- Ruthenium phosphine-pyridone catalyzed cross-coupling of alcohols to form α-alkylated ketones
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An efficient and green route to access diverse functionalized ketones via dehydrogenative-dehydrative cross-coupling of primary and secondary alcohols is demonstrated. Selective and tunable formation of ketones or alcohols is catalyzed by a recently developed proton responsive ruthenium phosphine-pyridone complex. Light alcohols such as ethanol could be used as alkylating agents in this methodology. Moreover, selective tandem double alkylation of isopropanol is achieved by sequential addition of different alcohols.
- Sahoo, Apurba R.,Lalitha, Gummidi,Murugesh,Bruneau, Christian,Sharma, Gangavaram V.M.,Suresh, Surisetti,Achard, Mathieu
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p. 10727 - 10731
(2018/05/31)
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- Characterization of hydroxy fatty acid dehydrogenase involved in polyunsaturated fatty acid saturation metabolism in Lactobacillus plantarum AKU 1009a
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Hydroxy fatty acid dehydrogenase, which is involved in polyunsaturated fatty acid saturation metabolism in Lactobacillus plantarum AKU 1009a, was cloned, expressed, purified, and characterized. The enzyme preferentially catalyzed NADH-dependent hydrogenation of oxo fatty acids over NAD+-dependent dehydrogenation of hydroxy fatty acids. In the dehydrogenation reaction, fatty acids with an internal hydroxy group such as 10-hydroxy-cis-12-octadecenoic acid, 12-hydroxy-cis-9-octadecenoic acid, and 13-hydroxy-cis-9-octadecenoic acid served as better substrates than those with α- or β-hydroxy groups such as 3-hydroxyoctadecanoic acid or 2-hydroxyeicosanoic acid. The apparent Km value for 10-hydroxy-cis-12-octadecenoic acid (HYA) was estimated to be 38 μM with a kcat of 7.6 × 10-3 s-1. The apparent Km value for 10-oxo-cis-12-octadecenoic acid (KetoA) was estimated to be 1.8 μM with a kcat of 5.7 × 10-1 s-1. In the hydrogenation reaction of KetoA, both (R)- and (S)-HYA were generated, indicating that the enzyme has low stereoselectivity. This is the first report of a dehydrogenase with a preference for fatty acids with an internal hydroxy group.
- Takeuchi, Michiki,Kishino, Shigenobu,Park, Si-Bum,Kitamura, Nahoko,Ogawa, Jun
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- A new vanadium(IV)-bridged polyoxotungstate containing mixed valence-antimony(III,V)
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A new mixed-valence SbV/III containing vanadium-substituted polyoxotungstate Na10[{SbV(OH)3} 2{VIV-O(H2O)}2{Sb IIIW9O33}2]·32H2O (1-Na) has been synthesized by routine synthetic reaction and characterized by IR, XPS, elemental analysis. The polyoxoanion [{SbV(OH)3}2{V IVO(H2O)}2{SbIIIW9O33}2]10 (1) consists of two trilacunary species β-B-SbIIIW9O 33 connected by two VIVO(H2O) groups and two SbV(OH)3 units. The cyclic voltammetry and catalytic activity of 1-Na for the oxidation of n-hexadecane under green condition have been measured.
- Wang, Bin,Xu, Ling-Xiao,Meng, Rui-Qi,Suo, Lin,Li, Bao,Wu, Li-Xin,Bi, Li-Hua
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p. 274 - 278
(2013/10/22)
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- Organoruthenium-supported polyoxotungstate - Synthesis, structure and oxidation of n-hexadecane with air
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A ruthenium complex, KNa[Ru2(C6H6) 2(CH3COO)6] (Ru-KNa), and its polyoxotungstate derivative, Na6[{Ru(C6H6)}2W 8O28(OH)2]·16H2O (Ru-Na), have been successfully isolated from routine synthetic reactions and characterized by X-ray single-crystal structure analysis, IR spectroscopy and elemental analysis. A remarkable aspect of Ru-KNa is that it has two ligand types, benzene and acetate, and the acetate ligands are connected exclusively by a central Na cation to form a dimeric sandwich-type structure, which is further connected by K cations to construct the 3D structures. Based on complex Ru-KNa, the compound Ru-Na was synthesized, and it consists of two {Ru(C 6H6)} units linked to a [W8O 28(OH)2]10- fragment by three Ru-O(W) bonds to result in an assembly with idealized C2 symmetry in which the polyanions form 3D structures by the connection of Na chains. Subsequently, the compound Ru-Na was anchored on (3-aminopropyl)triethoxysilane (apts) modified SBA-15 to prepare the solid catalysts, which were characterized by powder XRD, N2 adsorption measurements and FTIR spectroscopy. Finally, the catalytic efficiency of Ru-Na was assessed in the oxidation of n-hexadecane with air without any additives and solvents. The results indicated that Ru-Na is a heterogeneous catalyst and exhibits higher catalytic activity than previously reported Ru-containing polyoxotungstates. Copyright
- Meng, Rui-Qi,Wang, Bin,Sui, Hui-Min,Li, Bao,Song, Wei,Wu, Li-Xin,Zhao, Bing,Bi, Li-Hua
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p. 1935 - 1942
(2013/05/23)
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- Transition Metal Cluster Catalyst
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The present invention provides a catalyst, which has enough catalytic activity as a transition metal particle catalyst including platinum family and the like, is easily separable from products, is reusable and is easily prepared. To prepare the transition metal cluster catalyst of the present invention, an insoluble complex is prepared by forming a complex between a polymer with nitrogen-containing group, such as pyridinium and ammonium group in the principal chain, and a later transition metal compound; and then reducing the complex with a reductant. The transition metal forms clusters, which are stabilized by the polymers. Namely, the present invention is a transition metal cluster catalyst, wherein transition metal clusters are supported by a polymer, which is obtained by reduction reaction of a complex of a transition metal and a polymer with nitrogen-containing group. The transition metal cluster catalyst of the present invention is an extremely useful catalyst for oxidation, reduction, cross-coupling, Heck reaction, alkylation reaction and the like.
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Page/Page column 4
(2009/12/23)
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- Development of a convoluted polymeric nanopalladium catalyst: α-alkylation of ketones and ring-opening alkylation of cyclic 1,3-diketones with primary alcohols
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A novel solid-phase catalyst of palladium nanoparticles, nano-Pd-V, was prepared from PdCl2 with main-chain viologen polymers via complexation and reduction. This insoluble nanocatalyst nano-Pd-V efficiently promoted α-alkylation of ketones with primary alcohols in the presence of Ba(OH)2·H2O under atmospheric conditions without organic solvents. The nano-Pd-V catalyst was reused without loss of catalytic activity. Ring-opening alkylation of cyclic 1,3-diketones with primary alcohols was also catalyzed by the nano-Pd-V catalyst.
- Yamada, Yoichi M.A.,Uozumi, Yasuhiro
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p. 8492 - 8498
(2008/02/09)
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- A solid-phase self-organized catalyst of nanopalladium with main-chain viologen polymers: α-alkylation of ketones with primary alcohols
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A novel solid-phase self-organized catalyst of palladium nanoparticles was prepared from PdCl2 with main-chain viologen polymers via complexation and reduction. This insoluble nanocatalyst nano-Pd-V efficiently promoted α-alkylation of ketones with primary alcohols in the presence of Ba(OH)2·H2O under atmospheric conditions without organic solvents. The nano-Pd-V catalyst was reused without loss of catalytic activity.
- Yamada, Yoichi M. A.,Uozumi, Yasuhiro
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p. 1375 - 1378
(2007/10/03)
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- Reaction of α-Silyl Esters with Grignard Reagents: A Synthesis of β-Keto Silanes and Ketones. Preparation of the Douglas Fir Tussock Moth Pheromone
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A variety of α-diphenylmethylsilyl esters have been prepared and reacted with Grignard reagents.The reaction is relatively slow in refluxing THF and can be controlled to allow the addition of 1 equiv of the Grignard reagent, providing the corresponding β-keto silane.Protiodesilylation of the β-keto silane results in the overall conversion of an ester to a ketone.This ester to ketone methodology has been applied to a two-step synthesis of the pheromone of the Douglas fir tussock moth.The β-keto silanes are viable precursors to regioselectively generated enol silyl ethers.The reaction of ethyl 2-methyl-2-(diphenylmethylsilyl)propionate with vinylmagnesium bromide or 2-methyl 1-propenylmagnesium bromide results in the addition of 2 equiv of the Grignard reagent, the second in a Michael fashion.
- Larson, Gerald L.,Hernandez, David,Lopez-Cepero, Ingrid Montes de,Torres, Luz E.
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p. 5260 - 5267
(2007/10/02)
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- Cycloalkanones. 8. Hypocholesterolemic activity of long chain ketones related to pentadecanone
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Aliphatic analogs of 2,8 dibenzylcyclooctanone which included C15-C18 ketones have been investigated for hypocholesterolemic activity in rats. The position of the carbonyl group in the chain for maximum activity appears to be the 2 position. 2 Hexadecanone reduced serum cholesterol levels significantly without altering serum triglyceride levels. This drug was not estrogenic at effective doses which is in contrast to the cyclooctanones which possess this activity.
- Wyrick,Hall,Piantadosi,Fenske
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p. 219 - 222
(2007/10/12)
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