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Certain chromones and benzoxanthones were prepared by heating at 300–325° a mixture of 1‐or 2‐naphthol with either phenyl o‐hydroxybenzoate or o‐hydroxynaphthoate or a β‐ketoester. The yields and purity of the products are superior to those obtained by the published procedures.

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A general method for the preparations of pyranthiones is particularly useful for preparing substituted xanthiones which are unavailable by established procedures. Reaction of a xanthone with p‐tosyl isocyanate or with trichloroacetyl isocyanate produces the corresponding imino derivatives, which upon treatment with n‐butylamine followed by hydrogen sulfide gives the desired xanthione in good yield.