Environmental Futures Research Institute, Griffith University, Southport 4222, Queensland, Australia.
School of Environment and Science, Griffith University, Southport 4222, Queensland, Australia.
J Org Chem. 2020 Mar 6;85(5):3490-3496. doi: 10.1021/acs.joc.9b03221. Epub 2020 Feb 24.
The structures of the sponge-derived dibrominated bis-indole alkaloids, namely, echinosulfone A () and the echinosulfonic acids A to D (-), have been revised based upon reanalysis of their NMR spectroscopic and MS spectrometric data, comparison of this data with those reported for structurally related compounds, and based on their common biogenesis. The reinterpreted spectroscopic evidence has been corroborated by the total synthesis of the revised structure of echinosulfone A (). This was achieved by bis-carbonylation at C-3 of the magnesium salt of 6-bromoindole with triphosgene to afford the new dibrominated bis-indole ketone, bis(6-bromo-1-indol-3-yl)methanone (), followed by N-sulfonation of one indole moiety to furnish 6-bromo-3-(6-bromo-1-indole-3-carbonyl)-1-indole-1-sulfonate (). The five marine alkaloids corrected herein each contain an indole sulfamate and are all carbon-bridged dibrominated bis-indoles: echinosulfone A () is a di(1-indol-3-yl)methanone, while the echinosulfonic acids A to D (-) are methyl 2,2-bis(1-indol-3-yl) acetates.
基于对其 NMR 波谱和 MS 谱数据的重新分析、与结构相关化合物报道的数据比较以及基于它们共同的生物发生，对海绵衍生的二溴双吲哚生物碱，即 echinosulfone A () 和 echinosulfonic 酸 A 至 D (-) 的结构进行了修订。重新解释的光谱证据通过 echinosulfone A 的修订结构的全合成得到了证实（）。这是通过三光气在镁盐 6-溴吲哚的 C-3 处进行双羰基化反应得到新的二溴双吲哚酮，双（6-溴-1-吲哚-3-基）甲酮（），然后对一个吲哚部分进行 N-磺化得到 6-溴-3-(6-溴-1-吲哚-3-羰基)-1-吲哚-1-磺酸酯（）。本文更正的 5 种海洋生物碱均含有吲哚磺酰胺，且均为碳桥联二溴双吲哚：echinosulfone A () 是二 (1-吲哚-3-基) 甲酮，而 echinosulfonic 酸 A 至 D (-) 是甲基 2,2-双 (1-吲哚-3-基) 乙酸酯。
