- The tris(trimethylsilyl)silane/thiol reducing system: A tool for measuring rate constants for reactions of carbon-centered radicals with thiols
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An extension of the well-known 'free-radical-clock' methodology is described that allows one to determine the rate constants of carbon-centered radicals with a variety of thiols by using the tris(trime-thylsilyl)silane/thiol couple as a reducing system. A
- Chatgilialoglu, Chryssostomos
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Read Online
- A sustainable process for the production of 2-methyl-1,4-butanediol by hydrogenation of biomass-derived itaconic acid
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Pd-ReOx/C catalysts with different Re contents were prepared and employed to catalyze the aqueous hydrogenation of itaconic acid in this study. The Pd-ReOx/C catalysts were characterized by XRD, TEM, BET, NH3-TPD and H2-TPR. Results showed that the addition of ReOx species in supported Pd catalysts promoted the direct conversion of itaconic acid to 2-methyl-1,4-butanediol. The promoting effect was ascribed to the interaction between Pd and ReOx species, as has been proved by the characterizations. A 2-methyl-1,4-butanediol yield of above 80% could be obtained over Pd-3ReOx/C under the reaction condition of 180 °C, 4 MPa H2.
- Liu, Xiaoran,Wang, Xicheng,Liu, Qiang,Xu, Guoqiang,Li, Xuemin,Mu, Xindong
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Read Online
- Chemoselective and Tandem Reduction of Arenes Using a Metal–Organic Framework-Supported Single-Site Cobalt Catalyst
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The development of heterogeneous, chemoselective, and tandem catalytic systems using abundant metals is vital for the sustainable synthesis of fine and commodity chemicals. We report a robust and recyclable single-site cobalt-hydride catalyst based on a porous aluminum metal–organic framework (DUT-5 MOF) for chemoselective hydrogenation of arenes. The DUT-5 node-supported cobalt(II) hydride (DUT-5-CoH) is a versatile solid catalyst for chemoselective hydrogenation of a range of nonpolar and polar arenes, including heteroarenes such as pyridines, quinolines, isoquinolines, indoles, and furans to afford cycloalkanes and saturated heterocycles in excellent yields. DUT-5-CoH exhibited excellent functional group tolerance and could be reusable at least five times without decreased activity. The same MOF-Co catalyst was also efficient for tandem hydrogenation–hydrodeoxygenation of aryl carbonyl compounds, including biomass-derived platform molecules such as furfural and hydroxymethylfurfural to cycloalkanes. In the case of hydrogenation of cumene, our spectroscopic, kinetic, and density functional theory (DFT) studies suggest the insertion of a trisubstituted alkene intermediate into the Co–H bond occurring in the turnover limiting step. Our work highlights the potential of MOF-supported single-site base–metal catalysts for sustainable and environment-friendly industrial production of chemicals and biofuels.
- Antil, Neha,Kumar, Ajay,Akhtar, Naved,Begum, Wahida,Chauhan, Manav,Newar, Rajashree,Rawat, Manhar Singh,Manna, Kuntal
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supporting information
p. 1031 - 1040
(2022/01/19)
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- METHOD FOR REDUCTION OF ORGANIC MOLECULES
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A method for the reduction organic molecules comprising a Ruthenium-Triphosphine complex with aromatic ligands at the phosphors which are ortho or meta substituted.
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Paragraph 0050; 0052; 0053; 0054; 0055
(2018/02/06)
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- Aqueous-phase hydrogenation of biomass-derived itaconic acid to methyl-γ-butyrolactone over Pd/C catalysts: Effect of pretreatments of active carbon
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The effect of active carbon pretreatment on the catalytic performance of Pd/C catalysts in the hydrogenation of itaconic acid was studied. The catalysts were prepared by deposition-precipitation and characterized by XRD, BET, NH3-TPD, TEM and F
- Li, Sha,Wang, Xicheng,Liu, Xiaoran,Xu, Guoqiang,Han, Sheng,Mu, Xindong
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- Synthesis of 3-substituted tetrahydrofuran and 4-substituted tetrahydropyran derivatives by cyclization of dicarboxylic acids with InBr 3/TMDS
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An efficient reduction followed by cyclization of diacid compounds with the InBr3/TMDS system is reported. This system allows the formation of five- and six-membered ring ethers substituted in the 3- or 4-position. Copyright
- Pehlivan, Leyla,Metay, Estelle,Delbrayelle, Dominique,Mignani, Gerard,Lemaire, Marc
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supporting information; scheme or table
p. 4689 - 4693
(2012/09/22)
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- Mechanism of the hydrogenolysis of ethers over silica-supported rhodium catalyst modified with rhenium oxide
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The Rh-ReOx/SiO2 (Re/Rh = 0.5) exhibited high activity in the hydrogenolysis of ethers with an OH group. The CO bond neighboring CH2OH group was selectively dissociated: The hydrogenolysis of tetrahydro-5-methyl-2-furfuryl alcohol and 2-isopropoxyethannol gave 1,5-hexanediol and ethanol + isopropanol, respectively. This tendency suggests the regioselective CO dissociation mechanism via anion intermediate formed by the attack of hydride and the subsequent protonation of the anion.
- Koso, Shuichi,Nakagawa, Yoshinao,Tomishige, Keiichi
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scheme or table
p. 221 - 229
(2011/07/06)
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- Selective and flexible transformation of biomass-derived platform chemicals by a multifunctional catalytic system
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(Figure Presented) A sustainable supply chain: The controlled transformation of the biomassderived platform compounds levulinic acid (LA) and itaconic acid (IA) into the corresponding lactones, diols, or cyclic ethers (see picture) by using a multifunctional molecular catalyst is described.
- Geilen, Frank M. A.,Engendahl, Barhel,Harwardt, Andreas,Marquardt, Wolfgang,Klankermayer, Juergen,Leitner, Walter
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supporting information; experimental part
p. 5510 - 5514
(2010/09/16)
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- Process for preparing alpha- and beta-methyl-gamma-butyrolactone and 3-methyltetrahydrofuran
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The present invention pertains to a novel process for preparing alpha- and beta-methyl-gamma-butyrolactones (MeGBL) and/or 3-Methyltetrahydrofuran (MeTHF) from 3-(hydroxymethyl)tetrahydrofuran (HOMeTHF), 3-formyltetrahydrofuran (FTHF) or a mixture thereof
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- Process for the preparation of 3-methyltetrahydrofuran
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Disclosed is a process for the preparation of 3-methyltetrahydrofuran (MeTHF) from 3-(hydroxymethyl)tetrahydrofuran (HOMeTHF) or 3-formyltetrahydrofuran (FTHF) by contacting HOMeTHF or 3-formyltetrahydrofuran with a secondary alcohol in the presence of a
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- Manufacture of 3-methyl-tetrahydrofuran from alpha-methylene-gamma-butyrolactone in a single step process
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Disclosed is a single step continuous hydrogenation process for the preparation of 3-methyl-tetrahydrofuran from alpha-methylene-gamma-butyrolactone, in the presence of a catalytic metal.
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- Anti-Markovnikov Hydrofunctionalization of Olefins Mediated by Rhodium-Porphyrin Complexes
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A rationally designed mechanistic approach to anti-Markovnikov olefin hydrofunctionalization and its application to the synthesis of heterocycles are described. Porphyrin-rhodium complexes have been shown to exhibit remarkable reactivity and selectivity for each step of the proposed catalytic cycle (see scheme). A critical step of this reaction sequence is a new, facile, and remarkably general carbon-heteroatom bond-forming reductive elimination.
- Sanford, Melanie S.,Groves, John T.
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p. 588 - 590
(2007/10/03)
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- Process for the preparation of 3-methyltetrahydrofuran
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Disclosed is a process for the preparation of 3-methyltetrahydrofuran (MeTHF) from 3-(hydroxymethyl)tetrahydrofuran (HOMeTHF) by contacting HOMeTHF with hydrogen in the presence of an acidic, supported catalyst comprising a Group VIII metal.
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Page/Page column 6-7
(2008/06/13)
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- Process for purifying tetrahydrofurans used as starting material for polyether polyols
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Tetrahydrofurans suitable for use as starting materials in the synthesis of polyether polyols without causing coloration in the product polyether polyols can be obtained by contacting crude tetrahydrofurans with a mineral acid or a strongly acidic cation-
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- Process for producing 3-methyltetrahydrofuran
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A process for producing 3-methyltetrahydrofuran, wherein in a first step, prussic acid is reacted with methyl methacrylate to produce methyl 3-cyanoisobutyrate. The methyl 3-cyanoisobutyrate is then reacted with water and sulfuric acid to produce a resultant product which is reacted with a C1 -C8 aliphatic alcohol to produce a methylsuccinic acid ester. The methylsuccinic acid ester is catalytically hydrogenated to prepare the 3-methyltetrahydrofuran. Alternatively, the methyl 3-cyanoisobutyrate is hydrated to produce methyl 3-carbamoylisobutyrate, which is then reacted with a formic acid ester to form a methylsuccinic acid ester and formamide and the resultant methylsuccinic acid ester is catalytically hydrogenated. The 3-methyltetrahydrofuran is produced in high selectivity and in a commercially advantageous manner from inexpensive reactants. The 3-methyltetrahydrofuran is useful as a commoner for producing polyether glycol, which is utilized as starting raw material for preparing spandex fiber.
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- THE USE OF ACYL DERIVATIVES OF N-HYDROXY-2-THIOPYRIDONE IN A SIMPLE SYNTHESIS OF PYRROLIDINES AND TETRAHYDROFURANS
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Photolysis of the N-hydroxy-2-thiopyridone derivatives of 3-N-acetylallylamino, 3-N,N-diallylamino and 3-allyloxy-propionic acids gave cleanly derivatives of N-acetyl-3-methylpyrrolidine, N-allyl-3-methylpyrrolidine and of 3-methyltetrahydrofuran respectively.The corresponding reaction with 3-allylthiopropionic acid afforded a radical which fragmented to ethylene and the allylthio radical without cyclization.
- Castagnino, Enzo,Corsano, Stefano,Barton, Derek, H. R.
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p. 2983 - 2986
(2007/10/02)
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- OXYGEN YLIDES-II. PHOTOCHEMICAL AND RHODIUM-CATALYZED REACTIONS OF DIAZOMETHANE WITH (S)-2-METHYLOXETANE
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Photolysis of diazomethane in (S)-2-methyloxetane gives 2- and 3-methyltetrahydrofuran (1:3.2), the latter being formed with 21 percent net retention of configuration.In contrast, rhodium acetate catalysis yields racemic 3-methyltetrahydrofuran exclusively.
- Kirmse, Wolfgang,Chiem, Pham Van
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p. 197 - 200
(2007/10/02)
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- Onium Ylide Chemistry. 3. Evidence for Competing Oxonium Ylide Formation with C-H Insertion in Meerwein's Reaction of Methylene and Methylene-d2 with Dialkyl Ethers
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Meerwein's reaction of singlet methylene, produced by photolysis of diazomethane, with dialkyl ethers has been reinvestigated on the basis of reactions using CD2N2.In competition with methylene insertion into the various C-H bonds, about 10percent of methyl alkyl ether and small amounts of dimethyl ether formation are also observed.This indicates evidence for competing attack of methylene on oxygen leading to the corresponding intermediate methylenedialkyloxonium ylides which are immediately protonated by methyl alkohol (or water)impurity present in the reaction medium togive the corresponding methyldialkyloxonium ions.Dealkylative cleavage of the latter gives the observed methyl alkyl ethers.By the use of deuterium-labeled diazomethane CD2N2 it has been shown that ethylene and propylene formed under the reaction conditions are coming predominantly from diazomethane itself and not via intramolecular β-elimination of the oxonium ylides.
- Olah, George A.,Doggweiler, Hans,Felberg, Jeff D.
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p. 2116 - 2120
(2007/10/02)
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- Etude des transformations catalytiques sur alumine de β-tetrahydrofurylmethanols
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The products obtained by treatment of β-tetrahydrofurylmethanols at 310-330 deg C, using alumina as catalyst are studied.The nature of the products-furans, tetrahydrofurans, aliphatic and cyclic dienes-shows that beside the simple dehydration side reactions take place leading, as the case may be, to dehydrogenation, raduction, ring opening and fragmentation.
- Infarnet, Yves,Accary, Armand,Huet, Jean
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p. 261 - 266
(2007/10/02)
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- Organic Tellurium and Selenium Chemistry. Reduction of Tellurides, Selenides, and Selenoacetals with Triphenyltin Hydride
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Preparative and mechanistic details are described for the conversion of selenides into hydrocarbons RH> by heating with triphenyltin hydride at about 120 deg C.The process has been extended to selenoacetals in a form that constitutes a reduction methods for carbonyl compounds RR'C(SePh)2 -> RR'CH2>.Selective reduction of selenoacetals in the presence of thioacetals is possible.Cold-labeled species can be prepared by using triphenyltin deuteride.Tellurides are available easily without problems arising from exposure to air provided that the work is done in a photographic darkroom equipped with a red safety light.These tellurides, as well as the corresponding dichlorides , are reduced under very mild conditions (25-80 deg C) by triphenyltin hydride.The selenium- and tellurium-based chemistry has been used for the unusual process of reducing an epoxide in the presence of a ketone carbonyl.
- Clive, Derrick L. J.,Chittattu, Gim J.,Farina, Vittorio,Kiel, William A.,Menchen, Steven M.,et al.
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p. 4438 - 4447
(2007/10/02)
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- Preparation of tetrahydrofuran
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Tetrahydrofuran is prepared by the vapor phase reaction of a compound selected from 1,4-butanediol, monoesters of 1,4-butanediol, diesters of 1,4-butanediol and mixtures thereof in the presence of water and an acid catalyst wherein the catalyst is selected from phosphoric acid on a suitable support and eta alumina at a temperature of from about 200° to about 325° C followed by the recovery of the tetrahydrofuran by distillation.
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- Hydrogenation of epoxides
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A process for producing a substituted tetrahydrofuran which comprises contacting an epoxide with molecular hydrogen and a Group VIII metal hydrogenation catalyst at a temperature between 50° and 250°C and a pressure between 10 and 5000 psig, wherein the c
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- Dihydrofuran preparation
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A process for preparing a substituted or unsubstituted dihydrofuran from a substituted or unsubstituted butadiene monoxide which comprises contacting the butadiene monoxide with a catalyst comprising a hydrogen halide selected from the group consisting of
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