Polyketo-enols and chelates. Synthesis of acetyl- and alkoxycarbonyl-xanthyrones

Abstract

New xanthyrones having acetyl and alkoxycarbonyl substituents have been prepared by addition of anions from substituted 6-methylpyran-2-ones to alkoxymethylene β-dicarbonyl compounds, and also by the ‘melt’ assembly procedure. Reaction of xanthyrones with boiling water gives substituted phenols, the position of the substituents in the latter enabling substitution assignments to the pyrone ring to be confirmed. Spectral (n.m.r., u.v., and i.r.) data for the sixteen currently available xanthyrones are considered.