11)11] on New Organic Compounds of Nitro[ien. 159 



forehead often accompanied by palpitation of the heart. Whilst, 

 however, the derivatives of benzene and naphthalene usually acquire 

 an odour of anise by the introduction of the triazo-complex, the 

 perfume connected with such substances as the azoimides of ethyl 

 acetfite. ethyl alcohol, acetone, ether and acetic acid, is quite devoid 

 of the anise character, and is indeed much fainter than that of the 

 parent compound in each case. 



The method by which these aliphatic azoimides have been pre- 

 pared is extremely simple. It depends on interaction of the cor- 

 responding halogen derivative with sodium azide ; for example, 



CHg-CO-CHoCl + NaNg = CHg'CO-CR/Ns + NaCl, 



and appears to be almost general. The reaction has been lately 

 applied to the nitrosochlorides of pinene, dipentene, the limonenes 

 and terpineols, and it has been further found that the azoimide 

 complex may be exchanged for the nitroxy-group in nitrosates, such 

 as those of amylene and dipentene. 



The various degrees of stability displayed by the azoimide nucleus 

 is the feature which chiefly concerns chemists. Three principal types 

 of decomposition may be recognized. The environment least con- 

 ducive to stability betrays itself in the liberation of two nitrogen 

 atoms in the elemental form, leaving the third atom attached to the 

 carbon which originally carried all three. This is exhibited by 

 triazoautipyrine, which loses nitrogen spontaneously at common 

 temperatures, and passes into a bright red azo-compound. Triazo- 

 acetone undergoes this change more slowly, but may be stimulated 

 into activity by the catalytic effect of alkali, a property which it 

 shares with triazocamphor, 



/CH-N3 /C:NH 



\co \co 



Sometimes excess of alkali must be used and the temperature raised, 

 as in the case of triazoacetic acid, salts of which, when thrown into 

 hot caustic potash, immediately begin to liberate two-thirds of their 

 nitrogen as gas. The acid azides offer further illustrations of this 

 decomposition, and here the phenomenon is accompanied by a remark- 

 able atomic transformation, first brought to light by Curtius, later 

 studied by Schroeter and others, the denuded nitrogen atom actually 

 changing places with the carbon which formerly carried the triazo- 

 group. with the result that e-socyanates are produced : 



X-CO-Ng ^XN:C:0 + K.. 



Sometimes this alteration is explosive, as in the case of triazoacetic 

 azide, Ng-CHo- CO- N3. 



