Nitropyrazoles 14. Synthesis of 1,3,4-trinitropyrazole and its behavior in the nucleophilic substitution reactions. General method of synthesis of 5-substituted 3,4-dinitropyrazoles

Abstract

For the first time pyrazole containing three nitro groups in the pyrazole cycle, viz., 1,3,4 tri nitropyrazole, was obtained by N nitration of 3,4 dinitropyrazole. 1,3,4 Trinitropyrazole enters the cine substitution reaction of N nitro group under the action of O , N , and C nucleophyls under mild conditions. Thus, general method of synthesis of 5 substituted 3,4 dinitropyrazoles containing free NH fragment was worked out.

Polynitro-substituted pyrazoles and triazoles as potential energetic materials and oxidizers

“…13 Thus, it was useful to develop a general method to aminate a variety of nitropyrazoles. In an initial study, amination of pyrazoles using O-tosylhydroxylamine with ammonium nitropyrazolates led readily to N-amino nitropyrazoles in moderate to good yields for most nitropyrazoles (5)(6)(7)(8)(9). Although amination of 4-nitropyrazole with O-tosylhydroxylamine only produced trace amounts of 1-amino 4-nitropyrazole (4), its reaction with hydroxylamine-O-sulfonic acid and potassium carbonate gave the desired product in 75% yield (Scheme 2).…”

“…Owing to the electron-withdrawing effect of substituent groups bonded to the pyrazole ring, some N-amino nitropyrazoles, such as 1-amino-3,5-dinitropyrazole ( 5) and 1-amino-3,4-dinitro-5-cyanopyrazole (7), failed to undergo Mannich reactions with trinitroethanol. Fully substituted nitropyrazoles including 1-amino-3,4-dinitro-5-azidopyrazole (8) and 1,4-diamino-3,5-dinitropyrazole (9) reacted readily with trinitroethanol to produce the corresponding N-trinitroethylamino pyrazoles (10 and 11). Additionally, trinitroethylation of 4 and of 1-amino-3,4-dinitro pyrazole (6) gave 12 and 13 as well (Scheme 3).…”

“…For example, both C-and N-nitrated pyrazoles have been examined to give 1,3,4-trinitropyrazole, which is very moisture sensitive. 8 Compared with N-nitration of azoles, N-trinitroethyl amination is considered to be a more favorable strategy giving rise to remarkable improvements in densities and detonation properties. 9 More importantly, they are stable enough to be handled safely.…”

Synthesis of 1-(N-nitropyrazolyl)-1Н-tetrazoles – a new type of heteronuclear N-nitropyrazole derivatives

“…As reported in the literature, 14,[38][39][40][41][42][43][44][45] N-nitration in the majority of cases proceeds selectively, giving only one isomer. In the monosubstituted 3(5)-Rpyrazole series, N-nitration occurs at the endocyclic nitrogen atom, which is the most distant from the 3(5)-R Chemistry of Heterocyclic Compounds 2015, 51(8), 695-703 Table 2.…”

Synthesis of 3,4,5-trinitropyrazole

“…Earlier, 1 we have obtained for the first time 1,3,4 tri nitropyrazole 1, a derivative with three nitro groups in the pyrazole ring (Scheme 1).…”