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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Solution-state conformations of natural products from chiroptical spectroscopy: the case of isocorilagin

Full text
Author(s):
Sprenger, R. F. [1] ; Thomasi, S. S. [1] ; Ferreira, A. G. [1] ; Cass, Q. B. [1] ; Batista Junior, J. M. [1]
Total Authors: 5
Affiliation:
[1] Univ Fed Sao Carlos, Dept Chem, UFSCar Rod Washington Luis Km 235, BR-13565305 Sao Carlos, SP - Brazil
Total Affiliations: 1
Document type: Journal article
Source: ORGANIC & BIOMOLECULAR CHEMISTRY; v. 14, n. 13, p. 3369-3375, 2016.
Web of Science Citations: 17
Abstract

Isocorilagin, the alpha-anomer of the ellagitannin corilagin, has been frequently reported in the literature as a constituent of various plant species. Its identification is based mainly on the smaller value for the coupling constant of its anomeric proton when compared to that of corilagin. A careful investigation of the corilagin structure in both methanol and DMSO solutions using NMR, electronic and vibrational CD, and DFT and MD calculations confirmed that isocorilagin is the result of a solvent-induced conformational transition of corilagin, rather than its diastereoisomer. Corilagin changes from B-1,B-4 and degrees S-5 conformations of the beta-glucose core in DMSO-d(6) to an inverted C-1(4) conformation in methanol-d(4), which accounts for NMR observables attributed to the alleged alpha-anomer. This misassignment reinforces the risks of relying upon a single technique for structural elucidation and stereochemical analysis of complex natural products, especially those containing saccharide moieties. (AU)

FAPESP's process: 11/11021-3 - Characterization of Five Species of Breaker-Stone by Liquid Chromatography Hyphenated to Tandem Mass Spectrometry (LC-MSn) and coupled to Nuclear Magnetic ressonance spectroscopy (LC-SPE-NMR)
Grantee:Ricardo da Fontoura Sprenger
Support Opportunities: Scholarships in Brazil - Doctorate
FAPESP's process: 13/01710-1 - Enzyme ligand: new models of screening
Grantee:Quezia Bezerra Cass
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 14/25222-9 - Vibrational chiroptical spectroscopy for stereochemical characterization of small molecules and macromolecules
Grantee:João Marcos Batista Junior
Support Opportunities: Research Grants - Young Investigators Grants
FAPESP's process: 15/07089-2 - Vibrational chiroptical spectroscopy for stereochemical characterization of small molecules and macromolecules
Grantee:João Marcos Batista Junior
Support Opportunities: Scholarships in Brazil - Young Researchers