- Two-Phase Oxidations with Aqueous Hydrogen Peroxide Catalyzed by Amphiphilic Pyridinium and Diazinium Salts
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Amphiphilic pyridinium and diazinium salts were shown to be effective catalysts in two-phase (water/chloroform or water/dichloromethane) sulfoxidations and N-oxidations with hydrogen peroxide under mild conditions. This unprecedented oxidation method utilizes covalent bonding of hydrogen peroxide to a simple pyridinium or diazinium nucleus to increase the lipophilicity of the hydroperoxide species and to subsequently activate it for oxidations in a non-polar medium. The catalytic efficiency was found to depend on the type of heteroarenium core and on the lipophilicity of the catalyst. Five series of heteroarenium catalysts were prepared and investigated: 1-Alkyl-3,5-dicyanopyridinium, 1-alkyl-3,5-dinitropyridinium, 1-alkyl-3-cyanopyrazinium, 1-alkyl-4-cyanopyrimidinium and 1-alkyl-4-(trifluoromethyl)pyrimidinium triflates (alkyl=butyl, hexyl, octyl, decyl, dodecyl and hexadecyl). Among them, the 1-octyl-3,5-dinitropyridinium and 1-decyl-4-(trifluoromethyl)pyrimidinium triflates were found to be superior catalysts, showing the best stability and the highest catalytic activity, achieving acceleration by a factor of 350 relative to the non-catalyzed reaction. In contrast to other organocatalytic two-phase oxidations that use hydrogen peroxide, the presented method is characterized by high chemoselectivity and low catalyst loading (5mol%) and with the reactions being performed under mild conditions, that is, at 25 C using diluted hydrogen peroxide and a non-basic aqueous phase. The catalysts have simple structures and are readily available from commercial materials. Practical applications are demonstrated via the oxidation of several types of sulfides and amines.
- Hartman, Tomá?,?turala, Ji?í,Cibulka, Radek
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p. 3573 - 3586
(2016/01/25)
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- Process for the preparation of amine oxides
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The present invention provides a process for the preparation of amine oxide by reacting a tertiary or a secondary amine with hydrogen peroxide as an oxidant in the presence of a recyclable heterogeneous catalyst comprising a layered double hydroxide exchanged with an anion in the presence of an additive selected from the group consisting of benzonitrile, propionitrile, isoburyronitrile, benzamide and isobutyramide.
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Page/Page column 7
(2008/06/13)
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- The first example of catalytic N-oxidation of tertiary amines by tungstate-exchanged Mg-Al layered double hydroxide in water: A green protocol
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A green process, using a recyclable tungstate-exchanged Mg-A1 layered double hydroxide (LDH-WO42-) heterogenised catalyst and aqueous H2O2 oxidant in water, leads to N-oxidation of aliphatic tert-amines to amine N-oxides in quantitative yields, at a high rate at room temperature.
- Choudary,Bharathi,Venkat Reddy,Lakshmi Kantam,Raghavan
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p. 1736 - 1737
(2007/10/03)
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- Use of amine oxide in the H2 O2 oxidation of aliphatic mercaptan to sulfonic acid
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Hydrocarbyl mercaptans are oxidized to sulfonic acids by reaction with aqueous hydrogen peroxide in the presence of an inorganic base (e.g. sodium hydroxide) and a tert-amine oxide. The product is in the form of a sulfonate salt. The reaction rate is increased and undesirable free-oil by-product is decreased by the inclusion of the amine oxide catalyst.
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- AMINE OXIDES-XIII IODINE COMPLEXES WITH NON-AROMATIC AMINE OXIDES
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EDA-iodine complex with trialkylamine oxides in dichloromethane have been investigated spectrophotometrically.Thermodynamic (KADc,-ΔG0) and spectral (ΕADλ) characteristics of these complexes were determined.The absorption band of iodine in the visible region was blue-shifted with a variable maximum, depending on the structure of the amine oxide.The KADc and ΕADλ values were calculated using a modified method.A non-linear relationship KADc=(R), where R is the number of carbon atoms in the alkyl chain, was found.
- Devinsky, F.,Leitmanova, A.,Lacko, I.,Krasnec, L.
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p. 5707 - 5710
(2007/10/02)
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- Topical medicament preparations
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Topical therapeutic compositions are disclosed which contain from about 0.1 to 70 percent by weight of a water-soluble tertiary amine oxide and a therapeutic agent selected from the group consisting of erythromycin, benzoyl peroxide, hydrocortisone, tetracycline, 5-fluorouracil, and propranolol. The amine oxide enhances penetration of the therapeutic agent into and through the skin.
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