Synthesis and chemical properties of 8-lithio-4-oxopyrazolo[5,1-c][1,2,4]triazines

Abstract

Unstable under normal conditions sodium and lithium 3-tert-butyl-8-lithio-7-R-4-oxopyrazolo[5,1-c][1,2,4]triazin-1-ides were generated for the first time by the reaction of 8-bromo-7-R-3-tert-butyl-4-oxopyrazolo[5,1-c][1,2,4]triazines (R = H, NHCOCF₃) with BuⁿLi in THF in the −97H÷−84 °C temperature range. The triazinides were trapped in the reactions with various electrophiles (H₂O, CH₃I, ArCHO, DMF, R¹COCl) to selectively synthesize new C(8)-functionalized 4-oxopyrazolo[5,1-c][1,2,4]triazines.