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Oxidation of enol acetate of flavanone with thallium(III) nitrate or phenyliodonium diacetate: a convenient new route to isoflavone and flavone


A new high-yield method has been described for the preparation of isoflavone by oxidation of enol acetate of flavanone with thallium(III) nitrate or phenyliodonium diacetate in trimethyl orthoformate in the presence of 70 % perchloric acid at room temperature. Flavone could also be prepared in high yield from the enol acetate by oxidation with the same reagents in glacial acetic acid at room temperature. Some key intermediates of these oxidations were investigated with quantum chemical (HF and DFT) methods.

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We are grateful to the National Research Foundations (OTKA K-81701 and K105871 as well as TÁMOP 4.2.2./B-10/1-2010-0024) for the financial support of our research. We also thank the National Information Infrastructure Development Institute (NIIFI 10038) for CPU time. A.M. thanks for the Zoltán Magyary postdoctoral fellowship program. The computational research was realized in the frames of TÁMOP 4.2.4. A/2-11-1-2012-0001 National Excellence Program—Elaborating and operating an inland student and researcher personal support system convergence program. The project was subsidized by the European Union and co-financed by the European Social Fund.

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Correspondence to Attila Mándi or Sándor Antus.

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Németh, I., Kiss-Szikszai, A., Gulácsi, K. et al. Oxidation of enol acetate of flavanone with thallium(III) nitrate or phenyliodonium diacetate: a convenient new route to isoflavone and flavone. Monatsh Chem 145, 849–855 (2014).

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