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Application of Lanthanide Shift Reagent to the ¹H-NMR Assignments of Acridone Alkaloids.

ABSTRACT: This study investigates the application of the paramagnetic shift reagent tris(dipivaloylmethanato)-europium(III) in NMR spectral studies of permethoxyacridone alkaloids (1-3) and pyranoacridone alkaloids (4-6). The induced chemical shifts (??) of all protons were observed for the same molecule, and were compared to deduce the positions resulting from the distance nearby the Eu(dpm)₃. Assignment of the H-2, H-4 and H-8 of polysubstituted acridones could be distinguished based on the least-squares method of lanthanide-induced shifts plotted against the mole ratios of Eu(dpm)₃ to the substrate. The developed method is not only potentially useful for determining the planar structures of polysubstituted compounds, such as acridones, anthraquinones, xanthones, flavonoids, and phenanthrenes, but also applicable for their stereochemistry.

SUBMITTER: Lam SH

PROVIDER: S-EPMC7698746 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature

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Application of Lanthanide Shift Reagent to the 1H-NMR Assignments of Acridone Alkaloids.

Lam Sio-Hong SH Hung Hsin-Yi HY Kuo Ping-Chung PC Kuo Daih-Huang DH Chen Fu-An FA Wu Tian-Shung TS

Molecules (Basel, Switzerland) 20201117 22

This study investigates the application of the paramagnetic shift reagent tris(dipivaloylmethanato)-europium(III) in NMR spectral studies of permethoxyacridone alkaloids (1-3) and pyranoacridone alkaloids (4-6). The induced chemical shifts (∆δ) of all protons were observed for the same molecule, and were compared to deduce the positions resulting from the distance nearby the Eu(dpm)3. Assignment of the H-2, H-4 and H-8 of polysubstituted acridones could be ...[more]

PMID: 33213112

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