Synthesis of a new bluish pigment from the reaction of a methylpyranoanthocyanin with sinapaldehyde

• Type: Article in International Scientific Journal
• Date: 2011

Authors

Joana Oliveira (Author) FCUP; Nuno Mateus (Author) FCUP; Victor de Freitas (Author) FCUP

Journal

Title: Tetrahedron Letters

Vol. 52 No. 1

Pages: 1996-2000

ISSN: 0040-4039

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 13 Citations

Scopus - 15 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-002-SBY

DOI: 10.1016/j.tetlet.2011.02.079

Abstract (EN): The synthesis of a new pigment with a bluish color was obtained from the reaction of methylpyranomal-vidin-3-glucoside with sinapaldehyde and its formation mechanism seems to involve a charge-transfer reaction pathway. The structure of this compound was fully characterized by LC/DAD-MS and NMR. Its equilibrium forms present in water at different pH values and the respective ionization constants were determined by UV-visible spectroscopy. The results revealed the presence of three equilibria involving only deprotonation reactions at the 7-OH and 4'-OH positions of the pyranoanthocyanin moiety and at the 4'"-OH of the syringol moiety (pK(a1) = 3.64 +/- 0.01; pK(a2) = 8.02 +/- 0.01; pK(a3) = 11.19 +/- 0.01).

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 5