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      Permanent link:
      https://www.ias.ac.in/article/fulltext/seca/019/01/0005-0013

    • Keywords

       

      Coumarin; Rectangular Plate; Umbelliferone; Orcinol; Anhydrous Potassium Carbonate

    • Abstract

       

      Claisen migrations of the allyl ether of 4∶7-dimethyl-5-hydroxy-coumarin gives rise to three isomeric compounds depending upon the conditions, (I) 6-allyl-5-hydroxy-4∶7-dimethyl coumarin (high yield), (II) the corresponding chroman (high yield), and (III) 8-allyl-5-hydroxy-4∶7-dimethyl coumarin (low yield). (II) has been shown to be a chroman by comparison with the corresponding methyl coumaran obtained by authentic methods from (I). The acetate of the above coumarin undergoes Fries reaction to give the 6-acetyl compound. Claisen migrations of the allyl ether of 7-hydroxy-5-methyl-coumarin yields only the 8-allyl-derivative. The difference in the behaviour of the derivatives of 5- and 7-hydroxy coumarins and the special conditions of the chroman and coumaran ring closure ofo-allyl phenols are discussed.

    • Author Affiliations

       

      B Krishnaswamy1 2 K Ranganadha Rao1 2 T R Seshadri1 2

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

       
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