Synthesis of the tricyclic indole alkaloids, dilemmaones A and B

Lambson, Katharine E.; Dacko, Christopher A.; McNeill, Jeffrey M.; Akhmedov, Novruz G.; Söderberg, Björn C.G.

doi:10.1016/j.tet.2019.130714

Cited by 8 publications

(3 citation statements)

References 46 publications

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Section: Resultsmentioning

confidence: 99%

Anti-Virus Isoindolinone alkaloids with rare oxocyclopenta[f]isoindole frameworks isolated from the stems of flue cured tobacco

Liu

et al. 2022

Preprint

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Background The large scale tobacco planting in Yunnan produces a large amount of waste, including stems, roots, low grade and defective tobacco leaves. Therefore, the multipurpose utilization of the by-product of tobacco is an interesting topic. In order to increase medicinal value of tobacco and the comprehensive utilization of its by-products, our group had investigated the chemical constituents of the stems of Y-202, a cultivar of tobacco with high resistance to tobacco mosaic virus (TMV), which originated from K326 by ethylmethane sulfonate (EMS) mutagenesis. Results As a result, four new isoindolinone-type small molecule alkaloids named nicoisoindoles A–D (1–4), along with four known isoindole derivatives (5–8) were isolated. Nicoisoindoles A–D represent a new subclass of isoindolinone alkaloids with rare cyclopenta[f]isoindole-1-one frameworks. Among them, nicoisoindole C (3) possesses an unusual N-2-(5-methoxy-6-methylpyridin-2-yl)ethyl moiety, while nicoisoindole D (4) has a novel a N-(3-methyl-6-oxo-1,6-dihydropyridin-2-yl)methyl substituent. Interestingly, compounds 1, 3, and 4 showed high anti-TMV activities with inhibition rates of 43.8, 58.8, and 67.8% at the concentration of 20 µM, and IC50 values of 23.6, 19.5 and 15.4 µM, respectively, even more potent than that of positive control. In order to study whether the oxocyclopenta[f]isoindole-1-ones have more broad antiviral activities, compounds 1–4 were also tested for their anti-rotavirus activities, and they exhibited potential anti-rotavirus activities with therapeutic index (TI) valves in the range of 13.0-18.5. Conclusions The successful isolation and structure identification of oxocyclopenta[f]isoindole-1-ones provide materials for the screening of anti-virus activities inhibitors, and also contribute to the development and utilization of the waste from tobacco cultivation.

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Section: Resultsmentioning

confidence: 99%

Anti-Virus Isoindolinone alkaloids with rare oxocyclopenta[f]isoindole frameworks isolated from the stems of flue cured tobacco

Liu

et al. 2022

Preprint

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“…There still two rings should also be existed in compound 1 to meet 8 degrees of unsaturation. By comparison with the published literature, the benzene ring, N-methylene, and amide carbonyl should be formed a isoindolin-1-one nucleus [12,13], while the -CH 2 CH 2 CO-moiety also should be linked to benzene ring to form a pentacyclic ketone [26,27]. In addition, the existance of isoindolin-1-one nucleus was supported by the HMBC correlations from H 2 -3 to C-1, C-4, C-3a, and C-7a, and from H-7 to C-1, while C-8 linked to C-6, C-10 linked to C-5 to form pentacyclic ketone moiety was also supported by the HMBC correlations from H 2 -8 to C-5/C-6/C-7, and from H 2 -9 to C-5/C-6 (Fig.…”

Section: Structure Characterization Of Compounds 1-8mentioning

confidence: 96%

Antivirus isoindolinone alkaloids with rare oxocyclopenta[f]isoindole frameworks isolated from the stems of flue cured tobacco

Liu

et al. 2022

Chem. Biol. Technol. Agric.

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Background Since Nicotiana tabacum (tobacco) has important significance to humans for their medicinal uses, to find antivirus activities inhibitors from tobacco, increase its medicinal value, and comprehensive utilization of its by-products, our group had investigated the chemical constituents of the stems of Y-202, a cultivar of tobacco which high resistance to tobacco mosaic virus (TMV). Results Four new isoindolinone-type alkaloids, nicoisoindoles A–D (1–4), along with four known isoindole derivatives (5–8) were isolated. Compounds 1–4 represent a new subclass of isoindolinone alkaloids with rare cyclopenta[f]isoindole-1-one frameworks. Among them, nicoisoindole C (3) possesses an unusual N-2-(5-methoxy-6-methylpyridin-2-yl) ethyl moiety, while nicoisoindole D (4) has a novel a N-(3-methyl-6-oxo-1,6-dihydropyridin-2-yl)methyl substituent. Interestingly, compounds 1, 3, and 4 showed high anti-TMV activities with inhibition rates of 43.8%, 58.8%, and 67.8% at the concentration of 20 μM, and IC50 values of 23.6, 19.5 and 15.4 μM, respectively, even more potent than that of positive control. Conclusions The successful isolation and structure identification of new oxocyclopenta[f]isoindole-1-ones provide materials for the screening of antivirus activities inhibitors, and contribute to the development and utilization of the waste from tobacco cultivation. Graphical Abstract

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“…We analyzed 42 journal articles and 61 separate Pd-catalyzed reactions (Figure ). ,,,,− ,,,,,− There is a preference for lower mol % ranges, but more reactions are performed at 5 mol %, which is particularly apparent in older articles. There is a larger variation in ppm values for the 4–5 mol % category, most likely due to the large variation in reaction volume.…”

Section: Stille Cross-couplingmentioning

confidence: 99%

Pd-Catalyzed Cross-Couplings: On the Importance of the Catalyst Quantity Descriptors, mol % and ppm

Horbaczewskyj

Fairlamb

2022

Org. Process Res. Dev.

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This Review examines parts per million (ppm) palladium concentrations in catalytic cross-coupling reactions and their relationship with mole percentage (mol %). Most studies in catalytic cross-coupling chemistry have historically focused on the concentration ratio between (pre)catalyst and the limiting reagent (substrate), expressed as mol %. Several recent papers have outlined the use of “ppm level” palladium as an alternative means of describing catalytic cross-coupling reaction systems. This led us to delve deeper into the literature to assess whether “ppm level” palladium is a practically useful descriptor of catalyst quantities in palladium-catalyzed cross-coupling reactions. Indeed, we conjectured that many reactions could, unknowingly, have employed low “ppm levels” of palladium (pre)catalyst, and generally, what would the spread of ppm palladium look like across a selection of studies reported across the vast array of the cross-coupling chemistry literature. In a few selected examples, we have examined other metal catalyst systems for comparison with palladium.

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Synthesis of the tricyclic indole alkaloids, dilemmaones A and B

Cited by 8 publications

References 46 publications

Anti-Virus Isoindolinone alkaloids with rare oxocyclopenta[f]isoindole frameworks isolated from the stems of flue cured tobacco

Anti-Virus Isoindolinone alkaloids with rare oxocyclopenta[f]isoindole frameworks isolated from the stems of flue cured tobacco

Antivirus isoindolinone alkaloids with rare oxocyclopenta[f]isoindole frameworks isolated from the stems of flue cured tobacco

Pd-Catalyzed Cross-Couplings: On the Importance of the Catalyst Quantity Descriptors, mol % and ppm

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