Search for physiologically active compounds. Part VI. Synthesis of halo and nitro derivatives of dihydroxy xanthones

Abstract

The condensation of resorcinol and 4-chloro resorcinol with chloro- and nitro-substituted β-resorcylic acids, has yielded the corresponding tetrahydroxy benzophenones, which with the exception of those containing nitro groups, could be cyclised to the respective 3:6-dihydroxy xanthones. In the case of condensations with orcinol, however, 1:6-dihydroxy xanthones could be directly isolated. A number of halo and nitro derivatives of 3:6-dihydroxy xanthone have also been prepared by direct halogenation and nitration of the xanthone, as well as by substitution in the intermediate benzophenone and subsequent cyclisation.