Xanthone

Synthesis

Xanthone can be prepared by the heating of phenyl salicylate:

Various other methods of synthesis given are:

• Heating a mixture of salicylic acid, phenol, and acetic anhydride.
• Warming o-phenoxybenzoic acid with sulfuric acid or phosphorous pentoxide.
• Distillation of o-phenoxybenzoyl chloride under vacuum.
• Heating of aspirin or o-hydroxybenzophenone.

Derivatives

Multiple methods have been reported for synthesizing xanthone derivatives:

• The Michael-Kostanecki method uses an equimolar mix of a polyphenol and a salicylic acid derivative, which are heated with a dehydrating agent in a condensation reaction.
• The Friedel-Crafts method has a benzophenone intermediate.
• The Robinson-Nishikawa method is a variant of the Hoesch synthesis but with low yields.
• The Asahina-Tanase method synthesizes some methoxylated xanthones, and xanthones with acid-sensitive substituents.
• The Tanase method is used to synthesize polyhydroxyxanthones.
• The Ullman method condenses a phenol with an O-chlorobenzene and cyclizes the resulting diphenylether.

Xanthone derivatives

Xanthone forms the core of a variety of natural products, such as mangostin or lichexanthone. These compounds are sometimes referred to as xanthones or xanthonoids. Over 200 natural xanthones have been identified. Many are phytochemicals found in plants in the families Bonnetiaceae, Clusiaceae, and Podostemaceae. They are also found in some species of the genus Iris. Some xanthones are found in the pericarp of the mangosteen fruit (Garcinia mangostana) as well as in the bark and timber of Mesua thwaitesii.

References

References

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