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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.)

Absolute configuration assignment of caffeic acid ester derivatives from Tithonia diversifolia by vibrational circular dichroism: the pitfalls of deuteration

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Ccana-Ccapatinta, Gari V. [1] ; Sampaio, Bruno L. [1] ; dos Santos, Jr., Fernando M. [2] ; Batista, Jr., Joao M. [2] ; Da Costa, Fernando B. [1]
Total Authors: 5
[1] Univ Sao Paulo, AsterBioChem Res Team, Lab Pharmacognosy, Sch Pharmaceut Sci Ribeirao Preto, Ave Cafe S-N, BR-14040903 Ribeirao Preto, SP - Brazil
[2] Univ Fed Sao Carlos, Dept Chem, Rod Washington Luis Km 235, BR-13565905 Sao Carlos, SP - Brazil
Total Affiliations: 2
Document type: Journal article
Source: TETRAHEDRON-ASYMMETRY; v. 28, n. 12, p. 1823-1828, DEC 15 2017.
Web of Science Citations: 3

Recently, it was observed that infrared (IR) and vibrational circular dichroism (VCD) calculations including deuterated hydroxyl groups in phenolic and saccharide moieties improved significantly the agreement with experimental data obtained in methanol-d(4). In the present study, the relative and absolute configurations of three methanol-soluble caffeic acid ester derivatives 1-3, isolated from Tithonia diversifolia, were established by a combined use of experimental and calculated C-13 NMR chemical shifts, as well as electronic circular dichroism (ECD) and VCD spectroscopies. Interestingly, the attempt to reproduce the deuteration pattern arising from possible isotopic exchange in methanol-d(4) solution led to nearly mirror image calculated VCD spectra for 1 when compared to the non-deuterated molecule with the same absolute configuration. This latter fact can potentially lead to absolute configuration misassignments. A closer inspection of the vibrational chiroptical properties of 1 revealed that the deuteration status of the tertiary hydroxyl group at C-2 is critical for the correct reproduction of experimental VCD data in protic solvents. Therefore, in the case of stereochemical analysis of polar chiral natural product molecules, a combination of VCD and ECD is recommended. (C) 2017 Elsevier Ltd. All rights reserved. (AU)

FAPESP's process: 15/07089-2 - Vibrational chiroptical spectroscopy for stereochemical characterization of small molecules and macromolecules
Grantee:João Marcos Batista Junior
Support type: Scholarships in Brazil - Young Researchers
FAPESP's process: 14/16850-6 - Metabolomic and chemometric approach for the study of chemotaxonomy, authentication and quality control of the species of the subfamily Barnadesioideae (Asteraceae)
Grantee:Gari Vidal Ccana Ccapatinta
Support type: Scholarships in Brazil - Doctorate
FAPESP's process: 14/25222-9 - Vibrational chiroptical spectroscopy for stereochemical characterization of small molecules and macromolecules
Grantee:João Marcos Batista Junior
Support type: Research Grants - Young Investigators Grants
FAPESP's process: 14/26866-7 - Metabolomics, enzymatic targets and in silico tools in the search of bioactive compounds from plants
Grantee:Fernando Batista da Costa
Support type: Regular Research Grants
FAPESP's process: 16/23794-0 - Stereochemistry of complex natural compounds by vibrational optical activity: acetogenins
Grantee:Fernando Martins dos Santos Junior
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 11/13361-6 - Evaluation of seasonal variation of the main secondary metabolites and anti-inflammatory activity of extracts of Tithonia diversifolia (Hemsl.) A. Gray (Asteraceae)
Grantee:Bruno Leite Sampaio
Support type: Scholarships in Brazil - Doctorate