cas 7529-22-8, 4-Methylmorpholine N-oxide | Articles data

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A concise synthesis of N-(trideuteromethyl)morpholine-N-oxide monohydrate
An efficient synthesis of N-(trideuteromethyl)morpholine N-oxide monohydrate (3) is described. The procedure applies the tocopheryl protecting group, and makes use of sodium percarbonate as the oxidant and water donor, thus avoiding both the troublesome direct alkylation of morpholine and the unsuitable oxidation by aqueous hydrogen peroxide. Overall yields of purified material range above 90%.
Rosenau, Thomas,Potthast, Antje,Kosma, Paul
p. 1972 - 1974
(1999)
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PRODUCTION OF AN AMINE OXIDE BY OXIDATION OF A TERTIARY AMINE
A method for producing an amine oxide by oxidation of a tertiary amine in a reactor under continuous introduction of tertiary amine in a reaction fluid and export of amine oxide, wherein a suitable surface-to-volume ratio and/or a suitable flow speed with corresponding surface/volume loads are selected in the continuous process. The reaction fluid is usually reacted in the reactor with a laminar flow.
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Paragraph 0079

(2019/10/23)

Preparation method for N-methylmorpholine-N-oxide (NMMO)
The invention provides a preparation method for N-methylmorpholine-N-oxide (NMMO). The method comprises the following steps: (1) adding a nanocrystalline metal oxide into N-methylmorpholine(NMM), mixing and stirring to enable the nanocrystalline metal oxide to be uniformly mixed with the NMM; (2) dropwise adding a hydrogen peroxide solution into mixed liquid of the NMM and a catalyst; (3) raising the temperature to accelerate the reaction process; (4) performing filtering and reduced pressure distillation on a solution prepared in (3) to obtain a required NMMO solution. The method for preparing the NMMO provided by the invention has the advantages of fast reaction rate, low reaction temperature, few by-products and the like.
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Paragraph 0032-0053

(2019/10/08)

Optimized preparation method of N-methylmorpholine-N-oxide
The invention belongs to the technical field of chemical synthesis, and particularly relates to an optimized preparation method of N-methylmorpholine-N-oxide. The N-methylmorpholine-N-oxide (NMMO) isan organic solvent in a cellulose spinning process. The synthesis methods commonly used in the field mainly comprise a hydrogen peroxide peroxidation method and a molecular oxygen-aldehyde catalytic oxidation method; wherein the hydrogen peroxide method is widely applied due to the advantages of mild reaction conditions, high product quality and the like, and catalysts commonly used in the conventional hydrogen peroxide catalysis method comprise basic ion exchange resin, copper hydroxide, manganese dioxide, quaternary ammonium salt compounds and the like; however, these catalysts have higher requirements on the reaction conditions. Researches show that when titanium dioxide is used as a catalyst, the temperature for preparing N-methylmorpholine-N-oxide can be reduced, the yield of N-methylmorpholine-N-oxide is greatly increased, the reaction temperature is only 40 DEG C, and the yield can be increased to 90%; so that the production energy consumption is reduced, and the method has goodindustrial production and popularization significance.
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Paragraph 0038-0059

(2019/12/02)

Comparison of riboflavin-derived flavinium salts applied to catalytic H2O2 oxidations
A series of flavinium salts, 5-ethylisoalloxazinium, 5-ethylalloxazinium, and 1,10-ethylene-bridged alloxazinium triflates, were prepared from commercially available riboflavin. This study presents a comparison between their optical and redox properties, and their catalytic activity in H2O2 oxidations of sulfide, tertiary amine, and cyclobutanone. Reflecting the difference between the π-conjugated ring structures, the flavinium salts displayed very different redox properties, with reduction potentials in the order of: 5-ethylisoalloxazinium > 5-ethylalloxazinium > 1,10-ethylene-bridged alloxazinium. A comparison of their catalytic activity revealed that 5-ethylisoalloxazinium triflate specifically oxidises sulfide and cyclobutanone, and 5-ethylalloxazinium triflate smoothly oxidises tertiary amine. 1,10-Bridged alloxazinium triflate, which can be readily obtained from riboflavin in large quantities, showed moderate catalytic activity for the H2O2 oxidation of sulfide and cyclobutanone.
Sakai, Takuya,Kumoi, Takuma,Ishikawa, Tatsuro,Nitta, Takahiro,Iida, Hiroki
supporting information
p. 3999 - 4007
(2018/06/08)

Novel low viscous, green and amphiphilic N-oxides/phenylacetic acid based Deep Eutectic Solvents
Four novel Deep Eutectic Solvents (DESs) were prepared by mixing phenylacetic acid (which is a natural molecule present in honey) with amine N-oxides, which are molecules easily biodegradable in nature. Three of these N-oxides are amphiphilic. The novel DESs have very low freezing points (from ??34?°C to 20?°C) and they have very low viscosity, much lower than the most common and used DES in literature so far (choline chloride/urea mixture). The conductivity values resulted low and the ionicity analysis showed these DESs to be “super ionic”. Their polarity resulted high enough and it can be compared with other commonly used solvents or ionic liquids.
Germani, Raimondo,Orlandini, Matteo,Tiecco, Matteo,Del Giacco, Tiziana
p. 233 - 239
(2017/05/29)

Renewable waste rice husk grafted oxo-vanadium catalyst for oxidation of tertiary amines to N-oxides
Low cost renewable waste rice husks (RH) have been used as a support for grafting of an oxo-vanadium Schiff base via covalent attachment for the oxidation of tertiary amines to N-oxide. The synthesis of the desired RH grafted oxo-vanadium complex involves prior functionalization of the RH support with amino-propyltrimethoxysilane (APTMS) followed by its reaction with salicylaldehyde to get an RH-functionalized Schiff base which subsequently reacted with vanadyl sulphate to get the targeted oxo-vanadium catalyst. The synthesized catalyst was found to be an efficient heterogeneous catalyst and afforded an excellent yield of corresponding N-oxides via oxidation of tertiary amines with hydrogen peroxide as an oxidant. Furthermore, the synthesized catalyst was found to be quite stable and showed consistent activity for five runs without any loss in activity.
Panwar, Vineeta,Bansal, Ankushi,Ray, Siddharth S.,Jain, Suman L.
p. 71550 - 71556
(2016/08/05)

Selectivity Modulation of the Ley–Griffith TPAP Oxidation with N-Oxide Salts
A wide variety of novel non-hygroscopic N-oxide tetraphenylborate salts were synthesized and evaluated as co-oxidants in the Ley–Griffith (TPAP) oxidation of benzylic and allylic alcohols under non-anhydrous conditions. The novel DABCOO·TPB (2:1) salt was herein unearthed as a viable competitor to the first-generation NMO·TPB (2:1) salt, but more importantly gave increased performance under oxidative competition. X-ray crystal structure analysis and NMR spectroscopy revealed that depending on the crystallization conditions 1:1, 2:1 or 3:2 N-oxide–tetraphenylborate salts could be formed.
Moore, Peter W.,Jiao, Yanxiao,Mirzayans, Paul M.,Sheng, Lexter Ng Qi,Hooker, Jordan P.,Williams, Craig M.
p. 3401 - 3407
(2016/07/26)

Toward chemistry-based design of the simplest metalloenzyme-like catalyst that works efficiently in water
Enzymes exhibit overwhelmingly superior catalysis compared with artificial catalysts. Current strategies to rival enzymatic catalysis require unmodified or minimally modified structures of active sites, gigantic molecular weight, and sometimes the use of harsh conditions such as extremely low temperatures in organic solvents. Herein, we describe a design of small molecules that act as the simplest metalloenzyme-like catalysts that can function in water, without mimicking enzyme structures. These artificial catalysts efficiently promoted enantioselective directtype aldol reactions using aqueous formaldehyde. The reactions followed Michaelis-Menten kinetics, and heat-resistant asymmetric environments were constructed in water.
Kitanosono, Taku,Kobayashi, Shu
supporting information
p. 133 - 138
(2015/02/19)

2,2,2-Trifluoroacetophenone as an organocatalyst for the oxidation of tertiary amines and azines to N-oxides
A cheap, mild and environmentally friendly oxidation of tertiary amines and azines to the corresponding Noxides is reported by using polyfluoroalkyl ketones as efficient organocatalysts. 2,2,2-Trifluoroacetophenone was identified as the optimum catalyst for the oxidation of aliphatic tertiary amines and azines. This oxidation is chemoselective and proceeds in high-to-quantitative yields utilizing 10 mol% of the catalyst and H2O2 as the oxidant.
Limnios, Dimitris,Kokotos, Christoforos G.
supporting information
p. 559 - 563
(2014/04/03)

Trichloroacetonitrile-hydrogen peroxide: A simple and efficient system for the selective oxidation of tertiary and secondary amines
A variety of tertiary and secondary amines were efficiently oxidized to their corresponding N-oxides and nitrones, respectively, using the trichloroacetonitrile-hydrogen peroxide system. The in situ generated trichloromethylperoxyimidic acid is the active reagent for the oxidation processes.
Nikbakht, Fatemeh,Heydari, Akbar
p. 2513 - 2516
(2014/05/06)

13C GIAO DFT calculation as a tool for configuration prediction of N-O group in saturated heterocyclic N-oxides
Tropane, tropinone, pseudopelletierine and cocaine were oxidized in situ in a nuclear magnetic resonance (NMR) tube providing mixtures of exo/endo N-oxides. Observed 13C chemical shifts were correlated with values calculated by gauge-including atomic orbitals density functional theory (DFT) OPBE/6-31G* method using DFT B3LYP/6-31G* optimized geometries. The same method of 13C chemical shift calculation was applied on series of methyl-substituted 1-methylpiperidines and their epimeric N-oxides described in literature. The results show that using this undemanding calculation method enables assignment of configuration of N-O group in N-epimeric saturated heterocyclic N-oxides. The approach enables assigning of the configuration with high degree of certainty even if NMR data of only one isomer are available. An improved method of in situ oxidation of starting amines in an NMR tube is also described. Copyright
Pohl, Radek,Potmischil, Francisc,Dracinsky, Martin,Vanek, Vaclav,Slavetinska, Lenka,Budesinsky, Milos
body text
p. 415 - 423
(2012/08/27)

The observed and calculated 1H and 13C chemical shifts of tertiary amines and their N-oxides
A series of model tertiary amines were oxidized in situ in an NMR tube to amine N-oxides and their 1H and 13C NMR spectra were recorded. Next, the chemical shifts induced by oxidation (Δλ) were calculated using different GIAO methods investigating the influence of the method [Hartree-Fock (HF), Moeller-Plesset perturbation, density functional theory (DFT)], the functional applied in the DFT (B3LYP, BPW, OPBE, OPW91) and the basis set used [6-31G*, 6-311G**, 6-311 + + G** and 6-311 + + G(3df,3pd)]. The best results were obtained with the HF/6-311 + + G** and OPBE/6-311 + + G** methods. The computation/experiment comparison approach was used for the configuration prediction of chiral amine N-oxides-(R) and (S)-agroclavine-6-N-oxide.
Pohl, Radek,Dracinsky, Martin,Slavetinska, Lenka,Budesinsky, Milos
experimental part
p. 320 - 327
(2011/12/22)

Oxidation of organic compounds by sulfonated porous carbon and hydrogen peroxide
The oxidation of organic compounds by sulfonated porous carbon and H 2O2 was studied at room temperature. Alkyl and aryl sulfides were oxidized to the corresponding sulfoxides or sulfones in excellent yields. Secondary alcohols were also converted to the corresponding esters/lactones and aldehydes to methyl esters in good yields. Moreover, aliphatic tertiary amines and substituted pyridines were oxidized to N-oxides.
Shokrolahi, Arash,Zali, Abbas,Keshavarz, Mohammad Hossein
experimental part
p. 1427 - 1432
(2012/04/18)

Synthesis of the perdeuterated cellulose solvents N-methylmorpholine N-oxide (NMMO-d11) and N,N-dimethylacetamide (DMAC-d9)
The synthesis of the perdeuterated cellulose solvents NMMO-d11 (9) and N,N-dimethylacetamide-d9 (14) is described. NMMO-d 11 was obtained according to a five-step approach from non-labeled diglycolic acid (1) via diethylene glycole-d8 (4) and its bis-tosylate (5), which underwent cyclization with benzylamine to N-benzylmorpholine (6). The removal of the benzyl protecting group, methylation and N-oxidation completed the synthesis. DMAc-d9 (14) was obtained from deuterated acetic acid (10) and dimethylamine-carbon dioxide complex (17) with acidic alumina as the catalyst according to a solvent-free gas-solid reaction. Copyright
Adelwoehrer, Christian,Yoneda, Yuko,Nakatsubo, Fumiaki,Rosenau, Thomas
p. 28 - 32
(2008/09/18)

Process for the preparation of amine oxides
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, isobutyronitrile, benzamide and isobutyraride.
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(2008/06/13)

Method for the enantioselective preparation of 3,3-diphenyl-2,3-epoxy propionic acid esters
The invention relates to a method for the enantioselective preparation of the glycide ester (I) by (a) dihydroxylating a corresponding 3-phenyl cinnamic acid ester (II) by osmium (VIII) oxide catalysis in the presence of a Sharpless ligand and an oxidant to give a dihydroxy ester (III), (b) selectively converting the hydroxy function in the 2 position of the dihydroxy ester (III) to a leaving group, (c) intramolecularly substituting the leaving group by the hydroxy function in the 3 position to the glycide ester (I). In formulae (I), (II), and (III), R1 represents C1-C10 alkyl, aryl or arylalkyl, which can optionally be substituted, and R2 represents C1-C10 alkyl, aryl, arylalkyl, halogen, C1-C10 alkoxy, acyloxy or amide, which can be optionally substituted, and n is 0 to 5.
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(2008/06/13)

Process for the preparation of amine oxides
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 6-7

(2008/06/13)

Flavin catalyzed oxidations of sulfides and amines with molecular oxygen
Novel biomimetic, aerobic oxidation with an organocatalyst was performed. The oxidations of organic substrates such as sulfides, secondary amines, N-hydroxylamines, and tertiary amines with molecular oxygen (1 atm) or even in air in the presence of 5-ethyl-3-methyllumiflavinium perchlorate catalyst and hydrazine monohydrate in 2,2,2-trifluoroethanol occur highly efficiently to give the corresponding oxidized compounds in excellent yields along with water and molecular nitrogen, which are environmentally benign. The TON of the oxidation of sulfides amounts to 19000. Copyright
Imada, Yasushi,Iida, Hiroki,Ono, Satoshi,Murahashi, Shun-Ichi
p. 2868 - 2869
(2007/10/03)

Process for the preparation of amine oxides
The present invention provides a process for the preparation of high quality amine oxide by reacting a tertiary or secondary amine with hydrogen peroxide as an oxidant in presence of a recyclable heterogeneous layered double hydroxide exchanged with one of the anions of transition metal oxides as a catalyst in a solvent selected from the group consisting of water, water containing dodecylbenzenesulfonic acid sodium salt as additive, and a water miscible organic solvent.
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(2008/06/13)

Process for the preparation of amine oxides
The present invention provides a process for the preparation of high quality amine oxide by reacting a tertiary or secondary amine with hydrogen peroxide as an oxidant in presence of a recyclable heterogeneous layered double hydroxide exchanged with one of the anions of transition metal oxides as a catalyst in a solvent selected from the group consisting of water, water containing dodecylbenzenesulfonic acid sodium salt as additive, and a water miscible organic solvent.
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(2008/06/13)

Ruthenium catalyzed oxidation of tertiary nitrogen compounds with molecular oxygen: An easy access to N-oxides under mild conditions
A variety of tertiary nitrogen compounds have been efficiently oxidized to their corresponding N-oxides in excellent yields with molecular oxygen as a sole oxidant and ruthenium trichloride as catalyst.
Jain, Suman L.,Sain, Bir
p. 1040 - 1041
(2007/10/03)

Chemoselective electrophilic oxidation of heteroatoms by hydroperoxy sultamst
The synthesis of novel hydroperoxy sultams 1b-d and their potential as renewable chemoselective electrophilic oxidants for a wide range of nitrogen, sulfur, and phosphorus heteroatoms in nonaqueous media is described. Reactions of 1b,c with secondary amines 10f,g yielded the hydroxysultams 2b,c and nitrone 11f or radical 11g depending on the substrate and stoichiometry, while tertiary amines 10a-d gave amine oxides 11a-d. Compounds 1c,d oxidized various thioethers 12a-g to sulfoxides 13a-g smoothly that were isolated by chromatography in nearly quantitative yields. 1c was regenerated from 2c by treatment of the latter with acidified H2O2. Kinetic studies of the reaction of 1c with 1,4-thioxane 12f suggest that the reaction follows the second-order kinetics, first order in substrate and first order in oxidant with the second-order rate constant several orders of magnitude larger than that of the corresponding reaction with hydrogen peroxide and tert-butyl hydroperoxide without the need for any acid or heavy metal catalysts. The phosphines 14a,b were also oxidized by 1c to the respective phosphine oxides 15a,b readily in quantitative yields. The reactions may be conducted at ambient temperature or lower and appear to proceed via a nonradical mechanism. Reactions are sensitive to steric as well as electronic factors.
Gelalcha, Feyissa Gadissa,Schulze, Baerbel
p. 8400 - 8406
(2007/10/03)

Process for the preparation of amine oxides
A process for the preparation of high quality amine oxides by reacting a tertiary or secondary amine with hydrogen peroxide as an oxidant in the presence of a recyclable heterogeneous layered double hydroxide exchanged with one of the anions of transition metal oxides as a catalyst in an organic solvent at a temperature ranging between 10-25° C. for a period of 1-6 hours under continuous stirring and separating the product by simple filtration and subsequently evaporation of solvents by known methods.
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(2008/06/13)

The first example of catalytic N-oxidation of tertiary amines by tungstate-exchanged Mg-Al layered double hydroxide in water: A green protocol
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
p. 1736 - 1737
(2007/10/03)

A new method for oxidation of tertiary amine by molecular oxygen/aldehyde/Fe2O3 system
Oxidation of tertiary amines to tertiary amine N-oxides was achieved in moderate to high yields, by using Fe2O3 as catalyst, with molecular oxygen in the presence of isovaleraldehyde under mild conditions.
Wang, Fan,Zhang, Hao,Song, Guoqiang,Lu, Xiaoling
p. 11 - 14
(2007/10/03)

Mild and Efficient Flavin-Catalyzed H2O2 Oxidation of Tertiar Amines to Amine N-Oxides
A mild and highly effective H2O2 oxidation of tertiary amines has been developed by the use of flavin catalysis. Eight aliphatic amines were oxidized to their corresponding N-oxides in fast and selective reactions. For all substrates a considerable rate enhancement was observed compared to the noncatalyzed reactions. The product N-oxides were isolated in good yields using this mild oxidation system based on the environmentally attractive oxidant H2O2. As the catalyst, an N1N5- dialkylated flavin was used as an analogue of the biologically important flavin redox cofactor. The catalytic cycle proposed for the flavin catalysis accounts for the observation that, in addition to the hydrogen peroxide oxidant, molecular oxygen is required for the initiation of the process.
Bergstad, Katarina,B?ckvall, Jan-E.
p. 6650 - 6655
(2007/10/03)

On the preparation of amine N-oxides by using dioxiranes
The reaction of heterocyclic aromatic amines, anilines and tertiary amines with dimethyldioxirane (DMD) was examined. Treatment of heterocyclic aromatic amines and anilines with a slight excess of DMD at 0°C afforded the corresponding N-oxides in quantitative conversion yields. In addition, the oxidation was chemoselective in the presence of carbon-carbon double bonds. On the other hand, most of the tertiary amines assayed did afford also quantitative yields of the corresponding N. oxides, although reaction conditions, in particular regarding the amount of DMD required, depended on each substrate. Additional studies carried out on selected substrates suggested that certain N-oxides derived from tertiary amines deactivate DMD.
Ferrer, Marta,Sanchez-Baeza, Francisco,Messeguer, Angel
p. 15877 - 15888
(2007/10/03)

Action d'un Tetrafluoroborate d'Oxaziridinium sur les Amines et les Imines
The Oxaziridinium salt 1 derived from dihydroisoquinolin is an oxygen transfer reagent to primary amines leading to nitrosoderivatives (if R = Alkyl) or nitro compounds (if R = Aryl), to tertiary amines leading to N-oxides, and to secondary amines and imines leading to the corresponding nitrone.
Hanquet, Gilles,Lusinchi, Xavier
p. 12185 - 12200
(2007/10/02)

Deuterium Isotope Effects on the Oxygen Atom Transfer Reactions of α-Azo Hydroperoxides
Cyclic α-azo hydroperoxide 1 (cis-3-bromo-4,5-dihydro-5-hydroperoxy-4,4-dimethyl-3,5-diphenyl-3H-pyrazole) and acyclic α-azo hydroperoxide 2 were converted to the ROOD analogues 1-d and 2-d.The reactions of 1 and 1-d in CDCl3 at 34 deg C with amines, diphenyl sulfide, and 2,3-dimethyl-2-butene yielded the corresponding amine oxides, sulfoxides, and epoxides in better than 90percent yields.The reactions were found to be of the first order in both hydroperoxide and substrate (second order overall).Deuterium isotope effects (kH/kD) of 1.3+/-0.1 were found for the oxidation of the three types of substrate.The reactions of 2 and 2-d with benzyl methyl sulfide and 2,3-dimethyl-2-butene, carried out in C6D6 at 34 deg C, produced the corresponding sulfoxide and epoxide in 90percent+ yields.As expected, the reactions were of the second order overall (first order in hydroperoxide) in the aprotic medium.Values of kH/kD of 1.3+/-0.1 were found for these oxidations.The mechanistic implications of these results are discussed.
Baumstark, Alfons L.,Vasquez, Pedro C.
p. 1939 - 1942
(2007/10/02)

An Unprecedented Selective Autoxidation of Tertiary Amines to Amine Oxides
Tertiary amines have been found to react directly with molecular oxygen under high O2 pressures to give in an unexpected result the corresponding N-oxide in high yields.
Riley, Dennis P.,Correa, Paul E.
p. 1563 - 1564
(2007/10/02)

Topical medicament preparations
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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(2008/06/13)

Selective reactions with cytochalasin D
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Chappuis,Tamm
p. 521 - 537
(2007/10/02)

OXIDATION OF AMINES AND SULFIDES BY 3-BROMO-4,5-DIHYDRO-5-HYDROPEROXY-4,4-DIMETHYL-3,5-DIPHENYL-3H-PYRAZOLE
The reaction of 3-bromo-4,5-dihydro-5-hydroperoxy-4,4-dimethyl-3,5-diphenyl-3H-pyrazole with tertiary amines and sulfides produced amine oxides and sulfoxides in high yield with k2s for amines similar to those reported for reaction of amines with a 4a-hydroperoxyflavin.
Baumstark, Alfons L.,Christope, Douglas R.
p. 4591 - 4594
(2007/10/02)

Oxidation of Amines by a 4a-Hydroperoxyflavin
Kinetic and product studies have been carried out for the reaction of 12 tertiary amines, secondary amines, and secondary hydroxylamines with the 4a-hydroperoxide of N5-ethyl-3-methyllumiflavin (4a-FlEtOOH).All reactions were found to be first order in 4a-FlEtOOH and amine in t-BuOH solvent.Transfer from t-BuOH to the aprotic solvent dioxane decreases the second-order rate constant by ca. threefold, but does not change the kinetic order in reactants (i.e., no external proton source is required).The reactions with the secondary and tertiary amines are quantitative, yielding secondary hydroxylamines and tertiary amine oxides along with the flavin pseudobase (4a-FlEtOH).Secondary hydroxylamines yield with 4a-FlEtOOH nitrones and 4a-FlEtOH.The free radical trap 2,6-di-tert-butyl-4-methylphenol does not influence the rate constants or product yields.This finding, along with the observation that rate constants are not related to the stability of cation radicals derived from amine, establishes that free radical processes are not involved in the N-oxidation reactions.The N-oxidation reactions are best explained as occurring through nucleophilic attack of amine nitrogen upon the terminal oxygen of the 4a-FlEtOOH molecule with back donation of the hydroperoxy hydrogen to the internal peroxy oxygen.Comparison of the second-order rate constants ( on the basis of the amine pKa's in H2O) provides the nucleophilic order secondary hydroxylamines > tertiary amines > secondary amines.The disappearance of 4a-FlEtOOH from solution in the presence of primery amines is much slower than with secondary amines and the reaction does not follow a simple rate law nor is 4a-FlEtOH a major product.In t-BuOH the spontaneous first-order rate constant for decomposition of 4a-FlEtOOH exceeds that for the decomposition of H2O2 by more than 400-fold while the second-order rate constant for N-oxidation of N,N-dimethylbenzylamine by 4a-FlEtOOH exceeds that for N-oxidation by H2O2 by 36000-fold (and N-oxidation by t-BuOOH by > 400000).These results are discussed in terms of the involvement of 4a-hydroperoxyflavin cofactor in the metabolism of amines by the hepatic flavoprotein microsomal oxidase.
Ball, Sheldon,Bruice, Thomas C.
p. 6498 - 6503
(2007/10/02)

A BIOMIMETIC HETEROATOM OXIDATION
The oxidation of amines and sulfides to N-oxides, sulfoxides and sulfones is smoothly accomplished using 2-hydroperoxyhaxafluoro-2-propanol (HPHI).
Ganem, Bruce,Biloski, Alan J.,Heggs, Richard P.
p. 689 - 690
(2007/10/02)