Synthesis and Comparison of the Reactivity of 3,4,5-1H-Trinitropyrazole and Its N-Methyl Derivative

3,4,5-Trinitro-1H-pyrazole (1) has been obtained via nitration of 3,5-dinitropyrazole with mixture of sulfuric and nitric acids. Compound 1 reacts with excess ammonia and aliphatic amines, in the presence of bases with NH-azoles, phenols, thiols, and triflouroethanol at mild conditions in water. All these reactions occur as the nucleophilic substitution of the nitro-group at position 4 in 1 affording 4-R-3,5-dinitropyrazoles. The product of methylation of 1, N-methyl-3,4,5-trinitropyrazole (4), also reacts with thiols, phenols, oximes, ammonia, amines, and NH-azoles. The reactions proceed with high yields but nucleophilic substitutions in these cases occur regioselectively at position 5 in 4 to afford 5-R-3,4-dinitropyrazoles.