Synthesis and crystal structures of 7,8-bromo (dibromo)-3-tert-butylpyrazolo[5,1-c][1,2,4]triazines

Abstract

Graphical abstract Single crystal structures in a series of 7-bromo-, 8-bromo-, and 7,8-dibromo-3- tert -butylpyrazolo[5,1- c ][1,2,4]triazin-4(1 H )-ones have been investigated by X-ray diffraction. Novel 7-bromo- and 7,8-dibromo-3- tert -butylpyrazolo[5,1- c ][1,2,4]triazines were synthesized by reduction of triazine carbonyl with dehydrative aromatization in acidic media, and their XRD structural features were compared with that of the 4-oxo analogs. The lengths and bond angles and the packing of molecules in crystals have been considered. Non-valence interactions for some of the studied compounds were observed. Correlations between the presence of bromine atoms at different positions and structural features are determined. Supplementary Information The online version contains supplementary material available at 10.1007/s11224-021-01768-0.

CRYSTAL STRUCTURE OF 3-tert-BUTYL- PYRAZOLO[5,1-с][1,2,4]TRIAZINE-3,4-DIYL DICARBOXYLATES

“…Due to pronounced structural features of carboxylate 4a brominated at the С7 position, it was interesting to investigate by single crystal XRD the structure of similar compound 4b containing bromine atoms at С7 and С8 positions. Previously undescribed compound 4b was isolated in treating aromatic 7,8-dibromopyrazolotriazine 5 [ 26 ] with N-bromosuccinimide in the presence of benzoic acid (Scheme 2).…”