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    • Keywords


      Baicalein; Wogonin; Aqueous Sodium Hydroxide; Hydriodic Acid; Dibenzoylmethane

    • Abstract


      Since there was an element of uncertainty in the methods employed in the past for the synthesis of 5∶7∶8-hydroxyflavone derivatives, an unambiguous method has now been worked out. The required ketone, 2-hydroxy-3∶4∶6-trimethoxyacetophenone has been prepared by the partial methylation of 2∶4-dihydroxy-3∶6-dimethoxyacetophenone which is obtained directly from 1∶4-dimethoxy-2∶6-dibenzyloxybenzene by the Hoesch reaction. It has been converted into 5∶7∶8-trimethoxyflavone (wogonin-dimethyl ether) and 5∶7∶8∶4′-tetramethoxyflavone by the Baker-Venkataraman procedure. Even the above dihydroxyketone could be used for this purpose fairly satisfactorily and it yields as an intermediate stage 5∶8-dimethoxy-7-hydroxyflavone. Demethylation with hydrodic acid even under mild conditions is not satisfactory. Nor-wogonin is best obtained by employing anhydrous aluminium chloride in benzene solution for this reaction.

    • Author Affiliations


      V D Nageswara Sastri1 T R Seshadri1

      1. Department of Chemistry, Andhra University, India
    • Dates


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