- Oxidation of primary amines to N-monoalkylhydroxylamines using sodium tungstate and hydrogen peroxide-urea complex
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The sodium tungstate-catalyzed (10 mol %) oxidation of primary amines with a urea-hydrogen peroxide complex (UHP) gives the corresponding N-monoalkylhydroxylamines, which are important biologically active compounds, in good to excellent yields. The method is applicable for a wide range of primary amines, including chiral benzylic amines, α-1,2-hydroxylamine and α-amino esters.
- Heydari, Akbar,Aslanzadeh, Saied
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- Das Hydrierprodukt eines β-Nitro-N-nitrosoamins ist kein 1,2,3-Triazolidin, sondern ein β-Hydroxylamino-N-nitrosoamin
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It is shown, by spectroscopy, that the product of catalytic hydrogenation of N,2-dimethyl-2-nitro-N-nitrosopropylamine (1) consists of a 5:1 mixture of (E)- and (Z)-2-hydroxylamino-N,2-dimethyl-N-nitrosopropylamine (3) and does not contain - as had been claimed - any 1,2-dihydroxy-1,2,3-triazolidine (2).Thus there is still no evidence for the existence of the N(OH)N(OH) functionality.The structure of intermediates on the way to 1 are also revised.
- Egger, Notker,Hoesch, Lienhard,Dreiding, Andre S.
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Read Online
- Ultrasonic promoted synthesis of Ag nanoparticle decorated thiourea-functionalized magnetic hydroxyapatite: A robust inorganic-organic hybrid nanocatalyst for oxidation and reduction reactions
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In this research, ultrasonic synthesis is applied for the fabrication of a novel catalyst, based on immobilization of silver nanoparticles (AgNPs) on thiourea functionalized magnetic hydroxyapatite. A recoverable Ag nano-catalyst is constructed by decoration of AgNPs on the surface of thiourea modified magnetic hydroxyapatite. Magnetic hydroxyapatite is used as an organic-inorganic hybrid support for the catalyst. The organic-inorganic hybrid support is prepared by co-precipitation, followed by its surface modification through covalent functionalization of 1-(3,5-bis(trifluoromethyl)phenyl)-3-propyl)thiourea. The fabricated catalyst has been characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), powder X-ray diffraction (XRD), nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and Brunauer-Emmett-Teller (BET) analysis. The nanoparticles are mostly tubular in shape and their particle sizes are smaller than 100 nm. This nanocatalyst shows efficient and robust catalytic activity in different reactions, including selective reduction of 4-nitrophenol (4NP) and oxidation of primary amines by applying NaBH4and urea hydrogen peroxide (UHP) as reagents, respectively. The catalyst shows good reusability in 10 sequential reaction runs.
- Bahadorikhalili, Saeed,Arshadi, Hosein,Afrouzandeh, Zahra,Ma'mani, Leila
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p. 8840 - 8848
(2020/06/08)
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- TREATMENT OF DRUG RESISTANT GLIOMAS
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The present disclosure describes the use of 2,4-disulfonyl phenyl tert-butyl nitrone (2,4- ds-PBN) in the treatment of temozolomide drug resistant gliomas. The 2,4-ds-PBN may be used combined with other chemo- and radiotherapies and surgery, including temozolomide, to reduce glioma occurrence, recurrence, spread, growth, metastasis, and vascularization, and to inhibit development of temozolomide resistance.
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Page/Page column 21-22
(2019/04/16)
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- Formation of radicals during heating lysine and glucose in solution with an intermediate water activity
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Heating glucose with lysine under alkaline conditions (pH 7.0-10.0) was found to take place with consumption of oxygen together with formation of brown-colored compounds. Highly reactive intermediary radicals were detected when lysine and glucose were heated at intermediate water activity at pH 7.0 and 8.0. The detection was based on initial trapping of highly reactive radicals by ethanol followed by spin trapping of 1-hydroxyethylradicals with α-(4-pyridyl N-oxide)-N-tert-butylnitrone (POBN) and Electron Spin Resonance (ESR) spectroscopy. The generation of reactive intermediary radicals from the Maillard reactions was favored by enhancing alkaline conditions (pH 8.0) and stimulated by presence of the transition metal ion Fe2+. The stability of the nitrone spin traps, N-tert-butyl-α-phenylnitrone and POBN was examined in buffered aqueous solutions within the pH range 1-12, and found to be less temperature dependent at acidic pH compared to alkaline conditions. A low rate (kobs) of hydrolysis of POBN was found at the used experimental conditions of 70°C and pH 7.0 and 8.0, which made this spin trap method suitable for the detection of radicals in the Maillard reaction system.
- Yin,Andersen,Thomsen,Skibsted,Hedegaard
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p. 643 - 650
(2013/08/23)
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- Facile reduction of nitroarenes into anilines and nitroalkanes into hydroxylamines via the rapid activation of ammonia· borane complex by supported gold nanoparticles
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Gold nanoparticles supported on titania catalyse, even at a ppm loading level, the quantitative reduction of nitroarenes into anilines and nitroalkanes into alkylhydroxylamines by the ammonia× borane complex. No dehalohalogenation was seen in the case of chloro- or bromonitroarenes, while ester, cyano, or carboxylic acid functionalities also remain intact. The nitroarene to aniline reduction pathway does not require nitrosoarenes as intermediate products. Copyright
- Vasilikogiannaki, Eleni,Gryparis, Charis,Kotzabasaki, Vasiliki,Lykakis, Ioannis N.,Stratakis, Manolis
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supporting information
p. 907 - 911
(2013/05/08)
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- Synthesis and biological evaluations of novel apocynin analogues
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We have designed and synthesized a series of novel apocynin analogues, and evaluated their biological activity. Compound 10, an apocynin dimer analogue, compound 12, the lipoic acid (LA) and apocynin conjugate, were the most potent in protecting cells from lipopolysaccharide (LPS)-induced cytotoxicity, had significant activity scavenging ROS induced by LPS, and greatly decreased LPS-induced P67phox protein expression. SAR analysis suggests that modification of apocynin can increase its activity. Our results demonstrate that arming apocynin with a powerful antioxidant such as lipoic acid is a valid strategy to design new apocynin analogues with enhanced biological activity.
- Lu, Xiaoyu,Wan, Sainan,Jiang, Jie,Jiang, Xiaojian,Yang, Wenjing,Yu, Pei,Xu, Lipeng,Zhang, Zaijun,Zhang, Gaoxiao,Shan, Luchen,Wang, Yuqiang
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experimental part
p. 2691 - 2698
(2011/06/27)
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- Selective synthesis of N-Alkyl hydroxylamines by hydrogenation of nitroalkanes using supported palladium catalysts
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The selective hydrogenation of nitroalkanes to the corresponding N-alkyl hydroxylamines is achieved at room temperature with excellent yields (up to 98 %), by using common supported palladium catalysts. The reaction temperature is key to the highly selective formation of the hydroxylamines, which proceeds smoothly in a H2 atmosphere without additives. The catalyst can be recycled up to five times.
- Takenaka, Yasumasa,Kiyosu, Takahiro,Choi, Jun-Chul,Sakakura, Toshiyasu,Yasuda, Hiroyuki
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experimental part
p. 1166 - 1168
(2011/12/02)
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- NOVEL COMPOUNDS AS CANNABINOID RECEPTOR LIGANDS
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Disclosed herein are cannabinoid receptor ligands of formula (I) wherein A1, A5, Rx, X4, and z are as defined in the specification. Compositions comprising such compounds, and methods for treating conditions and disorders using such compounds and compositions are also disclosed.
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Page/Page column 37; 77
(2010/04/23)
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- Spin trapping of Au-H intermediate in the alcohol oxidation by supportedand unsupported gold catalysts
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Electron paramagnetic resonance (EPR) spectroscopy and spin trapping were used to explore the mechanism of alcohol oxidation over gold catalysts. Reaction of secondary alcohols with supported and unsupported gold catalysts (e.g., Au/CeO2, polymer-Incarcerated Au nanoparticles,PPh 3-protected Au nanoparticles) In the presence of spin tr aps led to the formation of a hydrogen spin adduct. Using Isotope labeling, we confirmed that the hydrogen In the spin adduct originates from the cleavage of the C-H bond In the alcohol molecule. The formation of thehydrogen spin adduct most likely results from the abstraction of hydrog en from the Au surface by a spin trap. These results thus strongly suggest Intermediate formation of Au-H species during alcohol oxidation. The role of oxygen In this mechanism Is to restore the catalytic activity rather than oxidize alcohol. This was further confirmed by carrying out gold-catalyzed alcohol oxidation In the absence of oxygen, with nitroxidesas hydrogen abstractors. The support (e.g., metal oxides) can activate oxygen and act as an H abstractor from the gold surface and hence lead t o a faster recovery of the activity. Peroxyl radicals were also observedduring alcohol oxidation, consistent with a free-radical autoxidation m echanism. However, this mechanism Is likely to be a minor side reaction,which does not lead to the formation of an appreciable amount of oxidat ion products.
- Conte, Marco,Miyamura, Hiroyuki,Kobayashi, Shu,Chechik, Victor
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supporting information; experimental part
p. 7189 - 7196
(2009/09/30)
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- New highly efficient method for the synthesis of tert-alkyl nitroso compounds
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The syntheses of tert-alkyl nitroso compounds RCH2CMe 2N=O from commercially available tert-alkyl amines RCH 2CMe2NH2 proceed cleanly via the intermediacy of the benzoyl derivatives RCH2CMe2NHOC(O)Ph and the corresponding hydroxylamines RCH2CMe2NHOH. Since the intermediates require no purification in the course of the transformations, the overall yields of the isolated crystalline nitroso dimers (75-80% for R = H, 75% for R = Me and 66% for R = Me3C) are based on the corresponding amine precursors. In the latter case (R = Me3C), significant steric demands and hydrophobicity of Me3CCH2CMe2 group necessitate the application of more efficient reagents and conditions on the debenzoylation and oxidation steps. The syntheses are perfectly suitable for scale-up and were successfully performed on up to 500-mmol scale. Georg Thieme Verlag Stuttgart.
- Quek, Ser Kiang,Lyapkalo, Ilya M.,Huynh, Han Vinh
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p. 1423 - 1426
(2007/10/03)
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- Novel ampiphilic fluorocarbon molecular vectors for biomedical and medical use
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Novel ampiphilic fluorocarbon molecules applicable as vectors for active ingredients, active molecules comprising such a vector and the use thereof in the pharmaceutical field, particularly for the production of medicaments.
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- Aryl nitrone therapeutics and methods for treating inflammatory bowel disease
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Disclosed are methods for treating or preventing inflammatory bowel disease (IBD) using aryl nitrone compounds. Pharmaceutical compositions containing aryl nitrone compounds which are useful for the treatment or prophylaxis of IBD are also disclosed.
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- 3,4,5-trisubstituted aryl nitrone compounds, pharmaceutical compositions containing the same and methods for treating inflammation
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Disclosed are 3,4,5-trisubstituted aryl nitrone compounds and pharmaceutical compositions containing such compounds. The 3,4,5-trisubstituted aryl nitrone compounds have the formula: where R1-R4are as defined in the specification. The disclosed compositions are useful as therapeutics for inflammation-related conditions in mammals, such as arthritis, and as analytical reagents for detecting free radicals.
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(2008/06/13)
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- Use of aryl nitrone compounds in methods for treating neuropathic pain
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3,4,5-trisubstituted aryl nitrone compounds having the formula: where R1—R4 are as defined in the specification are useful as therapeutics for neuropathic pain conditions in mammals.
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- Synthesis of N-substituted N-nitrosohydroxylamines as inhibitors of mushroom tyrosinase
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A series of N-substituted N-nitrosohydroxylamines including six new compounds were synthesized and examined for inhibition of mushroom tyrosinase. Corresponding hydroxylamines were reacted with n-butyl nitrite to give substituted nitrosohydroxylamines as their ammonium salt. The N-substituted hydroxylamines were prepared from the primary amines via the oxaziridine, or from the carbonyl compounds via the oxime. Most of the nitrosohydroxylamines tested inhibited mushroom tyrosinase. Among them, N-cyclopentyl-N-nitrosohydroxylamine exhibited the most potent activity (IC50=0.6 μM), as powerful as that of tropolone, one of the most powerful inhibitors. As removal of nitroso or hydroxyl moiety, the enzyme inhibitory activity was completely diminished. Both N-nitroso group and N-hydroxy group were suggested to be essential for the activity, probably by interacting with the copper ion at the active site of the enzyme. Lineweaver-Burk plotting showed that cupferron was a competitive inhibitor but that N-cyclopentyl-N-nitrosohydroxylamine was not.
- Shiino, Mitsuhiro,Watanabe, Yumi,Umezawa, Kazuo
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p. 1233 - 1240
(2007/10/03)
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- α-(2-hydroxyphenyl) nitrone compounds, pharmaceutical compositions containing the same and methods for treating inflammation
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Disclosed are novel α-(2-hydroxyphenyl) nitrone compounds and pharmaceutical compositions containing such compounds. The disclosed compositions are useful as therapeutics for inflammation-related conditions in mammals, such as arthritis, and as analytical reagents for detecting free radicals.
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- α-aryl-N-alkylnitrones and pharmaceutical compositions containing the same
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Disclosed are novel α-aryl-N-alkylnitrone compounds and pharmaceutical compositions containing such compounds. The disclosed compositions are useful as therapeutics for preventing and/or treating neurodegenerative, autoimmune and inflammatory conditions in mammals and as analytical reagents for detecting free radicals.
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- Aryl nitrone therapeutics for the treatment of inflammatory bowel disease
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Disclosed are methods for treating or preventing inflammatory bowel disease (IBD) using aryl nitrone compounds. Pharmaceutical compositions containing aryl nitrone compounds which are useful for the treatment or prophylaxis of IBD are also disclosed.
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- Thiophene nitrone compounds
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Disclosed are novel thiophene nitrone compounds and pharmaceutical compositions containing such compounds. The disclosed compositions are useful as therapeutics for preventing and/or treating neurodegenerative, autoimmune and inflammatory conditions in mammals and as analytical reagents for detecting free radicals.
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- Increased intensity of tert-butoxyl radical emission in 4-chloro-2- methylphenoxyacetic acid (MCPA) synthesis
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The important herbicide, 2-methyl-4-chlorophenoxyacetic acid (MCPA) was synthesized by the chlorination of 2-methylphenoxyacetic acid with tert-butyl hypochlorite in the presence of methyl N,N-dimethylglycinate as a catalyst, giving a high yield and regioselectivity. The reaction was investigated using the spin-trapping technique in electron paramagnetic resonance measurement conditions, with nitrosodurene as a spin trap. Increased intensity emission of the tert-butoxyl radical (2.9 times in relation to the starting level) was observed after the catalyst had been introduced into the reaction mixture, indicating a free radical mechanism for the reaction.
- Jezierski, Adam,Zakrzewski, Jerzy,Moszczyski, Wiesaw
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p. 1229 - 1232
(2007/10/03)
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- Thioether furan nitrone compounds
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Disclosed are novel thioether furan nitrone compounds and pharmaceutical compositions containing such compounds. The disclosed compositions are useful as therapeutics for preventing and/or treating neurodegenerative, autoimmune and inflammatory conditions in mammals and as analytical reagents for detecting free radicals.
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- Synthesis of Functionalized Acyclic Nitrone Spin Traps
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Four new spin traps with functionalized acyclic nitrone stuctures, EtCH(CH2CH2CO2Et)CH=N(O)CMe3 (3), EtCH(CH2CH2CH2OH)CH=N(O)CMe3 (4), EtCH(CH2CH2CN)CH=N(O)CMe3 (6), EtCH(CH2CH2CO2H)CH=N(O)CMe3 (10), were prepared and characterized by infrared spectrometry, mass spectrometry and 1H NMR. - keywords: Enamine Alkylation, Functionalized Aldehyde, Acyclic Nitrone, Spin Trap, Nitroxide
- Zhang, Yongkang,Xu, Guangzhi
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p. 1475 - 1478
(2007/10/02)
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- Oxidation of Hydroxylamine Derivatives. VI. Anodic Oxidation of N-Alkyl-β-hydroxyhydroxylamines in Aqueous Buffer Solution
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Anodic oxidation of N-alkylhydroxylamines with and without a β-hydroxy group was studied by cyclic voltammetry and controlled potential electrolysis in aqueous buffer solution of pH 8.8.The hydroxylamines with a β-hydroxy group were oxidized initially to the corresponding nitroxides and gave the final products via two routes; i) cleavage of the (α)C-(β)C bond to give aldehydes and oximes, and ii) disproportionation of the nitroxides to form the nitroso compounds.The hydroxylamines without a β-hydroxy group did not undergo cleavage of the (α)C-(β)C bond and gave nitroso compounds.Substituents on the α and β carbons affected the product distribution.When a phenyl group or two methyl groups were present on the (β)C, or one methyl group was present on both (α)C and (β)C, (α)C-(β)C bond cleavage was predominant. Keywords - N-alkyl-β-hydroxyhydroxylamine; anodic oxidation; C-C bond fission; C-nitroso compound; aldehyde; oxime; azoxy compound
- Ozaki, Shigeko,Nishiguchi, Susumu,Masui, Masaichiro
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p. 2609 - 2616
(2007/10/02)
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- INFLUENCE OF LAMELLAR LIQUID CRYSTALLINE MEDIA IN THE HYDROLYSIS OF 4-SUBSTITUTED BENZYLIDENE t-BUTYLAMINE N-OXIDES.
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Cationic lamellar liquid crystalline morphologies decrease the rate of hydrolysis of a series of 4-substituted benzylidene t-butylamine N-oxides compared to aqueous solutions. Rate constants for the aqueous acid hydrolysis decrease as the electron releasing effect increases and they are linear when plotted against sigma ** plus -substitutent constants. Rho-values indicate a less sensitive reactivity series than the benzoic acids and a more sensitive reactivity in lamellar solvents. Reaction rates for the series in the latter solvent parallel the hydrophobic substituent constants. Three different lamellar morphologies were identified in the aqueous surfactant systems.
- Bacon,Neubert,Wildman,Ott
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p. 307 - 321
(2007/10/02)
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- INHIBITION OF HYDROLYSIS BY LAMELLAR LIQUID CRYSTALLINE SOLVENTS.
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The rate of hydrolysis of benzylidene t-butylamine N-oxide decreases as the concentration of dodecylammonium chloride in water increases until the lamellar liquid crystalline mesophase is formed. Based on the aggregate-substrate association constant plot the partitioning of the substrate into the hydrocarbon region and the electrostatic effect causes this maximum inhibition.
- Bacon,Thomas
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- 1-Aryl- und 1-Alkyl-2-phthalimido-diazen-1-oxide, diacylierte Vertreter von trisubstituierten Triazen-1-oxiden: Bildung, Eigenschaften, Stereoisomerisierung und Fragmentierung
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Oxidatively generated phthalimido-nitrene (1) reacts with nitrosobenzene (8a), p-nitrosotoluene (8b), o-nitrosotoluene (8c), p-dimethylamino-nitrosobenzene (8d), p-methoxycarbonyl-nitrosobenzene (8e), 1,1-dimethyl-1-nitrosoethane (8f) and nitrosocyclohexane (8g) to give the respective 1-substituted (Z)-2-phthalimidodiazene-1-oxides 14a-g.The constitution of the 2-imidodiazene-1-oxides 14 is deduced from their spectroscopic properties.The UV. spectra of 14a-e are similar with those of the corresponding nitrobenzenes 18, thus supporting the concept of comparibility of the phthalimido-N group with an O-atom and indicating that the phthalimido group is not in conjugation with the diazene-oxide function.This is in contrast to situation in the non-acylated trisubstituted triazene-1-oxides 12, where conjugation is extended over the chain of all three N-atoms as exhibited by the UV. spectra of (Z)-1,3,3-triphenyl-, (Z)-3,3-dimethyl-1-phenyl-, (Z)-3-methyl-1,3-diphenyl-, (Z)-1-(1,1-dimethylethyl)-3,3-diphenyl-, and (Z)-1-(1,1-dimethylethyl)-3,3-dimethyltriazene-1-oxide (12a-e).These triazene-1-oxides are formed by the reaction of 1,1-disubstituted hydrazines 11 with three mol-equiv. of nitroso compounds 8 or from equimolar amounts of 11 and 8 in the presence of mercury oxide.Over 90percent of 1,2-diphenyldiazeneoxide (19, R=C6H5) are isolated by the reaction 11+3 8a.Possible mechanisms of the reaction of 11 with 8, and of the formation of 12 via triazanols D and of 19 (R=C6H5) via N-phenyl-hydroxylamine (20, R=C6H5) are given in Scheme 6 (in the latter case with experimental evidence).An independent synthesis of 12c confirms the constitutional assignment for 12.The (Z)-configuration of the 2-imidodiazene-1-oxides 14 follows from comparison of their UV. and 1H-NMR. spectra with those of the corresponding (E)-isomers 31, obtained by irradiation of 14 above 300 nm.Only (E)-1-phenyl- and (E)-1-(p-tolyl)-2-phthalimido-diazene-1-oxide (31a and 31b, respectively) could be isolated.The (E)-isomer 31a isomerizes back thermally to its thermodinamically more stable isomer 14a.This reaction is accompanied by thermal fragmentation into phthalimido-phthalimide (35) and phthalimide (36).The same products, together with N-phenylphthalimide (38), are also obtained by thermolysis of 14a in boiling decaline.A radical mechanism is proposed for this reaction.Irradiation of 14 below 300 nm splits the molecule into 1 and the corresponding nitroso compound 8.The nitrene 1 can be trapped by cyclohexene to give 7-phthalimido-7-azabicycloheptane (32) in 60percent yield.In the absence of a trapping agent, the nitrene 1 furnishes 35 (18percent) and 36 (35percent), presumably via its dimer 1,4-bis(phthaloyl)-2-tetrazene (33), which is photolytically cleaved to nitrogen and two molecules of phthalimido radical (34), the precursor of 35 and 36.Hydrazinolyses of 12a, 12b and 12f generates the corresponding N-substituted hydroxylamines 20 (R=C6H5 or p-CH3C6H4 or (CH3)3C, resp.) in more than 95percent yield.A mechanism for the formation of 20 is proposed.
- Hoesch, Lienhard,Koppel, Bruno
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p. 864 - 889
(2007/10/02)
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- HYDROLYSIS REACTIONS IN AQUEOUS LAMELLAR LIQUID CRYSTALLINE MEDIA.
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Introduction of a quaternary ammonium head group into aqueous dodecylammonium chloride solutions gives an optically clear lamellar mesophase. Inhibition in the rate of hydrolysis of benzylidene t-butylamine N-xoide is greater in the lamellar phase of the mixed amphiphile system than in a similar phase containing only dodecylammonium head groups. This suggests maximum inhibition of the reaction may not be due to electrostatic effects but to partitioning of the substrate into the less compact hydrocarbon regions.
- Bacon
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p. 101 - 108
(2007/10/02)
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- REARRANGEMENTS OF N-SUBSTITUTED HYDROXYLAMINES - POTENTIAL GENERATORS OF NITRENIUM IONS
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The transformations of N-substituted hydroxylamines into Schiff bases by the action of phosphorus pentachloride, which have only been observed previously in the aromatic series (the so-called Stieglitz rearrangement), also occur among aliphatic monosubstituted and N,N-disubstituted hydroxylamines and their salts.The Schiff bases which form can be regarded as the product from stabilization of the intermediate nitrenium ions RNH+ and R2N+, but it is not possible to confirm the participation of the latter in reactions by interaction with the solvent.
- Stolyarov, B. V.,Krylov, A. I.
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p. 1523 - 1528
(2007/10/02)
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