- Polyoxomolybdate-Calix[4]arene Hybrid: A Catalyst for Sulfoxidation Reactions with Hydrogen Peroxide
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An easily accessible polyoxomolybdate-calix[4]arene hybrid 1 has been synthesized and applied as a heterogeneous catalyst in the sulfoxidation of thioethers to sulfoxides and to sulfones under strictly stoichiometric amounts of 30% H2O2 in CH3CN as the solvent. This study represents the first promising example of successful employment of calixarenes-polyoxometalate (POM) hybrid materials in the area of catalytic oxidations.
- Meninno, Sara,Parrella, Alessandro,Brancatelli, Giovanna,Geremia, Silvano,Gaeta, Carmine,Talotta, Carmen,Neri, Placido,Lattanzi, Alessandra
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Read Online
- New reactions of γ-halocarbanions: Underestimated reactive intermediates in organic synthesis
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Short-lived γ-halocarbanions can be trapped by active electrophiles such as aldehydes, imines, and Michael acceptors to give anionic adducts, which undergo intramolecular substitution to give substituted tetrahydrofurans, pyrrolidines, and cyclopentanes. This has underlain a new method for the synthesis of these valuable ring systems. We have determined the acidity of the γ-halocarbanion precursors and have shown that the halogen atoms in the γ-position relative to the carbanion center exert a significant stabilizing effect on the carbanion.
- Barbasiewicz,Judka,Makosza
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Read Online
- New reactions of γ-halocarbanions: Simple synthesis of substituted tetrahydrofurans
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The treatment of 4-chlorobutyronitrile, 3-chloropropyl phenyl sulfone, and other related compounds with a base afforded γ-halocarbanions that undergo fast intramolecular substitution of the halogen to produce substituted cyclopropanes. We found that these short-lived carbanionic intermediates can be trapped with active external electrophilic partners, such as aldehydes, to give the aldol anions. These anions then undergo rapid intramolecular substitution of chloride to produce 2,3- disubstituted tetrahydrofurans. Under the right conditions, yields of tetrahydrofurans are excellent. Similar reactions with ketones gives 2,2,3-trisubstituted furans, but this process is usually less efficient. Ratios between the rates of intramolecular and intermolecular processes were qualitatively estimated by competitive experiments. It was shown that y-halo and y-trimethylammonium substituents substantially increase the kinetic CH acidity of alkane nitriles and sulfones.
- Makosza, Mieczyslaw,Judka, Marek
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Read Online
- Synthesis of Na22[((RE)4(H2O)6Sb6O4)(SbW10O37)2(SbW8O31)2] [(RE)III = Y, Gd, Tb, Dy, Ho, Er, Tm, Yb]: Synthesis, characterization and catalytic application
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A series of eight rare-earth substituted antimony tungstates with the formulae [((RE)4(H2O)6Sb6O4)(SbW10O37)2(SbW8O31)2]22– [(RE)III = Y(1), Gd(2), Tb(3), Dy(4), Ho(5), Er(6), Tm(7), Yb(8)] has been synthesized under ambient conditions. The compounds were isolated using rare-earth salts and Na9[B-α-SbW9O33]?19.5 H2O as precursors along with sodium dihydrogen phosphate in 1 M NaCl solution. The addition of dihydrogen phosphate was found to be a crucial step for the isolation of these polyanions. The polyanions were characterized by various analytical techniques such as single crystal X-ray diffraction (1a – 6a) (SC-XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA). The compounds were found to show efficient heterogeneous catalytic activity for oxidation of thioethers.
- Gupta, Rakesh,Hussain, Firasat,Kaushik, Reetam,Khan, Imran
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Read Online
- Mild and Diazo-Free Synthesis of Trifluoromethyl-Cyclopropanes Using Sulfonium Ylides
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The synthesis of several 1,1-disubstituted trifluoromethyl-cyclopropanes (TFCPs), known as tert-butyl bioisosteres, has been achieved from the reaction between trifluoromethylalkenes and unstabilized sulfonium ylides in yields of ≤97%. This method offers
- Cyr, Patrick,Flynn-Robitaille, Jo?l,Boissarie, Patrick,Marinier, Anne
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Read Online
- Electrochemical oxygenation of sulfides with molecular oxygen or water: Switchable preparation of sulfoxides and sulfones
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A practical and eco-friendly method for the controllable aerobic oxygenation of sulfides by electrochemical catalysis was developed. The switchable preparation of sulfoxides and sulfones was effectively controlled by reaction time, in which both molecular oxygen and water can be used as the oxygen source under catalyst and external oxidant-free conditions. The electrochemical protocol features a broad substrate scope and excellent site selectivity and is successfully applied to the modification of some sulfide-containing pharmaceuticals and their derivatives. This journal is
- Li, Jin-Heng,Li, Yang,Sun, Qing,Xue, Qi,Zhang, Ting-Ting
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supporting information
p. 10314 - 10318
(2021/12/17)
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- Flow Electrosynthesis of Sulfoxides, Sulfones, and Sulfoximines without Supporting Electrolytes
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An efficient electrochemical flow process for the selective oxidation of sulfides to sulfoxides and sulfones and of sulfoxides toN-cyanosulfoximines has been developed. In total, 69 examples of sulfoxides, sulfones, andN-cyanosulfoximines have been synthesized in good to excellent yields and with high current efficiencies. The synthesis was assisted and facilitated through a supporting electrolyte-free, fully automated electrochemical protocol that highlights the advantages of flow electrolysis.
- Amri, Nasser,Wirth, Thomas
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p. 15961 - 15972
(2021/07/20)
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- Tetrameric Lanthanide-Substituted Silicotungstate {Ln8Si4W40} Nanoclusters: Synthesis, Structural Characterization, Electrochemistry, and Catalytic Application for Oxidation of Thioethers
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All the title nanoclusters 1–10 with the molecular formula [(Ln2SiW10O38)4(W3O8)(OH)4(H2O)2]26? [LnIII =Sm (1), Eu (2), Gd (3), Tb (4), Dy (5), Ho (6), Er (7), Tm (8), Yb (9), and Y (10)] have been synthesized and isolated as mixed sodium and potassium salts. These nanoclusters are characterized by various analytical techniques such as FT-IR, UV/Vis, Photoluminescence, Single crystal X-ray diffraction, Electrochemistry, ICP-AES and Thermogravimetric analysis, and Powder X-ray diffraction. The {Ln8Si4W40} complexes show high efficiency and selectivity for the oxidation of thioethers using H2O2 as green oxidant. It is worth mentioning that the catalyst can be recovered even after five cycles of reaction with only a slight loss in its activity.
- Khan, Imran,Das, Vivek,Teillout, Anne-Lucie,Mbomekallé, Isra?l-Martyr,de Oliveira, Pedro,Sahoo, Subash Chandra,Hussain, Firasat
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supporting information
p. 1071 - 1081
(2021/03/16)
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- Single-Molecule Magnetic, Catalytic and Photoluminescence Properties of Heterometallic 3d–4f [Ln{PZn2W10O38(H2O)2}2]11? Tungstophosphate Nanoclusters
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A series of eleven lanthanide containing di-Zinc (II) substituted heterometallic 3d–4f sandwich-type tungstophosphate nanoclusters [Ln{PZn2W10O38(H2O)2}2]11? (Ln=NdIII, SmIII, EuIII, GdIII, TbIII, DyIII, HoIII, ErIII, TmIII, YbIII, and LuIII) have been synthesized by a single step reaction procedure. These clusters were characterized by various analytical techniques such as single crystal X-ray diffraction (SC-XRD), fourier transform infrared (FT-IR) spectroscopy, high-resolution electro-spray ionization mass spectrometry (HR-ESI-MS), inductively coupled plasma atomic emission spectroscopy (ICP-AES), solid UV/Vis, photoluminescence spectroscopy, powder X-ray diffraction (P-XRD) and thermogravimetric analysis (TGA). All the polyanions are isostructural and consists of a lanthanide ion sandwiched between two units of (1,5) isomer of di-Zn substituted α-Keggin type tungstophosphate. The complexes Sm-2 a, Eu-3 a, Tb-5 a, and Dy-6 a show good photoluminescence behavior. The catalytic properties were examined for the oxidation of thioethers. The catalyst is stable with a high turn over frequency (TOF) of 6250 h?1 and can be recovered even after 5 consecutive cycles. Furthermore, magnetic properties revealed that Gd-4 a, Tb-5 a, Dy-6 a, Er-8 a, and Yb-10 a show single-molecule magnetic properties.
- Das, Vivek,Khan, Imran,Hussain, Firasat,Sadakane, Masahiro,Tsunoji, Nao,Ichihashi, Katsuya,Kato, Chisato,Inoue, Katsuya,Nishihara, Sadafumi
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p. 3819 - 3831
(2021/09/22)
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- Interfacing sugar-based surfactant micelles and Cu nanoparticles: A nanoreactor for C-S coupling reactions in water
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A simple and sustainable synergistic catalytic protocol by interfacing nanomicelles and metal nanoparticles (MNPs) is reported for C-S coupling reactions in water. The sugar-based surfactant GluM was synthesized by introducing a PEG chain to stabilize MNPs and self-assembled to form nanomicelles. Cu2O nanoparticles were generated via in situ reduction of copper salt in an aqueous solution of the sugar-based surfactant. The nature of the interaction between nanomicelles and Cu2O nanoparticles was revealed by XPS, XRD, in situ IR, TEM, and 1H NMR. A broad substrate scope with moderate to excellent yields was documented and the recycling of the GluM/Cu aqueous mixture was surprising.
- Ge, Xin,He, Xi,Liu, Xuemin,Qian, Chao,Song, Weili,Yang, Jinguo,Zhou, Shaodong
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supporting information
p. 6322 - 6329
(2021/09/10)
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- On the important transition of sugar-based surfactant as a microreactor for C-S coupling in water: From micelle to vesicle
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A reversible, temperature-induced micelle-to-vesicle transition of a sugar-based pseudogemini surfactant (C11D12) was employed for copper-catalyzed C-S coupling in water. The phase behavior and morphology of the C11D12 aqueous solution were investigated by DLS and cryo-TEM. The aggregates undergo a series of transitions upon increasing the temperature: spherical micelles were initially transformed into large vesicles, but they eventually transformed into smaller vesicles. The vesicular catalytic protocol accommodates an excellent substrate scope with moderate to high yields. The mechanisms of temperature-induced aggregate transition and vesicular catalysis were elucidated by experimental results and DFT calculations. It was revealed that the charge layer of the vesicle grants stronger nucleophilicity to the PhSO2-Cu-D12Ga intermediate. Furthermore, the aqueous reaction medium can be recycled and reused several times after easily separating the precipitated product.
- Ge, Xin,Lei, Qiuyun,Liao, Xiong,Liu, Xuemin,Song, Weili,Wu, Lei,Wu, Siyuan,Zhou, Shaodong
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- Method for synthesizing sulfone compounds under photocatalysis condition
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The invention belongs to the technical field of compound preparation, and particularly relates to a method for synthesizing sulfone compounds under a photocatalysis condition. Aromatic hydrazine and sulfinate are used as raw materials, and under the action of alkali and a solvent, a sulfone compound is generated through reaction under the condition of air or oxygen under the illumination of visible light. According to the method disclosed by the invention, aryl hydrazine is used as an arylation reagent, polyacid salt is used as a catalyst or an organic photosensitizer is used as a catalyst, and the sulfones compound can be efficiently synthesized by coupling with sulfinate under the condition of room temperature through visible light irradiation. The method has good substrate universalityand relatively mild reaction conditions, is not only a substitute for synthesizing sulfone compounds by coupling from simple substrates reported at present, but also broadens the new application of the polyacid salt in the field of photocatalysis.
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Paragraph 0169-0173
(2021/03/31)
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- Selective oxidation of (hetero)sulfides with molecular oxygen under clean conditions
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The development of eco-friendly and switchable catalytic systems for the conversion of a sole raw-material into distinct high-value products is a particularly attractive concept and a daunting synthetic challenge. In the present work, the first example of efficient and selective oxidation of sulfides to sulfones and sulfoxides using molecular oxygen under clean conditions was established.
- Liu, Kai-Jian,Deng, Ji-Hui,Yang, Jie,Gong, Shao-Feng,Lin, Ying-Wu,He, Jun-Yi,Cao, Zhong,He, Wei-Min
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supporting information
p. 433 - 438
(2020/02/13)
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- Selectivity switch in the aerobic oxygenation of sulfides photocatalysed by visible-light-responsive decavanadate
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Nanometre-sized metal oxides are promising species for the development of visible-light-responsive photocatalysts for the selective transformation of organic functional groups. In this article, we report that decavanadate ([V10O28]6-, V10) behaved as an efficient visible-light-responsive photocatalyst in the product-selective oxygenation of sulfides achieved using O2 (1 atm) as the green oxidant. In particular, we revealed that visible-light-responsive photocatalysis of V10 showed remarkable activity for the oxygenation of structurally diverse sulfides to form the corresponding sulfones using O2 in methyl ethyl ketone (MEK). Furthermore, by simply adding water to the reaction mixture, the product selectivity of sulfide oxygenation can be significantly switched toward the production of sulfoxides, without concomitant loss of photocatalytic activity. Based on experimental evidence, we inferred the following mechanistic steps for this photocatalytic system: the aerobic oxygenation of sulfides to form the corresponding sulfoxides initiated by a visible-light-induced photoredox reaction of V10. As for the formation of sulfones, MEK-derived peroxide species as the co-catalysts are probably involved in the oxygenation of sulfoxides to sulfones. The selectivity switch of the V10-photocatalysed reaction brought about by water addition is most likely achieved by suppressing the formation of MEK-derived peroxide species. This journal is
- Li, Chifeng,Mizuno, Noritaka,Murata, Kei,Ishii, Kazuyuki,Suenobu, Tomoyoshi,Yamaguchi, Kazuya,Suzuki, Kosuke
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supporting information
p. 3896 - 3905
(2020/07/09)
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- Switchable Synthesis of Aryl Sulfones and Sulfoxides through Solvent-Promoted Oxidation of Sulfides with O2/Air
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A practical and switchable method for the synthesis of aryl sulfones and sulfoxides via sulfide oxidation was developed. The chemoselectivities of products were simply controlled by reaction temperature using O2/air as the terminal oxidant and oxygen source. The broad substrate scope, easy realization of gram-scale production, and the simplification of a sulfide oxidation system render the strategy attractive and valuable.
- Cheng, Zhen,Sun, Pengchao,Tang, Ailing,Jin, Weiwei,Liu, Chenjiang
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supporting information
p. 8925 - 8929
(2019/11/14)
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- Electrochemical oxidations of thioethers: Modulation of oxidation potential using a hydrogen bonding network
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A highly efficient chemo-selective electrochemical oxidation of thioethers to sulfoxides and sulfones was developed. The hydrogen bonding network generated from hexafluoro-2-propanol (HFIP) and acetic acid (AcOH) plays an important role in the modulation of oxidation potential. The hydrogen bonding network complexes strongly with the sulfoxide, making it less prone to further oxidation. Therefore, thioethers can be selectively electrochemically oxidized to sulfoxides and over-oxidization could be minimized. Moreover, this modulation of oxidization via hydrogen bonding was supported by density functional theory (DFT) calculations and cyclic voltammetry experiments.
- Liu, Shiwen,Chen, Bocheng,Yang, Yi,Yang, Yuhao,Chen, Qianjin,Zeng, Xiaojun,Xu, Bo
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- A highly efficient reusable homogeneous copper catalyst for the selective aerobic oxygenation sulfides to sulfoxides
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Readily available copper showed efficient activity and great selectivity for the homogeneous catalysis of oxidation of sulfides to sulfoxides using molecular oxygen as the oxidant. The reaction proceeds under mild conditions in the presence of a catalytic amount of TEMPO. Importantly, the catalysts could be conveniently recovered and reused. And this methodology was proved to be applicable for the transformation of various aromatic and aliphatic sulfides into the corresponding sulfoxides with high conversion and high selectivity.
- Ren, Cheng,Fang, Runxing,Yu, Xiaochun,Wang, Shun
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supporting information
p. 982 - 986
(2018/02/13)
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- An environmentally benign and selective electrochemical oxidation of sulfides and thiols in a continuous-flow microreactor
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A practical and environmentally benign electrochemical oxidation of thioethers and thiols in a commercially-available continuous-flow microreactor is presented. Water is used as the source of oxygen to enable the oxidation process. The oxidation reaction utilizes the same reagents in all scenarios and the selectivity is solely governed by the applied potential. The procedure exhibits a broad scope and good functional group compatibility providing access to various sulfoxides (15 examples), sulfones (15 examples) and disulfides (6 examples). The use of continuous flow allows the optimal reaction parameters (e.g. residence time, applied voltage) to be rapidly assessed, to avoid mass- and heat-transfer limitations and to scale the electrochemistry.
- Laudadio, Gabriele,Straathof, Natan J. W.,Lanting, Menno D.,Knoops, Benny,Hessel, Volker,No?l, Timothy
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supporting information
p. 4061 - 4066
(2017/09/07)
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- Visible-Light Photocatalysis of Aerobic Oxidation Reactions Using Carbazolic Conjugated Microporous Polymers
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Carbazolic conjugated microporous polymer (C-CMP) is obtained via straightforward carbazole-based oxidative coupling polymerization. C-CMP exhibits high porosity and a specific surface area of 1137 m2 g-1, and it is thermally stable to 600 °C in nitrogen. C-CMP is shown to be a highly effective heterogeneous photocatalyst for a wide range of reactions, including the oxidative coupling of primary amines, aerobic dehydrogenation of nonactive secondary amine substrates such as pharmaceutically relevant nitrogen heterocycles, and selective oxidation of sulfide using molecular oxygen and visible light. This work highlights the potential of developing photoactive N-containing CMPs as a highly stable, molecularly tunable, reusable, and metal-free visible light photocatalysts for a wide variety of organic transformations.
- Su, Chenliang,Tandiana, Rika,Tian, Bingbing,Sengupta, Ananya,Tang, Wei,Su, Jie,Loh, Kian Ping
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p. 3594 - 3599
(2016/07/06)
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- Lithium-titanium exchange of tertiary α-sulfonyl carbanions: Synthesis, structure, dynamics and reactivity of bis(1-sulfonylalkyl) titaniums
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Lithium-titanium exchange of tertiary α-sulfonyl carbanions with ClTi(OiPr)3 and Cl2Ti(OiPr)2 in diethyl ether gave bis(1-sulfonylalkyl) titaniums and not the corresponding (1-sulfon-ylalkyl) titaniums. X-ray crystal structure analysis of di(iso-propoxy) bis[1-(phenylsulfonyl) cyclobutyl]titanium and di-(isopropoxy) bis[1-(phenylsulfonyl) isopropyl]titanium showed asymmetric distorted octahedral complexes, having hexaco-ordinate Ti atoms, two C-Ti bonds, four Ti-O bonds, and two four-membered Ti-O-S-Cα rings. According to 1H NMR spectroscopy bis(1-sulfonylcycloalkyl) titaniums are non-flux-ional at room temperature. This suggests that chiral bis(1-sulfonylalkyl) titaniums should be configurationally stable. The bis(1-sulfonylalkyl) titaniums are stable at room temperature towards β-H elimination. They selectively add to benzaldehyde in the presence of acetophenone but do not react with methyl iodide. The reaction of tertiary acyclic α-sulfonyl carbanions with ClTi(OiPr)3 in tetrahydrofuran (THF) gives different titanium derivatives with unspecified structures, which not only selectively react with benzaldehyde in the presence of acetophenone but are also alkylated by methyl iodide.
- Hess, Thomas,Raabe, Gerhard,Gais, Hans-Joachim
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p. 7134 - 7147
(2015/03/04)
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- Ammonium salt catalyzed oxidation of organosulfides to organosulfoxydes
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The selective oxidation of aromatic and aliphatic organosulfides with H2O2/H2O catalyzed by metal free ammonium salts has been explored. Reactions were performed using 2.5-5 mol % of catalyst loadings, isolating the corres
- Secci, Francesco,Frongia, Angelo,Piras, Pier Paolo
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p. 603 - 605
(2014/01/23)
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- Silica-supported molybdenum complex: A novel, selective and reusable organic-inorganic hybrid catalyst for eco-friendly oxidation of sulfides and olefins
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A novel, highly efficient and reusable molybdenum based catalyst has been synthesized by covalent grafting of 2,6-diacetylpyridine-monosalicyloylhydrazone onto functionalized silica followed by complexation with MoO 2(acac)2, and the resulting organic-inorganic hybrid material was found to be highly effective catalyst for oxidation of various sulfides and olefins to their corresponding sulfoxides/sulfones and epoxides, respectively. The catalyst was characterized by elemental analysis (CHN), diffuse reflectance UV-Vis, 13C CPMAS NMR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and BET surface area analysis, energy dispersive X-ray fluorescence (ED-XRF), Fourier-transform infrared (FT-IR) and atomic absorption spectroscopy (AAS). Mild reaction conditions, high turnover frequency, high selectivity, easy recovery and reusability of the catalyst render the present protocol very useful to address the industrial needs and environmental concerns.
- Sharma,Pandey, Amit,Gulati, Shikha
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- Intramolecular addition of γ-chloro carbanions to electrophilic groups: Synthesis of tricyclic tetrahydrofurans, pyrrolidines, and cyclopentanes
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Carbanions of 3-chloropropyl phenyl sulfones containing electrophilic groups such as carbonyl and imino groups in the ortho position of the phenyl ring add intramolecularly to these groups to give aldol-type anions. These anions undergo intramolecular 1,5
- Wojtasiewicz, Anna,Barbasiewicz, Michal,Makosza, Mieczyslaw
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experimental part
p. 1885 - 1894
(2010/07/18)
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- COMPOUNDS AND COMPOSITIONS AS MODULATORS OF GPR119 ACTIVITY
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The invention provides compounds, pharmaceutical compositions comprising such compounds and methods of using such compounds to treat or prevent diseases or disorders associated with the activity of GPR119.
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Page/Page column 114-115
(2009/04/25)
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- γ-diphenylphosphinoxy carbanions: Slow reacting analogues of-halocarbanions
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Carbanion of diphenylphosphinyl ester of 3-hydroxypropyl phenyl sulfone undergoes slow 1,3-intramolecular nucleophilic substitution to give substituted cyclopropane. It can be efficiently trapped by external electrophiles such as aldehydes to produce aldo
- Makosza, MieczysLaw,Wojtasiewicz, Anna
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experimental part
p. 857 - 864
(2009/12/03)
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- Sulfone derivatives as 5-HT7 receptor ligands
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The present invention relates to sulfone derivatives of formula (I): Ar—SO2—CR2R3-L-N(R1)2??I wherein Ar, L, R1, R2 and R3 are as defined herein, and pharmaceutically
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Page/Page column 6
(2010/02/09)
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- 24-Sulfur-substituted analogs of 1 alpha, 25-dihydroxy vitamin D3
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The present invention provides novel C24-sulfone analogs of 1α,25-dihydroxy vitamin D3, compositions comprising these compounds and methods of using these compounds as selective inhibitors of CYP24. In particular, the compounds of the invention are useful for treating diseases which benefit from a modulation of the levels of 1α,25-dihydroxy vitamin D3, for example, cell-proliferative disorders.
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- New synthesis of substituted cyclopentanes via reactions of γ-chlorocarbanions with electron-deficient alkenes
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Carbanions of 3-chloropropyl pentachlorophenylsulfone, although they undergo fast cyclization to the corresponding cyclopropyl sulfone, can be trapped with electrondeficient alkenes to produce carbanionic adducts that enter intramolecular substitution to
- Ma?kosza, Mieczys?aw,Judka, Marek
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p. 717 - 719
(2007/10/03)
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- Successive carbon-carbon bond formation by sequential generation of radical and anionic species with manganese and catalytic amounts of PbCl2 and Me3SiCl
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Three-component coupling reactions of iodoalkanes, α,β-unsaturated nitriles (or esters), and carbonyl compounds are achieved in good to excellent yields with a moderate reducing system derived from manganese metal and a catalytic amount of PbCl2 and Me3SiCl. Although the role of PbCl2 is unclear, addition of a catalytic amount of the salt is essential for reducing the iodoalkane. The reaction proceeds with primary, secondary, and tertiary iodoalkanes. Both acrylonitrile and acrylic esters can be employed as activated olefins, while the reaction with an alkyl vinyl ketone gives a complex mixture. Ketones and aldehydes can be used as the third component and the diastereoselectivity of the anionic addition is approximately 1: 1-2: 1 ratio. By using the heterogenerative process, i.e., successive 1,4-addition by radical and anionic internal addition, cyclopropanation of electron- deficient olefins is achieved with chloroiodomethane, manganese, PbCl2, Me3SiCl, and DMAP.
- Takai, Kazuhiko,Ueda, Takashi,Ikeda, Norihiko,Ishiyama, Takaya,Matsushita, Hiroshi
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p. 347 - 353
(2007/10/03)
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- 24-sulfur-substituted analogs of 1alpha, 25-dihydroxy vitamin D3
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The present invention provides novel C24-aryl sulfone analogs of 1α,25-dihydroxy vitamin D3, compositions comprising these compounds and methods of using these compounds as selective inhibitors of CYP24. In particular, the compounds of the invention are useful for treating diseases which benefit from a modulation of the levels of 1α,25-dihydroxy vitamin D3, for example, cell-proliferative disorders.
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- Should anionised benzylic sulfones be considered as carbenoids?
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Na·Hg reduction of benzyl sulfones 1c-e in aprotic solvent conditions affords stilbenes 4c-e, an olefination process best explained by assuming that the corresponding sulfone carbanion, which was formed under these conditions, is decomposed into a carbene species.
- Jolivet,Uguen
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p. 7907 - 7911
(2007/10/03)
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- The phenylthiocyclopropylsilyl group: A useful latent hydroxy group
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The α-dimethyl(1-phenylthio)cyclopropylsilyl group was used as a new masked hydroxy group. Three procedures have been devised to allow the oxidation of this silicon group in the presence of various functionalities. The desired alcohols are obtained in high yields with retention of configuration at the carbon centre. (C) 2000 Elsevier Science Ltd.
- Angelaud, Rémy,Landais, Yannick
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p. 2025 - 2036
(2007/10/03)
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- α-Fluorination of methyl phenyl sulfoxide and related compounds by molecular fluorine: A novel method for the introduction of fluorine into sulfoxides bearing α-H atoms
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Direct formation of α-fluorosulfones from sulfoxides bearing α-H atoms merely by reaction with molecular fluorine (5% F2/N2) is reported, and a novel non-Pummerer-type mechanism is proposed for this α-fluorination reaction.
- Toyota, Akemi,Ono, Yoshinori,Chiba, Jun,Sugihara, Takumichi,Kaneko, Chikara
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p. 703 - 708
(2007/10/03)
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- Enzymic hydroxylation and sulfoxidation of cyclopropyl compounds by fungal biotransformation
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A series of compounds containing a cyclopropyl ring adjacent to the position of oxidation during fungal biotransformation has been prepared and subjected to enzymic oxidation using Mortierella isabellina or Rhizopus arrhizus.Carbon hydroxylation and sulfoxidation reactions were observed, but in neither case did opening of the cyclopropyl ring occur.Both these reactions were subject to inhibition by carbon monoxide but not by cyanide ion, properties characteristic of cytochrome P-450 dependent mono-oxygenase enzymes.Hydroxylation at a cyclopropyl C-H bond has been studied by the use of phenylcyclopropane and phenylthiirane as substrates for the mono-oxygenase of M. isabellina.The former was not oxidized, but the latter was converted to phenyl glyoxylic acid in moderate yield.
- Holland, Herbert L.,Chernishenko, Michael J.,Conn, Morgan,Munoz, Anthony,Manoharan, T. Samuel,Zawadski, Michael A.
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p. 696 - 700
(2007/10/02)
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- Unusual Two-Bond 13C,13C Coupling Constants in Sulphones
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A measurable coupling between carbon atoms through the SO2 group is observed in a series of structurally diverse sulphones.In open-chain (single coupling path) sulphones this 2J coupling ranges from 5.5 to 27.2 Hz, while in cyclic (multiple coupling path) sulphones values ranging from 4.3 to 21.6 Hz are observed.Sulphides and sulphoxides do not exhibit a corresponding coupling of comparable magnitude.A positive sign for this coupling is derived from the data of cyclic sulphones.Whereas substituents and branching at the coupling termini exert minor influences on the coupling, the most important factor determining the magnitude of the 2J(CSC) coupling is the hybridization of the coupling carbon atoms.A linear relationship between the 2J value and the s character product of the C-S bond forming C orbitals is established.KEY WORDS Sulphones 13C NMR Geminal 13C,13C coupling
- Ruecker, Christoph,Fritz, Hans
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p. 1103 - 1108
(2007/10/02)
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- ELIMINATION AND ADDITION REACTIONS. PART 39. VARIATION OF NUCLEOFUGALITY WITH TRANSITION STATE STRUCTURE-1,3- AND 1,2-ELIMINATIONS FROM CARBANIONS COMPARED.
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Phenylsulphonyl-activated 1,3-eliminations have been investigated with the objective of determining nucleofugalities of six leaving groups.In cyclohexane-1,3-diyl and propane-1,3-diyl system unactivated 1,2-elimination of 'poor' leaving groups occurs faster than 1,3-elimination.In 2,2-dimethylpropane-1,3-diyl substrates, however, quantitative 1,3-eliminations occur and the nucleofugalities of Br, Cl, OTs, PhSO2, PhS, PhO, have been determined.In a linear free energy relationship extending over 15 pKa units and 12 rank units, an excellent correlation of nucleofugality with the pKa of the conjugate acid of the leaving group is found.It is concluded from the comparison with 1,2-eliminations previously studied that 1,3-elimination involves considerable leaving group separation and ring formation in the transition state.With bromide as leaving group, the 2,2-dimethylpropane-1,3-diyl system is 1000 times more reactive in cyclopropane formation than the propane-1,3-diyl system; this is the first quantitation of the Thorpe-Ingold effect in homocyclic ring formation.With chloride and tosylate leaving groups, smaller accelerations are observed.
- Issari, Bahram,Stirling, Charles J. M.
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p. 1043 - 1052
(2007/10/02)
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