• Nuclear oxidation in flavones and related compounds - Part XII. Constitution and Synthesis of Pedicin and Its Allies

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      https://www.ias.ac.in/article/fulltext/seca/027/05/0375-0390

    • Keywords

       

      Bromine; Methoxyl Group; Aqueous Sodium Hydroxide; Nobiletin; Dimethyl Sulphate

    • Abstract

       

      Pedicin is considered to be apara-dihydroxy chalkone and this constitution is confirmed by its synthesis from 2-hydroxy-3: 4: 6-trimethoxy chalkone using the method of nuclear oxidation with persulphate. The synthetic pedicin could be readily converted into pedicellin and pedicinin. Under the ordinary conditions of chalkone-flavanone conversion it yields isopedicin which is therefore given the constitution of 6-hydroxy-5: 7: 8-trimethoxy flavanone. The constitutions of pedicinin and methyl pedicinin are discussed on the basis of the analogies presented in an earlier paper on oxidative demethylation using nitric acid and fresh data derived from the conversion of 2: 5-dihydroxy-3: 4: 6-trimethoxy acetophenone and pentamethoxy acetophenone into hydroxy-quinone-ketone analogous to pedicinin. It is concluded that pedicinin and methyl pedicinin have the hydroxy-quinone-chalkone structure. Methyl pedicinin which is an intermediate stage in the formation of pedicinin is now found to occur in the leaves ofD. pedicellata. A scheme of biogenesis of pedicin and its allies is given. The most conclusive evidence for this scheme as well as for the mechanism of the pedicin-pedicinin change and incidentally for the pedicellin-pedicinin change also, is the gentle oxidation of pedicin to the trimethoxy-quino-chalkone and further stepwise hydrolysis to methyl pedicinin and pedicinin. Using diazomethane for partial methylation it is possible to methylate pedicinin to methyl pedicinin.

    • Author Affiliations

       

      K Visweswara Rao1 T R Seshadri1

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

       
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