- Calcium borohydride: A reagent for facile conversion of carboxylic esters to alcohols and aldehydes
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Calcium borohydride reduces both aliphatic and aromatic esters to alcohols completely in the presence of alkene catalysts. The intermediate borates formed during the reduction of aromatic esters are converted to aldehydes with aqueous NaOCl in good yields.
- Narasimhan,Ganeshwar Prasad,Madhavan
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- A simple alkene-catalyzed reduction of aromatic esters to alcohols by zinc borohydride
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Reactivity of Zn(BH4)2 was modified by adding cyclohexene to achieve the reduction of aromatic esters to alcohols which reaction was not possible previously because of the mild nature of the reagent. Functional groups like Cl and nitro were tolerated.
- Narasimhan,Madhavan,Ganeshwar Prasad
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- Fatty alcohol synthesis from fatty acids at mild temperature by subsequent enzymatic esterification and metal-catalyzed hydrogenation
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Fatty alcohols are important products in chemical industry to be used in the formulation of surfactants and lubricants. This work describes a two step approach for the production of myristyl alcohol under neat conditions by combining a lipase catalyzed esterification of myristic acid and myristyl alcohol with a ruthenium catalyzed hydrogenation of the intermediate myristyl myristate. The esterification was carried out in a bubble column reactor with the commercial immobilized lipase B from Candida antarctica as a biocatalyst, while the hydrogenation was conducted under pressurized conditions being catalyzed by the homogeneous chemocatalyst Ru-Macho-BH. By investigating the reaction steps separately, comparable reaction rates were found for the esterification of short chain and long chain alcohols. Additionally, the hydrogen pressure could be reduced to 35 bar compared to the current industrial Lurgi process. Characterization of cross interactions by the reactants myristic acid and sodium myristate in the hydrogenation demonstrates that the metal catalyst was completely deactivated, even at a low amount of 0.5 mol% of myristic acid. Complete conversion of myristic acid in the esterification with equal amounts of myristic acid and myristyl alcohol was obtained, overcoming any limitation in the hydrogenation. In comparison to the Lurgi process starting also from fatty acid and fatty alcohols, the chemoenzymatic two step reaction sequence could be realized at lower reaction temperatures of 60 and 100 °C as well as lower hydrogen pressures of 35 bar. This journal is
- Betke, Tobias,Gr?ger, Harald,Kleber, Joscha,Liese, Andreas,Schlipk?ter, Kim E.
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- OXO ACIDS AND BRANCHED FATTY ACID ESTERS FROM RHIZOMES OF COSTUS SPECIOSUS
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Key Word Index - Costus speciosus; Costaceae; rhizomes; tetradecyl 13-methylpentadecanoate; tetradecyl 11-methyltridecanoate; 14-oxotricosanoic acid; 14-oxoheptacosanoic acid; 15-oxooctacosanoic acid; 5α-stigmast-9(11)-en-3β-ol; diosgenin; sitosterol; triacontanol; triacontanoic acid. Five new compounds, isolated from the rhizomes of Costus speciosus have been characterized as tetradecyl 13-methylpentadecanoate, tetradecyl 11-methyltridecanoate, 14-oxotricosanoic acid, 14-oxoheptacosanoic acid and 15-oxo-octacosanoic acid by spectral and chemical studies.Triacontanol, 5α-stigmast-9(11)-en-3β-ol, triacontanoic acid, sitosterol and diosgenin have also been isolated and identified.
- Gupta, Madan M.,Verma, Ram K.,Akhila, Anand
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- Synthesis and surface-active properties of novel cleavable gemini surfactants
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A novel series of quaternary ammonium gemini compounds having a butynylene spacer and different hydrocarbon chain lengths (CGBu8-16) were prepared. Carbonate group inserted between the hydrocarbon chains and the polar heads make these compounds hydrolyzable. The degradation under hydrolysis of these novel series will lead to the generation of fatty alcohols and readily degradable compounds. The reagents used are biodegradable, renewable, or reusable. The surface activities and foamability in aqueous solution of the cleavable gemini compounds containing n-octyl, n-decyl, and n-dodecyl chains meet the criteria for being good surfactants and showed stable foams even at low concentrations.
- Gilbert, Elangeni Ana,Guastavino, Javier Fernando,Murguía, Marcelo César
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- Redox-active ligand based Mn(i)-catalyst for hydrosilylative ester reduction
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Herein a Mn(i) catalyst bearing a redox-active phenalenyl (PLY) based ligand is reported for the efficient hydrosilylation of esters to alcohols using the inexpensive silane source polymethylhydrosiloxane (PMHS) under mild conditions. Mechanistic investigations suggest a strong ligand-metal cooperation where a ligand-based single electron transfer (SET) process initiates the reaction through Si-H bond activation.
- Chakraborty, Soumi,Das, Arpan,Mandal, Swadhin K.
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supporting information
p. 12671 - 12674
(2021/12/04)
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- Borane evolution and its application to organic synthesis using the phase-vanishing method
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Although borane is a useful reagent, it is difficult to handle. In this study, borane was generated in situ from NaBH4 or nBu4NBH4 with several oxidants using a phase-vanishing (PV) method. The borane generated was directly reacted with alkenes, affording the desired alcohols in good yields after oxidation with H2O2 under basic conditions. The selective reduction of carboxylic acids with the evolved borane was examined. The organoboranes generated by the PV method successfully underwent Suzuki–Miyaura coupling. Using this PV system, reactions with borane can be carried out easily and safely in a common test tube.
- Soga, Nene,Yoshiki, Tomo,Sato, Aoi,Kawamoto, Takuji,Ryu, Ilhyong,Matsubara, Hiroshi
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supporting information
(2021/03/26)
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- Enantiomeric synthesis of natural alkylglycerols and their antibacterial and antibiofilm activities
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Alkylglycerols (AKGs) are bioactive natural compounds that vary by alkyl chain length and degree of unsaturation, and their absolute configuration is 2S. Three AKGs (5l–5n) were synthesised in enantiomerically pure form, and were characterised for the first time together with 12 other known and naturally occurring AKGs (5a–5k, 5o). Their structures were established using 1H and 13C APT NMR with 2D-NMR, ESI-MS or HRESI-MS and optical rotation data, and they were tested for their antibacterial and antibiofilm activities. AKGs 5a–5m and 5o showed activity against five clinical isolates and P. aeruginosa ATCC 15442, with MIC values in the range of 15–125 μg/mL. In addition, at half of the MIC, most of the AKGs reduced S. aureus biofilm formation in the range of 23%–99% and P. aeruginosa ATCC 15442 biofilm formation in the range of 14%–64%. The antibiofilm activity of the AKGs assessed in this work had not previously been studied.
- Fernández Montoya, Deicy J.,Contreras Jordan, Luis A.,Moreno-Murillo, Bárbara,Silva-Gómez, Edelberto,Mayorga-Wandurraga, Humberto
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supporting information
p. 2544 - 2550
(2019/11/13)
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- Hydrosilylation of Esters Catalyzed by Bisphosphine Manganese(I) Complex: Selective Transformation of Esters to Alcohols
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Selective and efficient hydrosilylations of esters to alcohols by a well-defined manganese(I) complex with a commercially available bisphosphine ligand are described. These reactions are easy alternatives for stoichiometric hydride reduction or hydrogenation, and employing cheap, abundant, and nonprecious metal is attractive. The hydrosilylations were performed at 100 °C under solvent-free conditions with low catalyst loading. A large variety of aromatic, aliphatic, and cyclic esters bearing different functional groups were selectively converted into the corresponding alcohols in good yields.
- Bagh, Bidraha,Behera, Rakesh R.,Ghosh, Rahul,Khamari, Subrat,Panda, Surajit
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supporting information
p. 3642 - 3648
(2020/04/20)
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- Novel clamp metal complex and application thereof
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The invention discloses a method for preparing a novel clamp-shaped complex and application of the novel clamp-shaped complex in the reaction of catalytic hydrogenation of carboxylic acid ester compounds to produce corresponding alcohols and reaction of carbon dioxide catalytic hydrogenation to form formamide compounds. Carboxylic acid esters and hydrogen as raw materials or carbon dioxide, hydrogen and amine compounds as raw materials are reacted in an organic solvent condition or a solvent-free condition in the presence of a transition metal complex as a catalyst to respectively form the corresponding alcohol compounds and/or corresponding formamide compounds. The method has the advantages of being high in reaction efficiency, good in selectivity, mild in conditions, economical, environmentally-friendly, and simple in operation, and has good promotion and application prospects.
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Paragraph 0410-0412; 0434-0437; 0511-0514
(2019/04/26)
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- Diaminodiphosphine tetradentate ligand and ruthenium complex thereof, and preparation methods and applications of ligand and complex
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The invention discloses a diaminodiphosphine tetradentate ligand and a ruthenium complex thereof, and preparation methods and applications of the ligand and the complex, and provides a ruthenium complex represented by a formula I, wherein L is a diaminodiphosphine tetradentate ligand represented by a formula II, and X and Y are respectively and independently chlorine ion, bromine ion, iodine ion,hydrogen negative ion or BH4. According to the present invention, the ruthenium complex exhibits excellent catalytic activity in the catalytic hydrogenation reactions of ester compounds, has high yield and high chemical selectivity, is compatible with conjugated and non-conjugated carbon-carbon double bond, carbon-carbon triple bond, epoxy, halogen, carbonyl and other functional groups, and hasgreat application prospects.
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Paragraph 0301-0303; 0305
(2019/11/04)
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- Selective Hydroboration of Carboxylic Acids with a Homogeneous Manganese Catalyst
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Catalytic reduction of carboxylic acid to the corresponding alcohol is a challenging task of great importance for the production of a variety of value-added chemicals. Herein, a manganese-catalyzed chemoselective hydroboration of carboxylic acids has been developed with a high turnover number (>99?000) and turnover frequency (>2000 h-1) at 25 °C. This method displayed tolerance of electronically and sterically differentiated substrates with high chemoselectivity. Importantly, aliphatic long-chain fatty acids, including biomass-derived compounds, can efficiently be reduced. Mechanistic studies revealed that the reaction occurs through the formation of active manganese-hydride species via an insertion and bond metathesis type mechanism.
- Barman, Milan K.,Das, Kuhali,Maji, Biplab
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p. 1570 - 1579
(2019/01/30)
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- Mechanistic study of the selective hydrogenation of carboxylic acid derivatives over supported rhenium catalysts
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The structure and performance of TiO2-supported Re (Re/TiO2) catalysts for selective hydrogenation of carboxylic acid derivatives have been investigated. Re/TiO2 promotes selective hydrogenation reactions of carboxylic acids and esters that form the corresponding alcohols, and of amides that generate the corresponding amines. These processes are not accompanied by reduction of aromatic moieties. A Re loading amount of 5 wt% and a catalyst pretreatment with H2 at 500 °C were identified as being optimal to obtain the highest catalytic activity for the hydrogenation processes. The results of studies using various characterization methods, including X-ray diffraction (XRD), X-ray absorption fine structure (XAFS), X-ray photoelectron spectroscopy (XPS), and scanning transmission electron microscopy (STEM), indicate that the Re species responsible for the catalytic hydrogenation processes have sub-nanometer to a few nanometer sizes and average oxidation states higher than 0 and below +4. The presence of either a carboxylic acid and/or its corresponding alcohol is critical for preventing the Re/TiO2 catalyst from promoting production of dearomatized byproducts. Although Re/TiO2 is intrinsically capable of hydrogenating aromatic rings, carboxylic acids, alcohols, amides, and amines strongly adsorb on the Re species, which leads to suppression of this process. Moreover, the developed catalytic system was applied to selective hydrogenation of triglycerides that form the corresponding alcohols.
- Toyao, Takashi,Ting, Kah Wei,Siddiki, S. M. A. Hakim,Touchy, Abeda S.,Onodera, Wataru,Maeno, Zen,Ariga-Miwa, Hiroko,Kanda, Yasuharu,Asakura, Kiyotaka,Shimizu, Ken-ichi
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p. 5413 - 5424
(2019/10/29)
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- Iron-catalyzed AlkylAlkyl negishi coupling of organoaluminum reagents
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The first iron-catalyzed cross-coupling reaction of alkyl halides with alkylaluminum reagents (alkylalkyl Negishi coupling) is developed using an iron/bisphosphine catalyst system. The reaction shows high functional group tolerance: various primary alkyl halides possessing a non-protected indole, carboxyl, or hydroxy group are coupled with primary alkylaluminum reagents in good yields. Potassium fluoride plays a key role to promote the reaction by generating an aluminate species, which facilitates the transmetalation between the organoaluminum and the iron catalyst.
- Agata, Ryosuke,Kawamura, Shintaro,Isozaki, Katsuhiro,Nakamura, Masaharu
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supporting information
p. 238 - 241
(2019/03/13)
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- Selective Hydrogenation of Carboxylic Acids to Alcohols or Alkanes Employing a Heterogeneous Catalyst
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The chemoselective hydrogenation of carboxylic acids to either alcohols or alkanes is reported, employing a heterogeneous bimetallic catalyst consisting of rhenium and palladium supported on graphite. α-Chiral carboxylic acids were hydrogenated without loss of optical purity. The catalyst displays a reverse order of reactivity upon hydrogenation of different carboxylic functions with esters being less reactive than amides and carboxylic acids. This allows for chemoselective hydrogenation of an acid in the presence of an ester or an amide function.
- Ullrich, Johannes,Breit, Bernhard
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p. 785 - 789
(2018/02/14)
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- Mechanism of supported Ru3Sn7 nanocluster-catalyzed selective hydrogenation of coconut oil to fatty alcohols
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As a promising hydrotreating catalyst, it was previously reported that Ru?OSn (Ru electronically interacts with Sn oxides) on RuSn/SiO2 was the active site for fatty acid hydrogenation, but here in this work we found that Ru3Sn7 nanoclusters on RuSn/SiO2 were responsible for the selective hydrogenation of diverse fatty acids and coconut oil to fatty alcohols. The XPS results indicated no interaction between Snδ+ and Ru0, suggesting that SnOx may exist as isolated species. In contrast, the binding energy shifts of Ru0 and Sn0 in the XPS spectra demonstrated a strong interaction, as a result of the formation of Ru3Sn7 alloy nanoclusters. It was demonstrated that the highest yield of fatty alcohol was obtained with a Sn/Ru ratio of 7/3 (hydrogenation rate: 2.45 g g-1 h-1), and the careful selection of the Sn/Ru ratio and reduction temperatures greatly suppressed the formation of Sn and SnO2 phases. The ratio of the stearyl alcohol formation rate to its consumption rate was 40.8 with Ru3Sn7/SiO2 under the selected conditions. In catalysts with a Sn/Ru ratio higher than 7/3, the presence of additional SnO2 catalyzes the formation of undesired esters at a rate of 0.31 g g-1 h-1. Excess SnO2 would be reduced to Sn at temperatures higher than 600 °C, while Sn can catalyze ester by-product formation at a rate of 0.88 g g-1 h-1. The DFT calculations showed that CH3COOH adsorbs on the Ru3Sn7 (111) surface via Sn-O interactions at the two top sites of adjacent surface Sn atoms, and such adsorption was mainly due to the electrostatic interactions between the molecule and the positively charged surface Sn atoms. The charge density difference (CDD) plots of co-adsorbed CH3CO? and OH? intermediates indicated the bonding relationships between Sn-O and Ru-α-C, suggesting that the surface Sn atoms also took part in the catalytic reaction as an important surface sorption site as well as a Ru3Sn7 structure component, while Ru atoms bonded with α-C and hydrogenated the adsorbed intermediate species with the adsorbed H? to the final alcohol. A further indication that Ru3Sn7 was the active species in the bimetallic Ru-Sn catalyst was given by the much lower energy barrier for hydrogenation of acetic acid in Ru3Sn7 (111) (81.0 kJ mol-1) compared to Ru (0001) (123.5 kJ mol-1).
- Luo, Zhicheng,Bing, Qiming,Kong, Jiechen,Liu, Jing-Yao,Zhao, Chen
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p. 1322 - 1332
(2018/03/13)
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- Rhenium-Loaded TiO2: A Highly Versatile and Chemoselective Catalyst for the Hydrogenation of Carboxylic Acid Derivatives and the N-Methylation of Amines Using H2 and CO2
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Herein, we report a heterogeneous TiO2-supported Re catalyst (Re/TiO2) that promotes various selective hydrogenation reactions, which includes the hydrogenation of esters to alcohols, the hydrogenation of amides to amines, and the N-methylation of amines, by using H2 and CO2. Initially, Re/TiO2 was evaluated in the context of the selective hydrogenation of 3-phenylpropionic acid methyl ester to afford 3-phenylpropanol (pH2 =5 MPa, =5 MPa, T=180 °C), which revealed a superior performance over other catalysts that we tested in this study. In contrast to other typical heterogeneous catalysts, hydrogenation reactions with Re/TiO2 did not produce dearomatized byproducts. DFT studies suggested that the high selectivity for the formation of alcohols in favor of the hydrogenation of aromatic rings is ascribed to the higher affinity of Re towards the COOCH3 group than to the benzene ring. Moreover, Re/TiO2 showed a wide substrate scope for the hydrogenation reaction (19 examples). Subsequently, this Re/TiO2 catalyst was applied to the hydrogenation of amides, the N-methylation of amines, and the N-alkylation of amines with carboxylic acids or esters.
- Toyao, Takashi,Siddiki,Morita, Yoshitsugu,Kamachi, Takashi,Touchy, Abeda S.,Onodera, Wataru,Kon, Kenichi,Furukawa, Shinya,Ariga, Hiroko,Asakura, Kiyotaka,Yoshizawa, Kazunari,Shimizu, Ken-Ichi
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supporting information
p. 14848 - 14859
(2017/10/27)
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- Selective conversion of coconut oil to fatty alcohols in methanol over a hydrothermally prepared Cu/SiO2 catalyst without extraneous hydrogen
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A novel one-pot approach selects a hydrothermally synthesized Cu/SiO2 catalyst (consisting of Cu2O·SiO2 and Cu0 surface species) to catalyze the reduction of a series of fatty esters, fatty acids, and coconut oil to fatty alcohols at 240 °C in methanol without extraneous hydrogen, attaining around 85% conversion and 100% selectivity.
- Wu, Liubi,Li, Lulu,Li, Bolong,Zhao, Chen
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p. 6152 - 6155
(2017/07/10)
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- TiO2-Supported Re as a General and Chemoselective Heterogeneous Catalyst for Hydrogenation of Carboxylic Acids to Alcohols
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TiO2-supported Re, Re/TiO2, was found to promote selective hydrogenation of carboxylic acids having aromatic and aliphatic moieties to the corresponding alcohols. Re/TiO2showed superior results compared to other transition-metal-loaded TiO2and supported Re catalysts for selective hydrogenation of 3-phenylpropionic acid. 3-phenylpropanol was produced in 97 % yield under mild conditions (5 MPa H2at 140 °C). Contrary to typical heterogeneous catalysts, Re/TiO2does not lead to the formation of dearomatized byproducts. The catalyst is recyclable and shows a wide substrate scope in the synthesis of alcohols (22 examples; up to 97 % isolated yield).
- Toyao, Takashi,Siddiki, S. M. A. Hakim,Touchy, Abeda S.,Onodera, Wataru,Kon, Kenichi,Morita, Yoshitsugu,Kamachi, Takashi,Yoshizawa, Kazunari,Shimizu, Ken-Ichi
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supporting information
p. 1001 - 1006
(2017/02/05)
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- Harnessing open-source technology for low-cost automation in synthesis: Flow chemical deprotection of silyl ethers using a homemade autosampling system
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An inexpensive homemade 3-axis autosampler was used to facilitate the automation of an acid catalysed flow chemical desilylation reaction. Harnessing open-source software technologies (Python, OpenCV), an automated computer-vision controlled liquid-liquid extraction step was used to provide effective inline purification. A Raspberry Pi single-board computer was employed to interface with the motors used in the autosampler and actuated fluidic valves.
- O'Brien, Matthew,Konings, Lisette,Martin, Matthew,Heap, Jordan
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supporting information
p. 2409 - 2413
(2017/06/01)
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- Unsupported Nanoporous Gold Catalyst for Chemoselective Hydrogenation Reactions under Low Pressure: Effect of Residual Silver on the Reaction
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For the first time, H-H dissociation on an unsupported nanoporous gold (AuNPore) surface is reported for chemoselective hydrogenation of C=C, C=C, C=N, and C=O bonds under mild conditions (8 atm H2 pressure, 90 °C). Silver doping in AuNPore, which was inevitable for its preparation through a process of dealloying of Au-Ag alloy, exhibited a remarkable difference in catalytic activity between two catalysts, Au>99Ag1NPore and Au90Ag10NPore.The former was more active and the latter less active in H2 hydrogenation, while the reverse tendency was observed for O2 oxidation. This marked contrast between H2 reduction and O2 oxidation is discussed. Further, Au>99Ag1NPore showed a high chemoselectivity toward reduction of terminal alkynes in the presence of internal alkynes which was not achieved using supported gold nanoparticle catalysts and other previously known methods. Reductive amination, which has great significance in synthesis of amines due to its atom-economical nature, was also realized using Au>99Ag1NPore, and the Au>99Ag1NPore/H2 system showed a preference for the reduction of aldehydes in the presence of imines. In addition to this high chemoselectivity, easy recovery and high reusability of AuNPore make it a promising heterogeneous catalyst for hydrogenation reactions.
- Takale, Balaram S.,Feng, Xiujuan,Lu, Ye,Bao, Ming,Jin, Tienan,Minato, Taketoshi,Yamamoto, Yoshinori
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supporting information
p. 10356 - 10364
(2016/08/31)
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- METHOD FOR PRODUCING OXIDE
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Provided is a method of oxidizing a substrate with excellent oxidizing power to yield a corresponding oxide. The method can employ a commercially available imide compound as intact as a catalyst and can produce the oxide in a high yield under mild conditions. A method for producing an oxide according to the present invention includes performing oxidation of a substrate in the presence of oxygen and ozone under catalysis of an imide compound to yield a corresponding oxide. The imide compound has a cyclic imide skeleton represented by Formula (I). In the formula, n is selected from 0 and 1; and X is selected from an oxygen atom and an —OR group, where R is selected from hydrogen and a hydroxy-protecting group.
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Paragraph 0137-0139
(2016/06/28)
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- Highly efficient tetradentate ruthenium catalyst for ester reduction: Especially for hydrogenation of fatty acid esters
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A new tetradentate ruthenium complex has been developed for hydrogenation of esters. The catalysts structure features a pyridinemethanamino group and three tight chelating five-membered rings. The structure character is believed to be responsible for its high stability and high carbonylation-resistant properties. Thus, this catalyst shows outstanding performance in the catalytic hydrogenation of a variety of esters, especially for fatty acid esters, which may be used in practical applications. New insight on designing hydrogenation catalyst for reducing esters to alcohols has been provided through theoretical calculations.
- Tan, Xuefeng,Wang, Yan,Liu, Yuanhua,Wang, Fangyuan,Shi, Liyang,Lee, Ka-Ho,Lin, Zhenyang,Lv, Hui,Zhang, Xumu
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supporting information
p. 454 - 457
(2015/03/05)
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- A General, Practical Triethylborane-Catalyzed Reduction of Carbonyl Functions to Alcohols
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A combination of the abundant and low-cost triethylborane and sodium alkoxide generates a highly efficient catalyst for reduction of esters, as well as ketones and aldehydes, to alcohols using an inexpensive hydrosilane under mild conditions. The catalyst system exhibits excellent chemoselectivity and a high level of functional group tolerance. Mechanistic studies revealed a resting state of sodium triethylalkoxylborate that is the product of the reaction of BEt3 with sodium alkoxide. This borate species reacts with hydrosilane to form NaBEt3H, which rapidly reduces esters.
- Peng, Dongjie,Zhang, Mintao,Huang, Zheng
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supporting information
p. 14737 - 14741
(2015/10/19)
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- Electron transfer reduction of nitriles using SmI2-Et 3N-H2O: Synthetic utility and mechanism
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The first general reduction of nitriles to primary amines under single electron transfer conditions is demonstrated using SmI2 (Kagan's reagent) activated with Lewis bases. The reaction features excellent functional group tolerance and represents an attractive alternative to the use of pyrophoric alkali metal hydrides. Notably, the electron transfer from Sm(II) to CN functional groups generates imidoyl-type radicals from bench stable nitrile precursors.
- Szostak, Michal,Sautier, Brice,Spain, Malcolm,Procter, David J.
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supporting information
p. 1092 - 1095
(2014/03/21)
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- Benzylation of arenes with benzyl ethers promoted by the in situ prepared superacid BF3-H2O
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An efficient and environmentally friendly benzylation of arenes with benzyl ethers as benzyl donors using BF3-Et2O to generate in situ the superacid BF3-H2O as an efficient promotor has been described. A wide variety of functional groups have been investigated and found to be compatible to give the desired diarylmethanes in yields of up to 99%. The crucial role of the moisture content in this transformation has been demonstrated by detailed investigations. This journal is the Partner Organisations 2014.
- Li, Yu,Xiong, Yan,Li, Xueming,Ling, Xuege,Huang, Ruofeng,Zhang, Xiaohui,Yang, Jianchun
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supporting information
p. 2976 - 2981
(2014/06/10)
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- Spiralisones A-D: Acylphloroglucinol hemiketals from an Australian marine brown alga, Zonaria spiralis
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An intertidal sample of the Australian marine brown alga, Zonaria spiralis, exhibited promising kinase inhibitory and antibacterial activity. Chemical analysis returned six phloroglucinol-derived lipids, the new hemiketal spiralisones A-D (1-4) and the known chromones 5-6, and the known norsesquiterpenoid apo-9′-fucoxanthinone (7). Structures 1-7 were assigned on the basis of detailed spectroscopic analysis, biosynthetic considerations and total synthesis. Spiralisones undergo facile acid-mediated dehydration to yield the corresponding chromones, revealing for the first time that brown algal chromones may be handling artifacts rather than natural products. Hemiketals 1 and 2, and chromone 6, displayed inhibitory activity against the neurodegenerative disease kinase targets CDK5/p25, CK1δ and GSK3β, while hemiketals 1, 3 and 4, and chromone 6, displayed growth inhibitory activity against the Gram-positive bacteria Bacillus subtilis (ATCC 6051 and 6633). The promising kinase inhibitory and antibacterial properties of the Z. spiralis extract were attributed to the cumulative effect of many moderately potent phloroglucinol-derived lipid co-metabolites. The Royal Society of Chemistry 2012.
- Zhang, Hua,Xiao, Xue,Conte, Melissa M.,Khalil, Zeinab,Capon, Robert J.
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p. 9671 - 9676
(2013/01/16)
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- Ruthenium (II) sulfoxides-catalyzed hydrogenolysis of glycols and epoxides
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New selective deoxygenation reactions are needed for the efficient conversion of biomass-derived oxygenates to useful chemicals, including fuels. A new catalytic system is reported here for the selective hydrogenolysis of glycols to hydrocarbons. We find that cis-[RuCl2(sulfoxide) 4] {sulfoxides: TMSO = tetramethylene sulfoxide; DMSO = dimethyl sulfoxide} catalyze the hydrogenolysis of glycols to alcohols and hydrocarbons by molecular hydrogen at 190-200 °C and 6.8-26 atm; the product yields range from moderate to excellent. The acid generated by catalysts in situ serves the purpose of dehydration step, hence added Bronstead acid as co-catalyst is not a prerequisite. Under similar conditions epoxides are converted primarily to mono-alcohols and hydrocarbons.
- Murru, Siva,Nicholas, Kenneth M.,Srivastava, Radhey S.
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p. 460 - 464
(2012/10/30)
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- O-alkyl-N-acyl-N-phenylhydroxylamines as photochemical alkoxy radical precursors
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A simple and efficient technique for the photolysis of alkoxy radical precursors is developed. Irradiation of O-alkyl-N-acyl-N-phenylhydroxylamines, as representative alkoxy radical precursors, with ultraviolet light (254 nm) results in homolytic N-O bond cleavage to generate singlet alkoxy and acylaminyl caged radical pairs. These radicals, depending on the solvent employed, either escape from the cage to form fragmentation products, or undergo in-cage reactions to produce photorearrangement products. The homolytic cleavage of the N-O bond is analyzed using time-dependent density functional theory calculations. The nature of the N-acyl substituent on the O-alkyl-N-acyl-N- phenylhydroxylamines is shown to influence their ability to generate radicals. Furthermore, identification and trapping of the alkoxy radicals is demonstrated. Georg Thieme Verlag Stuttgart · New York.
- Chowdhury, Nilanjana,Anoop, Anakuthil,Singh, N.D. Pradeep
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experimental part
p. 1745 - 1754
(2012/07/27)
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- Sinularioside, a triacetylated glycolipid from the Indonesian soft coral Sinularia sp., is an inhibitor of NO release
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Chemical analysis of the Indonesian soft coral Sinularia sp. (order Alcyonacea, family Alcyoniidae) afforded a known glucosylcerebroside of the sarcoehrenoside-type and sinularioside (2), a new naturally triacetylated glycolipid containing two α-d-arabinopyranosyl residues and a myristyl alcohol unit. Their complete stereostructures were solved by interpretation of MS and NMR data along with CD analysis of degradation products. Sinularioside proved to moderately inhibit LPS-induced NO release, providing interesting clues into the poorly understood structure-activity relationships for anti-inflammatory glycolipids.
- Putra, Masteria Yunovilsa,Ianaro, Angela,Panza, Elisabetta,Bavestrello, Giorgio,Cerrano, Carlo,Fattorusso, Ernesto,Taglialatela-Scafati, Orazio
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body text
p. 2723 - 2725
(2012/06/01)
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- COPOLYHYDROXYALKYLGLUTAMINES FUNCTIONALISED WITH HYDROPHOBIC GROUPS, AND USES THEREOF, ESPECIALLY IN THERAPEUTICS
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The invention relates to novel biodegradable materials which are based on modified polyamino acids and which can be used for the vectorisation of active principle(s) (AP). The invention also relates to novel pharmaceutical, cosmetic, dietary or phytosanitary compositions based on said polyamino acids. The aim of the invention is to provide a novel polymer raw material which can be used for the vectorisation of active principles and which can optimally fulfil all required specifications in said area, namely: biocompatibility, biodegradability and the ability to become easily associated with many active principles or to solubilise said principles and to release same in vivo. Said aim is achieved with novel copolyhydroxyalkylglutamines comprising glutamine units and optionally glutamate units and bearing hydrophobic groups containing between 8 and 30 carbon atoms. Said copolyhydroxyalkylglutamines are amphiphilic and can be easily and economically transformed into particles for the vectorisation of active principles, whereby said particles can form stable aqueous colloidal suspensions.
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- Highly selective and efficient hydrogenation of carboxylic acids to alcohols using titania supported Pt catalysts
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Selective hydrogenation of carboxylic acids to alcohols and alkanes has been achieved under remarkably mild reaction temperatures and H2 pressures (333 K, 0.5 MPa) using Pt/TiO2 catalyst.
- Manyar, Haresh G.,Paun, Cristina,Pilus, Rashidah,Rooney, David W.,Thompson, Jillian M.,Hardacre, Christopher
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supporting information; experimental part
p. 6279 - 6281
(2010/10/19)
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- Polyglutamic Acids Functionalised by Histidine Derivatives and Hydrophobic Groups and the Uses Thereof, in Particular for Therapeutic Purposes
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The invention relates to novel biodegradable materials based on modified polyamino acids and suitable, in particular, for vectoring active substance(s) (AS). Said invention also relates to novel pharmaceutical, cosmetic, dietary or plant protective compositions which are based on said polyamino acids. The aim of said invention is to provide a novel polymer raw material usable for vectoring the AS and capable to optimally meet all specification in this area: biocompatibility, biodegradability, ability to become easily associated with many active substances or to solubilise them and to release said active substances in vivo. The aim is attained to 30 carbon atoms. Said polyglutamates modified by histidine derivatives are soluble with pH lower than 5 and are easily and economically convertible into active substance vectorization particles which are able to form stable aqueous colloidal suspensions. On the contrary, said modified polyglutamates are insoluble in water with a physiological pH (7.4), and thereby have to be precipitated on an injection site in the case of a subcutaneous injection.
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- Polyamino acids functionalized by hydrophobic grafts bearing an anionic charge and applications thereof, such as therapeutic applications
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The present invention relates to novel materials based on biodegradable polyamino acids that are useful especially for the vectorization of active principle(s) (AP). The invention further relates to novel pharmaceutical, cosmetic, dietetic or phytosanitary compositions based on these polyamino acids. The object of the invention is to provide a novel polymer starting material that is capable of being used for the vectorization of AP and makes it possible on the one hand to achieve high polymer/AP ratios, and on the other hand optimally to satisfy all the specifications required in the case in point: biocompatibility, biodegradability, ability to associate easily with numerous active principles or to solubilize them, and ability to release these active principles in vivo. This object is achieved by the present invention, which relates first and foremost to linear polyamino acids comprising aspartic units or glutamic units and having hydrophobic grafts comprising hydrophobic groups containing from 8 to 30 carbon atoms, at least one of these hydrophobic grafts having at least one anionic charge and/or one or more mutually identical or different ionizable groups each capable of giving rise to at least one anionic charge. These polymers are amphiphilic and anionic and are capable of being converted easily and economically to particles for the vectorization of active principles, these particles themselves being capable of forming stable aqueous colloidal suspensions.
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- Self-precipitating pharmaceutical formulations for the moified release of an active principle
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The present invention relates to novel pharmaceutical formulations for the release of an active principle (AP) over a sustained period of time of several days, or even several weeks. The invention relates, in a first aspect, to a liquid formulation comprising at least one active principle (AP) and an aqueous suspension based on collo?dal particles of a polymer (PO), wherein said formulation satisfies the following four conditions: (a) the polymer (PO) is a polyamino acid comprising glutamic residues, wherein some glutamic residues each carry a pendant cationic group (CG), said cationic groups being identical or different from one another, andother glutamic residues each carry a pendent hydrophobic group (GH), said hydrophobic groups (GH) being identical or different from one another, (b) the pHf value of the pH of said formulation is between 3.0 and 6.5; (c) at the pHf value, the polymer (PO) forms a collo?dal solution which associates spontaneously and noncovalently with the active principle (AP); (d) 1 ml of said formulation precipitates during mixing with a volume of 1 ml of a test buffer solution Tp. The invention also relates to a process for the preparation of such formulations and to a process for the preparation of medicaments including such formulations.
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- PRODUCTION OF DETERGENT RANGE ALCOHOLS
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This invention relates to a process for the production of a mixture of detergent-range alcohols having an average of between 8 and 20 carbon atoms per molecule. The process includes the steps of providing a hydrocarbon stream containing olefins and paraffins in which more than 5% by volume of olefin molecules in the hydrocarbon stream have a total number of carbon atoms which is different from the total number of carbon atoms of the most abundant two carbon numbers of olefins in the hydrocarbon stream; reacting the hydrocarbon stream with CO and an alcohol in the presence of a catalyst in a hydroesterification reaction to form a hydrocarbon stream containing esters and paraffins; separating esters from the hydrocarbon stream containing esters and paraffins; and subjecting the esters to a hydrogenation reaction to provide the mixed alcohol product.
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Page/Page column 3
(2009/01/24)
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- Reduction of carboxylic acid derivatives using diphenylsilane in the presence of a Rh-PPh3 complex
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Reductions of carboxylic acid derivatives by silanes in the presence of rhodium complexes were studied. Carboxylic esters were reduced to alcohols by diphenylsilane catalyzed by [RhCl(cod)]2/4PPh3 or [RhCl(PPh3)3] at room temperature in up to 99% yields. For example, ethyl decanoate and ethyl phenylacetate were converted to decanol and 2-phenylethanol in 98 and 92% yields, respectively. Carboxylic acids were also reduced by this reducing system to the corresponding alcohols in high yields. Furthermore, N-monosubstituted amides were reduced to secondary amines in moderate to good yields. For sterically hindered amides, the yields were moderate, and imines were produced in competitive yields.
- Ohta, Tetsuo,Kamiya, Masahiro,Nobutomo, Mami,Kusui, Keisuke,Furukawa, Isao
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p. 1856 - 1861
(2007/10/03)
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- Serine carbonates
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Serine carbonates of formula I are precursors for organoleptic compounds, masking agents and antimicrobial agents. Further they are alternative substrates for malodor producing enzymes. The symbols in formula I are defined in claim 1.
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- Compounds having protected hydroxy groups
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The present invention relates to compounds with protected hydroxy groups of formula (I) These compounds are precursors for organoleptic agents, such as fragrances, and masking agents and for antimicrobial agents. When activated, the compounds of formula (I) are cleaved and form one or more organoleptic and/or antimicrobial compounds.
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- Compounds having protected hydroxy groups
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The present invention relates to compounds with protected hydroxy groups of formula (I) These compounds are precursors for organoleptic agents, such as fragrances, and masking agents and for antimicrobial agents. When activated, the compounds of formula (I) are cleaved and form one or more organoleptic and/or antimicrobial compounds.
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- A novel, efficient, and highly selective O-Bn bond cleavage reaction via a rare K-induced electron transfer process
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A new, efficient and highly selective deprotective method of both benzyl and benzylidene groups for protection of monohydroxyl and dihydroxyl, respectively, has been developed by using the system K-t-BuNH2-t-BuOH-18-crown-6. This method is valu
- Shi, Lei,Wu, Jiong Xia,Fu, Min Zhang,Yong, Qiang Tu
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p. 1505 - 1507
(2007/10/03)
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- Beta-ketoester compounds
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The beta-ketoesters of formula I are useful as precursors for organoleptic compounds, especially for flavors, fragrances and masking agents and antimicrobial compounds.
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- Ketone precursors for organoleptic compounds
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The invention discloses ketones of formula I: wherein, Y is an optionally substituted alkyl, cycloalkyl, or cycloalkylalkyl, wherein each alkyl group is straight or branched and each alkyl and cycloalkyl group is saturated or unsaturated; R1is hydrogen or a C1-6alkyl group that is substituted, saturated or unsaturated, straight or branched; A is a chromophoric substituted aromatic ring or ring system; n is an integer; and with the proviso that formula I is not 2-ethoxy-1-phenyl-ethanone. These compositions are useful for the delivery of organoleptic compounds, especially of flavors, fragrances, masking agents and antimicrobial compounds.
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- A novel hydrogen transfer hydroalumination of alkenes with triisobutylaluminum catalyzed by Pd and other late transition metal complexes
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Hydrogen transfer hydroalumination of terminal alkenes and dienes can be achieved with 1.1 equiv. of (i-Bu)3Al and catalytic amounts of Cl2Pd(PPh3)2 and other late transition metal complexes containing Co, Rh, Ni, and Pt at ambient temperature in high yields.
- Gagneur, Sebastien,Makabe, Hidefumi,Negishi, Ei-Ichi
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p. 785 - 787
(2007/10/03)
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- Zirconium borohydride - A versatile reducing agent for the reduction of electrophilic and nucleophilic substrates
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Zirconium borohydride, a potential reducing agent, reduces acids, esters, imines to the corresponding alcohols and secondary amines in good yield at room temperature within two hours. This facile reducing property was taken advantage off in the synthesis of pheromones and some novel chiral precursors for asymmetric synthesis.
- Narasimhan,Balakumar
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p. 4387 - 4395
(2007/10/03)
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- Studies on phytochemicals: Part XVII-Phenolics from the roots of Jatropha gossypifolia
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From the roots of Jatropha gossypifolia a hitherto unknown long chain ester, tetradecyl (E)-ferulate 1 has been isolated along with jatropholone-B 2, ferulic acid 3 and fraxetin 4. The last two compounds are reported for the first time this species.
- Das, Biswanath,Kashinatham, A.
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p. 1077 - 1078
(2007/10/03)
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- Method of encapsulation and microcapsules produced thereby
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Microcapsules are prepared by dispersing or dissolving an active component or components in a solid matrix-forming material that has been thermally softened to form an encapsulation composition. The encapsulation composition is injected as an intact stream into a quenching liquid to provide solid microcapsules.
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- β-carboxy sulfonamide ACAT inhibitors
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β-Carboxy sulfonyl compounds of the formula STR1 wherein R1 is aryl, R3 is hydrogen or alkyl, R3 and R4 are hydrogen or alkyl, Y is --O--, --S--, or --NR2 --, and R5 is alkyl or aryl are potent inhibitors of the enzyme acyl CoA:cholesterol acyltransferase (ACAT) and are thus useful for treating hypercholesterolemia and atherosclerosis.
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- Alkene-catalysed reductions of esters by calcium borohydride
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Addition of catalytic amount of an alkene dramatically enhances the rate of reduction of esters to alcohols by calcium borohydride.Cyclooctadiene (COD) is found to be very effective as a catalyst.Aliphatic esters are easily converted to the alcohols while ethyl benzoate shows stepwise reduction to benzaldehyde and benzylalcohol.
- Narasimhan, S.,Prasad, K. Ganeshwar,Prasanna, R.
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p. 489 - 490
(2007/10/02)
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- Telluroxide Elimination by Oxidation of Alkyl Aryl Tellurides: Remarkable Effect of Added Triethylamine
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Treatment of various alkyl phenyl tellurides with 1-2 mol equiv. of m-chloroperbenzoic acid in diethyl ether in the presence of triethylamine at 25 deg C for 2 h affords the corresponding alkenes highly selectively in fair to good yields.From stereochemical studies using erythro- and threo-phenyl 3-phenylbutan-2-yl tellurides as substrates it was revealed that although Et3N partly faciliates E2 elimination of the telluroxide, the main reaction course is the telluroxide syn-elimination (Ei elimination).Without the addition of Et3N the elimination was quite slow in many cases, and in fact the compounds derived from the addition of m-chlorobenzoic acid to tetradecyl and cyclohexyl phenyl telluroxides were isolated, the pyrolysis (ca. 250 deg C) of which afforded tetradec-1-ene and cyclohexene, respectively.A 2-pyridyltelluro moiety was revealed for the first time to be a better leaving group than a phenyltelluro moiety in telluroxide elimination.
- Nishibayashi, Yoshiaki,Komatsu, Naoki,Ohe, Kouichi,Uemura, Sakae
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p. 1133 - 1138
(2007/10/02)
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- Improved method for the selective conversion of aliphatic esters to alcohols by zinc borohydride in tetrahydrofuran
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Selective conversion of aliphatic esters to the corresponding alcohols has been achieved in excellent yields by zinc borohydride in tetrahydrofuran under mild conditions (67 deg C, 6 hr).Unsaturated esters produce the corresponding diols.
- Narasimhan, S,Palmer, Prem
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p. 701 - 702
(2007/10/02)
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