- Hydrogenation of 4-propylphenol over carbon-supported palladium catalyst without external hydrogen: Effect of carbon support and palladium loading
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The ring hydrogenation of 4-propylphenol in aqueous ethanol solution was studied over graphite- and activated carbon-supported palladium catalysts (Pd/G and Pd/C) with 0.15 wt % of palladium loadings without using external hydrogen. Decomposition of ethan
- Nagasawa, Yoshiyuki,Hiraishi, Yushi,Horyo, Daiki,Sobu, Tomoki,Taniguchi, Kenkichi,Nanao, Hidetaka,Sato, Osamu,Yamaguchi, Aritomo,Shirai, Masayuki
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p. 431 - 434
(2021/03/15)
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- 4-Propylphenol Hydrogenation over Pt-Pd Bimetallic Catalyst in Aqueous Ethanol Solution without External Hydrogen
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Ring-hydrogenation of 4-propylphenol (4-PP) to 4-propylcyclohexanone, cis- and trans-4-propylcyclohexanols proceeded over graphite-supported palladium catalysts (Pd/G) in aqueous ethanol solution at 573K without using external hydrogen gas. Compared to Pd
- Kusumawati, Etty Nurlia,Nagasawa, Yoshiyuki,Nanao, Hidetaka,Sasaki, Takehiko,Sato, Osamu,Shirai, Masayuki,Yamaguchi, Aritomo
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p. 1968 - 1971
(2022/01/12)
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- Fine-Bubble-Slug-Flow Hydrogenation of Multiple Bonds and Phenols
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We describe a promising method for the continuous hydrogenation of alkenes or alkynes by using a newly developed fine-bubble generator. The fine-bubble-containing slug-flow system was up to 1.4 times more efficient than a conventional slug-flow method. When applied in the hydrogenation of phenols to the corresponding cyclohexanones, the fine bubble-slug-flow method suppressed over-reduction. As this method does not require the use of excess gas, it is expected to be widely applicable in improving the efficiency of gas-mediated flow reactions.
- Iio, Takuya,Nagai, Kohei,Kozuka, Tomoki,Sammi, Akhtar Mst,Sato, Kohei,Narumi, Tetsuo,Mase, Nobuyuki
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supporting information
p. 1919 - 1924
(2020/11/09)
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- Liquid-phase Hydrodeoxygenation of 4-Propylphenol to Propylbenzene: Reducible Supports for Pt Catalysts
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Pyrolysis and liquefaction biocrudes obtained from lignocellulose are rich in phenolic compounds that can be converted to renewable aromatics. In this study, Pt catalysts on reducible metal oxide supports (Nb2O5, TiO2), along with irreducible ZrO2 as a reference, were investigated in the liquid-phase hydrodeoxygenation (HDO) of 4-propylphenol (350 °C, 20 bar H2, organic solvent). The most active catalyst was Pt/Nb2O5, which led to the molar propylbenzene selectivity of 77 percent, and a yield of 75 percent (98 percent conversion). Reducible metal oxide supports provided an increased activity and selectivity to the aromatic product compared to ZrO2, and the obtained results are among the best reported in liquid-phase. The reusability of the spent catalysts was also studied. The spent Pt/Nb2O5 catalyst provided the lowest conversion, while the product distribution of the spent Pt/ZrO2 catalyst changed towards oxygenates. The results highlight the potential of pyrolysis or liquefaction biocrudes as a source of aromatic chemicals.
- González Escobedo, José Luis,Karinen, Reetta,Lahtinen, Jouko,Lassi, Ulla,Lindblad, Marina,M?kel?, Eveliina,Neuvonen, Jouni,Puurunen, Riikka L.
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- Surface Modification of a Supported Pt Catalyst Using Ionic Liquids for Selective Hydrodeoxygenation of Phenols into Arenes under Mild Conditions
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The selective and efficient removal of oxygenated groups from lignin-derived phenols is a critical challenge to utilize lignin as a source for renewable aromatic chemicals. This report describes how surface modification of a zeolite-supported Pt catalyst using ionic liquids (ILs) remarkably increases selectivity for the hydrodeoxygenation (HDO) of phenols into arenes under mild reaction conditions using atmospheric pressure H2. Unmodified Pt/H-ZSM-5 converts phenols into aliphatic species as the major products along with a slight amount of arenes (10 % selectivity). In contrast, the catalyst modified with an IL, 1-butyl-3-methylimidazolium triflate, keeps up to 76 % selectivity for arenes even at a nearly complete conversion of phenols. The IL on the surface of Pt catalyst may offer the adsorption of phenols in an edge-to-face manner onto the surface, thus accelerating the HDO without the ring hydrogenation.
- Ohta, Hidetoshi,Tobayashi, Kanako,Kuroo, Akihiro,Nakatsuka, Mao,Kobayashi, Hirokazu,Fukuoka, Atsushi,Hamasaka, Go,Uozumi, Yasuhiro,Murayama, Haruno,Tokunaga, Makoto,Hayashi, Minoru
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supporting information
p. 14762 - 14766
(2019/11/13)
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- Electrocatalytic Upgrading of Lignin-Derived Bio-Oil Based on Surface-Engineered PtNiB Nanostructure
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The development of robust electrocatalysts for electrocatalytic hydrogenation (ECH) of guaiacol and related lignin model monomers is necessary for the stabilization or upgrading of bio-oil. Additionally, the efficiency of biomass conversion to bio-oil products remains below the minimum requirements for its implementation at scale. Herein, a PtNiB/CMK-3 catalyst with pronounced ECH performance in the conversion of guaiacol and related model lignin monomers to bio-oil under optimally mild conditions, through a modulation strategy that modified the electronic structure of PtNi via boron alloying, is prepared. Notably, the optimized PtNiB/CMK-3 exhibited an inspiring high faradaic efficiency of 86.2%, which is significantly higher (13.7 times) than that of the PtNi/CMK-3 without B-doping (6.3%). Experimental results and theoretical calculations showed that the B-doping optimized the PtNiB alloy surface electron structure, simultaneously promoting substrate and intermediate adsorption and the ECH process. In addition, the uniform dispersion of PtNiB nanoparticles embedded within the mesoporous channels of CMK-3 ensures an enhanced utilization efficiency, leading to improvements in stability and bio-oil product generation. The lab-scale ECH experiment of guaiacol also certified the scale-up potential. This work opens a promising avenue to the rational design of advanced and highly efficient electrocatalysts for biomass upgrading.
- Zhou, Yulin,Gao, Yijing,Zhong, Xing,Jiang, Wenbin,Liang, Yulin,Niu, Pengfei,Li, Meichao,Zhuang, Guilin,Li, Xiaonian,Wang, Jianguo
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- Aliphatic C-H Bond Oxidation with Hydrogen Peroxide Catalyzed by Manganese Complexes: Directing Selectivity through Torsional Effects
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Substituted N-cyclohexyl amides undergo aliphatic C-H bond oxidation with H2O2 catalyzed by manganese complexes. The reactions are directed by torsional effects leading to site-selective oxidation of cis-1,4-, trans-1,3-, and cis-1,2-cyclohexanediamides. The corresponding diastereoisomers are unreactive under the same conditions. Competitive oxidation of cis-trans mixtures of 4-substituted N-cyclohexylamides leads to quantitative conversion of the cis-isomers, allowing isolation and successive conversion of the trans-isomers into densely functionalized oxidation products with excellent site selectivity and good enantioselectivity.
- Milan, Michela,Bietti, Massimo,Costas, Miquel
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supporting information
p. 2720 - 2723
(2018/05/22)
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- Construction of Distant Stereocenters by Enantioselective Desymmetrizing Carbonyl-Ene Reaction
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An efficient desymmetrizing carbonyl-ene reaction of 1-substituted 4-methylenecyclohexanes with glyoxal derivatives was thus executed by a chiral N,N′-dioxide/NiII catalyst, providing facile access to cyclohexene derivatives bearing two remote 1,6-related stereocenters. This distal stereocontrol methodology originates from the efficient interaction between the catalyst with enophiles, discrimination of the two chair conformations of olefinic components, and the intrinsic six-membered transition-state structure of ene process.
- Luo, Weiwei,Lin, Lili,Zhang, Yu,Liu, Xiaohua,Feng, Xiaoming
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p. 3374 - 3377
(2017/07/15)
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- Examples of xylochemistry: Colorants and polymers
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Against the backdrop of modern sustainable chemistry and valorization of biomass for chemical raw materials, the syntheses of indigo dyes and polyamides as representatives of two classes of everyday chemical products based on xylochemicals are described. Wood-derived starting materials were transformed into functional materials using the principles of green chemistry to expand the scope of products gained from renewable resources. The indigo dyes were synthesized in a short, straightforward sequence starting from vanillin. Two polyamides, representatives of an important class of polymers, were obtained from 4-propylcyclohexanol, which is one of the longest known (and most abundant) hydrogenative depolymerization products of lignin.
- Kühlborn, Jonas,Danner, Ann-Kathrin,Frey, Holger,Iyer, Rishab,Arduengo, Anthony J.,Opatz, Till
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supporting information
p. 3780 - 3786
(2017/08/23)
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- Transfer hydrogenation of 4-propylphenol using ethanol and water over charcoal-supported palladium catalyst
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The aromatic hydrogenation of 4-propylphenol to 4-propylcyclohexanone, cis- and trans-4-propylcyclohexanols proceeded over a charcoal-supported palladium catalyst (Pd/C) in water-ethanol cosolvent at 573 K without using any external hydrogen gas. The ring hydrogenation activities in water-ethanol cosolvent over Pd/C were higher than those with a conventional method using externally supplied hydrogen gas. Both water and ethanol were indispensable for the ring hydrogenation in the water-ethanol cosolvent at 573 K.
- Nagasawa, Yoshiyuki,Nanao, Hidetaka,Sato, Osamu,Yamaguchi, Aritomo,Shirai, Masayuki
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p. 643 - 645
(2016/07/06)
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- NUCLEUS HYDROGENATION METHOD FOR AROMATIC COMPOUND USING ALCOHOL AND WATER
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PROBLEM TO BE SOLVED: To provide a method for the nucleus hydrogenation of an aromatic compound without using hydrogen for the improvement of safety and the diversification of a hydrogen source. SOLUTION: Provided is a method for the nucleus hydrogenation
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Paragraph 0018-0024
(2018/08/23)
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- Low temperature hydrodeoxygenation of phenols under ambient hydrogen pressure to form cyclohexanes catalysed by Pt nanoparticles supported on H-ZSM-5
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The hydrodeoxygenation of various phenols to form cyclohexanes was achieved at 110 °C under an H2 atmosphere at ambient pressure using a Pt/H-ZSM-5 catalyst and octane as the solvent.
- Ohta, Hidetoshi,Yamamoto, Kentaro,Hayashi, Minoru,Hamasaka, Go,Uozumi, Yasuhiro,Watanabe, Yutaka
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p. 17000 - 17003
(2015/11/27)
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- Selective nickel-catalyzed conversion of model and lignin-derived phenolic compounds to cyclohexanone-based polymer building blocks
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Valorization of lignin is essential for the economics of future lignocellulosic biorefineries. Lignin is converted into novel polymer building blocks through four steps: catalytic hydroprocessing of softwood to form 4-alkylguaiacols, their conversion into 4-alkylcyclohexanols, followed by dehydrogenation to form cyclohexanones, and Baeyer-Villiger oxidation to give caprolactones. The formation of alkylated cyclohexanols is one of the most difficult steps in the series. A liquid-phase process in the presence of nickel on CeO2 or ZrO2 catalysts is demonstrated herein to give the highest cyclohexanol yields. The catalytic reaction with 4-alkylguaiacols follows two parallel pathways with comparable rates: 1) ring hydrogenation with the formation of the corresponding alkylated 2-methoxycyclohexanol, and 2) demethoxylation to form 4-alkylphenol. Although subsequent phenol to cyclohexanol conversion is fast, the rate is limited for the removal of the methoxy group from 2-methoxycyclohexanol. Overall, this last reaction is the rate-limiting step and requires a sufficient temperature (>250°C) to overcome the energy barrier. Substrate reactivity (with respect to the type of alkyl chain) and details of the catalyst properties (nickel loading and nickel particle size) on the reaction rates are reported in detail for the Ni/CeO2 catalyst. The best Ni/CeO2 catalyst reaches 4-alkylcyclohexanol yields over 80 %, is even able to convert real softwood-derived guaiacol mixtures and can be reused in subsequent experiments. A proof of principle of the projected cascade conversion of lignocellulose feedstock entirely into caprolactone is demonstrated by using Cu/ZrO2 for the dehydrogenation step to produce the resultant cyclohexanones (≈80 %) and tin-containing beta zeolite to form 4-alkyl-ε-caprolactones in high yields, according to a Baeyer-Villiger-type oxidation with H2O2.
- Schutyser, Wouter,Van Den Bosch, Sander,Dijkmans, Jan,Turner, Stuart,Meledina, Maria,Van Tendeloo, Gustaaf,Debecker, Damien P.,Sels, Bert F.
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p. 1805 - 1818
(2015/06/02)
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- Nanocomposite shuttle-supported palladium nanoparticles as a PH-triggered phase transfer catalyst for the aerobic oxidation of alcohols
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Abstract We synthesize a novel mesoporous nanocomposite shuttle. It can reversibly transfer between the organic and water phase in response to pH. It was used as the precursor to load palladium nanoparticles for the aerobic oxidation of alcohols. The whole oxidation process with the catalyst is highly efficient and chemo-selective. The nanocomposite shuttle can take Pd nanoparticles to an organic phase for catalyzing, and then come back to the aqueous phase, thus benefiting the separation and recycling of the catalysts. The catalyst is stable and can be reused for at least five runs. The catalyst we discovered not only makes the whole reaction homogeneous, but can also can be separated by decanting.
- Zhu, Yaoqin,Xu, Jia,Lu, Ming
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p. 1213 - 1219
(2015/06/02)
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- Copper nanoparticles on dichromium trioxide: A highly efficient catalyst from copper chromium hydrotalcite for oxidant-free dehydrogenation of alcohols
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Stable copper(0) nanoparticles supported on chromium (Cu(0)/Cr2O3) are prepared from the composite precursor copper chromium hydrotalcite. The resulting Cu(0)/Cr2O3 catalyst is first used in the selective dehydrogenation of alcohols to aldehydes. More impressively, these dehydrogenations are performed without oxidants and yields of products are high. The stability of Cu(0)/Cr2O3 is also assessed by studying its recoverability and reusability for up to five cycles.
- Zhu, Yaoqin,Shen, Mengnan,Xia, Yonggen,Lu, Ming
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p. 152 - 156
(2015/03/30)
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- Aqueous-phase hydrodeoxygenation of 4-propylphenol as a lignin model to n-propylbenzene over Re-Ni/ZrO2 catalysts
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Aqueous-phase hydrodeoxygenation of 4-propylphenol as a lignin model to n-propylbenzene was carried out over various Ni based catalysts. Among the catalysts tested, Re-Ni/ZrO2 showed the best catalytic performance. Addition of Re decreased the Ni particle size and greatly improved the catalytic activity. H2 pressure, Re to Ni ratio and reaction temperature were tuned in the optimization of reaction conditions for favorable formation of n-propylbenzene. Under the conditions of 300 °C and 4 MPa H2, the yield of n-propylbenzene reached 54% over Re-Ni/ZrO2 (Re/Ni ratio 0.33) catalyst. It is suggested that the formation of n-propylbenzene proceeds via the hydrogenation of 4-propylphenol to form 4-propylcyclohexanol, followed by the dehydration to give 4-propylcyclohexene and the subsequent dehydrogenation to n-propylbenzene.
- Feng, Bo,Kobayashi, Hirokazu,Ohta, Hidetoshi,Fukuoka, Atsushi
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- Selective hydrodeoxygenation of lignin-related 4-propylphenol into n-propylbenzene in water by Pt-Re/ZrO2 catalysts
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Bimetallic Pt-Re/ZrO2 catalysts were developed for the selective hydrodeoxygenation of 4-propylphenol as a lignin model to n-propylbenzene in water. The addition of Re to Pt/ZrO2 improved the catalyst stability and product selectivity. Reaction temperature greatly affected not only reaction efficiency but also product distribution. n-Propylbenzene was obtained in up to 73% yield with ca. 80% selectivity. After the reaction, the catalyst was deactivated possibly due to water-induced wrapping of Pt nanoparticles in ZrO2. The reaction may involve the hydrogenation of 4-propylphenol to 4-propylcyclohexanol, followed by the dehydration to give 4-propylcyclohexene and the subsequent dehydrogenation to n-propylbenzene.
- Ohta, Hidetoshi,Feng, Bo,Kobayashi, Hirokazu,Hara, Kenji,Fukuoka, Atsushi
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p. 139 - 144
(2014/07/07)
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- Oxidation of primary and secondary alcohols to the corresponding carbonyl compounds with molecular oxygen using 1,1-diphenyl-2-picrylhydrazyl and WO 3/Al2O3 as catalysts
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The oxidation of primary and secondary alcohols to their corresponding carbonyl compounds proceeds with high efficiency under molecular oxygen in the presence of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and tungsten oxide/alumina (WO3/Al2O3). The method is environmentally benign, because the reaction requires only molecular oxygen as the terminal oxidant and gives water as a side product. Various aromatic, alicyclic, and aliphatic alcohols can be converted to their corresponding carbonyl compounds in excellent yields. It is noteworthy that the oxidative transformation of the alcohols proceeds chemoselectively in the presence of other functional groups. In addition, a plausible catalytic pathway is proposed.
- Zhu, Yaoqin,Xu, Jian,Lu, Ming
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- Hydrodeoxygenation of bio-derived phenols to hydrocarbons using RANEY Ni and Nafion/SiO2 catalysts
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A simple, green, cost- and energy-efficient route for converting phenolic components in bio-oil to hydrocarbons and methanol has been developed, with nearly 100% yields. In the heterogeneous catalysts, RANEY Ni acts as the hydrogenation catalyst and Nafion/SiO2 acts as the Bronsted solid acid for hydrolysis and dehydration.
- Zhao, Chen,Kou, Yuan,Lemonidou, Angeliki A.,Li, Xuebing,Lercher, Johannes A.
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experimental part
p. 412 - 414
(2010/04/04)
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- Ionic-liquid-like copolymer stabilized nanocatalysts in ionic liquids: II. Rhodium-catalyzed hydrogenation of arenes
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Rhodium nanoparticles stabilized by the ionic-liquid-like copolymer poly[(N-vinyl-2-pyrrolidone)-co-(1-vinyl-3-butylimidazolium chloride)] were used to catalyze the hydrogenation of benzene and other arenes in ILs. The nanoparticle catalysts can endure forcing conditions (75 °C, 40 bar H2), resulting in high reaction rates and high conversions compared with other nanoparticles that operate in ILs. The hydrogenation of benzene attained record total turnovers of 20,000, and the products were easily separated without being contaminated by the catalysts. Other substrates, including alkyl-substituted arenes, phenol, 4-n-propylphenol, 4-methoxylphenol, and phenyl-methanol, were studied and in most cases were found to afford partially hydrogenated products in addition to cyclohexanes. In-depth investigations on reaction optimization, including characterization of copolymers, transmission electron microscopy, and an infrared spectroscopic study of nanocatalysts, were also undertaken.
- Zhao, Chen,Wang, Han-zhi,Yan, Ning,Xiao, Chao-xian,Mu, Xin-dong,Dyson, Paul J.,Kou, Yuan
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- Stereoselective hydrogenation of lignin degradation model compounds
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Di-μ-chloro-bis(η4-1,5-hexadiene)dirhodium(I) in a two-phase hexane-aqueous medium catalyzes the diastereoselective H2-hydrogenation of lignin degradation model compounds 4-propylphenol, 2-methoxy-4-propylphenol, and 2,6-dimethoxy-4-propylphenol. The all-cis diastereomer is obtained selectively when the phenolic hydroxy group is protected as a methyl ether or when a model compound possessing two methoxy substituents adjacent to the phenolic hydroxy group is used. The relative stereochemistries of the hydrogenated products are established by X-ray crystal structure analysis and (or) 1H NMR.
- Hu,James,Rettig,Lee
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p. 1234 - 1239
(2007/10/03)
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- 2-Heterocyclicalkyl-3,3a,4,5,6,7-hexahydro-3-phenyl-7-(phenylmethylene)-2H-indazoles
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Compounds of the formula STR1 wherein R, X1, X2, A and B are as defined herein, and their N-oxides and acid addition salts thereof, are provided which have been found to possess anti-inflammatory activity. In addition, methods for preparing such compounds, pharmaceutical compositions containing such compounds, and methods for using such compositions as anti-inflammatory agents are also provided.
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- 2-Aminoalkyl-3,3a,4,5,6,7-hexahydro-3-phenyl-7(phenylmethylene)-2H-indazoles
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Compounds of the following formula and their acid addition and quaternary salts and N-oxides SPC1 Wherein X is hydrogen, chloro, fluoro, trifluoromethyl, lower alkyl, or lower alkoxy, R is hydrogen or lower alkyl, A is alkylene of 1 to 8 carbons, and B is --NH2, EQU1 wherein R1 is lower alkyl and R2 is phenyl or phenyl-lower alkyl are disclosed. These compounds are useful as central nervous system depressants.
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