核苷研究4: 3-甲硫基-7-氧代吡唑并(5, 4-e)-1, 2, 4-三嗪核苷合成研究

对3-甲硫基-7-氧代吡唑并(5, 4-e)-1, 2, 4-三嗪的成苷反应进行了研究。当保护基为乙酰基时, 生成的核苷β-体为主产物。当保护基为苯甲酰基时全部是β-体。端位构型用1H NMR确定。在五元环中, 顺位质子比反位质子裂分常数大。

Studies on nucleosides IX synthesis of nucleosides of pyrazolo (5, 4-e)-1, 2, 4-triazine derivatives

The ribonucleosides of pyrazolo (5, 4-e)-1, 2, 4-triazine derivatives derivatives were synthesized. The α, β-isomes were distinguished with 1H NMR. β-isomer was the major product in acetyl protected ribonucleosides. In benzoyl protected ribonucleosides, no α-isomer was formed. The JH^1H^2 of cis isomer was bigger than that of trans in five membered ring.