In boiling 2.5 N solution of KOH in 40% (w/w) aqueous EtOH, the lactams (±)-5a, b, d were hydrolyzed to an extent of 75-98% within 8-20 h, attaining equilibrium with the corresponding ω-amino acid derivatives (±)-6a, b, d. The potassium salt (±)-8, generated in situ from the translactam acid (±)-7, was equilibrated with the ring-opened product (±)-6f and the recyclized cis isomer (±)-5f in a ratio of 57 : 15 : 28 within ca. 45 h under similar reaction conditions. The cis-N-(2-arylethyl) analog (-)-9 was converted into the trans-lactam acid (+)-13, a key synthetic precursor for the 8-hydroxy-9, 10-dimethoxybenzo [a] quinolizidine-type Alangium alkaloids, through application of such alkaline hydrolytic cis-trans equilibration followed by debenzylation.
在 40% (w/w) EtOH
水溶液中煮沸 2.5 N KOH 溶液中,内酰胺 (±)-5a、b、d 在 8-20 小时内
水解至 75-98%,与相应的内酰胺达到平衡。 ω-
氨基酸衍
生物(±)-6a、b、d。由反式内酰胺酸(±)-7原位生成的
钾盐(±)-8与开环产物(±)-6f和回收的顺式异构体(±)-5f以57的比例进行平衡: 15 : 28 内约。在相似的反应条件下45小时。顺式-N-(2-芳基乙基)类似物(-)-9被转化为反式-内酰胺酸(+)-13,这是8-羟基-9, 10-二
甲氧基苯并[a]喹里西啶-的关键合成前体。八角豆
生物碱,通过应用这种碱性
水解顺反平衡,然后脱苄基。