Decarboxylation and electrophilic substitution in 3-tert-butyl-4-oxopyrazolo[5,1-c][1,2,4]triazines

Abstract

Reactivity of 7-R-3-tert-butyl-4-oxo-4,6-dihydropyrazolo[5,1-c][1,2,4]triazine-8-carboxylic acids (R = NH₂, N₃, H) and products of their decarboxylation towards different electrophilic agents (chloroacetone, Boc₂O/NaN₃, DMF/POCl₃, TMSBr, N-halosuccinimides, and HNO₂) was studied. A selective synthesis of new C(7),C(8)-functionalized and N(1)-tert-butyloxycarbonyl-substituted 4-oxopyrazolo[5,1-c][1,2,4]triazines was performed. The structures of the synthesized compounds were confirmed by IR and NMR spectroscopy, high resolution mass spectrometry and single crystal X-ray diffraction analysis.