13 Amauroascus属菌の生産する降圧作用を有するアルカロイド WF6237の構造と合成

概要

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In the course of our screening program for biologically active principles from fermentation sources, a novel alkaloid WF6237 (designated as amauromine) with vasodilating activity was isolated from Amauroascus sp. No. 6237. The structure of amauromine was determined to be 1a by means of chemical and spectroscopic evidence. Total synthesis of amauromine was also investigated. First, a model compound, debromo-8,8a-dihydroflustramine C 17 was synthesized by taking advantage of thioclaisen rearrangement reaction followed by ring closure with desulfurization by NaH. Syntheses of amauromine 1a and tetra-hydroamauromine 2 were achieved starting from L-tryptophan. The key intermediate 29 was obtained by simultaneous thioclaisen rearrangement reaction at the two centers on 28. Amauromine 1a was synthesized by desulfurization with low valent titanium reagent on 29, though the yield was low. Synthesis of tetrahydroamauromine 2 was accomplished by reduction with modelately activated Ra-Ni on 30. To our knowledge, this is the first synthesis of natural product containing reversed isoprenoid unit at C-3 of indole skeletone.
天然有機化合物討論会の論文
1983-09-15