8aS)-octahydro-8-hydroxyindolizine-5-carboxylate (22). By functional-group interconversions, 21 was transformed into piclavine A (1) and indolizidine 209D (2). Similarly, (5R,8R,8aS)-octahydro-5-pentylindolizine-8-methanol (37), the final relay for indolizidine 209B (3), was obtained from 22.
从
L-谷氨酸二乙酯盐酸盐和四氢-2,5-二甲氧基
呋喃中获得的1 H-
吡咯衍
生物用BBr 3环化为(5 S)-5,6,7,8-四氢-8-氧代
吲哚嗪5-
羧酸酯(18)。在Pd / C上于AcOH中催化18氢化,得到(5 S,8a R)-八氢
吲哚嗪-5-
羧酸乙酯(21),而在Rh / Al 2 O 3上于EtOH / AcOH 99:1中进行氢化,主要得到乙基(5 S,8 S,8a S)-八氢-8-羟基
吲哚嗪-5-
羧酸酯(22)。通过功能组互变,将21转化为
吡克拉维甲A(1)和
吲哚并立定209D(2)。同样地,从22获得了(5 R,8 R,8a S)-八氢-5-戊基多唑嗪-8-
甲醇(37),这是
吲哚并立定209B (3)的最终继电器。