- Small bite-angle P-OP ligands for asymmetric hydroformylation and hydrogenation
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A series of small bite-angle phosphine-phosphite (P-OP) ligands have been synthesized by a two-step method. The key intermediate was prepared by an unprecedented asymmetric carbonyl reduction of a phosphamide using the CBS (Corey-Bakshi-Shibata) catalyst. The topology of these ligands (a configurationally stable stereogenic carbon with two heteroatom substituents) and their small bite-angle (created by the close proximity of the two ligating groups to the metal center) together provide a rigid asymmetric environment around this center, enabling high stereoselectivity in hydroformylations and hydrogenations of standard substrates.
- Fernandez-Perez, Hector,Benet-Buchholz,Vidal-Ferran, Anton
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- Aerial oxidation of tetrahydrofuran to 2-hydroxotetrahydrofuran in the presence of a trimeric CuI complex [Cu3L3] (HL = tBuNHC(S)NHP(S)(OiPr)2) and trapping of the unstable product at recrystallization
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The reaction of the potassium salt of N-thiophosphorylated thiourea tBuNHC(S)NHP(S)(OiPr)2 (HL) with Cu(NO3)2 in aqueous EtOH leads to the trinuclear [Cu3(tBuNHC(S)NP(S)(OiPr) 2-S,S′)3] ([Cu3L3]) complex. It was established that [Cu3L3] provokes the aerobic oxidation of tetrahydrofuran to 2-hydroxotetrahydrofuran and traps the latter at crystallization. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
- Luckay, Robert C.,Sheng, Xia,Strasser, Christoph E.,Raubenheimer, Helgard G.,Safin, Damir A.,Babashkina, Maria G.,Klein, Axel
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- Tautomerism and vapor-phase transformations of 2-hydroxytetrahydrofuran
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The relative stability of 2-hydroxytetrahydrofuran and the tautomeric 4-hydroxybutanal was determined by the semi-empirical AM1 method. It was concluded that the cyclic tautomer predominates in the gas phase at 25°C. Vapor-phase dehydration of 2-hydroxytetrahydrofuran in the presence of porcelain and silica gel L leads to a quantitative yield of 2,3-dihydrofuran.
- Lebedev,Leite,Fleisher,Stonkus
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- DOUBLE BOND MIGRATION OF ALLYL ETHERS OVER SOLID BASE CATALYSTS
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Double bond migrations of allyl ethers were carried out over various solid base catalysts.Magnesium oxide, CaO, SrO, and La2O3 exhibited high activities.High cis/trans ratios in the products suggest that the reaction proceed via cis-?-allylic anions as intermediates
- Matsuhashi, Hiromi,Hattori, Hideshi,Tanabe, Kozo
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- Highly efficient rhodium catalysts for the asymmetric hydroformylation of vinyl and allyl ethers using C1-symmetrical diphosphite ligands
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Here, we describe the successful application of novel glucofuranose-derived 1,3-diphosphites in the rhodium-catalysed asymmetric hydroformylation of vinyl acetate, 2,5-dihydrofuran and 2,3-dihydrofuran. In the hydroformylation of vinyl acetate, total regioselectivity and high ee (up to 73%) were obtained. When 2,3- and 2,5-dihydrofuran were the substrates, total chemo- and regioselectivities were achieved together with ees up to 88%. These results correspond to the highest ee values reported to date in the asymmetric hydroformylation of these substrates. The HP-NMR studies of the [RhH(CO) 2(L)] species (L=15 and 17) demonstrated that both ligands coordinate to the Rh centre in an eq-eq fashion. The complex [RhH(CO)2(15)] was detected as a single isomer with characteristic features of eq-eq coordination. However, the broadening of the corresponding signals indicated that this species is rapidly interchanging in solution. In contrast, complex [RhH(CO) 2(17)] was detected as a mixture of two conformational isomers at low temperature due to the greater flexibility of the monocyclic backbone of this ligand.
- Gual, Aitor,Godard, Cyril,Castillon, Sergio,Claver, Carmen
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- Fine-tunable monodentate phosphoroamidite and aminophosphine ligands for Rh-catalyzed asymmetric hydroformylation
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A biaryl-based monophosphoroamidite L1-L4a-f and aminophosphine L5-L7a-f ligand library was screened in the Rh-catalyzed asymmetric hydroformylation of several vinylarenes and heterocyclic olefins. Our results indicate that the selectivity is strongly dependent on the ligand parameters and on the substrate type. Enantioselectivities (up to 46%) were moderate in the hydroformylation of several vinylarenes S1-S5 and promising (up to 58%) for the more challenging heterocyclic olefins S6-S9.
- Mazuela, Javier,Pmies, Oscar,Dieguez, Montserrat,Palais, Laetitia,Rosset, Stephane,Alexakis, Alexandre
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- Hoveyda-Type Quinone-Containing Complexes – Catalysts to Prevent Migration of the Double Bond under Metathesis Conditions
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Three new quinone-containing Hoveyda-type complexes have been synthesised and fully characterised. Their ability to suppress undesired double-bond migration along the carbon chain during metathesis reactions was examined. It was proved that these catalysts decrease the amounts of undesired side-products with a shifted double bond in the reaction mixture.
- Kajetanowicz, Anna,Milewski, Mariusz,Rogińska, Joanna,Gajda, Roman,Wo?niak, Krzysztof
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- Chiral Diaryliodonium Phosphate Enables Light Driven Diastereoselective α-C(sp3)-H Acetalization
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C(sp3)-H bond functionalization has emerged as a robust tool enabling rapid construction of molecular complexity from simple building blocks, and the development of asymmetric versions of this reaction creates a powerful methodology to access enantiopure sp3-rich materials. Herein, we report the stereoselective functionalization of C(sp3)-H bonds of cyclic ethers employing a photochemically active diaryliodonium salt in combination with an anionic phase-transfer catalyst. The synthetic strategy outlined herein allows for regio- and stereochemical control in the α-C-H acetalization of furans and pyrans using alcohol nucleophiles, thus providing the ability to control the configuration at the stereogenic exocyclic acetal carbon.
- Ye, Baihua,Zhao, Jie,Zhao, Ke,McKenna, Jeffrey M.,Toste, F. Dean
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- Rh-catalyzed asymmetric hydroformylation of heterocyclic olefins using chiral diphosphite ligands. Scope and limitations
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(Chemical Equation Presented) We used a series of diphosphite ligands to study the effect of the ligand backbone, the length of the bridge, and the substituents of the biphenyl moieties and determine the scope of this type of ligand in the Rh-catalyzed asymmetric hydroformylation of several hetereocylic olefins. By carefully selecting the ligand components, we achieved high chemo-, regio-, and enantioselectivities in different substrate types. Unprecedentedly high enantioselectivities for five-membered heterocyclic olefins were therefore obtained. Note that both enantiomers of the hydroformylation products can be synthesized using the same ligand by a simple substrate change. For the seven-membered heterocyclic dioxepines, our results are among the best obtained. Also, both enantiomers of the hydroformylation products can be obtained by using pseudoenantiomer ligands or by carefully tuning the ligand parameters.
- Mazuela, Javier,Coll, Mercedes,Pamies, Oscar,Dieguez, Montserrat
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- Synthesis and Properties of Furan Derivatives 2. Role of the Halogen in RMgX in Reactions with Alkoxytetrahydrofurans
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Heating 2-methoxytetrahydrofuran with ethylmagnesium bromide in benzene at reflux leads to the formation of 2-ethoxytetrahydrofuran and slight amounts of 4-methoxy-1-hexanol.Under analogous conditions, 2-ethoxytetrahydrofuran is quantitatively cleaved by
- Polivin, Yu. N.,Trofimova, M. V.,Karakhanov, R. A.,Ageev, E. A.
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- Synergistic chemiluminescence nanoprobe: Au clusters-Cu2+-induced chemiexcitation of cyclic peroxides and resonance energy transfer
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An interesting chemiluminescence (CL) phenomenon of cyclic peroxides originating from tetrahydrofuran hydrogen peroxide (THF-HPO) in the presence of BSA-stabilized Au NCs (Au?BSA NCs) was found for the first time. In this CL system, Au?BSA NCs can greatly accelerate the decomposition of THF-HPO, and then chemiluminescence resonance energy transfer (CRET) occurs between excited dioxetane derivatives and the Au?BSA NCs, yielding enhanced CL emission which can be further enhanced more than 10 times by the addition of copper ions. Based on this, a synergistic CL nanoprobe with a special signal amplification strategy was developed.
- Lv, Yi,Song, Hongjie,Su, Yingying,Sun, Mingxia,Zhang, Kexin
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- First successful application of diphosphite ligands in the asymmetric hydroformylation of dihydrofurans
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Good enantioselectivities and excellent regioselectivities are achieved in the Rh-catalyzed asymmetric hydroformylation of 2,5- and 2,3-dihydrofuran using diphosphite ligands; whereby the backbone of the ligand is crucial to suppressing isomerization and obtaining high ee's. The Royal Society of Chemistry 2005.
- Dieguez, Montserrat,Pamies, Oscar,Claver, Carmen
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- Method for synthesizing cyclopropanecarboxaldehyde from 1,4-butanediol
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The invention relates to a method for synthesizing cyclopropanecarboxaldehyde from 1,4-butanediol. The method has the advantages of accessible raw materials, low cost and simple technique, can implement one-step reaction, has high efficiency, and can implement continuous operation.
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Paragraph 0054-0058; 0064-0068
(2021/03/13)
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- Olefin reaction in the catalyst and the olefin production
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PROBLEM TO BE SOLVED: To provide a catalyst for obtaining an olefin in high selectivity with a vicinal diol as a raw material.SOLUTION: A catalyst for olefination reaction for use in a reaction to produce an olefin by a reaction of a polyol, having two adjacent carbon atoms each having a hydroxy group, with hydrogen comprises: a carrier; at least one oxide selected from the group consisting of oxides of the group 6 elements and oxides of the group 7 elements supported on the carrier; and at least one metal selected from the group consisting of silver, iridium, and gold supported on the carrier.SELECTED DRAWING: None
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Paragraph 0145-0146; 0149
(2020/10/31)
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- Highly Electrophilic Titania Hole as a Versatile and Efficient Photochemical Free Radical Source
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Photogenerated holes in nanometric semiconductors, such as TiO2, constitute remarkable powerful electrophilic centers, capable of capturing an electron from numerous donors such as ethers, or nonactivated substrates like toluene or acetonitrile, and constitute an exceptionally clean and efficient source of free radicals. In contrast with typical free radical precursors, semiconductors generate single radicals (rather than pairs), where the precursors can be readily removed by filtration or centrifugation after use, thus making it a convenient tool in organic chemistry. The process can be described as an example of dystonic proton coupled electron transfer.
- Hainer, Andrew,Marina, Nancy,Rincon, Stefanie,Costa, Paolo,Lanterna, Anabel E.,Scaiano, Juan C.
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supporting information
p. 4531 - 4535
(2019/03/19)
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- Importance of Zeolite Wettability for Selective Hydrogenation of Furfural over Pd@Zeolite Catalysts
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The metal-catalyzed selective hydrogenation of biomass-derived molecules is in great demand but is challenging due to the complex reaction pathways. Herein, we report a persuasive example for achieving selective hydrogenation of furfural over Pd catalysts by controllable sorption of molecules in zeolite micropores. The key to this success is fixation of Pd nanoparticles inside of silicalite-1 zeolite with controllable wettability (Pd@S-1-OH) by functionalizing silanol groups into the zeolite framework. In the hydrogenation of furfural as a model reaction, the Pd@S-1-OH catalyst with appropriate hydrophilicity exhibits extraordinary selectivity for the formation of furan, giving furan selectivity as high as >99.9% with a complete conversion of furfural, outperforming the conventional Pd nanoparticles supported on zeolite crystals (Pd/S-1) and S-1 zeolite fixed Pd catalysts without an artificially functionalized silanol group (Pd@S-1). The extraordinary performance of Pd@S-1-OH is reasonably attributed to the controllable diffusion of molecules within the hydrophilic zeolite micropores, which favors the adsorption of furfural and a series of byproducts but promotes the desorption of furan. Very importantly, Pd@S-1-OH is stable and gives the furan productivity of ～583.3 g gPd-1 day-1 in a continuous test.
- Wang, Chengtao,Liu, Zhiqiang,Wang, Liang,Dong, Xue,Zhang, Jian,Wang, Guoxiong,Han, Shichao,Meng, Xiangju,Zheng, Anmin,Xiao, Feng-Shou
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p. 474 - 481
(2018/01/17)
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- One-pot catalytic selective synthesis of 1,4-butanediol from 1,4-anhydroerythritol and hydrogen
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A physical mixture of ReOx-Au/CeO2 and carbon-supported rhenium catalysts effectively converted 1,4-anhydroerythritol to 1,4-butanediol with H2 as a reductant. The combination of these two catalysts in a one-pot reaction dramatically increased the selectivity of 1,4-butanediol as well as the conversion of 1,4-anhydroerythritol. The yield of 1,4-butanediol reached ～90%, which is the highest yield from erythritol and 1,4-anhydroerythritol so far, furthermore, at a relatively low reaction temperature of 413 K. This reaction involves the ReOx-Au/CeO2-catalyzed deoxydehydration of 1,4-anhydroerythritol to 2,5-dihydrofuran and ReOx/C-catalyzed successive isomerization, hydration and reduction reactions of 2,5-dihydrofuran.
- Wang, Tianmiao,Liu, Sibao,Tamura, Masazumi,Nakagawa, Yoshinao,Hiyoshi, Norihito,Tomishige, Keiichi
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supporting information
p. 2547 - 2557
(2018/06/18)
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- Efficient endo Cycloisomerization of Terminal Alkynols Catalyzed by a New Ruthenium Complex with 8-(Diphenylphosphino)quinoline Ligand and Mechanistic Investigation
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Several new ruthenium complexes supported by the P,N-donor ligand 8-(diphenylphosphino)quinoline (DPPQ) were synthesized, including [RuCl2(DPPQ)2] (1), [Ru(μ-Cl)(DPPQ)2]2(BPh4)2 (2), and [RuCl(DPPQ)2Py](BF4) (3). Complex 2, with only 1 mol % loading, was found to be catalytically active for the endo cycloisomerization of various terminal alkynols to endo-cyclic enol ethers in moderate to excellent yields. In particular, the 7- and 8-endo heterocyclization can be achieved efficiently to give the seven-membered 3-benzoxepine and eight-membered 3-benzo[d]oxocine derivatives. The stoichiometric reactions of 2 with various alkynol substrates have been carried out to investigate the mechanism, which led to a series of seven-, six-, and five-membered oxacyclocarbene ruthenium complexes including [RuCl(DPPQ)2{=CCH2C6H4CH2CH2O}](BPh4) (12) and [RuCl(DPPQ)2{=CCH2(CH2)nCH2O}](BPh4) (n=3, 12′; n=2, 13; n=1, 14). The quantitative transformation of oxacyclocarbene 12 into catalyst 2 and 3-benzoxepine 5 a as well as the efficient catalytic activity of 12 for the endo-cyclization of 2-(2-ethynylphenyl)ethanol (4 a) demonstrated that 12 is a key intermediate involved in the catalytic cycle. Moreover, comparative studies on the modeling reactions and catalytic activity of the series of oxacyclocarbene complexes indicated that the different catalytic activity of 2 for the endo-cycloisomerization of different types of alkynols can be related to the reactivity of the respective ruthenium oxacyclocarbene intermediates.
- Cai, Tao,Yang, Yu,Li, Wei-Wei,Qin, Wen-Bing,Wen, Ting-Bin
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p. 1606 - 1618
(2018/01/11)
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- Asymmetric Hydroformylation of Heterocyclic Olefins Mediated by Supramolecularly Regulated Rhodium-Bisphosphite Complexes
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Rhodium complexes derived from conformationally transformable α,ω-bisphosphite ligands combined with a suitable alkali metal BArF salt as a regulation agent (RA) provide high regio- and enantioselectivities in the asymmetric hydroformylation (AHF) of three heterocyclic olefins. The outcome of the AHF could be exquisitely regulated by choosing the appropriate RA with an increase in the ee, the reversal of the regioselectivity, or the complete suppression of one byproduct.
- Rovira, Laura,Vaquero, Mónica,Vidal-Ferran, Anton
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supporting information
p. 10397 - 10403
(2015/11/03)
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- Libraries of bisdiazaphospholanes and optimization of rhodium-catalyzed enantioselective hydroformylation
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Twelve chiral bis-3,4-diazaphospholane ligands and six alkene substrates (styrene, vinyl acetate, allyloxy-tert-butyldimethylsilane, (E)-1-phenyl-1,3- butadiene, 2,3-dihydrofuran, and 2,5-dihydrofuran) probe the influence of steric bulk on the activity and selectivity of asymmetric hydroformylation (AHF) catalysts. Reaction of an enantiopure bisdiazaphospholane tetraacyl fluoride with primary or secondary amines yields a small library of tetracarboxamides. For all six substrates, manipulation of reaction conditions and bisdiazaphospholane ligands enables state-of-the-art performance (90% or higher ee, good regioselectivity, and high turnover rates). For the nondihydrofuran substrates, the previously reported ligand, (S,S)-2, is generally most effective. However, optimal regio- and enantioselective hydroformylation of 2,3-dihydrofuran (up to 3.8:1 α-isomer/β-isomer ratio and 90% ee for the α-isomer) and 2,5-dihydrofuran (up to 1:30 α-isomer/β- isomer ratio and 95% ee for the β-isomer) arises from bisdiazaphospholanes containing tertiary carboxamides. Hydroformylation of either 2,3- or 2,5-dihydrofuran yields some of the β-formyl product. However, the absolute sense of stereochemistry is inverted. A stereoelectronic map rationalizes the opposing enantiopreferences
- Adint, Tyler T.,Wong, Gene W.,Landis, Clark R.
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p. 4231 - 4238
(2013/06/05)
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- Catalytic conversion of furan to gasoline-range aliphatic hydrocarbons via ring opening and decarbonylation reactions catalyzed by Pt/γ-Al 2O3
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Conversion of furan in the presence of H2 catalyzed by Pt/γ-Al2O3 at 573 K and 1.4 bar leads to the formation of alkanes and alkenes, some in the gasolinerange, including C7 hydrocarbons, butenes, propene, and propane.
- Runnebaum, Ron C.,Nimmanwudipong, Tarit,Doan, Jonathan,Block, David E.,Gates, Bruce C.
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experimental part
p. 664 - 666
(2012/10/07)
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- METHOD FOR PRODUCING VINYL ETHER COMPOUND
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The invention provides a method for producing a vinyl ether compound, characterized in that the method includes isomerizing an allyl ether compound represented by formula (I) or (II): (wherein R1 represents a C1 to C6 alkyl group; each of R2, R3, and R4 independently represents a hydrogen atom, a C1 to C6 alkyl group, or a C3 to C6 alkenyl group; and n is 1 or 2) in the presence of hydrogen, a monodentate tris(ortho-substituted aryl) phosphite, and a rhodium compound. The vinyl ether compound is useful as a raw material, an intermediate, etc. for producing pharmaceuticals, agrochemicals, polymers, etc.
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(2011/02/19)
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- RECYCLABLE METATHESIS CATALYSTS
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Highly active, recoverable and recyclable transition metal-based metathesis catalysts and their organometallic complexes including dendrimeric complexes are disclosed, including a Ru complex bearing a 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene and styrenyl ether ligand. The heterocyclic ligand significantly enhances the catalytic activity, and the styrenyl ether allows for the easy recovery of the Ru complex. Derivatized catalysts capable of being immobilized on substrate surfaces are also disclosed. The present catalysts can be used to catalyze ring-closing metathesis (RCM), ring-opening (ROM) and cross metatheses (CM) reactions, and promote the efficient formation of various trisubstituted olefins at ambient temperature in high yield.
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- Conversion of cis-2-butene-1,4-diol to hydrofurans on Pd/SiO2 and Pt/SiO2 catalysts under mild conditions: A FT-IR study
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The gas-phase interaction of cis-2-butene-1,4-diol (C-2-OL) with silica supported Pd and Pt nanoparticles has been studied using infrared spectroscopy at room temperature. Samples were prepared according to standard recipes and characterized through TEM and the IR spectroscopy of adsorbed carbon monoxide at room temperature. Whereas the reaction with hydrogen of C-2-OL in ethanol solutions yields hydrogenated products through a complex network, and no reaction takes place in the absence of hydrogen, in the present case C-2-OL is converted first to 2,5-dihydrofuran (2,5-DHF) and water. This step occurs on the silica support at room temperature, probably through the intermediacy of the surface species -Si-O-CH2-CHCH-CH2-OH. The presence of Pd nanoparticles allows, at ca. 100 °C, the subsequent isomerization of 2,5-DHF to 2,3-dihydrofuran (2,3-DHF). The same reaction requires a higher temperature (ca. 150 °C) with the Pt catalyst. At higher temperatures, the expected dehydrogenation of both 2,5- and 2,3-DHFs to furan takes place. On the support alone at 350 °C 2,5-DHF is converted to furan, and 2,3-DHF to carbonyl-containing species (as suggested in the literature), through thermal reactions.
- Mauriello, Francesco,Garrone, Edoardo,Musolino, Maria Grazia,Pietropaolo, Rosario,Onida, Barbara
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scheme or table
p. 27 - 34
(2010/12/18)
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- HETEROCYCLIC ANTIVIRAL COMPOUNDS
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Compounds having the formula A-R wherein A is a hetereoaryl and R is Ia, Ib or Ic and wherein A, R, R1, R2a, R2b, R2c, R3a, R3b, R4, R5, R6, Ra, Rb, Rc, Rd, X, X1, X2 and n are as are as defined herein are Hepatitis C virus NS5b polymerase inhibitors. Also disclosed are compositions and methods for treating an HCV infection and inhibiting HCV replication. R is
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- Selective and efficient cycloisomerization of alkynols catalyzed by a new ruthenium complex with a tetradentate nitrogen-phosphorus mixed ligand
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The new ruthenium complex [Ru(N3P)(OAc)][BPh4] (4), in which N3P is the N,P mixed tetradentate ligand N,N-bis[(pyridin-2-yl)methyl]-[2(diphenylphosphino)phenyl]methanamine was synthesized. The complex was found to be catalytically active for the endo cycloisomerization of alkynols. The catalytic reactions can be used to synthesize five-, six-, and seven-membered endo-cyclic enol ethers in good to excellent yields. A catalytic cycle involving a vinylidene intermediate was proposed for the catalytic reactions. Treatment of complex 4 with PhC≡CH and H2O gave the alkyl complex [Ru(CH2PhJ(CO)(N 3P)][BPh4] (30), which supports the assumption that the catalytic reactions involve addition of a hydroxyl group to the C=C bond of vinylidene ligands.
- Liu, Fei Nian,Su, Fu Hai,Wen, Ting Bin,Sung, Herman H.-Y.,Williams, Ian D.,Jia, Guochen
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experimental part
p. 7889 - 7897
(2010/09/10)
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- High chemo and regioselective formation of alcohols from the hydrocarbonylation of alkenes using cooperative ligand effects
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The hydrocarbonylation of alkenes, including allyl alcohol, catalysed by rhodium complexes and wide angle bidentate ligands together with PEt 3, gives alcohols as the primary products with high chemo and regio-selectivity.
- Boogaerts, Ine T.I. F.,White, Daniel F. S.,Cole-Hamilton, David J.
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supporting information; experimental part
p. 2194 - 2196
(2010/07/08)
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- Impurity reduction in Olefin metathesis reactions
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The present invention relates to the use of isomerization inhibitors in olefin metathesis reactions. The inhibitors are low molecular weight organic acids such as formic acid, acetic acid, benzoic acid, and the like.
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- Prevention of undesirable isomerization during olefin metathesis
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1,4-Benzoquinones have been found to prevent olefin isomerization of a number of allylic ethers and long-chain aliphatic alkenes during ruthenium-catalyzed olefin metathesis reactions. Electron-deficient benzoquinones are the most effective additives for the prevention of olefin migration. This mild, inexpensive, and effective method to block olefin isomerization increases the synthetic utility of olefin metathesis via improvement of overall product yield and purity. Copyright
- Hong, Soon Hyeok,Sanders, Daniel P.,Lee, Choon Woo,Grubbs, Robert H.
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p. 17160 - 17161
(2007/10/03)
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- RUTHENIUM COMPOUNDS, THEIR PRODUCTION AND USE
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A new class of compounds is disclosed that in preferred embodiments relate to Ru-based catalysts suitable for use in olefin metathesis reactions. Such compounds demonstrate high rates of catalytic turnover in comparison with other Ru catalysts known in the art. Moreover, the catalysts are highly stable, and readily suited to attachment to a solid support via the anionic ligands. In preferred embodiments the compounds present significant advantages by permitting facile isolation of active catalyst. The invention also pertains to methods of producing the catalysts, and their use in catalyzing olefin metathesis reactions.
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Page/Page column 35; 38
(2008/06/13)
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- NOVEL FLUOROPOLYMER, RESIST COMPOSITIONS CONTAINING THE SAME, AND NOVEL FLUOROMONOMERS
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There is provided a fluorine-containing copolymer having an aliphatic monocyclic structure in the polymer trunk chain which has a number average molecular weight of from 500 to 1,000,000 and is represented by the formula (Ma):- (M1) - (M2a) - (N) - in which the structural unit M1 is a structural unit derived from an ethylenic monomer having 2 or 3 carbon atoms and at least one fluorine atom, the structural unit M2a is at least one structural unit which introduces an aliphatic monocyclic structure in the polymer trunk chain and is represented by the formula (a): wherein R1 is at least one hydrocarbon group selected from the group consisting of a divalent hydrocarbon group having 1 to 8 carbon atoms and constituting a ring which may be further substituted with a hydrocarbon group or a fluorine-containing alkyl group and a divalent hydrocarbon group having ether bond which has the sum of carbon atoms and oxygen atoms of 2 to 8, constitutes a ring and may be further substituted with a hydrocarbon group or a fluorine-containing alkyl group; R2 is an alkylene group which has 1 to 3 carbon atoms and constitutes a ring; R3 and R4 are the same or different and each is a divalent alkylene group which has 1 or 2 carbon atoms and constitutes a ring; n1, n2 and n3 are the same or different and each is 0 or 1, the structural unit N is a structural unit derived from a monomer copolymerizable with the monomers to introduce the structural units M1 and M2a, and the structural units M1, M2a and N are contained in amounts of from 1 to 99 % by mole, from 1 to 99 % by mole and from 0 to 98 % by mole, respectively. The fluorine-containing polymer possesses excellent dry etching resistance and transparency in a vacuum ultraviolet region.
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- Preparation of preparing substituted indanones
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a process for the preparation of indanones of the formula II from, indanones of the formula I or of indanones of the formula IIa from indanones of the formula Ia comprises reacting an indanone of the formula I or Ia with a coupling component.
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- Fragrance precursors
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The invention relates to fragrance precursors, In particular, the invention relates to the use of several classes of compounds which may act as fragrance precursors, e,g., in cosmetic products such as deodorants and antiperspirants and in laundry products such as detergents and fabric softners. These compounds are odorless, but upon contacting the skin as example, in skin care compositions or in personal care compositions, produce fragrances. The compounds also produce fragrances when used in the presence of lipases, e.g. as used in (laundry) detergents, thus providing a prolongation of the fabric scenting effect. The compounds under consideration are compounds of the formula I: The substituents are defined in the specification.
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- Radiation curing of dihydrofuran derivatives
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Process for producing coatings or moldings by radiation curing, which involves using high-energy light to irradiate radiation-curable compositions containing 1-100% by weight, based on the total amount of free-radically or cationically polymerizable compounds, of compounds A) containing at least one cationically polymerizable 2,3-dihydrofuran group.
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- Hydrogenation of 2,5-dihydrofuran to tetrahydrofuran
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The influence of different factors on the hydrogenation reaction of 2,5-dihydrofuran to tetrahydrofuran over different commercial catalysts has been studied. The results of kinetic studies are represented.
- Bobyleva,Kryukov,Abreimova,Egorova
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p. 130 - 133
(2007/10/03)
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- Mutual catalytic conversions of unsubstituted furan and pyran systems
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The conversions of furan, di- and tetrahydrofuran, and di- and tetrahydropyran on a molybdenum catalyst in a hydrogen atmosphere have been investigated. The studied cyclic systems readily undergo mutual conversions at 125-215°C and also undergo a hydrogenation-dehydrogenation reaction. Expansion of the unsubstituted furan rings to pyran without the introduction into the reaction medium of components capable of generating methyl radicals are described by us for the first time.
- Anderson,Simonyan,Lukevics
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p. 1406 - 1408
(2007/10/03)
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- Quantum chemical investigation by the AM1 method of the catalytic cyclodehydration of 1,4-butanediol
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1,4-Butanediol is converted into tetrahydrofuran in the presence of silica gel at temperatures of 245-340°C. The mechanism of the conversion of 1,4-butanediol has been studied by the quantum chemical AM1 method with full optimization of the geometry. It was established that two parallel reactions are possible depending on the conformation of the molecule. The cyclodehydration reaction is effected by conversion of a semicyclic conformer of the protonated diol molecule at a basic center of the catalyst by a concerted mechanism. The heat of the reaction forming tetrahydrofuran is - 161.768 kcal/mole. 1998 Plenum Publishing Corporation.
- Fleisher,Leite,Lebedev,Lukevics
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p. 533 - 537
(2007/10/03)
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- Formation of oxygenates in the propane oxidation over K+ modified Fe/SiO2 catalyst
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Oxygenates are formed in the propane oxidation over silica catalysts supporting a very small amount of Fe. Alkali addition to the catalysts can enhance the activity as well as the selectivity to acrolein and acetone.
- Teng, Yonghong,Kobayashi, Tetsuhiko
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p. 327 - 328
(2007/10/03)
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- Pyrazoloquinolines
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The invention relates to compounds of the formulas STR1 wherein X, R1, R2, and R3, are as described herein. These compounds are useful as antitumor agents. Pharmaceutical compositions containing compounds of formula I are also described. Methods for treating tumors which comprise administration of compounds of formula I are also described. Processes for preparing compounds of formula I are also described.
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- Asymmetric Hydroformylation of Heterocyclic Olefins Catalyzed by Chiral Phosphine-Phosphite-Rh(I) Complexes
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Asymmetric hydroformylation of heterocyclic olefins catalyzed by phosphine-phosphite-Rh(I) complexes has been investigated. Hydroformylation of symmetrical heterocyclic olefins such as 2,5-dihydrofuran, 3-pyrroline derivatives, and 4,7-dihydro-1,3-dioxepin derivatives afforded the optically active aldehydes as single products in 64-76% ee. Unsymmetrical substrates such as 2,3-dihydrofuran and N-(tert-butoxycarbonyl)-2-pyrroline gave a mixture of regioisomers. From N-(tert-butoxycarbonyl)-2-pyrroline was obtained N-(tert-butoxycarbonyl)pyrrolidine-2-carbaldehyde in 97% ee. The hydroformylation products from 2,5-dihydrofuran and N-(tert-butoxycarbonyl)-3-pyrroline have the opposite configurations to those from 2,3-dihydrofuran and N-(tert-butoxycarbonyl)-2-pyrroline, respectively, with the same catalyst. The new phosphine-phosphite ligand (R,S)-3,3′-Me2-BINAPHOS [= (A)-2-(diphenylphosphino)-1,1′-binaphthalen-2′-yl (S)-3,3′-dimethyl-1,1′-binaphthalene-2,2′-diyl phosphite] was prepared and its hydridorhodium complex was characterized by NMR spectroscopy. Using (R,S)-3,3′-Me2-BINAPHOS as a ligand, the enantioselectivity was improved for some substrates. In addition, higher catalytic activity was observed with this ligand for most of the substrates employed.
- Horiuchi, Toshihide,Ohta, Tetsuo,Shirakawa, Eiji,Nozaki, Kyoko,Takaya, Hidemasa
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p. 4285 - 4292
(2007/10/03)
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- 5,6,7,8-tetrahydronaphtho[2,3-b]furan and indano[5,6-b]furan amine compounds
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New compounds of formula: STR1 wherein: A-B, n and Y are as defined in the description, their optical isomers and physiologically tolerable salts thereof with appropriate acids. The products of the invention may be used as medicaments.
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- Catalytic dehydrogenation of ethylbenzene and tetrahydrofuran by a dihydrido iridium P-C-P pincer complex
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The P-C-P pincer complex, [IrH2{C6H3(CH2PBut 2)-2,6}] catalyses the transfer dehydrogenation of the donor-bearing substrates, ethylbenzene and tetrahydrofuran at temperatures as low as 150°C.
- Gupta, Mukta,Kaska, William C.,Jensen, Craig M.
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p. 461 - 462
(2007/10/03)
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- Isomerization reactions of the n-C4H9O and n-OOC4H8OH radicals in oxygen
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Reactions of n-C4H9O radicals have been investigated in the temperature range 343-503 K in mixtures of O2/N2 at atmospheric pressure. Flow and static experiments have been performed in quartz and Pyrex vessels of different diameters, walls passivated or not towards reactions of radicals, and products were analyzed by GC/MS. The main products formed are butyraldehyde, hydroperoxide C4H8O3 of MW 104, 1-butanol, butyrolactone, and n-propyl hydroperoxide. It is shown that transformation of these RO radicals occurs through two reaction pathways, H shift isomerization (forming C4H8OH radicals) and decomposition. A difference of activation energies ΔE = (7.7 ± 0.1 (σ)) kcal/mol between these reactions and in favor of the H-shift is found, leading to an isomerization rate constant κisom (n-C4H9O) = 1.3 × 1012 exp(-9,700/RT). Oxidation, producing butyraldehyde, is proposed to occur after isomerization, in parallel with an association reaction of C4H8OH radicals with O2 producing OOC4H8OH radicals which, after further isomerization lead to an hydroperoxide of molecular weight 104 as a main product. Butyraldehyde is mainly formed from the isomerized radical HOCCCC. + O2 ? →O=CCCC + HO2, since (i) the ratio butyraldehyde/(butyraldehyde + isomerization products) = 0.290 ± 0.035 (σ) is independent of oxygen concentration from 448 to 496 K, and (ii) the addition of small quantities of NO has no influence on butyraldehyde formation, but decreases concentration of the hydroperoxides (that of MW 104 and rt-propyl hydroperoxide). By measuring the decay of [MW 104] in function of (NO] added (0-22.5 ppm) at 487 K, an estimation of the isomerization rate constant OOC4H8OH→ HOOC4H7OH, κ5 ≈ 1011exp(- 17,600/RT) is made. Implications of these results for atmospheric chemistry and combustion are discussed. ?1996 John Wiley and Sons, Inc.
- Heiss, Adolphe,Sahetchian, Krikor
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p. 531 - 544
(2007/10/03)
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- NMR-DETECTION OF INTERMEDIATES DURING HOMOGENEOUS HYDROGENATION OF DIENES USING PARAHYDROGEN
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1.The 1H-NMR spectra of the reaction products of hydrogenations using parahydrogen reveal information about intermediates and thus the reaction mechanism. 2.Due to its high signal enhancement the method is uniquely suited for reactions, where the catalyst itself becomes chemically modified.
- Bargon J.,Kandels, J.,Kating, P.,Thomas, A.,Woelk, K.
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p. 5721 - 5724
(2007/10/02)
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- Synthesis, structure, and reactivity of metallacycle-carbene and -bis(carbene) complexes. A new intramolecular carbene-carbene coupling process
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Halide ion abstraction from the neutral iridiacyclopentadiene complexes, Ir(CR=CRCR=CR)(PPh3)2Cl (1, R = CO2CH3), and Ir(CR=CRCR=CR)(PPh3)2(CO)(Cl) (2, R = CO2CH3), le
- O'Connor, Joseph M.,Pu, Lin,Rheingold, Arnold L.
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p. 6232 - 6247
(2007/10/02)
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- Homolytic Reactions of Ligated Boranes. Part 11. Electron Spin Resonance Studies of Radicals Derived from Primary Amine-Boranes
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Photochemically generated t-butoxyl radicals react with the primary amine-boranes RNH2->BH3 (R = Me or But) to form, initially, the nucleophilic amine-boryl radical RNH2->BH2, which subsequently abstracts hydrogen from the parent amine-borane to give the more stable isomeric aminyl-borane radical RNH->BH3.The amine-boryl radicals can be intercepted by alkyl bromides or chlorides or by nitriles, with which they react by halogen-atom abstraction or by addition to the CN group to give iminyl radicals, respectively.The e. s. r. spectra of the aminyl-borane radicals show the presence of extensive hyperconjugative delocalisation of the unpaired electron onto the BH3 group .Monoalkylaminyl-borane radicals react readily with alkenes, with arenes, and with conjugated or cumulated dienes to transfer a β-hydrogen atom from boron to give alkyl, cyclohexadienyl, or allyl radicals, respectively.Hydrogen atom transfer to alkenes from the electrophilic MeNH->BH3 takes place with high regioselectivity to give the more stable alkyl radical when two adducts are possible; the rate of transfer increases as the ionisation potential of the alkene decreases along the series CH2=CH2 BH3 to give the isopropyl radical was determined to be ca. 2 x 103 dm3 mol-1 s-1 at 282 K.Competition experiments have been carried out to determine the relative rates of the various reactions undergone by RNH2->BH2 and RNH->BH3.The results are interpreted with the aid of ab initio molecular-orbital calculations at the 6-31G level for RNH2->BH2, RNH->BH3, RNH2->BH3, and RNHBH2 (R = H or Me), together with similar calculations for the isoelectronic organic counterparts in which the NB moiety is replaced by a CC grouping.
- Kirwan, J. Nicolas,Roberts, Brian P.
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p. 539 - 550
(2007/10/02)
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- 7-hydroxyguanine compounds
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Novel 7-hydroxyguanine compounds of the formula: STR1 wherein R is hydrogen atom, tetrahydropyranyl group or tetrahydrofuryl group, and R2 is hydrogen atom, tetrahydropyranyl group or tetrahydrofuryl group, provided that when R1 is hydrogen atom, R2 is tetrahydropyranyl group or tetrahydrofuryl group, and a salt thereof, which have excellent anti-tumor activity, process for preparing the compounds, and anti-tumor agent containing said compound as an active ingredient.
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- β-Halogeno Ether Synthesis of Olefinic Alcohols: Stereochemistry and Conformation of 2-Substituted 3-Halogenotetrahydro-pyran and furan Precursors
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Ring-scission of cis- or trans-2-alkyl- (or aryl-) 3-chlorotetrahydropyrans proceeds regioselectively and highly stereoselectively to give (E)-alk-4-en-1-ols, but in the parallel tetrahydrofuran series (Z)-/(E)-mixtures, dependent on percursor geometry, are formed.In this paper the stereochemistry and conformation of the tetrahydro-pyran and - furan precursors are considered.The cis/trans-composition of 2,3-dihalogenotetrahydro-pyrans and-furans made by various routes is reported.Reaction with Grignard reagents gives separable cis-/trans-mixtures the stereoisomeric composition of which, in the cases examined, does not depend on the stereoisomeric composition of the dihalide, but does vary with the halogen and the composition of the Grignard or dialkylmagnesium; possible reasons are discussed.The stereochemistry and conformation of the 2-alkyl- (or aryl-)3-chlorotetrahydropyrans is analysed by n.m.r. methods (J2a,3acis ca. 1.5 Hz; J2a,3atrans ca. 9.8 Hz) but assignments for the two tetrahydrofuran series with J2,3 2.6-3.6 and 4.3-5.9 are made uncertain by pseudorotation.The stereochemical identity of the two series is rigorously proved by isolation of cis- and trans-2-allyl-3-chlorotetrahydrofuran.On the one hand the former is hydrogenated to the cis-2-propyl compound, correlated with other members of the alkyl series, but on the other it is oxidised and the acid is converted into the cis-p-bromophenyl ester.The stereochemistry and conformation of the latter is rigorously demonstrated by an X-ray structure.The stereochemistries and conformations of the 2-deuterio- and 2-methoxy-3-chlorotetrahydropyrans are discussed, and consideration is then extended to the 2-alkyl-3-chloro-2-methyltetrahydro-pyran and -furan series.
- Crombie, Leslie,Wyvill, Robert D.
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p. 1971 - 1982
(2007/10/02)
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- Conversion of 1,4-Butanediol to Furan Compounds on Cobalt Catalysts in the Liquid Phase
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The transformation of 1,4-butanediol on cobalt catalysts applied to kieselguhr in the liquid phase under periodic and continuous conditions was investigated.When the reaction is carried out under periodic conditions, the principal reaction products are 2,3-dihydrofuran, tetrahydrofuran, and γ-butyrolactone.An increase in the selectivity of the formation of 2,3-dihydrofuran as the temperature is raised was established. 2,3-Dihydrofuran is obtained in 63-73 mole percent yields under optimum conditions. 2,3-Dihydrofuran is converted to tetrahydrofuran when the process is carried out under continuous conditions on a tableted cobalt catalyst.
- Geiman, I. I.,Bulenkova, L. F.,Lazdin'sh, A. A.,Veinberg, A. K.,Slavinskaya, V. A.,Avots, A. A.
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p. 314 - 316
(2007/10/02)
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