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Updated: Jun 25, 2026

Applications of Liquid-Chromatography Tandem Mass Spectrometry in Natural Products Research: Tropane Alkaloids as a Case Study
Published on: March 8, 2024
Piperidine and tetrahydropyridine alkaloids from Lobelia siphilitica and Hippobroma longiflora
Julie R Kesting1, Inge-Lise Tolderlund, Anders F Pedersen
1Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark.
Abstract:
The hyphenated technique HPLC-PDA-MS-SPE-NMR was used to assist targeted preparative-scale isolation of constituents of Lobelia siphilitica and Hippobroma longiflora (both Campanulaceae). This resulted in the isolation of two new alkaloids, (S)-2-[(2S,6R)-1-methyl-6-(2-oxo-2-phenylethyl)piperidin-2-yl]-1-phenylethyl acetate (3) and 6-[(E)-2-(3-methoxyphenyl)ethenyl]-2,3,4,5-tetrahydropyridine (4), the latter possessing a skeleton hitherto unseen among alkaloids of Lobelia and related genera. Lobeline (1), (1S,1'S)-2,2'-[(2R,6S)-1-methylpiperidine-2,6-diyl]bis(1-phenylethanol) (2), and lobetyolin (5) were also isolated. The structures of 1-5 were established using spectroscopic methods including homo- and heteronuclear two-dimensional NMR experiments and optical rotation data.
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