- Nickel-Catalyzed Asymmetric Hydrogenation of Cyclic Alkenyl Sulfones, Benzo[ b]thiophene 1,1-Dioxides, with Mechanistic Studies
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A highly efficient catalytic system based on the cheap transition metal nickel for the asymmetric hydrogenation of challenging cyclic alkenyl sulfones, 3-substituted benzo[b]thiophene 1,1-dioxides, was first successfully developed. A series of hydrogenation products, chiral 2,3-dihydrobenzo[b]thiophene 1,1-dioxides, were obtained in high yields (95-99%) with excellent enantioselectivities (90-99% ee). According to the results of nonlinear effect studies, deuterium-labeling experiments, and DFT calculation investigations, a reasonable catalytic mechanism for this nickel-catalyzed asymmetric hydrogenation was provided, which displayed that the two added hydrogen atoms of the hydrogenation products could be from H2 through the insertion of Ni-H and subsequent hydrogenolysis.
- Liu, Gongyi,Tian, Kui,Li, Chenzong,You, Cai,Tan, Xuefeng,Zhang, Heng,Zhang, Xumu,Dong, Xiu-Qin
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p. 668 - 675
(2021/02/06)
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- Niobium(V) oxido tris-carbamate as easily available and robust catalytic precursor for the selective sulfide to sulfone oxidation
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The oxidation of the sulfide function promoted by a variety of vanadium compounds has been largely explored, whereas the use of homogeneous catalytic systems based on the heavier group 5 metals remains less explored. We report the use of easily available niobium and tantalum carbamates, i.e. [M(O2CNMe2)5] (M = Nb, 1; M = Ta, 2), [Nb(O2CNMe2)4], 3, [NbO(O2CNEt2)3], 4, and [NbCl3(O2CNEt2)2], 5, as effective catalysts for the conversion of a series of alkyl aryl and aromatic sulfides into the corresponding sulfones. NMR investigations on the performant niobium catalyst 4 unexpectedly revealed the substantial stability of this compound in the protic catalytic environment, and a plausible catalytic cycle was obtained by DFT studies. The two active catalytic species, i.e. 4 and its minor mono-methoxide derivative, presumably interconvert to each other exploiting the versatile coordination of the carbamato ligand.
- Bresciani, Giulio,Ciancaleoni, Gianluca,Crucianelli, Marcello,Gemmiti, Mario,Marchetti, Fabio,Pampaloni, Guido
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- The Interrupted Pummerer Reaction in a Sulfoxide-Catalyzed Oxidative Coupling of 2-Naphthols
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A benzothiophene S-oxide catalyst, generated in situ by sulfur oxidation with H2O2, mediates the oxidative coupling of 2-naphthols. Key to the catalytic process is the capture and inversion of reactivity of a 2-naphthol partner, using an interrupted Pummerer reaction of an unusual benzothiophene S-oxide, followed by subsequent coupling with a second partner. The new catalytic manifold has been showcased in the synthesis of the bioactive natural products, (±)-nigerone and (±)-isonigerone. Although Pummerer reactions are used widely, their application in catalysis is rare, and our approach represents a new catalytic manifold for metal-free C?C bond formation.
- He, Zhen,Pulis, Alexander P.,Procter, David J.
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supporting information
p. 7813 - 7817
(2019/05/15)
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- A new phosphotungstate-supported rhenium carbonyl derivative: Synthesis, characterization and catalytic selective oxidation of thiophenes
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A monomeric phosphotungstate-supported rhenium carbonyl derivative, [N(CH3)4]6H4[P2W17O62{Re(CO)3}2]·25H2O (1), has been synthesized in a conventional solution system and structurally characterized by single crystal X-ray diffraction crystallography, IR spectroscopy, thermogravimetric (TG) analyses, X-ray powder diffraction (XRPD), and electrospray ionization mass spectrometry (ESI-MS). To our knowledge, this is the first time that the {Re2} fragment existing in the polyoxoanion has been observed in polyoxometalate-supported metal carbonyl derivatives. Moreover, UV-vis spectroscopy was employed to elucidate the stability of the polyoxoanion, and its electrochemical properties were also investigated. In particular, complex 1 could act as an efficient homogeneous catalyst for selective oxidation of thiophenes. For example, dibenzothiophene (DBT) undergoes up to 99% conversion and 99% sulfone selectivity in acetonitrile with 30% H2O2 as an oxidant.
- Lu, Jingkun,Feng, Junwei,Ma, Xinyi,Wang, Ping,Xu, Baijie,He, Peipei,Jia, Jiage,Ma, Pengtao,Niu, Jingyang,Wang, Jingping
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p. 7322 - 7328
(2019/12/09)
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- Method for preparing aromatic ring thiophthene-1,1-dioxide
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The invention provides a method for preparing aromatic ring thiophthene-1,1-dioxide. The method comprises the following steps: carrying out one-step cyclization on an ortho-position substituted aromatic ring and sodium alkylsulfinate, and carrying out a dehydration reaction, thereby obtaining the aromatic ring thiophthene-1,1-dioxide. The ortho-position substituted aromatic ring is of a structureof a compound of formula (I) as shown in the description. Compared with synthesis routes of a conventional method, the method for preparing the aromatic ring thiophthene-1,1-dioxide, which is providedby the invention, is easy in raw material obtaining, low in cost, gentle in reaction, easy to control, small in waste generation, small in pollution, simple in aftertreatment and in addition applicable to preparation of all types of aromatic ring thiophthene-1,1-dioxide, novel strategies are provided for the aromatic ring thiophthene-1,1-dioxide, and high production and application values can bemade.
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- Thiophene compounds and applications of thiophene compounds serving as USP7 inhibitors and antitumor drugs
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The invention discloses compounds shown in the formula I or nitrogen oxides, pharmaceutically acceptable salt or solvate of the compounds, a preparation method of the compounds, and applications of the compounds in pharmacy, and particularly provides the applications of the compounds serving as USP7 inhibitors and antitumor drugs. Pharmacodynamic experiment results show that the compounds in the formula I have inhibition effects on a USP7 enzyme and also have proliferation inhibition effects on human colon cancer cells HCT-116. Therefore, the compounds can be used for preparing the drugs for preventing or treating diseases related to tumors. The formula I is shown in the description.
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Paragraph 0066; 0072; 0073
(2019/01/16)
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- Preparation, characterization, and catalytic performances of a pyrazine dicarboxylate-bridging rare-earth-containing polytungstoarsenate aggregate for selective oxidation of thiophenes and deep desulfurization of model fuels
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A new polytungstoarsenate, K6LiH6[Ce4(H2O)14(pzdc)(H2pzdc)As3W29O103]·22H2O (1) (H2pzdc = 2,3-pyrazinedicarboxylic acid), was synthesized via a conventional aqueous solution method. In this synthetic approach, the organic ligand pyrazine dicarboxylate acid was introduced into the arsenotungstate system. The synthesized compound 1 was well characterized using elemental analysis, IR spectroscopy, UV-vis spectroscopy, thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD), and single-crystal X-ray diffraction. The catalytic activity of compound 1 was tested in acetonitrile to oxidize organosulfur compounds (benzothiophene (BT) and dibenzothiophene (DBT)) with hydrogen peroxide as an oxidant at room temperature. Two substrates were oxidized to their corresponding sulfones with high conversion and selectivity. Taking advantage of this remarkable catalytic move, the 1/H2O2/CH3CN system was further utilized in the oxidation of model fuels (MF) including a mixture of BT and DBT in octane. As a result, the organosulfur compounds in the model fuels were fully converted into their corresponding sulfones. Furthermore, the fluorescence properties of 1 were also investigated.
- Niu, Yanjun,Xu, Qiaofei,Wang, Yuan,Li, Zhao,Lu, Jingkun,Ma, Pengtao,Zhang, Chao,Niu, Jingyang,Wang, Jingping
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p. 9677 - 9684
(2018/08/06)
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- Iridium-Catalyzed Asymmetric Hydrogenation of Benzo[b]thiophene 1,1-Dioxides
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An efficient iridium-catalyzed asymmetric hydrogenation of substituted benzothiophene 1,1-dioxides is described. The use of iridium complexes with chiral pyridyl phosphinite ligands provides access to highly enantiomerically enriched sulfones with substituents at the 2- and 3-position. Sulfones of this type are of interest as core structures of agrochemicals and pharmaceuticals. Moreover, they can be further reduced to chiral 2,3-dihydrobenzothiophenes.
- Tosatti, Paolo,Pfaltz, Andreas
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supporting information
p. 4579 - 4582
(2017/04/11)
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- Reduced graphene oxide: A metal-free catalyst for aerobic oxidative desulfurization
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Nanocarbons have been extensively used as metal-free alternatives to metal catalysts in many oxidative processes owing to their functional groups or defects, which have the activation ability toward oxygen molecules. Herein, reduced graphene oxide (rGO) could be used as catalysts in oxidative desulfurization reactions for the first time to remove sulfur-containing compounds from fuels. Superior catalytic activity and stability are obtained in the aerobic oxidative desulfurization process catalyzed by rGO. A broad range of sulfur-containing aromatic substrates could be removed effectively in this catalytic system. Carbonyl groups have proved to play crucial roles during the oxidation process based on an XPS analysis, a chemical titration method and a series of comparative experiments. The chemically active defects are also beneficial to the catalytic performance because carbonyl groups could be generated in situ on these defects under the reaction conditions. Based on the EPR results, a radical pathway is proposed. Oxygen molecules could interact with the carbon atoms adjacent to carbonyl groups to form adsorbed super oxygen anion radicals (rGO-OO?-), which then attack the adjacent sulfur-centered cation radicals and generate the final product sulfone.
- Gu, Qingqing,Wen, Guodong,Ding, Yuxiao,Wu, Kuang-Hsu,Chen, Chengmeng,Su, Dangsheng
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p. 1175 - 1181
(2017/03/17)
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- A Mn(III) polyoxotungstate in the oxidation of organosulfur compounds by H2O2 at room temperature: An environmentally safe catalytic approach
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The tetrabutylammonium (TBA) salt of a Keggin-type polyoxometalate (POM), with the chemical formula TBA4H2[BW11Mn(H2O)O39]·H2O, TBABW11Mn, was evaluated as a catalyst in the oxidation by hydrogen peroxide of several organosulfur compounds, namely benzothiophene (BT), 2-methylbenzothiophene (2-MBT), 3-methylbenzothiophene (3-MBT), dibenzothiophene (DBT), 4-methyldibenzothiophene (4-MDBT) and 4,6-diethyldibenzothiophene (4,6-DEDBT), in acetonitrile at room temperature. All compounds were oxidized to their corresponding sulfones with high conversion and selectivity. Following the excellent results achieved, the BW11Mn/H2O2 in CH3CN system was tested in the oxidation of model fuels (MFs) consisting of a mixture of BTs and DBTs in hexane (MF1 containing mainly BTs and MF2 containing predominantly DBTs). In both cases, the organosulfur compounds from the model fuels were fully converted into their corresponding sulfones. Envisaging the development of a promising desulfurization procedure, the extraction of sulfur compounds from MF2 was attempted after the catalytic oxidation process. More than 98 mol% was removed using an ethanol/H2O mixture.
- Duarte, Tiago A.G.,Pires, Sónia M.G.,Santos, Isabel C.M.S.,Sim?es, Mário M.Q.,Neves, M. Gra?a P.M.S.,Cavaleiro, Ana M.V.,Cavaleiro, José A.S.
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p. 3271 - 3278
(2016/05/24)
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- Biomimetic oxidation of organosulfur compounds with hydrogen peroxide catalyzed by manganese porphyrins
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A biomimetic and environmentally benign approach, with potential application in the oxidative desulfurization procedure for several organosulfur compounds (thioanisol, diphenylsulfide, benzothiophene, 2-methylbenzothiophene, 3-methylbenzothiophene, benzothiophene-2-methanol and dibenzothiophene), is presented. The current methodology involves manganese porphyrins as catalysts, which are well-known biomimetic models of cytochrome P450 enzymes, and hydrogen peroxide as the oxygen source. [Mn(TDCPP)Cl] and [Mn(TPFPP)Cl], the manganese porphyrin complexes used in this study, proved to be very efficient catalysts, affording high conversions of all the substrates tested into the corresponding sulfones. The conversion of benzothiophene reaches 99.9% in 90 min, whereas the conversion of dibenzothiophene attains 99.9% after 120 min of reaction, both for a catalyst/substrate molar ratio of 150. The substituted benzothiophenes give rise to similar results, being the best conversions obtained for a catalyst/substrate molar ratio of 150. The oxidation of a model fuel (solution of benzothiophene, 3-methylbenzothiophene, 2-methylbenzothiophene, and dibenzothiophene in hexane) was performed using hydrogen peroxide and [Mn(TDCPP)Cl] as catalyst, achieving total conversion into the corresponding sulfones.
- Pires,Sim?es,Santos,Rebelo,Pereira,Neves,Cavaleiro
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experimental part
p. 51 - 56
(2012/10/08)
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- Synthesis and cytotoxic activity of lipophilic sulphonamide derivatives of the benzo[b]thiophene 1,1-dioxide
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In the search of new compounds with antineoplastic activity, we have analysed the effect of several structural modifications on the nucleus 6-benzo[b]thiophenesulphonamide 1,1-dioxide on its cytotoxic activity on tumour cells. Lipophilic substituents on t
- Villar,Encio,Migliaccio,Gil,Martinez-Merino
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p. 963 - 968
(2007/10/03)
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- A convenient synthesis of benzothiophene derivatives
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(Methylthio)- and 2-bromo-1-(methylthio)benzene are useful synthons to prepare monometallated and bimetallated intermediates which lead to 1-benzothiophenes functionalized in the three and/or two positions.
- Cabiddu, M.Grazia,Cabiddu, Salvatore,Cadoni, Enzo,Demontis, Stefania,Fattuoni, Claudia,Melis, Stefana
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p. 4529 - 4533
(2007/10/03)
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- A novel biotransformation of benzofurans and related compounds catalysed by a chloroperoxidase
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The oxidation of 3-alkyl benzofurans, indoles, and a benzothiophene by the chloroperoxidase from Caldariomyces fumago has been investigated. Under conditions in which the catalase activity of chloroperoxidase was minimised in the presence of chloride and hydrogen peroxide, 3-methylbenzothiophene was oxidised at sulfur but the indoles (5-9) and benzofurans (1-4) gave 2,3-diols as initial products. In the case of N-unsubstituted indoles, these tautomerised to give the corresponding lactam. In contrast, the diols (predominantly trans) formed from the benzofurans were sufficiently stable for isolation and full characterisation. This novel reaction has the potential to be developed into a useful synthetic biotransformation.
- Alvarez, Ricardo G.,Hunter, Iain S.,Suckling, Colin J.,Thomas, Michael,Vitinius, Ute
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p. 8581 - 8587
(2007/10/03)
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