Total syntheses of six brominated marinesponge bis(indole) alkaloids of the hamacanthin, spongotine, and topsentin classes are described. Retrosynthetic analysis shows that their structures all include the 1-(6'-bromoindol-3'-yl)-1,2-diaminoethane unit 13a. This key moiety has been prepared from brominated indolic N-hydroxylamine 5b via synthetic intermediate 8b.
Discovery of Topsentin Alkaloids and Their Derivatives as Novel Antiviral and Anti-phytopathogenic Fungus Agents
作者:Xiaofei Ji、Ziwen Wang、Ji Dong、Yuxiu Liu、Aidang Lu、Qingmin Wang
DOI:10.1021/acs.jafc.6b04020
日期:2016.12.7
Topsentin alkaloids and their derivatives were designed, synthesized, and characterized on the basis of NMR and mass spectroscopy. The antiviral activities against tobacco mosaic virus (TMV) and anti-phytopathogenic fungus activities of these alkaloids were evaluated for the first time. Alkaloids 1c, 1e, 2b, and 2d displayed significantly higher antiviral activities against TMV than Ribavirin, emerging
The synthesis of four natural bis(indole) alkaloids of topsentin class 1 and 2 is described. Their bis(indole) α-carbonylimidazoline and subsequently bis(indole) α-carbonylimidazole moieties have been built via the condensation between indolic α-ketothioimidate salts 4 and 1-(indol-3‘-yl)-1,2-diaminoethane 3. This compound results from the β-amino indolic hydroxylamine 5 by a two-step sequence. This
Neighboring Hydroxyl Group-Assisted Allylboration and Lewis Acid-Mediated Carbonyl-Ene Reaction for Access to a Hapalindole Cyclohexane Core with Multiple Contiguous Stereogenic Centers
3-indolyl-substituted homoallylicalcohols in good yields with excellent diastereoselectivies (up to >20:1 dr). The hydroxyl group not only played a vital role in the challenging allylboration but was elaborated for the subsequent construction of a hapalindole cyclohexane core by a highly diastereoselective Lewis acid-catalyzed carbonyl-ene reaction. In the overall process, four contiguous stereogeniccenters including
isolated marine tris-indole alkaloid, has been conducted. In this study, we accomplished the first asymmetric totalsynthesis of 5 via the construction of an imidazoline-linked bis-indolylmethane skeleton using a Friedel–Crafts-type reaction. Our synthesis enabled a detailed study of the antibacterial profile of 5. Compound 5 displayed bactericidal activity against Staphylococcus aureus, including methicillin-resistant
来自海绵的双吲哚生物碱是一类有趣的天然产物,具有多种活性。然而,仅对tulongicin A ( 5 )(一种先前分离的相关海洋三吲哚生物碱)进行了初步生物学研究。在这项研究中,我们通过使用弗里德尔-克来福特型反应构建咪唑啉连接的双吲哚基甲烷骨架,首次完成了5的不对称全合成。我们的合成能够对5的抗菌特性进行详细研究。化合物5对金黄色葡萄球菌(包括耐甲氧西林金黄色葡萄球菌(MRSA) 菌株)具有杀菌活性。