• V M Thakor

      Articles written in Proceedings – Section A

    • γ-Substitution in the resorcinol nucleus - Part XI. Friedel and crafts acylation of 4-nitroresorcinol

      R M Naik V M Thakor R C Shah

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      In extension of the previous work1, 2 Friedel and Crafts acylation has been studied with 4-nitroresorcinol. 4-Nitroresorcinol on Friedel-Crafts acetylation furnished 2: 6-dihydroxy-3-nitroacetophenone along with small amounts of the known 5-nitroresacetophenone, substitution occurring mainly in the γ-position. 4-Nitroresorcinol-l-methyl ether similarly gave 2-hydroxy 3-nitro-6-methoxyacetophenone as the sole product. Similar γ-substitution was observed on Friedel-Crafts propionylation, butyrylation and benzoylation of 4-nitroresorcinol. The constitutions in all the cases have been established by comparing with the products of nitration of the corresponding 2-acylresorcinols. This observation furnishes further proof of existence of chelation in 4-nitroresorcinol resulting in the preferential substitution in the γ-position.

    • Chromones - Part III. Kostanecki-robinson acylation of some ortho-hydroxyacetophenones

      R M Naik V M Thakor

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      Kostanecki-Robinson reaction has been studied with variousortho-hydroxyacetophenones. 2: 6-Dihydroxy-3-nitroacetophenone on Kostanecki-Robinson acetylation gave 5-hydroxy-2-methyl-6-nitrochromone and 5-hydroxy-2-methyl-3-acetyl-6-nitrochromone, and on benzoylation gave 5-hydroxy-6-nitroflavone and 5-hydroxy-3-benzoyl-6-nitroflavone. 2-Hydroxy-3-nitro-6-methoxyacetophenone, however, surprisingly, gave 5-hydroxy-2-methyl-8-nitrochromone, demethylation occurring after the chromone formation. 5-Nitroresacetophenone on similar acetylation and benzoylation gave 7-hydroxy-2-methyl-3-acetyl-6-nitrochromone and 7-hydroxy-3-benzoyl-6-nitroflavone respectively which were deacylated to the corresponding simple chromone and flavone derivatives. 2-Hydroxy-6-methoxyacetophenone on Kostanecki-Robinson acetylation gave 5-methoxy-2-methyl-3-acetyl-chromone along with 2-acetoxy-6-methoxyacetophenone, while on benzoylation a mixture of 5-methoxy- and 5-benzoyloxy-3-benzoylflavones was obtained.

    • Chromones - Part IV. Nitration of 5-hydroxychromone derivatives and their methyl ethers

      R M Naik A M Mehta V M Thakor G V Jadhav R C Shah

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