NMR structure characterization of a new vinylpyranoanthocyanin–catechin pigment (a portisin)

A new polyphenolic compound, the structure of which corresponds to a pyranomalvidin-3-glucoside linked to a (+)-catechin unit through a vinyl linkage, has been characterized by UV–vis, MS and NMR spectroscopy. This compound was obtained in an aqueous alcoholic solution from the reaction between a malvidin-3-glucoside–pyruvic acid derivative and (+)-catechin in the presence of acetaldehyde.