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Updated: Jan 13, 2026

Synthesis and Structure Determination of µ-Conotoxin PIIIA Isomers with Different Disulfide Connectivities
Published on: October 2, 2018
Structure Revision of Isomallotusinin to Mallotusinin by NMR-Based Conformational Analysis
Kosuke Kikuchi1, Yosuke Matsuo1, Yoshinori Saito1
1Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan.
Abstract:
A reexamination of the reported structure of isomallotusinin, previously proposed as an anomer of the ellagitannin mallotusinin, demonstrates that isomallotusinin is identical to mallotusinin, thus correcting a structural misassignment. This conclusion is supported by a detailed conformational analysis of mallotusinin, which bears a distinctive tetrahydroxydibenzofuranoyl (THDBF) group. Through a DFT-assisted analysis of 1H-1H coupling constants, we demonstrate that mallotusinin exists as a solvent-dependent equilibrium of 3S1 and 1C4 conformers. Our findings resolve a structural ambiguity in the literature and highlight the importance of considering conformational dynamics in the structural elucidation of conformationally flexible ellagitannins.
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