A simple and convenient transformation of berberine (1) into trans-, cis-, and unsaturated benzindenoazepines through regioselective C14-N bond cleavage of 8, 14-cycloberbines is described. Acidic treatment of the 8, 14-cycloberbine (2) effected regioselective ring opening to afford the trans-and cis-benzindenoazepines (7a and 7b) as the kinetically and thermodynamically controlled products, respectively. Dehydration of their N-methyl derivatives (11a and 11b) gave the unsaturated benzindenoazepine (20), which was obtained more efficiently from the 8, 14-cycloberbine (2) by treatment with p-toluenesulfonic acid in benzene followed by N-methylation. Similarly, the ring D-inverted 8, 14-cycloberbine (23) was converted to the corresponding trans-, cis-, and unsaturated benzindenoazepines (24a, 24b, and 27, respectively).
本研究描述了通过 8,14-环
小檗碱的区域选择性 C14-N 键裂解将
小檗碱 (1) 转化为反式、顺式和不饱和
苯并
茚并
氮杂卓的简单而方便的方法。对 8,14-环
小檗碱(2)进行酸性处理可实现区域选择性开环,得到反式和顺式
苯并
茚并
氮杂卓(7a 和 7b),它们分别是动力学和热力学控制产物。它们的 N-
甲基衍
生物(11a 和 11b)
脱水后得到了不饱和
苯并
茚并
氮杂卓(20),这种不饱和
苯并
茚并
氮杂卓是通过在
苯中使用
对甲苯磺酸处理 8、14-环
小檗碱(2),然后进行 N-
甲基化反应更有效地得到的。同样,环 D 反转的 8,14-环
小檗碱(23)被转化为相应的反式、顺式和不饱和
苯并
茚并
氮杂卓(分别为 24a、24b 和 27)。