Xanthene → Xanthone

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Reaction Steps

The above oxidation reaction may be carried out using dichromate anion such as sodium dichromate or potassium dichromate as the oxidizing agent. The reaction will proceed in from 15 minutes to 6 hours at a temperature of from 80° to 120°C. The amount of oxidizing agent is limited to the stoichiometric quantity required for oxidation of the 9-methylene group of the xanthene derivative. Suitable solvents for this conversion are, for example, water, acetic acid, tert-butyl alcohol, and the like, or combinations of these solvents. For example, by combining three moles of the xanthene derivative, Formula II, dissolved in acetic acid with four moles of sodium dichromate and refluxing the mixture for 1 to 3 hours, the corresponding xanthen-9-one derivative, Formula III, can be obtained.

Provenance & Evidence