Structure of a new xanthylium salt derivative

A new polyphenolic compound with a xanthylium skeleton has been synthesised from (+)-catechin and glyoxylic acid. its structural elucidation was achie ved by UV, MS and NMR spectroscopies. Its formation involved glyoxylic acid -mediated dimerisation of(+)-catechin 1 giving thus compound 2, followed by cyclisation to a xanthene derivative 3 which by oxidation afforded the xan thylium compound 4. The detection and structural determination of the xanth ene compound confirmed the postulated mechanism. (C) 1999 Published by Else vier Science Ltd. All rights reserved.