HETEROCYCLIC COMPOUNDS PART XXXIII. A NEW SYNTHESIS OF XANTHONES

Polyphosphoric acid has been found to be an efficient condensing agent for the synthesis of xanthones from \(o\)-hydroxycarboxylic acid and polyhydric phenols. Good yields of xanthones have been obtained from resorcinol, orcinol. phloroglucinol, \(\alpha\)- and \(\beta\)-naphthols by condensing them with salicylic acid in presence of polypbosphoric add.