• R N Goel

      Articles written in Proceedings – Section A

    • Modifications in the iodine oxidation of hydroxy flavanones and their methyl ethers

      R N Goel V B Mahesh T R Seshadri

      More Details Abstract Fulltext PDF

      A modified procedure for the action of iodine and silver acetate gives rise to purer products. Agreeing with earlier observations, hesperetin gives a good yield of 3-acetoxy hesperetin and hesperetin 7∶3′-dimethyl ether yields the 3-iodo-compound. The iodoflavanones invariably yield the corresponding flavones by the action of pyridine. In the treatment with alcoholic potash, those which have a free 5-hydroxyl,e.g., 3-iodo naringenin 7∶4′-dimethyl ether and 3-iodo hesperetin 7∶3′-dimethyl ether yield only the corresponding flavones; whereas 3-iodo-5∶7-dimethoxy flavanone having no free 5-hydroxyl group gives a mixture of products, containing the flavone, the flavonol and the 2-hydroxy-2-benzyl 4∶6-dimethoxy coumaranone. The difference seems to depend on the stability of the oxygen ring.

    • New synthesis of tamaraxetin, alpinone and izalpinin

      R N Goel T R Seshadri

      More Details Abstract Fulltext PDF

      A new and convenient method for the synthesis of tamaraxetin uses hesperetin. By the action of iodine and silver acetate, it is converted into 3-acetoxy-hesperetin and eventually into 3-hydroxy-hesperetin which undergoes dehydrogenation by means of iodine and potassium acetate to yield tamaraxetin.

      5-Hydroxy-7-methoxy-flavanone (pinostrobin) is converted into alpinone by Fenton’s oxidation and subsequent dehydrogenation yields izalpinin.

    • Nuclear methylation of chalkones and flavanones

      R N Goel A C Jain T R Seshadri

      More Details Abstract Fulltext PDF

      Nuclear methylation of 2:4-dihydroxy-chalkones (III) give rise to 3-C-methyl derivatives just as in the case of resacetophenone. C-Methylchalkone-derivatives (IV) with substituents in the side phenyl nucleus have also been prepared by this method. For comparison, they have been synthesised using 3-methyl-peonol and appropriate derivatives of benzaldehyde. C-Methyl-iso-liquiritigenin-dimethyl-ether (IVb) was cyclised to the corresponding 8-methyl-flavanone (VI).

      The flavanone, naringenin, when subjected to nuclear methylation under mild conditions yields 6-methyl-flavanone derivative (VIII) whereas under conditions in which the oxygen ring opens, beside the above 6-methyl flavanone (VIII), poly-C-methylated chalkones (XIIa+b) are formed just as in case of phloracetophenone.

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