Department of Chemistry, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia.
Malaysia Genome Institute , Jalan Bangi, 43000 Kajang , Selangor , Malaysia.
Org Lett. 2018 Dec 21;20(24):8014-8018. doi: 10.1021/acs.orglett.8b03592. Epub 2018 Dec 13.
Two new monoterpenoid indole alkaloids, alstoscholactine (1) and alstolaxepine (2), were isolated from Alstonia scholaris. Compound 1 represents a rearranged stemmadenine alkaloid with an unprecedented C-6-C-19 connectivity, whereas compound 2 represents a 6,7- seco-angustilobine B-type alkaloid incorporating a rare γ-lactone-bridged oxepane ring system. Their structures and absolute configurations were determined by spectroscopic analyses. Compound 1 was successfully semisynthesized from 19 E-vallesamine. Compound 2 induced marked vasorelaxation in rat isolated aortic rings precontracted with phenylephrine.
阿氏斯考来亭（1）和阿氏斯考来嗪（2）。化合物 1 代表了一种具有前所未有的 C-6-C-19 连接的重排 Stemmadenine 生物碱，而化合物 2 则代表了一种 6,7- 去甲-angustilobine B 型生物碱，其中包含一个罕见的γ-内酯桥接的氧杂环丁烷环系统。它们的结构和绝对构型通过光谱分析确定。化合物 1 可成功地由 19 E-瓦勒沙敏半合成得到。化合物 2 可引起预先用苯肾上腺素收缩的大鼠离体主动脉环显著松弛。
