Om V. Singh

Dehydrogenation of flavanones to flavones using thallium(III) acetate(TTA)

Abstract A facile conversion of flavanones to flavones by dehydrogenation of the former using thallium(III) acetate is described.

Oxidative 1,2-aryl rearrangement in flavanones using thallium(III) p-tolylsulphonate (TTS)= A new useful route to isoflavones

Abstract Oxidation of flavanones using thallium(III) p -tolylsulphonate (prepared in situ by the reaction of thallium(III) acetate and p -toluene sulphonic acid) in propionitrile leads to 1,2-aryl shift providing a new useful route to the synthesis of isoflavones.

Oxidation of Flavonols Via Oxythallation Using Thallium(III) Acetate(TTA) and Thallium(III) Nitrate(TTN) in Methanol

Abstract Oxidation of flavonols (1a-f), α-naphthoflavonol (3) and 6-propionylflavonols (5a-b) to 2,3-dimethoxy-3-hydroxy-flavanones (2a-f), 2,3-dimethoxy-3-hydroxy-α-naphthoflavanone (4) and 2,3-dimethoxy-3-hydroxy-6-propionylflavanones (6a-b), respectively, using thallium(III) acetate and thallium(III) nitrate in methanol is described. A mechanistic Scheme of these transformations has also been proposed.

Regioselective Synthesis of Methyl 2,3-Dihydro-2-aryl Benzofuran-3-Carboxylates Using Thallium(III) Nitrate

Abstract Flavanones (1a–d) undergo smooth ring contraction with thallium(III) nitrate in presence of perchloric acid and trimethyl orthoformate resulting in the formation of methyl 2,3-dihydro-2-arylbenzofuran-3-carboxylates (2a–d) in good yields. The mechanism of this oxidation has also been discussed.

Hypervalent iodine oxidation of aryl methyl ketones: A convenient route to methyl α-methoxyarylacetatos

Abstract Hypervalent iodine oxidation of aryl methyl ketones using two equivalents of iodosobenzene diacetate leads to 1,2-aryl migration followed by solvohyperiodination to yield the corresponding methyl α-methoxyarylacetates.

Oxidation of flavanones using thallium(III) salts: a new route for the synthesis of flavones and isoflavones

When treated with thallium(III) acetate in acetic acid or acetonitrile, flavanones undergo facile dehydrogenation to afford flavones whereas, upon treatment with thallium(III) toluene-p-sulfonate or thallium(III) nitrate in propionitrile or acetonitrile, respectively, they undergo oxidative 2,3-aryl migration to give isoflavones in high yield.

Oxidation of Flavonols Using Lead(IV) Acetate in Acidic Methanol

Abstract Oxidation of Flavonols (1a-h) and 6-propionyl-flavonols (1i-j) to 2,3-dimethoxy-3-hydroxyflavanones (2a-h) and 2,3-dimethoxy-3-hydroxyflavanones (2i-j), respectively using lead(IV) acetate in methanol in presence of perchloric acid and the mechanism of this transformation has been described.