Investigation and synthetic studies of bioactive Mitragyna alkaloids.

北米特拉吉那的叶子。在泰国和马来人的传统使用中被认为是鸦片的替代品。重新研究了该植物叶片中的生物碱成分，分离出一种主要的吲哚类生物碱米特拉金碱和一种新的次要生物碱-7 α -羟基- 7h -米特拉金碱。从光学纯醇开始，获得了米特拉金的对映选择性全合成。将米特拉金碱转化为假吲哚基衍生物，并对其C2、C3的立体化学性质进行了研究。以葡萄糖苷内酰胺为原料进行全合成和仿生转化，对新型米特拉金类生物碱中具有基本骨架的核苷进行了结构修正。粗生物碱合剂和米特拉吉九具有非麻醉性的抗痛感活性，并抑制平滑肌收缩。

The leaves of Mitragyna speciosa Korth. have been known as an opium substitute in traditional use by Thai and Malay natives. Reinvestigation of the alkaloidal constituents in the leaves of the plant resulted in the isolation of a major indole alkaloid, mitragynine, and a new minor alkaloid 7alpha-hydroxy-7H-mitragynine. Starting from an optically pure alcohol, an enantioselective total synthesis of mitragynine was attained. Mitragynine was converted into the pseudoindoxyl derivative and its stereochemistry of C2, C3 was elucidated. The structure of nauclefidine, having a basic skeleton in the new type of Mitragyne alkaloids, was revised based on the total synthesis and biomimetic transformation from the vincoside lactam. The crude alkaloid mixture and mitragynine showed non-narcotic antinociceptive activities and inhibited contraction of smooth muscle.