Acidic treatment of the 8, 14-cycloberbine (2), derived from berberine (1), in methanol afforded the cis-and trans-benzindanoazepines (7 and 8), whereas the reaction of 2 with p-toluenesulfonic acid in benzene yielded the benzindenoazepine (6) in an excellent yield. This simple conversion method was applied to the synthesis of the benzindenoazepine (21), the key intermediate for the total synthesis of (±)-cis-alpinigenine (22) and (±)-cis-alpinine (23).
从
小檗碱(1)中提取的 8、14-环
小檗碱(2)在
甲醇中进行酸性处理后,可得到顺式和反式
苯并
茚并
氮杂卓(7 和 8),而 2 与
对甲苯磺酸在
苯中反应则可得到
苯并
茚并
氮杂卓(6),且收率极高。这种简单的转化方法被用于合成
苯并
茚并
氮杂卓(21),它是全合成(±)-顺式-alpinigenine(22)和(±)-顺式-alpinine(23)的关键
中间体。