Fagopyrins are phenantroperylenequinones present in the flowers of Fagopyrum esculentum (buckwheat) endowed with photodynamic activity. It has been reported that fagopyrin extracts actually contain a complex mixture of closely related compounds, differing only on the nature of the perylenequinone substituents. We report our systematic and detailed study on the chemical composition of fagopyrin extracts by a combination of preparative and analytical techniques. The combined use of 1H-NMR and CD spectroscopy was found to be particularly suited to fully characterize all stereochemical aspects of the extracted fagopyrins. For the first time nine isomers have been structurally characterized and their stereochemistry fully elucidated. The presence of two different heterocyclic ring substituents, two stereogenic centers and the inherent axial chirality of the aromatic system provides a complex stereochemical relationships among isomers, thus giving account of the high level of molecular multiplicity found in the extract.

Fagopyrins from Buckwheat Flowers: Structural and Stereochemical Characterization Through Combined NMR/CD Spectroscopy and Theoretical Calculations / V. Galbusera, B. Lattuada, A. Pinto, A. Barbiroli, G. Borgonovo, E.M. Ragg. - In: CHEMISTRY. - ISSN 1521-3765. - (2024), pp. 1-9. [Epub ahead of print] [10.1002/chem.202400082]

Fagopyrins from Buckwheat Flowers: Structural and Stereochemical Characterization Through Combined NMR/CD Spectroscopy and Theoretical Calculations

A. Pinto
;
A. Barbiroli;G. Borgonovo
;
E.M. Ragg
Ultimo
2024

Abstract

Fagopyrins are phenantroperylenequinones present in the flowers of Fagopyrum esculentum (buckwheat) endowed with photodynamic activity. It has been reported that fagopyrin extracts actually contain a complex mixture of closely related compounds, differing only on the nature of the perylenequinone substituents. We report our systematic and detailed study on the chemical composition of fagopyrin extracts by a combination of preparative and analytical techniques. The combined use of 1H-NMR and CD spectroscopy was found to be particularly suited to fully characterize all stereochemical aspects of the extracted fagopyrins. For the first time nine isomers have been structurally characterized and their stereochemistry fully elucidated. The presence of two different heterocyclic ring substituents, two stereogenic centers and the inherent axial chirality of the aromatic system provides a complex stereochemical relationships among isomers, thus giving account of the high level of molecular multiplicity found in the extract.
CD spectroscopy; Density Functional Theory; NMR spectroscopy; atropisomerism; fagopyrins
Settore CHIM/06 - Chimica Organica
Settore BIO/10 - Biochimica
   PIANO DI SOSTEGNO ALLA RICERCA 2015-2017 - TRANSITION GRANT LINEA 1A PROGETTO "UNIMI PARTENARIATI H2020"
2024
16-apr-2024
Article (author)
File in questo prodotto:
File Dimensione Formato  
Chemistry A European J - 2024 - Galbusera - Fagopyrins from Buckwheat Flowers Structural and Stereochemical-1.pdf

accesso riservato

Descrizione: Online First
Tipologia: Publisher's version/PDF
Dimensione 3.29 MB
Formato Adobe PDF
3.29 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/1052168
Citazioni
  • ???jsp.display-item.citation.pmc??? 0
  • Scopus 0
  • ???jsp.display-item.citation.isi??? 0
social impact