while the ft compound is 

 formed by the action of methyl iodide on benzyl-allyl-aniline. 

 It has of late become impossible to reconcile the existence of 

 these stereoisomerides with the absence of isomerism in a number 

 of similar compounds, and the writer has examined the ft iodide 

 in the hope of gaining further knowledge as to the nature of the 

 isomerism. 



If the ft iodide be stereoisomer^ with the a compound and, 

 further, if it behave similarly in chloroform solution, namely, 

 dissociate partially into benzyl iodide and methyl-allyl-aniline, 

 then in chloroform solution ft should be transformed gradually 

 into a, since this is formed by the union of benzyl iodide and 

 methyl-allyl-aniline. It was found that a chloroform solution 

 of ft smelt strongly of benzyl iodide, and yet that the ft iodide 

 could be recovered unchanged even after the solution had been 

 boiled and allowed to stand for a week. 



It is therefore extremely probable that there is a structural 

 difference between these compounds. 



Hantzsch and Horn (Ber. 1902, 35, 883) state that the ft com- 

 pound is unsaturated because its chloride unites directly with 

 bromine and decolourizes potassium permanganate solution, neither 

 of which reactions is given by the pure ft compound. 



The writer has found by analysis (in previous analyses the 

 nitrogen and iodine only had been estimated, and the latter 

 wrongly) and a careful examination of its properties and reactions 

 that the so-called ft phenyl-benzyl-methyl-allyl-ammonium iodide 

 is really identical with phenyl-benzyl-dimethyl-ammonium iodide 

 previously described (Proc. Camb. Phil. Soc. 1901, XI. 113. Trans. 

 Chem. Soc. 1903, 83, 1409). The reaction between benzyl-allyl- 

 aniline and methyl iodide in which allyl iodide is removed is 

 therefore abnormal. 



Since the isomerism observed in certain hydrindamine salts 

 by Kipping has been shown to be due to the acid, there is no 

 known case of stereoisomerism, again excepting optical isomerism, 

 in substituted ammonium compounds containing only one nitrogen 

 atom; and, judging from the large number of negative results, 

 it is extremely probable that such isomerism does not exist. 



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