Microwave accelerated Pictet–Spengler reactions of tryptophan with ketones directed toward the preparation of 1,1-disubstituted indole alkaloids
作者:Fu-Ming Kuo、Ming-Chung Tseng、Ya-Hew Yen、Yen-Ho Chu
DOI:10.1016/j.tet.2004.10.025
日期:2004.12
Using the Pictet–Spengler reactions of tryptophan with aldehydes under acidic conditions at ambient temperature, diastereoisomers of 1,3-disubstituted-1,2,3,4-tetrahydro-β-carbolines could readily be furnished in short time (0.5–4 h) with good to excellent yields (50–98%). Though intrinsically slow in reaction rates, ketone reactions can be accelerated (from days to minutes) using microwaves in open
使用色氨酸与醛在环境温度下的酸性条件下的Pictet-Spengler反应,可以轻松地在短时间内(0.5–4小时)提供1,3-二取代-1,2,3,4-四氢-β-咔啉的非对映异构体),具有良好至极佳的收率(50–98%)。尽管反应速度本质上很慢,但在开放的容器中使用微波可以加速酮的反应(从几天到几分钟),分离产率高(67-99%),这使这些咔啉成为合成天然和非天然吲哚生物碱的可行反应中间体。 。简要讨论了两种吲哚生物碱的制备,即四氢-β-咔啉二酮哌嗪和四氢-β-咔啉乙内酰脲。