Difluorocarbene-triggered [1+5] annulation is developed to access 1,1-difluoro-1,9a-dihydropyrido[2,1-c][1,4]thiazine-3,4-dicarboxylate derivatives in satisfactory to good yields via the direct reaction of potassium bromodifluoroacetate and pyridinium 1,4-zwitterionic thiolates under heating. Pyridinium 1,4-zwitterionic thiolates first nucleophilically attack difluorocarbene generated from potassium
二氟卡宾触发的 [1+5] 环化反应得到 1,1-difluoro-1,9a-dihydropyrido[2,1- c ][1,4]thiazine-3,4-dicarboxylate 衍
生物,收率令人满意
溴二氟乙酸钾和
吡啶鎓 1,4-两性离子
硫醇盐在加热下的直接反应。
吡啶 1,4-两性离子
硫醇盐首先亲核攻击由
溴二氟乙酸钾生成的
二氟卡宾,然后对
吡啶进行分子内亲核加成。该方法提供了一种将二
氟甲基引入1,9a-
二氢吡啶并[2,1- c ][1,4]
噻嗪环,甚至修饰药物分子的快速途径。