Another method to produce synthesized xanthones is through the diaryl
ether intermediate. The diaryl ether intermediate can be obtained from the
condensation of a phenol with an o-chloro or –bromobenzoic acid. Then,
the biphenyl intermediate is converted to xanthone by ring formation
which can be accomplished through electrophilic cycloacylation (Sousa
and Pinto, 2005) (Figure 2.10).