1.2.4- Triazole 5- -3-nitro

Fig. 3.4 The ESR spectrum recorded in the reaction of 2-phenyl-4-nitro-1,2,3-triazole with 1,1,1-trimethylhydrazinium iodide in r-BuOK-DMSO after 25 minutes (top) and after 45 minutes (bottom left) from the beginning of reaction, computer simulation of ESR signal of radical anion (bottom right)...

ESR spectral parameters of radical anions of 2-phenyl-4-nitro-1,2,3-triazole, l-methyl-5-nitrobenzimidazole, and l-methyl-6-nitrobenzimidazole are illustrated in Scheme 3.28. 

The mass spectral characteristics are considered as a proof of the structure of l-aryl(heteryl)- and 2-aryl(heteryl)-4-nitro-l, 2,3-triazoles 141,177,602-604,1-org-anyl-4-nitro-l,2,3-triazoles [597], some 4-nitro-l,2,3-triazoles of potential interest as antiprotozoal agents [1328], The molecular ion peaks of the following 4-nitro-1,2,3-triazole derivatives are reported (Scheme 3.66) [1328],... 

The addition of phenyl azide to / -nitrostyrene gives l,5-diphenyl-4-nitro-1,2,3-triazole (77a) in about 20% yield, identical to the product obtained from bromonitrostyrene, described above.69 Apparently, cycloaddition occurs in both possible orientations the intermediate in one case undergoes dehydrogenation to give 77a (Ar = R = Ph), whereas the other adduct loses nitrous acid to produce 1,4-diphenyl-l,2,3-triazole (78) (Scheme 17). 

Azidofurazans and -furoxans undergo dipolar cycloaddition reactions with unsaturated compounds, in some cases regiospecifically. Thus, reaction of 3-amino-4-azidofurazan with l-morpholinyl-2-nitroethene (toluene, reflux, 70 hours) gives 4-nitro-1,2,3-triazole 204 in 87% yield (99MI1, 000KGS406). Cycloaddition of the same azide to alkynes was accomplished by formation of a mixture of position isomers 205 and 206. Regiospecific addition was observed only in singular cases... 

An analogous reaction with 2, 3/,5 -triacetyluridine and mesitylenesulfonyl-3-nitro-triazole or triisopropylbenzenesulfonyl-3-nitrotriazole proceeds with the same high yield. Treatment of the nitrotriazolyl nucleoside with ammonia leads to 2, 3, 5 -triacetyl-cytidine.[194]... 

This shows that the combination of diphenylphosphate and arylsulfonyl-3-nitro-triazole is a powerful phosphorylating agent in pyridine solution. 

The influence of different modifiers on extraction efficiency with a concentration of 4 mol% is pointed out in diagram 2. With pure supercritical carbon dioxide,only pentaerythrit-tetranitrate is recovered. Recovery of the other samples is below 1 %, indicating no mutual solubilities with supercritical carbon dioxide. Using modifiers, recoveries of nitro-triazole and cyclo-trimethylene-trinitramine can be greatly enhanced. 

For example, a mixture of 4 mol% 2-propanol with carbon dioxide extracts up to 35 percent of nitro-triazole and a mixture of 4 mol% acetonitrile extracts up to 95 percent of cyclo-trimethylene-trinitramine. 

Results indicate the good potential for pentaerythrit-tetranitrate in establishing the RESS process for the production of fine particles. The GAS process could be more suited for particle formation of nitroguanidine, cyclo-trimethylene-trinitramine and nitro-triazole. If additional small amounts of modifiers are acceptable, then the flexible handling of both RESS - and GAS-process can be proposed for cyclo-trimethylene-trinitramine and nitro-triazole. 

Amino-l-nitro-l,2,4-triazole (581), obtained by nitration of 5-amino-triazole with acetyl nitrate, rearranges, on heating, to the nitramino-triazole (582). ° The combined action of sodium hydroxide, potassium iodide, tri-ethylamine, and sodium dihydrogen phosphite on the chloro-nitro-triazole (583) results in a mixture of the rearranged triazole (584), 3-chloro-l,2,4-triazole, and the coupled product (585). The stable betaine (586) has been prepared by treatment of 4-phenyl-1,2,4-triazole with phenacyl bromide, followed by tri-ethylamine. The meso-ionic triazolium thiolate (537 X = S) reacts with chlorine to form the dichloride (587 X = SCU), which has been converted into the betaine (588) by the action of diethyl bromomalonate in the presence of triethylamine. ... 

Fig. 1. HeterocycHc amines usedia azo dyes, (a) 2-Amino-6-nitrohenzothiazo1e [6285-57-0], (b) 3-amiao-5-nitro-2,l-benzisothiazole [14346-19-1], (c) 3-amiQo-4JT-l,2,4-triazole [65312-61 -0], (d) 5-amiQo-l,2,4-thiadiazole [7552-07-0, (e) 4,4 -diamiQo-2,2 -biphenylsulfone [6259-19-4], (f)...

Nitropyrazoles rearrange to 4-nitropyrazoles in H2SO4 and to 3-nitropyrazoles thermally. Similar rearrangements are known for 7V-nitro-l,2,4-triazoles. 

That aminals and enamines are in equilibrium under certain conditions has been demonstrated (38). l,l-Di(N-morpholino)ethane 18, when heated with excess diethylamine for 24 hr at 60 and then treated with 4-nitro-phenylazide, gave the triazole (19) in 80% yield. The authors contend that... 

Most 3-hydroxy-l,2,4-triazoles exist in the hydroxy form 123 [76AHC(S1), pp. 377,389 84CHEC-I(5)733]. An exception is the 5-nitro derivative, which in the solid state possesses the 0x0 structure 124 (97JPC3605). 

Attempted dehydrocyclization of the 6-acylhydrazinopyrimidine 65 by heating with polyphosphoric acid led, instead, to pyrimidine ring rupture, yielding the l,l-diamino-2-nitro-2-(3-phenyl-l,2,4-triazol-5-yl)ethene 66. Cyclocondensation of the latter with triethyl orthoformate gave the fully aromatic triazolopyrimidine 67 (94JHC1171) (Scheme 23). 

Dinitro ketone 49 with potassium cyanide provided 5,6-dihydrooxazolo [3,2-/7][l,2,4]triazole 51. Its formation is due to the fact that primary attack by the cyanide anion is not directed at the ring C5 atom but rather at the carbonyl group to give the corresponding cyanohydrin 50 and the subsequent intramolecular displacement of the nitro group gives the final product (Scheme 8) (81 KGS 1403). 

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