3-azido-l,2,4-triazoles

Oxidation of 1,2-diaminobenzimidazole, leading to the formation in high yield of 3-aminobenzo-l,2,4-triazine 838, is thought to proceed through recyclization of an intermediate nitrene 836 (possibly via diazene intermediate 837) as evidenced by the formation of amine 838, with a high efficiency on the thermolysis of l-amino-2-azidobenzimidazole 835. The reaction works well also for other A -amino—azidoimidazoles and 4-amino-3-azido-l,2,4-triazoles. 

C NMR spectra of 3-nitro-l,2,4-triazol-5-one and seven of its salts with different amines have been studied. The chemical shifts of C-3 and C-5 are independent of the nature of the cation (Table 3.21) [560], NMR spectra of 1-nitro-1,4-dihydro-1-7/-l,2,4-triazol-5-one, 5-(3-azido-l,2,4-triazol-3-yl)-3-nitro-l,2,4-triazoles [611], l-alkyl-3-nitro-l,2,4-triazol-5-one [612], some 3-nitro-2-methyl-l,2,4-triazolone derivatives [613-615], and their mono- and dinitro energetic salts [616] have been discussed. 

Reactions of l-(2-azidoethyl)-3-azido-l,2,4-triazole with concentrated nitric acid and 5-nitrotetrazole gave l-(2-azidoethyl)-3-azido-l,2,4-triazolium... 

Diaminotriazole and derivs 5 D1148—D1149 5-azido-3-nitrosamino-l, 2,4-triazole 5 D1149... 

New fused tetrazoloazines that have been reported include tetrazolo[5,l-a]isoquinolines,665 tetrazolo[5, l-6]benzothiazoles,666 and tetrazolopyridines.667 Reactions of fused tetrazoloazines, or the azido isomers, that have been reported include hydrolytic cleavage of the pyrimidine ring of tetrazolopyrimidines,66 pyrolysis of 3-azido-pyridazine 2-oxides,66 and photolysis of azido-l,3,5-triazine.670 Dipole moments of 3-azido-1,2,4-triazole derivatives have also been reported.671... 

Bitriazolyl unit 96 was prepared as a surrogate ofbiaryl system by 1,3-dipolar q doaddition of methyl-5-azido-l,2,4-triazole-3-carboxylate (95) with a variety of alkynes in H2O/THF 2 1 at 80°C in the presence of Cu(I) (Scheme 5.28)7 ... 

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. 

Azide groups attached in the 5-position of a 1/7-1,2,4-triazole will react with terminal alkynes under mild, copper-catalyzed conditions to yield 3-(l,2,3-triazol-l-yl)-l,2,4-triazoles. The 1,2,4-triazoles 66a-j were prepared in this manner from the azido-1,2,4-triazole 65 in good yields (Equation 22 and Table 8) <2006BML2693>. 

The 1,3-dipolar cycloaddition of azido-l,2,5-oxadiazoles (azidofurazans) to dicarbonyl compounds has been studied and a new procedure for the synthesis of (l,2,3-triazol-l-yl)-l,2,5-oxadiazoles was proposed <2002MC159>. The cycloaddition of 4-amino-3-azido-l,2,5-oxadiazole 168 to nitriles with activated methylene groups has been studied, and 3-amino-4-(5-amino-l/7-l,2,3-triazol-l-yl)-l,2,5-oxadiazoles 169 and the products of their Dimroth rearrangement 170 have been synthesized <2004MC76>. 

Heating 4-amino-3-azido-4//-1,2,4-triazoles (229) in chlorobenzene to 110 °C gives the 3-amino-l,2,4,5-tetrazines (232). This reaction is explained by the intermediate formation of the nitrene (230) which opens to the formazane (231) and subsequent ring closure by nucleophilic attack of the hydrazono group on the nitrile function (66TL5369). 

Nitrosamino-5-Azido] -1,2,4-Triazole [Azido-5-nitrosamino-3-triazol-l, 2,4 (Ger)]. 

Azido-3-[(2-Hydroxy-1-Naphthyl)-azo]-l, 2,4-Triazole. See under Hydroxynaphthyl-azotriazole and R.Stolle W.Dietrich, J PraktChem 139, 193-210(1934) CA 28, 2714(1934)... 

Reduction of the dinitroso compd with SnCl2 coned HCl gives 3 Amino- -bydra-zino l,2,4-trtazole di-HCl, mp 217°(dec), which in an ice-cold aq soln NaN02 gives 5-Azido-3-nitrosamino- 1,2,4-triazole, an ocher amor solid, mp detonates at 134° (Ref 2)... 

---