• A new effect of hydrogen bond formation (chelation) - Part II. Constitution of despedicellin, dihydropedicinin and isopedicin

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      https://www.ias.ac.in/article/fulltext/seca/028/04/0198-0209

    • Keywords

       

      Ferric Chloride; Flavanone; Naringin; Aqueous Sodium Hydroxide; Dimethyl Sulphate

    • Abstract

       

      Though despedicellin and dihydropedicinin are prepared from chalkones and were earlier given the chalkone constitution, their properties indicate that they are flavanones. This constitution is also in accordance with the recent discovery of the new effect of hydrogen bonds on the stability of flavanones. It is confirmed by the following experiments. (1) The two compounds undergo partial methylation with diazomethane yielding 5-hydroxy-6: 7∶8-trimethoxy-flavanone which forms with nitric acid 6∶7-dimethoxy-quinoflavanone identical with the sample obtained from 5∶6∶7∶8-tetramethoxy flavanone. (2) Dihydropedicinin undergoes oxidation withp-benzoquinone to form allopedicinin which is different from pedicinin. Methylation of this with diazomethane yields 6∶7-dimethoxyquinoflavanone. (3) The estimation of active hydrogen atoms agrees with the flavanone and not chalkone structure for these two compounds. That isopedicin is also a flavanone is confirmed by its methylation with diazomethane to 5∶6∶7∶8-tetramethoxy flavanone. The constitution of the important reference compound, tetramethoxy flavanone is established by its conversion into the corresponding flavonol.

    • Author Affiliations

       

      G S Krishna Rao1 K Visweswara Rao1 T R Seshadri1

      1. Department of Chemistry, Andhra University, Waltair
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