7-Lithio-3-tert-butylpyrazolo[5,1-c][1,2,4]triazines have been generated for the first time using one-pot nucleophilic addition and metal-halogen exchange reactions in 7-bromopyrazolo[5,1-c][1,2,4]triazines. It was found that the stability of 7-lithio species depends highly on the substitution pattern at the C(4) ring position. The rate of the pyrazole ring opening reaction roughly followed the order of the electronegativity of substituents: rapid cycle cleavage took place already at −97 °C for C(4) = O, CH–Ar, CH–C≡CPh, while CH–Alk and CH₂ substituted derivatives were stable in these conditions (Ar = Ph, 4-tolyl; Alk = t-Bu, n-Bu, n-Pr). Quantum chemical modeling showed that the ring opening is accompanied with simultaneous shift of the Li atom towards N(6). Calculated free activation energies are in range from 12.7 to 15.0 kcal*mol⁻¹. Electrophile trapping of fairly stable 4-alkyl-1,7-metalated derivatives at −97 °C using H₂O, DMF or PhCHO allowed the selective side-chain functionalization. Tautomeric exo- and endocyclic double bond equilibrium in the isolated 4-oxo and 4-aryl substituted ring opening products is also discussed on the basis of IR, ¹H, ¹³C NMR, high resolution mass spectra and X-ray powder diffraction analysis.

7-Lithio-3-叔丁基吡唑并[5,1- c ] [1,2,4]三嗪首次使用一锅亲核加成反应和金属-卤素交换反应在7-溴吡唑并[5， 1- c ] [1,2,4]三嗪。发现7-lithio物种的稳定性高度取决于C（4）环位置上的取代模式。吡唑开环反应的速率大致遵循取代基的电负性的顺序：对于-C（4）= O，CH-Ar，CH-C≡CPh，在-97°C时已经发生了快速循环裂解Alk和CH ₂取代的衍生物在这些条件下是稳定的（Ar = Ph，4-tolyl; Alk =  t -Bu，n -Bu，n-Pr）。量子化学建模表明，开环伴随着Li原子向N（6）的同时移动。计算的自由活化能在12.7至15.0kcal * mol ^-1的范围内。使用H ₂ O，DMF或PhCHO在-97°C下对相当稳定的4-烷基-1,7金属化衍生物进行亲电捕获，从而实现了选择性侧链功能化。在IR，¹ H，¹³ C NMR，高分辨率质谱和X射线粉末衍射分析的基础上，还讨论了分离的4-氧代和4-芳基取代的开环产物中的互变异构体外和内环双键平衡。