160 Professor M. 0. Forsfer [May 5, 



Tlu' next class of transformation undergone by the triazo-complex 

 is more moderate. It was discovered by Dimroth. and may be de- 

 scribed as an unfolding of the three-atom nitrogen ring without loss 

 of the element, all three atoms of which remain in the form of a 

 chain such as occurs in diazoaminobenzene : triazen derivatives of 

 this type are, in fact, easily obtainable by the action of alkyl magne- 

 sium halides upon organic azoimides, 



CeHs-MgBr + C«H5-N3 = C„H5-N:N-X(MgBr)-C,H,. 



Although some external agency is usually necessary for this type of 

 transformation we have found cases in which it takes place sponta- 

 neously. For example, allylazoimide, a colourless, mobile liquid when 

 freshly prepared, rapidly changes into a white crystalline solid, con- 

 sisting of a diazoamino-compound isomeric with the original material, 

 whilst an attempt to prepare benzhydroximic azide led forthwith to 

 its isomeric transformation product, hydroxyphenyltetrazole, 



OeHs'C-Cl C\H5-C:N\ 



II -t- NaNg = I >N + XaCl. 



HO-N IIO-N-nX 



More recently, the lt;dian chemists, Palazzo and Oliveri-jMandala, 

 discovered that fulminic acid and methylcarbylamine, both highly 

 unsaturated compounds, also are capal)le of producing this effect on 

 the azoimide nucleus, converting hydrazoic acid into 1-hydroxytetra- 

 zole and 1-methyltetrazole respectively, whilst tetrazole itself is obtain- 

 able by the interaction of hydrazoic and prussic acids, 



HC:N\ 

 HCN + HX3 = I -N. 



HN-N/ 



The third class of alteration undergone by the triazo-group in- 

 volves its complete elimination from the molecule in combination with 

 hydrogen, its place being taken by the hydroxy-group. The simplest 

 illustration of this case followed attempts to prepare triazomethyl- 

 amine, Ns'CHa'NHo, which we found could not be realised because 

 derivatives of that substance display the remarkable property of libera- 

 ting hydrazoic acid when treated with cold water. The same thing 

 happens when triazotised carbon is associated with a halogen, triazo- 

 ethylene dibn)mide, for example, yielding hydrazoic and hydrobromic 

 acids after a few minutes contact with ice-cold water ; for this reason 

 it was not possible to realise triazoacetylene, the copper derivative 

 of which might be expected to excel that of acetylene itself in explo- 

 sibility. More generally, however, this type of decomposition re- 

 quires the action of alcoholic potiish for its completion. 



The behaviour of the triazo-group in respect of these three classes 

 of transformation is controlled by its molecular environment, but all 



