Heterocycles Containing Azide Groups

3-Azido-1,2,4-triazoles and 3,5-diazido-1,2,4-triazole, as well as 2-azidoimidazole, have been known for some time. A recent account of these is given as well as a report of a study of some of their salts with energetic anions, such as 3-azido-l,2,4-triazolium nitrate, for the purpose of energetic ionic liquids. 

2 6-Membered Rings - Triazines, Tetrazines, Heptazines, Pyrimidines 

The azido-tetrazole ring-chain isomerism in polyazido-triazines, -tetrazines and hepta-zine has been discussed by extensive calculations.  

For the diazido derivatives of 1,4-diazine, the pyrazine system, molecular surface electrostatic potential studies exisL All three isomers of azidopyridine are weU-known, but not further considered in this report whereas polyazido substituted pyridines, such as diazidopyridines, ranain unknown to present time. 

Note added in proof The sensitivity properties of tris(azidoethyl)amine have recently been determined experimentally, because the azidomethyl derivative (N3CH2 3N was too dangerous. The values of (N3CH2CH2)3N are comparable to those of RDX. 

---

The synthesis, characterization, and energetic properties of various heterocycles containing azide groups are reported. Compound 105 is prepared by the reaction of cyanuric chloride with sodium azide. The preparation of 106 utilizes the conversion of a pyrazole derivative by reaction with hydrazine to form the hydrazo intermediate which is subsequently reacted with NaN02. 2,5,8-Trichloro-s-heptazine is converted quantitatively into 2,5,8-triazido-s-heptazine (107) with trimethylsilyl azide. The nucleophilic reaction of hydrazine with 4,4, 6,6 -tetra(chloro)hydrazo-l,3,5-triazine... 

Boyer and Gunasekaren reported the synthesis of the furazan-based heterocycle NOTO (44), which contains 50 % by mass of nitrogen and is a liquid at room temperature. The flve-step synthesis of NOTO (44) starts from the diazotization of 4,4 -diamino-3,3 -azoxyfurazan (DAAF) (27), followed by reaction with sodium azide to form the diazide (42). Heating the diazide (42) as a solution in acetonitrile induces cyclization to the triazole (43) and this is followed by reduction and oxidation of the remaining azide group to complete the synthesis of NOTO (44). 

Azide reactions can be carried out on azides containing suitable additional functional groups to yield products which can undergo cyclization to form heterocycles. 

---