• Nuclear oxidation in the flavone series - Part I. A new synthesis of gossypetin and 8-hydroxy-galangin

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      Permanent link:
      https://www.ias.ac.in/article/fulltext/seca/025/05/0417-0426

    • Keywords

       

      Chrysin; Aqueous Sodium Hydroxide; Galangin; Anhydrous Potassium Carbonate; Dimethyl Sulphate

    • Abstract

       

      Nuclear oxidation leading to the preparation of 8-hydroxy-galangin and gossypetin has been carried out. 3∶7-dimethyl-ether of galangin and 3∶7∶ 3′∶4′-tetramethyl-ether of quercetin have been oxidised by means of potassium persulphate to the corresponding 5∶8-dihydroxy-compounds (quinols). Even the 5∶7-dihydroxy-compounds, 3-O-methyl-galangin and 3∶3′∶4′-O-trimethyl-quercetin could be oxidised to the corresponding 5∶7∶8-trihydroxy-derivatives in good yields. Subsequent methylation yields the fully methylated ethers of 8-hydroxy-galangin and gossypetin and demethylation the free hydroxy-flavonols. These experiments not only illustrate facile nuclear oxidation in the flavone series in support of the theory of biogenesis, but also constitute simple and elegant methods for the synthesis of 5∶7∶8-hydroxy-flavonols.

    • Author Affiliations

       

      K Visweswara Rao1 T R Seshadri1

      1. Department of Chemistry, Andhra University, Waltair
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