Crystal Structure Analysis of 4-Oxo, 4-hydroxy- and 4-alkyl-7-bromopyrazolo[5,1-c][1,2,4]triazines

Abstract

The crystal structures of 8-R¹-7-bromo-3-tert-butyl-1-R²-pyrazolo[5,1-c][1,2,4]triazin-4(1H)-ones 1a–c, 2a,c (R¹ = CN, CO₂Et, NO₂, R² = H, 1:1 and 3:1 solvates with DMSO; R¹ = CN, CO₂Et, R² = CH₂Boc), 8-R¹-7-bromo-3-tert-butyl-1-R²-1,4-dihydropyrazolo[5,1-c][1,2,4]triazin-4-ols 3a,b (R¹ = CN, R² = n-Bu; R¹ = Br, R² = CH₂Boc), 1,4-dihydro- and aromatic 7-R³-3-tert-butyl-4-R⁴-8-methylpyrazolo[5,1-c][1,2,4]triazines 5a,b, 6 (R³ = H, R⁴ = n-Pr; R³ = Br, R⁴ = n-Bu) were investigated by X-ray diffraction analysis. The structural preferences and different packing modes based on the intermolecular interactions were analyzed by the Hirshfeld surface and energy framework analysis.

Graphical Abstract

The crystal structures of ten 3-tert-butyl-4-oxo, 4-hydroxy- and 4-alkyl-7-bromopyrazolo[5,1-c][1,2,4]triazines including non-solvated, 1:1 and 3:1 solvates with DMSO were investigated by single crystal X-ray diffraction, Hirshfeld surface and energy framework analyses.