STUDIES ON THE SYNTHESIS OF THE INDOLE ALKALOIDS NGOUNIENSINE AND EPINGOUNIENSINE

[摘要] Tetracyclic keto lactam 2a has been synthesized by acylation of a mixture of esters 5, followed by saponification and further cyclization. Due to the presence of an exocyclic amide carbonyl group, epimerization at C-3 occurs to give the most stable cis relative configuration. Trans acetylpiperidine 4b has been prepared in five steps from pyridinium salt 9. Attempted direct cyclization of 4b to epingouniensine failed.

[发布日期] 1991-07-15

[关键词] NGOUNIENSINE;INDOLE;CYCLIZATION;2-CYANOTETRAHYDROPYRIDINE;N-ACYLPIPERIDINE