Revisiting empirical rules for the determination of the absolute configuration of cascarosides and other (ox-)anthrones

Author(s)

Demarque, Daniel P. ^{[1, 2]} ; Pinho, Danielle R. ^[2] ; Lopes, Norberto P. ^[2] ; Merten, Christian ^[1]

Affiliation

^[1] Ruhr Univ Bochum, Organ Chem 2, Phys Organ Chem, Univ Str 150, D-44801 Bochum - Germany

^[2] Univ Sao Paulo, Dept Fis & Quim, Nucleo Pesquisa Prod Nat & Sintet, Fac Ciencias Farmaceut Ribeirao Preto, Sao Paulo - Brazil

• Document type: Journal article
• Source: CHIRALITY; v. 30, n. 4, p. 432-438, APR 2018.
• Web of Science Citations: 1

Abstract

The introduction of the C-10-stereocenter of (ox-)anthrones by plant organisms is not stereospecific. Consequently, often, both (10S)- and (10R)-diastereomers can be found in the same plant. Motivated by the importance of a correct assignment of the configuration at C-10, this study revisits the nuclear magnetic resonance and electronic circular dichroism-based empirical rules for the determination of the absolute configuration by molecular dynamic simulations and electronic circular dichroism spectrum calculations. Furthermore, a vibrational circular dichroism spectroscopic characterization of these large and conformationally very flexible molecules reveals spectral signatures, which can be used to specifically distinguish the C-10 stereochemistry. A detailed analysis of the underlying vibrational modes suggests that the observed spectral pattern of the investigated cascarosides may be generally characteristic for the C-10-stereocenter of (ox-)anthrones and that they can be used for empirical spectra-structure correlations. (AU)

• FAPESP's process: 14/18052-0 - Tissue localization of tannins and Anthraquinones acting on gastrointestinal system
• Grantee: Daniel Pecoraro Demarque
• Support Opportunities: Scholarships in Brazil - Doctorate