- Epoxidation of chromones and flavonoids in ionic liquids
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A convenient and efficient procedure for the epoxidation of chromone, isoflavone, and chalcone derivatives using 1-butyl-3-methyl imidazolium tetrafluoroborate [bmim]BF4 as solvent and alkaline hydrogen peroxide as oxidant is described. All reactions proceed in good yields and faster than in conventional solvents. No evidence of formation of compounds derived from the opening of the epoxide ring was attained.
- Bernini, Roberta,Mincione, Enrico,Coratti, Antonietta,Fabrizi, Giancarlo,Battistuzzi, Gianfranco
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p. 967 - 971
(2007/10/03)
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- Dimethyldioxirane epoxidation of aurones and isoflavones
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The synthesis of the corresponding epoxides 2 and 4 by epoxidation of aurones (2-benzylidenebenzofuran-3(2H)-ones, 1) and isoflavones (3-aryl-4H-1-benzopyran-4-ones, 3) with dimethyldioxirane at subambient temperatures is reported. These acid- and base-se
- Adam,Hadjiarapoglou,Levai
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p. 436 - 438
(2007/10/02)
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- Studies in the chemistry of chromone epoxides
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Chromones and isoflavones, but not flavones, were epoxidized by alkaline hydrogen peroxide. 3-Substituted chromone epoxides were considerably more stable than others; one isoflavone epoxide was converted into a fluorohydrin, another into a 1,2-diol. The latter is a 2-hydroxychromanone and a similarly structured compound was obtained by the cyclisation of 2'-benzoyloxy-2,2-dibromoacetophenone. Acid-catalysed ring-opening of chromone epoxides occurred regioselectively yielding 3-hydroxychromanones. Base-catalysed ring-opening also occurred regioselectively but at the 3-position. Acid- and base-catalysed hydrolysis of 2-methy-lisoflavone epoxide resulted in cleavage of both heterocyclic rings, yielding, respectively, a 1,3- and a 1,2-diketone. This epoxide formed a cyclic sulphate with sulphuric acid.
- Donnelly, John A.,Keegan, John R.,Quigley, Killian
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p. 1671 - 1680
(2007/10/02)
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