- A novel heterometallic 3d-4f complex with an unusual [MnIV 4Nd4O4] core topology
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The complex [Mn4Nd4O4(Me-sao) 6(NO3)4(OMe)4(MeOH)2] (1) with an unprecedented [MnIV4Nd4O4] core topology was synthesized from MnCl2, Nd(NO3) 3 and Me-saoH2 in methanol at basic conditions (Me-saoH2 = 2′-hydroxyacetophenoxime). In 1 MnIV and NdIII ions are bridged by oxido and methoxido ligands to form an unusual topology including two distorted tetrahedral [Nd2Mn 2(μ4-O)] units. 1 crystallizes in the monoclinic space group P21/c with Z = 2 and lattice constants (at 100 K) a = 14.142(4), b = 19.365(5), c = 14.637(4) A, β = 90.32(3)°. Copyright
- Hallier, Kirstin,Holynska, Malgorzata,Dehnen, Stefanie
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- Zero-field splitting in {MnIII3(μ3-O)} core single-molecule magnets investigated by inelastic neutron scattering and high-field electron paramagnetic resonance spectroscopy
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The global zero-field splitting (ZFS) parameters of three, ferromagnetically coupled, μ3-κ3-[XO4]- (X = Cl, Re) capped, manganese(III) oximate single-molecule magnets, [Mn3O(R-sao)3(2,4′-bipyridine)3XO4] [X = Cl, R = Me, Et; X = Re, R = Me; Me-sao = 2-hydroxyphenylethanone oximate(2-)], with crystallographic trigonal symmetry were determined by use of inelastic neutron scattering and high-field/high-frequency electron paramagnetic resonance spectroscopy. ReO4- (O...O ca. 1.7 ?) is larger than ClO4- (O...O ca. 1.4 ?), which allows more parallel alignment of the local ZFS tensors. However, this chemical modification results in concomitant distortions in the equatorial ligand plane. Consistent parametrization of all spectroscopic data was achieved, and effective spin-reversal barriers determined from alternating current susceptibility data were shown to be in good accordance with the energy barriers deduced from spectroscopy.
- Sigrist, Marc,Tregenna-Piggott, Philip L.W.,Pedersen, Kasper S.,Sorensen, Mikkel A.,Barra, Anne-Laure,Hauser, Jürg,Liu, Shi-Xia,Decurtins, Silvio,Mutka, Hannu,Bendix, Jesper
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- Moessbauer and electronic spectral studies of iron(III) complexes of oximes.
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The hydroxo-bridge complexes of the type [Fe(2)(ligand-H)(4)(OH)(2)] with bidentate nitrogen-oxygen donor ligands, viz. 2-hydroxynaphthaldehydeoxime [hnoH(2)], 2-hydroxyacetphenoneoxime [haoH(2)], salicylaldooxime [SalH(2)], 2-hydroxypropiophenoneoxime [hnoH(2)] have been prepared. All the complexes have been characterized by elemental analysis, magnetic moments, electronic and Moessbauer spectral studies. Moessbauer parameters of the complexes clearly suggest high spin configuration of Fe(III) showing lower magnetic moment to that of the spin only value, i.e. 5.92 BM. It may be due to the antiferromagnetic interaction between Fe(III) centers.
- Chandra, Sulekh,Sangeetika,Sharma, Sunil Dutta
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- Copper-Catalyzed Three-Component Domino Cyclization for the Synthesis of 4-Aryl-5-(arythio)-2-(trifluoromethyl)oxazoles
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A copper-catalyzed oxidative cyclization of oxime, arylthiol, and trifluoroacetic anhydride for the construction of trisubstituted oxazoles has been developed. This transformation combines N-O bond cleavage, C-H functionalization, and intramolecular annulation, providing a practical protocol for the introduction of a trifluoromethyl (-CF3) group at oxazole rings.
- Xiao, Fuhong,Yuan, Shanshan,Huang, Huawen,Zhang, Feng,Deng, Guo-Jun
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supporting information
p. 8533 - 8536
(2019/10/17)
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- Fe(NO3)3·9H2O-catalyzed aerobic oxidative deoximation of ketoximes and aldoximes under mild conditions
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A mild, simple process for the effective aerobic oxidative deoximation of a wide range of ketoximes and aldoximes has been developed that utilizes Fe(NO3)3·9H2O as the single catalyst and molecular oxygen as the green oxidant. The environmentally benign protocol provides moderate to excellent yield and broad functional groups tolerance and is a valuable synthetic method for practical applications. According the relevant verification experiment, a plausible mechanism has been proposed.
- Li, Yongshu,Xu, Nizhou,Mei, Guangyao,Zhao, Yun,Zhao, Yiyong,Lyu, Jinghui,Zhang, Guofu,Ding, Chengrong
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supporting information
p. 810 - 814
(2018/08/09)
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- Calculation and experimental measurement of paramagnetic NMR parameters of phenolic oximate Cu(II) complexes
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We present a strategy for predicting the unusual 1H and 13C shifts in NMR spectra of paramagnetic bisoximato copper(ii) complexes using DFT. We demonstrate good agreement with experimental measurements, although 1H-13C correlation spectra show that a combined experimental and theoretical approach remains necessary for full assignment.
- Dawson, Daniel M.,Ke, Zhipeng,Mack, Frederick M.,Doyle, Rachel A.,Bignami, Giulia P. M.,Smellie, Iain A.,Bühl, Michael,Ashbrook, Sharon E.
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supporting information
p. 10512 - 10515
(2017/09/29)
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- Acid Catalyzed Direct-Amidation-Dehydrocyclization of 2-Hydroxy-acetophenones to Benzoxazoles by a One-Pot Sustainable Synthesis
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A series of 2-methyl-benzoxazoles have been synthesized starting from 2-hydroxy-acetophenones via a one-pot three steps reaction. Hydroxylamonium salt has been used as amidation agent. The reaction occurs with different anions, but the best results is achieved with hydroxylamonium hydrchloride. Despite the number of consecutive stages, the reaction is highly selective. Mild reaction conditions and various solvents can be used, but trifluoroacetic acid is the preferred. Almost, complete recovery of the trifluoroacetic acid can be achieved by vacuum distillation. The role of trifluoroacetic acid, as well as, of the hydroxylamonium salt suggests a cooperative effect leading to high selective formation of 2-methyl-benzoxazoles. Graphical Abstract: One-pot TFA catalyzed synthesis of benzoxazoles starting from 2-hydroxyacetophenones. (Chemical Equation Presented).
- Rancan, Elia,Aric, Fabio,Quartarone, Giuseppe,Ronchin, Lucio,Vavasori, Andrea
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p. 939 - 946
(2015/08/06)
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- Ruthenium Trichloride Catalyzed Highly Efficient Deoximation of Oximes to the Carbonyl Compounds and Nitriles without Acceptors
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An acceptor-free catalysis protocol for the deoximation of ketoximes and aldoximes using RuCl3 as the catalyst has been developed. Under the optimized conditions, various oximes were converted to ketones and nitriles with excellent isolated yields. An acceptor-free catalysis protocol for the deoximation of ketoximes and aldoximes using RuCl3 as the catalyst has been developed. Under the optimized conditions, various oximes were converted to ketones and nitriles with excellent isolated yields.
- Liu, Yuxiao,Yang, Na,Chu, Changhu,Liu, Renhua
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supporting information
p. 1011 - 1014
(2015/09/28)
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- Design and synthesis of new of 3-(benzo[d]isoxazol-3-yl)-1-substituted pyrrolidine-2, 5-dione derivatives as anticonvulsants
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A series of 3-(benzo[d]isoxazol-3-yl)-N-substituted pyrrolidine-2, 5-dione (7a-7d, 8a-8d, 9a-9c) have been prepared and evaluated for their anticonvulsant activities. Preliminary anticonvulsant activity was performed using maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ) tests after intraperitoneal (ip) injection into mice, which are the most widely employed models for early identification of anticonvulsant candidate. The acute neurological toxicity (NT) was determined applying rotorod test. The quantitative evaluation after oral administration in rats showed that the most active was 3-(benzo[d]isoxazol-3-yl)-1-(4-fluorophenyl) pyrrolidine-2, 5-dione (8a) with ED50 values of 14.90 mg/kg. Similarly the most potent in scPTZ was 3-(benzo[d]isoxazol-3-yl)-1-cyclohexylpyrrolidine-2, 5-dione (7d) with ED50 values of 42.30 mg/kg. These molecules were more potent and less neurotoxic than phenytoin and ethosuximide which were used as reference antiepileptic drugs.
- Malik, Sachin,Ahuja, Priya,Sahu, Kapendra,Khan, Suroor Ahmad
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- Synthesis of ketoximes via a solvent-assisted and robust mechanochemical pathway
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A versatile and robust mechanochemical route to ketone-oxime conversions has been established for a broad range of ketones via a simple mortar-pestle grinding method. The relative reactivity of aldehydes vs. ketones under these conditions has also been explored, along with an examination of the possible connection between reactivity and electronic substituent effects.
- Aakeroey, Christer B.,Sinha, Abhijeet S.
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p. 8168 - 8171
(2013/09/02)
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- Benzisoxazole 2-oxides as novel UV absorbers and photooxidation inhibitors
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Compounds with strong absorptions in the ultraviolet (UV) region of the spectrum, particularly the UVA and UVB, have seen much interest as UV screeners or absorbers in a wide variety of commercial products. A series of benzisoxazole 2-oxides have been synthesized and characterized by UV-vis spectroscopy. A number of derivatives have been shown to posses moderate to strong molar absorption coefficients in the UVB range (ca. 300 nm), the strongest being those derived from benzophenones. Three other derivatives containing additional electron withdrawing groups showed strong molar absorption coefficients in the UVA (ca. 340 nm). Solvent effects on the parent derivatives show changes in the molar absorption coefficients with little changes in the λmax values. Preliminary studies of these compounds as potential additives to prevent photooxidation of polystyrene showed considerable inhibition of polymer degradation with the parent unsubstituted benzisoxazole 2-oxide compounds being the most effective. Copyright 2013 John Wiley & Sons, Ltd. A series of benzisoxazole 2-oxides have been shown to posses moderate to strong molar absorption coefficients in the UVB range (ca. 300 nm) and three others with strong absorptions on the UVA (ca. 340 nm). Solvent effects of the parent derivatives show changes in the molar absorption coefficients with little changes in the λmax values. Preliminary studies of these compounds as potential additives to prevent photooxidation of polystyrene showed considerable inhibition of polymer degradation. Copyright
- Kociolek, Martin George,Casbohm, Jerry S.
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p. 863 - 867
(2013/10/01)
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- From antiferromagnetic to ferromagnetic exchange in a family of oxime-based MnIII dimers: A magneto-structural study
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The reaction of Mn(ClO4)2·6H2O, a derivatised phenolic oxime (R-saoH2) and the ligand tris(2-pyridylmethyl)amine (tpa) in a basic alcoholic solution leads to the formation of a family of cluster compounds of general formula [Mn III2O(R-sao)(tpa)2](ClO4) 2 (1, R = H; 2, R = Me; 3, R = Et; 4, R = Ph). The structure is that of a simple, albeit asymmetric, dimer of two MnIII ions bridged through one μ-O2- ion and the -N-O- moiety of the phenolic oxime. Magnetometry reveals that the exchange interaction between the two Mn III ions in complexes 1, 3 and 4 is antiferromagnetic, but that for complex 2 is ferromagnetic. A theoretically developed magneto-structural correlation reveals that the dominant structural parameter influencing the sign and magnitude of the pairwise interaction is the dihedral Mn-O-N-Mn (torsion) angle. A linear correlation is found, with the magnitude of J varying significantly as the dihedral angle is altered. As the torsion angle increases the AF exchange decreases, matching the experimentally determined data. DFT calculations reveal that the dyzπ*dyz interaction decreases as the dihedral angle increases leading to ferromagnetic coupling at larger angles.
- Barros, Wdeson P.,Inglis, Ross,Nichol, Gary S.,Rajeshkumar, Thayalan,Rajaraman, Gopalan,Piligkos, Stergios,Stumpf, Humberto O.,Brechin, Euan K.
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p. 16510 - 16517
(2013/12/04)
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- Synthesis of 1,2-benzisoxazole 2-oxides
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(Chemical Equation Presented) A series of 2-hydroxyaryl ketoximes were converted to the corresponding 1,2- benzisoxazole 2-oxides by treatment with iodobenzene diacetate (in acetic acid or methanol) or N-chlorosuccinimide in water. Both methods gave moderate to excellent yields for a variety of substituted oximes under mild conditions within short reaction times. The latter method has the advantages of an aqueous solvent and lack of halogenated organic by-products. Copyright Taylor & Francis Group, LLC.
- Kociolek, Martin G.,Hoermann, Olivia
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body text
p. 2632 - 2638
(2012/08/08)
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- Microwave-assisted efficient one-step synthesis of amides from ketones and benzoxazoles from (2-hydroxyaryl) ketones with acetohydroxamic acid using sulfuric acid as the catalyst
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Efficient one-step method for the synthesis of amides directly from ketones and benzoxazoles from (2-hydroxyaryl) ketones by the reaction of acetohydroxamic acid using sulfuric acid as catalyst was described.
- Madabhushi, Sridhar,Chinthala, Narsaiah,Vangipuram, Venkata Sairam,Godala, Kondal Reddy,Jillella, Raveendra,Mallu, Kishore Kumar Reddy,Beeram, China Ramanaiah
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scheme or table
p. 6103 - 6107
(2011/11/30)
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- Efficient microwave-assisted synthesis of oximes from acetohydroxamic acid and carbonyl compounds using BF3·OEt2 as the catalyst
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An efficient synthesis of oximes by reaction of carbonyls with acetohydroxamic acid using BF3·OEt2 as a catalyst is described.
- Sridhar, Madabhushi,Narsaiah, Chinthala,Raveendra, Jillella,Kondal Reddy, Godala,Kishore Kumar Reddy, Mallu,China Ramanaiah, Beeram
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experimental part
p. 4701 - 4704
(2011/09/20)
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- Synthesis of isoxazoline N -oxides via [hydroxy(tosyloxy)iodo]benzene (HTIB)-mediated oxidative N-O coupling
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An HTIB mediated oxidative N-O coupling strategy for the synthesis of some isoxazoline N-oxide derivatives from β-hydroxyketoximes is described, along with a comparative study of the efficiency of N-O coupling in two different solvents. A plausible mechanism for the conversion is proposed.
- Raihan, Mustafa J.,Kavala, Veerababurao,Habib, Pateliya Mujjamil,Guan, Qiao-Zhi,Kuo, Chun-Wei,Yao, Ching-Fa
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supporting information; experimental part
p. 424 - 434
(2011/04/17)
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- Identification and SAR of squarate inhibitors of mitogen activated protein kinase-activated protein kinase 2 (MK-2)
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A novel series of inhibitors for mitogen activated protein kinase-activated protein kinase 2 (MK-2) are reported. These squarate based inhibitors were identified via a high-throughput screen. An MK2 co-structure with the starting ligand was obtained and a structure based approach was followed to optimize potency and selectivity.
- Lovering, Frank,Kirincich, Steve,Wang, Weiheng,Combs, Kerry,Resnick, Lynn,Sabalski, Joan E.,Butera, John,Liu, Julie,Parris, Kevin,Telliez
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experimental part
p. 3342 - 3351
(2009/09/08)
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- A PROCESS FOR THE MANUFACTURE OF ZONISAMIDE
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The present invention describes an improved process for the preparation of 1,2Benzisoxazole-3-methanesulphonamide (Zonisamide), a well known anti-epileptic agent which possesses anti-convulsant and anti-neurotoxic effects. Other aspect of this invention are isolation of a key intermediate, viz., crystalline sodium chloride associated 1,2Benzisoxazole-3-methane sodium sulfonate (BOS-Na:NaCl). The isolated crude BOSNa:NaCl is directly converted to Zonisamide using controlled molar ratio of chlorosulfonic acid to avoid the disulfonated side products. The analytical characteristics like IR and XRD data of the BOS-Na:NaCl are also reported to confirm its nature.
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Page/Page column 9
(2010/02/11)
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- EPR and electronic spectral studies on copper(II) complexes of some N-O donor ligands
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Complexes, [Cu(ligand-H)2] of copper(II) with hidentate nitrogen-oxygen donor ligands, viz. 2-hydroxynaphthaldehydeoxime[hnoH 2], 2-hydroxyacetophenoneoxime [haOH2], salicyladoxime [salH2] and 2-hydroxypropiophenoneoxime [hmpH2] hate been prepared. The complexes have square-planar geometry. The effect of axial ligand has also been studied by EPR spectra of the pyridine adduct of these complexes. Spectral features for diadducts are different compared to the monoadducts. All these pyridine adducts have tetragonal geometry.
- Chandra, Sulekh,Sangeetika
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p. 203 - 206
(2007/10/03)
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- Microwave enhanced synthesis of oximes from ketones
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Microwave enhanced synthesis of oximes from ketones in high yields is reported.
- Mitra, Alok Kumar,De, Aparna,Karchaudhuri, Nilay
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p. 218 - 219
(2007/10/03)
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- Chemical Model Studies on the Mutagenesis of Benzofuran Dioxetanes in the Ames Test: Evidence for the Benzofuran Epoxide as Ultimate Mutagen
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The synthesis of the first benzofuran epoxide 3a was achieved by epoxidation of the benzofuran 1a with dimethyldioxirane and alternatively by deoxygenation of the benzofuran dioxetane 2a with sulfides. This labile epoxide formed with nucleophiles such as water, methanol, thiophenol, and imidazole the corresponding adducts 13a-16a. In contrast to epoxide 3a, the dioxetanes 2 required acid catalysis (CF3CO2H) for the addition of water, methanol, and azide ion to give the corresponding adducts 9-11; in the absence of nucleophiles the allylic hydroperoxides 8 were formed. The decomposition of benzofuran dioxetanes 2 in the polar, protic solvents water and methanol afforded not only the expected cleavage products 4 but also the 1,3-dioxols 5, the spiroepoxide dimer 6a, and the 1,4-dioxines 7. An intramolecular electron-transfer mechanism is postulated for the formation of the spiroepoxide, which subsequently dimerizes to 6a or rearranges into 5 and 7. Only the benzofuran epoxide 3a, besides the benzofuran dioxetanes 2, was mutagenic in the Salmonella typhimurium strain TA100. Therefore, we implicate the epoxide 3a as the ultimate mutagen responsible for the high mutagenic activity observed with dioxetane 2a in the Ames test. We postulate that in the oxidative metabolism of polycyclic arenes and heteroarenes the corresponding epoxides are generated from the intermediary dioxetanes by deoxygenation with sulfides.
- Adam,Hadjiarapoglou,Mosandl,Saha-M?ller,Wild
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p. 8005 - 8011
(2007/10/02)
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- Reactivity of 1,2-Benzisoxazole 2-Oxides
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Nitration, bromination, and reaction with acetic anhydride, with halogen acids, and with sodium alkoxide, have been explored in the 1,2-benzisoxazole 2-oxide series.The nitration proceeded by simple substitution; the other reactions took place with rupture of the heterocyclic ring.Deoxygenation to the 1,2-benzisoxazoles could be accomplished, under forcing conditions.
- Boulton, A. J.,Tsoungas, Petros G.,Tsiamis, Chris
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p. 695 - 698
(2007/10/02)
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