Total syntheses of 'abnormal-type' erythrinan alkaloids, (±)-coccolinine (1), (±)-isococculidine (2), (±)-coccuvinine (3) and (±)-cocculidine (4), are described. Mondon's glyoxylic ester synthesis was successfully applied in these syntheses. The key intermediate, 16-ethoxycarbamido-2, 15-dimethoxyerythrinan-7, 8-dione (7), was obtained by condensation of 3-ethoxycarbamido-4-methoxyphenylethylamine (5) with ethyl 4-methoxycyclohexanone-2-glyoxylate (6), followed by treatment with phosphoric acid. The ethoxycarbamido group at the C16 position was effectively employed as a regiospecific para-directing group in the isoquinoline ring closure.
描述了“异常型”赤藓聚糖
生物碱、(±)-coccolinine (1)、(±)-isococculidine (2)、(±)-cacculidine (3) 和 (±)-cocculidine (4) 的全合成。 Mondon 的
乙醛酸酯合成法已成功应用于这些合成中。关键中间体 16-乙氧基
脲基-2, 15-二甲氧基赤藓聚糖-7, 8-二酮 (7) 由 3-乙氧基
脲基-4-
甲氧基苯乙胺 (5) 与
4-甲氧基环己酮-2-
乙醛酸乙酯 (6) 缩合得到,然后用
磷酸处理。 C16位置的乙氧基
脲基团被有效地用作
异喹啉闭环中的区域特异性对位导向基团。