- METHOD FOR MANUFACTURING AN EPOXY COMPOUND AND METHOD FOR EPOXIDIZING A CARBON-CARBON DOUBLE BOND
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The present invention provides a method for producing an epoxy compound, comprising oxidizing a carbon-carbon double bond of an organic compound by hydrogen peroxide in the presence of a neutral inorganic salt and a mixed catalyst of a tungsten compound (a), at least one phosphorus compound selected from the group consisting of phosphoric acids, phosphonic acids, and salts thereof (b) and a surfactant (c), and an epoxidizing method comprising oxidizing a carbon-carbon double bond by hydrogen peroxide in the presence of the catalyst and the neutral inorganic salt.
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Page/Page column 11
(2012/05/07)
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- The ozonolysis of longifolene: A tool for the preparation of useful chiral compounds. Configuration determination of new stereogenic centers by NMR spectroscopy and X-ray crystallography
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The ozonolysis of (+)-longifolene (1) in different solvents (Et2O, CH2Cl2, CHCl3, acetone) at -80° provided quantitatively longifolene epoxide (3) as a single diastereoisomer in which the O-atom is endopositioned (Scheme 2). Upon warming to room temperature, the epoxide remained stable only in acetone and was isolated as a low-melting crystalline compound. In CH2Cl2, Et2O, or CHCl3 solution, epoxide 3 rapidly rearranged to the isomeric enols 4 and 5, which underwent further rearrangement to give the exo-aldehyde 6. On standing for several weeks in CH2Cl2 solution, or in CHCl3 and Et2O as well, at room temperature, aldehyde 6 slowly rearranged into its epimer 7. The aldehydes 6 and 7 were isolated on the preparative scale for further synthetic use. The addition of methylmagnesium iodide to 6 and 7 provided the corresponding alcohols 13/14 and 15/16. respectively, which were isolated as pure diastereoisomers (Scheme 4). The configurations of the new chiral centers in 13-16 were determined by NMR methods and X-ray crystallography.
- Dimitrov, Vladimir,Rentsch, Gudrun Hopp,Linden, Anthony,Hesse, Manfred
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p. 106 - 121
(2007/10/03)
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- A versatile cobalt(II)-Schiff base catalyzed oxidation of organic substrates with dioxygen: Scope and mechanism
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Cobalt(II) complex 1a-f derived from Schiff bases act as efficient catalysts during the oxidation of wide range of organic substrates(e.g. alkenes, alcohols, benzylic compounds and aliphatic hydrocarbons) with dioxygen in the presence of aliphatic aldehydes or ketones or ketoesters. EPR studies on 1a-f complexes suggest that the aliphatic carbonyl compounds promote the formation of a cobalt(II)-superoxo species responsible for the oxidation of organic compounds. These studies also demonstrate the role of ligands on cobalt in controlling the chemoselectivity of these oxidations. A plausible mechanistic rational is also provided for these oxidations.
- Punniyamurthy,Bhatia, Beena,Reddy, M. Madhava,Maikap, Golak C.,Iqbal, Javed
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p. 7649 - 7670
(2007/10/03)
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- Cobalt catalyzed oxidation of cyclic alkenes with molecular oxygen: Allylic oxidation versus double bond attack
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Cobalt (II) Schiff's base complex 1 and 2 exhibit a remarkable chemoselectivity during oxidation of cyclic alkenes with molecular oxygen in the presence of 2-methylpropanal. Catalyst 1 encourages the oxidation of double bond to give epoxide as the major product whereas catalyst 2 promotes mainly the allylic oxidation leading to allylic alcohols or enones.
- Madhava Reddy,Punniyamurthy,Iqbal, Javed
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p. 159 - 162
(2007/10/02)
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