Mahavir S. Khanna

α-tosyloxylation of enolizable ketones using thallium(III)p-tolylsulphonate (TTS)

Abstract Thallium(III) p -tolylsulphonate(TTS) in refluxing acetonitrile provides a new useful one step conversion of enolizable ketones to α-tosyloxy ketones. α-Tosyloxylation of enolizable ketones using Thallium(III) p -tolylsulphonate (TTS) in refluxing acetonitrile.

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 5-Acyl-α-Benzoyl-O-Hydroxy-Acetophenones: A Selective Synthesis of 2,5-Diacylcoumaran-3-Ones

Abstract Oxidation of 5-acyl-α-benzoyl-o-hydroxyacetophenones 3a-e with (diacetoxyiodo)benzene in methanolic potassium hydroxide (DAB-KOH-MeOH) provides a selective synthesis of 2,5-diacylcoumaran-3-one 4a-e in good yield.

Selective Oxidation of 6-Propionylflavonols and 6-Propionyl-2-Hetarylchromdnols Using Hypervalbnt Iodine Reagents in Methanol

Abstract Selective oxidation of 6-propionyl flavonols (1a-d) and 6-propionyl-2-hetarylchromonols (1e-f) to 2,3-dimethoxy-3-hydroxy-6-propionylf lavanones (2a-d) and 2,3-dimethoxy-3-hydroxy-6-propiony1-2-hetarylchromanones (2e-f), respectively, using [bis(trifluoroacetoxy)iodo]benzene(BTFAIB), [hydroxy(tosyloxy)-iodo] benzene (HTIB), iodobenzene diacetate (IBD) and iodosylbenzene (IB) in methanol has been described.

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.