Synthesis of 7,8-Nitro(dinitro)-3-<i>tert</i>-butyl-4-oxopyrazolo[5,1-<i>c</i>][1,2,4]triazines
3- tert -Butyl-8-nitro-7-R-pyrazolo[5,1- c ][1,2,4]triazin-4(6 H )-ones (R = H, Cl, Br, NO<sub>2</sub>, N<sub>3</sub>) were prepared by nitration using HNO<sub>3</sub>-H<sub>2</sub>SO<sub>4 </sub>of the corresponding 7-R-substituted 8-carboxylic acids or their analogues with a vacant C<sup>8 </sup>position. The latter were synthesized by diazotization of 3- tert -butyl-7-amino-4-oxo-4,6-dihydropyrazolo[5,1- c ][1,2,4]triazin-8-carboxylic acid. The electrophilic halogenation and cycloaddition of 7-azido- and 7-nitro derivatives were considered. The structures of the synthesized compounds were confirmed by IR, heteronuclear NMR spectroscopy, HRMS and single-crystal XRD.