- A safe and efficient flow oxidation of aldehydes with O2
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A safe, straightforward, and atom economic approach for the oxidation of aliphatic aldehydes to the corresponding carboxylic acids within a continuous flow reactor is reported. Typically, the reaction is performed at room temperature using 5 bar of oxygen in PFA tubing and does require neither additional catalysts nor radical initiators except for those already contained in the starting materials. In some cases, a catalytic amount of a Mn(II) catalyst is added. Such a flow process may prove to be a valuable alternative to traditionally catalyzed aerobic processes.
- Vanoye, Laurent,Aloui, Asma,Pablos, Mertxe,Philippe, Regis,Percheron, Aurelien,Favre-Reguillon, Alain,De Bellefon, Claude
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- Transformations of peroxide products of olefin ozonolysis in tetrahydrofuran in reactions with hydroxylamine and semicarbazide hydrochlorides
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Treatment with hydroxylamine and semicarbazide hydrochlorides of peroxide products obtained by ozonolysis of olefins in tetrahydrofuran gives mainly carboxylic acids and their derivatives.
- Ishmuratov,Legostaeva,Garifullina,Botsman,Muslukhov,Ishmuratova,Tolstikov
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- A green and efficient oxidation of alcohols by amphiphilic resin-supported gold nanoparticles in aqueous H2O2
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A green and highly efficient oxidation of alcohols in aqueous H 2O2 using amphiphilic resin (PS-PEG-NH2)-supported gold nanoparticles is described. The reaction proceeded with excellent yields and selectivities, in particular, for nonactivated alcohols without base. The catalyst, in addition, could be readily recovered by simple work-up and reused several times without significant loss of its catalytic activity.
- Xie, Ting,Lu, Min,Zhang, Wenwen,Li, Jun
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- Pentasaccharide resin glycosides with multidrug resistance reversal activities from the seeds of: Pharbitis nil
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Resin glycosides are novel P-glycoprotein inhibitors. In order to evaluate their multidrug resistance (MDR) reversal activities, we isolated seven new resin glycosides, pharbitins A-G (1-7) from the seeds of Pharbitis nil. Their chemical structures were determined by extensive application of high resolution 2D NMR techniques, HRESIMS and chemical methods. Compounds 1-4 and 6 were evaluated for their MDR reversal activities in KB/VCR, A549/T and K562/ADR cells. Among them, compound 2 showed moderate MDR reversal activity in KB/VCR cells, and increased the cytotoxicity of vincristine by 2.2-fold when incorporated at 25 μM. A structure-activity relationship study revealed that substituting Rha′′ C-3 with a trans-cinnamoyl group improves the MDR reversal activity. Also, an intracellular Rh123 accumulation assay demonstrated that compound 2 could inhibit the function of P-gp.
- Li, Jun,Wang, Wen-Qiong,Tang, Shuai,Song, Wei-Bin,Huang, Min,Xuan, Li-Jiang
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- Synthesis of α,β-unsaturated aldehydes as potential substrates for bacterial luciferases
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Bacterial luciferase catalyzes the monooxygenation of long-chain aldehydes such as tetradecanal to the corresponding acid accompanied by light emission with a maximum at 490?nm. In this study even numbered aldehydes with eight, ten, twelve and fourteen carbon atoms were compared with analogs having a double bond at the α,β-position. These α,β-unsaturated aldehydes were synthesized in three steps and were examined as potential substrates in vitro. The luciferase of Photobacterium leiognathi was found to convert these analogs and showed a reduced but significant bioluminescence activity compared to tetradecanal. This study showed the trend that aldehydes, both saturated and unsaturated, with longer chain lengths had higher activity in terms of bioluminescence than shorter chain lengths. The maximal light intensity of (E)-tetradec-2-enal was approximately half with luciferase of P. leiognathi, compared to tetradecanal. Luciferases of Vibrio harveyi and Aliivibrio fisheri accepted these newly synthesized substrates but light emission dropped drastically compared to saturated aldehydes. The onset and the decay rate of bioluminescence were much slower, when using unsaturated substrates, indicating a kinetic effect. As a result the duration of the light emission is doubled. These results suggest that the substrate scope of bacterial luciferases is broader than previously reported.
- Brodl, Eveline,Ivkovic, Jakov,Tabib, Chaitanya R.,Breinbauer, Rolf,Macheroux, Peter
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- Pentasaccharide resin glycosides from ipoma pes-caprae
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Pescapreins XXI-XXX (1-10), pentasaccharide resin glycosides, together with the known pescapreins I-IV and stoloniferin III were isolated from the aerial parts of Ipoma pes-caprae (beach morning-glory). The pescapreins are macrolactones of simonic acid B, partially esterified with different fatty acids. The lactonization site of the aglycone, jalapinolic acid, was located at C-2 or C-3 of the second saccharide moiety. Their structures were established by a combination of spectroscopic and chemical methods. Compounds 1-10 were evaluated for their potential to modulate multidrug resistance in the human breast cancer cell line MCF-7/ADR. The combined use of these new compounds at a concentration of 5 μg/mL increased the cytotoxicity of doxorubicin by 1.5-3.7-fold.
- Yu, Bang-Wei,Luo, Jian-Guang,Wang, Jun-Song,Zhang, Dong-Ming,Yu, Shi-Shan,Kong, Ling-Yi
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- Hydration of nitriles to amides in water by SiO2-supported Ag catalysts promoted by adsorbed oxygen atoms
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A series of silica-supported silver catalysts with similar Ag loading (5 or 7 wt%) but with different preparation methods (calcination in air and reduction by H2 or NaBH4) were prepared, and their structure was characterized by microscopy (STEM), X-ray absorption fine structure (XAFS), and CO-titration of surface oxygen atom. Ag is present as metal nanoparticle with a size range of 17-30 nm. Their surface was partially covered with oxygen atoms, and the surface coverage of the oxygen depends on the preparation condition. For hydration of 2-cyanopyridine as a test reaction, turnover frequency (TOF) per surface Ag species is estimated. TOF does not show a good correlation with Ag particle size, but it linearly increases with the coverage of the surface oxygen atoms on Ag particles. The Ag/SiO2 catalyst prepared by H 2 reduction at 700 °C shows the highest TOF and it acts as effective and recyclable heterogeneous catalyst for selective hydration of various nitriles to the corresponding amides. Kinetic and Raman spectroscopic studies suggest that the surface oxygen atom adjacent to Ag0 sites plays an important role in the dissociation of H2O.
- Shimizu, Ken-Ichi,Imaiida, Naomichi,Sawabe, Kyoichi,Satsuma, Atsushi
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- A dicationic ionic liquid-modified phosphotungstate hybrid catalyst for the heterogeneous oxidation of alcohols with H2O2
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An ionic hybrid catalyst 1,1'-(butane-1,4-diyl)-bis(3-methylimidazolium) phosphotungstate (abbreviated [Dmim]1.5PW) has been prepared by anion-exchange of the divalent ionic liquid (IL) 1,1'-(butane-1,4-diyl)-bis(3- methylimidazolium) di(bromide) with the Keggin phosphotungstic acid H 3PW12O40, and characterized by IR, 1H NMR, 13C NMR, ESI-MS, TG, SEM, XRD, BET surface area measurements, elemental analysis, and melting point. The hybrid material was evaluated as a catalyst for the oxidation of alcohols with aqueous hydrogen peroxide under various conditions. The catalytic performance of [Dmim] 1.5PW was also compared with related catalysts bearing other cations or anions. The new hybrid [Dmim]1.5PW proved to be an efficient liquid-solid heterogeneous catalyst for H2O2-based oxidation of alcohols, with the advantages of high conversion and selectivity, easy recovery, and quite good reusability. Science China Press and Springer-Verlag Berlin Heidelberg 2012.
- Leng, Yan,Zhao, Pingping,Zhang, Mingjue,Chen, Guojian,Wang, Jun
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- Identification of novel fatty acid glucosides from the tropical fruit Morinda citrifolia L.
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Two new fatty acid glucosides, 1,6-di-O-octanoyl-β-D-glucopyranose (1) and 6-O-(β-D-glucopyranosyl)-1-O-decanoyl-β-D-glucopyranose (2), were isolated from a methanol extract of the fruit of Morinda citrifolia L. along with five known saccharide fatty acid esters. The structures of these compounds were determined by combination of spectral and chemical analyses. These fatty acid glucosides exhibited inhibitory effect against copper-induced low-density lipoprotein oxidation. Compound 2 had the strongest effect, which was almost comparable to that of butylated hydroxytoluene.
- Kim, Hye-Kyeong,Kwon, Min-Kyong,Kim, Jin-Nam,Kim, Chang-Kwon,Lee, Yeon-Ju,Shin, Hee Jae,Lee, Joongku,Lee, Hyi-Seung
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- Effects of Sulfobetaine-Sodium Dodecanoate Micelles on Deacylation and Indicator Equilibrium
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Fractional micellar ionization, α, and micelle concentrations have been measured for mixed micelles of sodium dodecanoate (SDOD) and sulfobetaines (CnH2n+1N+Me2(CH2)3SO3-, SB3-n, n = 10, 12, 14, 16), and values of pHapp have been calculated from deprotonation of 1-dodecylpyridinium-4-aldoxime bromide.For 0.1 M total surfactant first-order rate constants of hydrolyses of 2,4-dinitrophenyl acetate and octanoate (DNPA and DNPO, respectively) and benzoic anhydride (Bz2O) go through maxima at a mole fraction of SDOD of ca. 0.5 for DNPA and DNPO and 0.8 for Bz2O.These rate maxima are fitted quantitatively in terms of reactions of OH- and dodecanoate ion on the assumption that sulfobetaine micelles increase the nucleophilicity of the carboxylate ion.This rate effect is ascribed to decreased hydration and ion-pairing of the dodecanoate ion in the mixed micelles, on the basis of 1H NMR spectrometry in mixtures of SDOD and SB3-14.Therefore, incorporation of dodecanoate ion in SB3-n slows reaction by "dilution" in the micelle, but this inhibition is offset by activation of the nucleophilic dodecanoate ion.
- Frescura, Vera L. A.,Marconi, Dilma M. O.,Zanette, Dino,Nome, Faruk,Blasko, Andrei,Bunton, Clifford A.
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- Molecular characterization, expression analysis, and role of ALDH3B1 in the cellular protection against oxidative stress
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Aldehyde dehydrogenase (ALDH) enzymes are critical in the detoxification of aldehydes. The human genome contains 19 ALDH genes, mutations in which are the basis of several diseases. The expression, subcellular localization, enzyme kinetics, and role of ALDH3B1 in aldehyde- and oxidant-induced cytotoxicity were investigated. ALDH3B1 was purified from Sf9 cells using chromatographic methods, and enzyme kinetics were determined spectrophotometrically. ALDH3B1 demonstrated high affinity for hexanal (Km=62μM), octanal (Km=8μM), 4-hydroxy-2-nonenal (4HNE; Km=52μM), and benzaldehyde (Km=46μM). Low affinity was seen toward acetaldehyde (Km=23.3mM), malondialdehyde (Km=152mM), and the ester p-nitrophenyl acetate (Km=3.6mM). ALDH3B1 mRNA was abundant in testis, lung, kidney, and ovary. ALDH3B1 protein was highly expressed in these tissues and the liver. Immunofluorescence microscopy of ALDH3B1-transfected human embryonic kidney (HEK293) cells and subcellular fractionation of mouse kidney and liver revealed a cytosolic protein localization. ALDH3B1-transfected HEK293 cells were significantly protected from the lipid peroxidation-derived aldehydes trans-2-octenal, 4HNE, and hexanal and the oxidants H2O2 and menadione. In addition, ALDH3B1 protein expression was up-regulated by 4HNE in ARPE-19 cells. The results detailed in this study support a pathophysiological role for ALDH3B1 in protecting cells from the damaging effects of oxidative stress.
- Marchitti, Satori A.,Brocker, Chad,Orlicky, David J.,Vasiliou, Vasilis
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- Activity of neutral and alkaline ceramidases on fluorogenic N -acylated coumarin-containing aminodiols
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Ceramidases catalyze the cleavage of ceramides into sphingosine and fatty acids. Previously, we reported on the use of the RBM14 fluorogenic ceramide analogs to determine acidic ceramidase activity. In this work, we investigated the activity of other amidohydrolases on RBM14 compounds. Both bacterial and human purified neutral ceramidases (NCs), as well as ectopically expressed mouse neutral ceramidase hydrolyzed RBM14 with different selectivity, depending on the N -acyl chain length. On the other hand, microsomes from alkaline ceramidase (ACER)3 knockdown cells were less competent at hydrolyzing RBM14C12, RBM12C14, and RBM14C16 than controls, while microsomes from ACER2 and ACER3 overexpressing cells showed no activity toward the RBM14 substrates. Conversely, N -acylethanolamine-hydrolyzing acid amidase (NAAA) overexpressing cells hydrolyzed RBM14C14 and RBM14C16 at acidic pH. Overall, NC, ACER3, and, to a lesser extent, NAAA hydrolyze fluorogenic RBM14 compounds. Although the selectivity of the substrates toward ceramidases can be modulated by the length of the N -acyl chain, none of them was specific for a particular enzyme. Despite the lack of specificity, these substrates should prove useful in library screening programs aimed at identifying potent and selective inhibitors for NC and ACER3.
- Casasampere, Mireia,Camacho, Luz,Cingolani, Francesca,Casas, Josefina,Egido-Gabás, Meritxell,Abad, José Luís,Bedia, Carmen,Xu, Ruijuan,Wang, Kai,Canals, Daniel,Hannun, Yusuf A.,Mao, Cungui,Fabrias, Gemma
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- Micellar Catalysis of Organic Reactions. 25. Orientational Effects in Hydroxy-Functionalized Micelles
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The basic hydrolysis of a number of aspirin derivatives in the presence of the hydroxy-functionalized micelles cetyl(2-hydroxyethyl)dimethylammonium bromide (CHEDAB), cetyl(2-hydroxypropyl)dimethylammonium bromide (CHPDAB), and (2-hydroxycetyl)trimethylammonium bromide (2-OH CTAB) and in the presence of cetyltrimethylammonium bromide (CTAB) has been compared.It has been found that of the hydroxy-functionalized micelles CHEDAB best discriminates between substrates with reaction centers at the micelle-water interface and those with reaction centers that are more deeplyburied in the micellar interior.This discrimination is shown in differences in the ratios of the optimum rates of hydrolysis in the hydroxy-functionalized micelles and in CTAB.It is also shown in the ratios of the calculated rates of reaction in the micellar pseudophase for the hydroxy-functionalized micelles and for CTAB.Thus the orientation of substrates within micellar aggregates is important in determining the magnitude of micellar catalysis.
- Broxton, Trevor J.,Christie, John R.,Sango, Xenia
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- Base-free direct oxidation of 1-octanol to octanoic acid and its octyl ester over supported gold catalysts
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The choice of a suitable support for gold nanoparticles (Au NPs) enabled the direct oxidation of unreactive aliphatic alcohol, 1-octanol, to octanoic acid and octyl octanoate in the absence of a base. Under optimized conditions, Au NPs supported on NiO (Au/NiO) exhibited remarkably high catalytic activities and excellent selectivities to octanoic acid (e.g., 97 %) at full conversion. In contrast to Au/NiO, Au/CeO2 selectively produced octyl octanoate as a major product in a base-free aqueous solution with a maximum selectivity of 82 % under optimized conditions.
- Ishida, Tamao,Ogihara, Yuichiro,Ohashi, Hironori,Akita, Tomoki,Honma, Tetsuo,Oji, Hiroshi,Haruta, Masatake
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- Ester Ammoniolysis: a New Enzymatic Reaction
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A new enzymatic reaction of carboxylic esters and ammonia (ammoniolysis) provides a synthetically useful and mild procedure for the enantioselective synthesis of amides.
- Zoete, Marian C. de,Kock-van Dalen, Alida C.,Rantwijk, Fred van,Sheldon, Roger A.
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- Secondary metabolites from Garcinia daedalanthera Pierre leaves (Clusiaceae)
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Two new glycerol esters, (S)-2-hydroxy-3-(octanoyloxy)propyl tetracosanoate (1) and (S)-3-(((S)-11-acetoxy octadecanoyl)oxy)propane-1,2-diyl diacetate (2), and eight known compounds, docosanedioic acid (3), 2,5-dimethylnonadecane (4), lupeol (5), stigmast
- Forestrania, Roshamur Cahyan,Anaya-Eugenio, Gerardo D.,Acu?a, Ulyana Mu?oz,Ren, Yulin,Elya, Berna,de Blanco, Esperanza Carcache
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- Selective Oxidation of Alcohols to Carbonyl Compounds and Carboxylic Acids with Platinum Group Metal Catalysts
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The use of platinum group metal (PGM) catalysts for the selective oxidation of various primary and secondary alcohols under mild conditions is described. High throughput screening (HTS) techniques have been used to identify trends in catalyst activity and product selectivity. Using air as oxidant and water as solvent 5% Pt, 1% Bi/C has been identified as an efficient catalyst for the transformation of 2-octanol to 2-octanone and 1-octanol to octanoic acid. To improve aldehyde selectivity the promotion of Pt/Al 2O3 and Ru/C catalysts has been investigated. The use of H2O2 as oxidant has been demonstrated as a suitable alternative to air.
- Anderson, Ross,Griffin, Ken,Johnston, Peter,Alsters, Paul L.
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- Polyoxometalate-based layered nano-tubular arrays: facile fabrication and superior performance for catalysis
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Keggin-type polyoxoanion PW12O403--containing one-dimensional nano-tubular arrays, with the structure polyethylenimine/polystyrenesulfonate/(poly(allylammonium)/polystyrenesulfonate)3(poly(allylammonium)/PW12O403-)8, were fabricated as a prototype using a layer-by-layer deposition technique in porous anodic aluminum oxide and polycarbonate templates with a pore diameter of 200 nm, and characterized by IR, UV-vis and SEM. The resulting nano-tubes have a uniform diameter of 180 ± 20 nm and a uniform wall thickness of 30 ± 5 nm. These arrays have shown superior performance in the UV light irradiated photo-degradation of Rhodamine B (selected as a representative dye) under mild conditions with respect to both the catalytic efficiency and operating convenience due to the confinement within the nano-tubes both in the latitudinal and radial direction. Remarkably, the catalytic activity of the nano-tubular arrays could be recovered by means of simple immersion in the polyoxoanion solution when the catalytic reactivity became reduced, which is vital in view of practical applications. The total organic carbon content changes and GC-MS measurements were conducted to identify the degradation products. The hydroxyl radical mechanism was found to be adopted by the photo-degradation reaction.
- Zhen, Hongpeng,Li, Xiaolin,Zhang, Lijuan,Lei, Huan,Yu, Chao,Zhou, Yunshan,Hassan, Sadaf U.,Qin, Libo,Asif, Hafiz Muhammad
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- Manganese-catalyzed direct oxidation of methyl ethers to ketones
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Direct C-H oxidation of alkyl ethers into ketones was achieved using 0.1 mol % of MnCl2 and 4, 4′, 4″-tri(tert-butyl)-2, 2′:6′, 2″-terpyridine (tBu-terpy) in the presence of mCPBA. Conversion of methyl ethers into ketones was particularly efficient and chemoselective. Electron-deficient oxygen functionalities survived under the reaction conditions. The present method broadens the utility of methyl ethers as stable protective groups for hydroxy functionalities and as precursors to carbonyl compounds. (Chemical equation presented).
- Kamijo, Shin,Amaoka, Yuuki,Inoue, Masayuki
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- Ag microparticles embedded in Si nanowire arrays: A novel catalyst for gas-phase oxidation of high alcohol to aldehyde
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A novel catalyst of silver microparticles embedded in a silicon nanowire array support (Ag@SiNW) was prepared by an in situ electroless metal deposition method; it exhibited high selectivity and stability for gas-phase oxidation of high alcohol to its corresponding aldehyde. The Royal Society of Chemistry.
- Zhang, Chenxi,Chen, Ping,Liu, Jian,Zhang, Yahong,Shen, Wei,Xu, Hualong,Tang, Yi
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- Resin glycosides. XVI. Marubajalapins I-VII, new ether-soluble resin glycosides from Pharbitis purpurea
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Fifteen new resin glycosides, marubajalapins I-XV, were isolated from the jalapin fraction of the aerial part (leaves and stems) of Pharbitis purpurea. Among them, the structures of marubajalapins I-VII have been determined on the basis of chemical and spectral data. They are the first examples of jalapins with operculinic acid E obtained previously as a minor glycosidic acid of the crude jalapin from Jalapae Braziliensis.
- Ono,Ueguchi,Murata,Kawasaki,Miyahar
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- Nanocell type Ru?quinone core-shell catalyst for selective oxidation of alcohols to carbonyl compounds
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Selective aerobic oxidation of alcohols to corresponding carbonyl compounds is one of the most important challenges in the modern chemical industry. The existing metal based heterogeneous catalysts provide low selectivity due to over-oxidation of aldehydes to acids and esters. We have found that coating of Ru nanoparticles by disodium anthraquinone-2,6-disulfonate (SQ) results in selective oxidation of aliphatic, unsaturated and aromatic alcohols to aldehydes. Analysis of core-shell Ru?SQ catalyst shows strong interaction between Ru and SQ leading to change of their electronic state and structure. In-situ study of alcohol oxidation using FTIR and electrochemistry indicates on hydrogen abstraction by shell quinone species with hydrogen transfer by quinone to Ru core for water generation. Thus, the catalyst behavior mimics nano-electrocell by separation of oxidation reaction over quinone and reduction of oxygen over Ru providing higher selectivity to aldehyde.
- Capron, M.,Hernández, W. Y.,Naghavi, N.,Ordomsky, V.,Vovk, E. I.,Wu, M.,Yang, Y.,Zhao, J. P.,Zhou, W. J.
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- Pt-Catalyzed selective oxidation of alcohols to aldehydes with hydrogen peroxide using continuous flow reactors
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The oxidation of alcohols to aldehydes is a powerful reaction pathway for obtaining valuable fine chemicals used in pharmaceuticals and biologically active compounds. Although many oxidants can oxidize alcohols, only a few hydrogen peroxide oxidations can be employed to continuously synthesize aldehydes in high yields using a liquid-liquid two-phase flow reactor, despite the possibility of the application toward a safe and rapid multi-step synthesis. We herein report the continuous flow synthesis of (E)-cinnamaldehyde from (E)-cinnamyl alcohol in 95%-98% yields with 99% selectivity for over 5 days by the selective oxidation of hydrogen peroxide using a catalyst column in which Pt is dispersed in SiO2. The active species for the developed selective oxidation is found to be zero-valent Pt(0) from the X-ray photoelectron spectroscopy measurements of the Pt surface before and after the oxidation. Using Pt black diluted with SiO2as a catalyst to retain the Pt(0) species with the optimal substrate and H2O2introduction rate not only enhances the catalytic activity but also maintains the activity during the flow reaction. Optimizing the contact time of the substrate with Pt and H2O2using a flow reactor is important to proceed with the selective oxidation to prevent the catalytic H2O2decomposition.
- Kon, Yoshihiro,Nakashima, Takuya,Yada, Akira,Fujitani, Tadahiro,Onozawa, Shun-Ya,Kobayashi, Shū,Sato, Kazuhiko
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- Positional assembly of enzymes in polymersome nanoreactors for cascade reactions
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In a good position: Nanoreactors can be constructed by the controlled positioning of glucose oxidase (GOX) and horseradish peroxidase (HRP) within the central water pool and block-copolymer membrane of polymersomes. A one-pot multistep reaction sequence is performed with the nanoreactor in combination with free Candida antarctica lipase B (CALB) in the bulk solution (see picture; ABTS: 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)). (Chemical Equation Presented)
- Vriezema, Dennis M.,Garcia, Paula M. L.,Sancho Oltra, Nuria,Hatzakis, Nikos S.,Kuiper, Suzanne M.,Nolte, Roeland J. M.,Rowan, Alan E.,Van Hest, Jan C. M.
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- Nanoshell carbon-supported cobalt catalyst for the aerobic oxidation of alcohols in the presence of benzaldehyde: An efficient, solvent free protocol
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A versatile, solvent free aerobic alcohol oxidation system has been established in the presence of benzaldehyde based on a heterogenous cobalt catalyst supported on nanoshell carbon (Co/NSC), which was prepared through the pyrolysis of a mixture of Co(II) phthalocyanine and phenol resin. The established system features equal efficiency toward both benzylic alcohols and aliphatic alcohols. The nanoshell carbon has been demonstrated to be a better supporting material for the present reaction than some other carbon materials, e.g., activated carbon. Mechanistic studies suggest that Co/NSC can catalyze the formation of oxidative intermediate peroxybenzoic acid as efficiently as homogeneous cobalt catalyst, and moreover, suppress the undesired Baeyer-Villiger side reaction. Co/NSC also exhibits good reusability, i.e., it can be reused for at least 10 times without significant loss of performance. Crown Copyright
- Kuang, Yongbo,Nabae, Yuta,Hayakawa, Teruaki,Kakimoto, Masa-Aki
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- Study on the performance and mechanism of aerobic oxidative desulfurization based on a dual-functional material possessing catalytic and adsorptive properties
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Herein, three polyoxometalates, namely K3PW12O40·10H2O, K6[α-P2W18O62]·14H2O, and K8H[P2W15V3O62]·9H2O, were successfully prepared and used in the air/n-octanaloxidative desulfurization (ODS) system. Among the compounds, the Dawson-type polyoxometalate K6[α-P2W18O62]·14H2O exhibited the best performance, with a 99.63% desulfurization ratio. Then, K6[α-P2W18O62]·14H2O was supported on graphene oxide (GO) to obtain K6P2W18O62/GO. The prepared catalysts were characterized by Fourier transform infrared spectroscopy (FTIR), 31P nuclear magnetic resonance (31P NMR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, transmission electron microscopy (TEM), and Boehm titration. Using K6P2W18O62/GO as a catalyst, a final sulfur removal ratio of 96.10% was achieved without extraction post-treatment due to the inherent adsorption capacity of the catalyst. In addition, the factors influencing the desulfurization process were investigated. The recovery experiment showed that the supported catalyst could be reused 5 times with slight catalyst deactivation. Finally, the reaction mechanism was proposed with the aid of gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS) and contrast tests.
- Dou, Shuai-yong,Wang, Rui
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- Surface phenomenon in micellar media: An excellent controlling factor for oxidation of fatty aldehyde in aqueous medium
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Oxidation of long chain aldehydes is truly tough in aqueous medium. So, an attempt has been made to oxidise octanal, a fatty aldehyde, by Cr(VI) in acidic aqueous media with the assistance of surfactants. The detailed kinetics of this successful micellar oxidation reaction has been studied spectrophotometrically under pseudo1st order condition at 25 °C (±0.1 °C). In promoting the oxidation reaction three hetero-aromatic bases i.e. 1, 10 – phenanthroline (Phen), 2-picolonic acid (PA) and 2, 2′ – bipyridine (Bpy) have been used in combination with the surfactants. Mixture of SDS and Bpy has come out to be the most effective among the others to enhance the oxidation rate maximum. Necessary spectral analysis and thermodynamic facts have also been produced in support of the whole process.
- Acharjee, Animesh,Chowdhury, Suman,Mahali, Kalachand,Rakshit, Atanu,Saha, Bidyut
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- Spontaneous product segregation from reactions in ionic liquids: Application in Pd-catalyzed aliphatic alcohol oxidation
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A methodology is introduced to separate polar reaction products from ionic liquids without the need for organic solvent extraction or distillation. We investigated product isolation after an alcohol oxidation performed in ionic liquids. Suitable ionic liquids were selected based on their mixing or demixing with a range of alcohols and the derived ketones. The aim was to obtain complete miscibility with the alcohol substrate at reaction temperature and a clear phase separation of the derived ketone product at room temperature. Six imidazolium based ionic liquids displayed this desired behaviour and were sufficiently stable to oxidation. These ionic liquids were then employed in the oxidation of non-activated aliphatic alcohols with molecular oxygen in the presence of palladium(ii) acetate. In 1-butyl-3-methylimidazolium tetrafluoroborate, 2-ketone yields of 79 and 86% were obtained for, respectively, 2-octanol and 2-decanol. After cooling to room temperature the ionic liquid expels the immiscible ketone and the product phase can be isolated by decantation. In addition, the ionic liquid acts as an immobilization medium for the palladium catalyst, allowing efficient catalyst recycling.
- Van Doorslaer, Charlie,Schellekens, Yves,Mertens, Pascal,Binnemans, Koen,De Vos, Dirk
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- Anionic N,O-ligated Pd(ii) complexes: Highly active catalysts for alcohol oxidation
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There is a need to develop effective catalytic methods for alcohol oxidation. Pd(ii) complexes have shown great promise as catalysts, however a comparatively small number of ligands have been reported so far. Herein we report the use of commercially available anionic N,O-ligands to produce highly active catalysts.
- Bailie, David S.,Clendenning, Grainne M. A.,McNamee, Laura,Muldoon, Mark J.
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- Insights in the aerobic oxidation of aldehydes
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The hydroformylation of olefins (oxo synthesis) is the most important process for the production of higher aldehydes (>C4). The liquid phase oxidation of the latter to carboxylic acids by molecular oxygen or air has been known for more than 150 years and is an industrially important process. However, in the recent literature, several different oxidizing reagents and catalytic processes have been reported for this oxidation but most of them have limitations as they use environmentally unacceptable reagents or unnecessarily sophisticated conditions. Herein, we re-evaluated the air oxidation of aldehydes. We show that under mild conditions (air or oxygen and non-optimized stirring), reactions are transfer limited and thus catalyst has no effect on reaction rate. Using efficient stirring (self-suction turbine), uncatalysed air oxidation of 0.8 M aldehyde is possible in 50 min at room temperature whereas less than 10 min was necessary with 10 ppm Mn(ii). Thus, recommendations for avoiding common pitfalls that may rise during the evaluation of new catalysts are made. The Royal Society of Chemistry 2013.
- Vanoye, Laurent,Favre-Reguillon, Alain,Aloui, Asma,Philippe, Regis,De Bellefon, Claude
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- Selenium catalysed oxidations with aqueous hydrogen peroxide. Part 3: Oxidation of carbonyl compounds under mono/bi/triphasic conditions
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The total synthesis of 3,5-bis(perfluorooctyl)phenyl butylselenide (1), a recyclable catalyst for oxidation reactions with hydrogen peroxide, is described. The catalyst can be used for oxidation of aldehydes and ketones under monophasic, but also fluorous biphasic or fluorous triphasic conditions.
- Ten Brink, Gerd-Jan,Vis, J.Martijn,Arends, Isabel W.C.E,Sheldon, Roger A
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- Dendritic phosphonates and the in situ assembly of polyperoxophosphotungstates: Synthesis and catalytic epoxidation of alkenes with hydrogen peroxide
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First and second-generation rigid dendrimers based on polyphenylated tetrahedral adamantane cores with four or sixteen peripheral phosphonate moieties, PD1 and PD2, respectively, were synthesized and characterized. Further reaction of the dendritic phosphonates with tungstic acid in the presence of hydrogen peroxide led to the stepwise in situ formation of mono- and dinuclear phosphoperoxotungstates. These assemblies were effective catalysts for the epoxidation of alkenes in an aqueous acetonitrile solvent.
- Vasylyev, Maxym V.,Astruc, Didier,Neumann, Ronny
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- Controlling factors in the ruthenium-catalyzed oxidation of primary alcohols with sodium bromate
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The homogeneous transition metal-catalyzed oxidation of alcohols via aldehydes to carboxylic acids has been investigated in detail.Special attention was focussed on the influence of the experimental conditions on the outcome of the reaction.In the oxidation of 1-octanol with sodium bromate and the catalyst rutheniumtrichloride even under mild reaction conditions (at 40 deg C for 90 min) there is almost quantitative conversion.By directing the reaction by choice of the amount of the oxidizing agent, either 1-octanol or caprylic acid could be obtained in yields of 90percent.Similar results were obtained with longer chain alcohols, demonstrating the general applicability of the approach.
- Behr, A.,Eusterwiemann, K.
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Read Online
- Crystal structures of two Bacillus carboxylesterases with different enantioselectivities
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Naproxen esterase (NP) from Bacillus subtilis Thai I-8 is a carboxylesterase that catalyzes the enantioselective hydrolysis of naproxenmethylester to produce S-naproxen (E > 200). It is a homolog of CesA (98% sequence identity) and CesB (64% identity), both produced by B. subtilis strain 168. CesB can be used for the enantioselective hydrolysis of 1,2-O-isopropylideneglycerol (solketal) esters (E > 200 for IPG-caprylate). Crystal structures of NP and CesB, determined to a resolution of 1.75 A and 2.04 A, respectively, showed that both proteins have a canonical α/β hydrolase fold with an extra N-terminal helix stabilizing the cap subdomain. The active site in both enzymes is located in a deep hydrophobic groove and includes the catalytic triad residues Ser130, His274, and Glu245. A product analog, presumably 2-(2-hydroxyethoxy)acetic acid, was bound in the NP active site. The enzymes have different enantioselectivities, which previously were shown to result from only a few amino acid substitutions in the cap domain. Modeling of a substrate in the active site of NP allowed explaining the different enantioselectivities. In addition, Ala156 may be a determinant of enantioselectivity as well, since its side chain appears to interfere with the binding of certain R-enantiomers in the active site of NP. However, the exchange route for substrate and product between the active site and the solvent is not obvious from the structures. Flexibility of the cap domain might facilitate such exchange. Interestingly, both carboxylesterases show higher structural similarity to meta-cleavage compound (MCP) hydrolases than to other α/β hydrolase fold esterases.
- Rozeboom, Henriette J.,Godinho, Luis F.,Nardini, Marco,Quax, Wim J.,Dijkstra, Bauke W.
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- Organic Sonochemistry - some illustrative examples of a new fundamental approach
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The sonochemical behaviour of several organic reactions, selected according to their mechanisms, has been examined. Their experimental evolution follows the prediction developed previously, that sonication promotes reactions proceeding through radical pathways.
- Einhorn,Einhorn,Dickens,Luche
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Read Online
- Bimetallic Co-Pd alloy nanoparticles as magnetically recoverable catalysts for the aerobic oxidation of alcohols in water
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Co-Pd bimetallic alloy nanoparticle catalysts were prepared from CoCl2, Pd(OAc)2and several capping agents with Li(C2H5)3BH. The nanoparticle catalysts were applied to the aerobic oxidation of a variety of alcohols in water to give the corresponding carbonyl products. The catalyst was magnetically recovered and reused for further oxidation. The nanoparticle catalysts were characterized with TEM, ICP, and XPS analyses.
- Ito, Yoshikazu,Ohta, Hidetoshi,Yamada, Yoichi M.A.,Enoki, Toshiaki,Uozumi, Yasuhiro
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- Acylguanidine derivatives of zanamivir and oseltamivir: Potential orally available prodrugs against influenza viruses
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Zanamivir (ZA) and guanidino-oseltamivir carboxylic acid (GOC) are very potent inhibitors against influenza neuraminidase (NA). The guanidinium moiety plays an important role in NA binding; however, its polar cationic nature also hinders the use of ZA and GOC from oral administration. In this study, we investigated the use of ZA and GOC acylguanidine derivatives as possible orally available prodrugs. The acylguanidine derivatives were prepared by coupling with either n-octanoic acid or (S)-naproxen. The lipophilic acyl substituents were verified to improve cell permeability, and may also improve the bioavailability of acylguanidine compounds. In comparison, the acylguanidines bearing linear octanoyl chain showed better NA inhibitory activity and higher hydrolysis rate than the corresponding derivatives having bulky branched naproxen moiety. Our molecular docking experiments revealed that the straight octanoyl chain could extend to the 150-cavity and 430-cavity of NA to gain extra hydrophobic interactions. Mice receiving the ZA octanoylguanidine derivative survived from influenza infection better than those treated with ZA, whereas the GOC octanoylguanidine derivative could be orally administrated to treat mice with efficacy equal to oseltamivir. Our present study demonstrates that incorporation of appropriate lipophilic acyl substituents to the polar guanidine group of ZA and GOC is a feasible approach to develop oral drugs for influenza therapy.
- Hsu, Peng-Hao,Chiu, Din-Chi,Wu, Kuan-Lin,Lee, Pei-Shan,Jan, Jia-Tsrong,Cheng, Yih-Shyun E.,Tsai, Keng-Chang,Cheng, Ting-Jen,Fang, Jim-Min
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- Nucleophilically Assisted Deacylation in Sodium Dodecanoate and Dodecyl Sulfate Micelles. Quantitative Evidence on Premicellar Complexes
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Hydrolyses of 2,4-dinitrophenyl acetate and octanoate (DNPA and DNPO, respectively) and benzoic anhydride (Bz2O) in the pH range 8.9-10.2 are inhibited by anionic micelles of sodium dodecyl sulfate (SDS), and reactions of fully micellar-bound substrates are very slow.The effect of micellized sodium dodecanoate, SDOD, depends on pH.At high pH reactions of DNPA and Bz2O involve OH- and are inhibited by SDOD, but there are significant rates at high .At low-pH reactions of DNPA and Bz2O are inhibited at low and assisted at high .The inhibition is due to formation of kinetically ineffective premicellar complexes and rate-surfactant profiles can be fitted quantitatively in terms of this model.When the substrates are fully micellar-bound rate constants in mixtures of SDOD and SDS follow the mole fraction of SDOD and second-order rate constants of nucleophilic attack by the dodecanoate ion at micellar surfaces are similar to those for the reactions of OAc- in water.
- Marconi, Dilma M. O.,Frescura, Vera L. A.,Zanette, Dino,Nome, Faruk,Bunton, Clifford A.
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- Acceptorless dehydrogenation of primary alcohols to carboxylic acids by self-supported NHC-Ru single-site catalysts
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The acceptorless dehydrogenation of diverse aromatic and aliphatic primary alcohols to corresponding carboxylic acids has been accomplished by self-supported NHC-Ru single-site catalysts under mild reaction conditions. Besides broad substrates with excellent activity, selectivity and good tolerance to sensitive functional groups, the solid single-site catalyst could be recovered and reused for more than 20 runs without deactivation. Remarkably, up to 1.8 × 104 turnover numbers could be achieved by this newly developed sustainable protocol in gram scale at low catalyst loading, highlighting its potential in industry.
- Yin, Shenxiang,Zheng, Qingshu,Chen, Jie,Tu, Tao
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p. 165 - 172
(2022/03/23)
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- Dehydrogenative alcohol coupling and one-pot cross metathesis/dehydrogenative coupling reactions of alcohols using Hoveyda-Grubbs catalysts
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In this study,in situformed ruthenium hydride species that were generated from Grubbs type catalysts are used as efficient catalysts for dehydrogenative alcohol coupling and sequential cross-metathesis/dehydrogenative coupling reactions. The selectivity of Grubbs first generation catalysts (G1) in dehydrogenative alcohol coupling reactions can be tuned for the ester formation in the presence of weak bases, while the selectivity can be switched to the β-alkylated alcohol formation using strong bases. The performance of Hoveyda-Grubbs 2nd generation catalyst (HG2) was improved in the presence of tricyclohexylphosphine for the selective synthesis of ester derivatives with weak and strong bases in quantitative yields. Allyl alcohol was used as self and cross-metathesis substrate for the HG2 catalyzed sequential cross-metathesis/dehydrogenative alcohol coupling reactions to obtain γ-butyrolactone and long-chain ester derivatives in quantitative yields.
- ?zer, Halenur,Arslan, Dilan,?ztürk, Bengi ?zgün
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supporting information
p. 5992 - 6000
(2021/04/12)
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- Catalytic alcohol oxidation using cationic Schiff base manganeseIII complexes with flexible diamino bridge
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Four Schiff base manganese(III) complexes with derivatives of [(R,R)-N,N’-bis(salicy1idene)-1,2-cyclohexanediaminato)] including substituents on salicylaldehyde such as 3-methoxy, 3,5-di-tert-butyl and 3,5-chloro were synthesized and characterized using a combination of IR, UV–Vis, and HR ESI-MS techniques. The catalytic activity of these complexes was tested in the oxidation of 1-phenylethanol to acetophenone, revealing very good performances for all of the four manganese complexes. The catalytic reactions were carried out in the presence of tert-butyl hydroperoxide (TBHP) as oxidant and imidazole as co-catalyst. Complex Mn-4, bearing electron withdrawing [(R,R)-N,N’-bis(3,5-di-chloro-salicylidene)-1,2-cyclohexanediaminato)] ligand was found to be the most stable of the tested Mn(III) complexes and was selected for the oxidation of several primary and secondary alcohols.
- Kakavand, Meysam,Mastrorilli, Piero,Mesto, Ernesto,Neshat, Abdollah,Osanlou, Farzane,Schingaro, Emanuela,Todisco, Stefano
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- Ruthenium(ii)-supported phosphovanadomolybdates [Ru(dmso)3PMo6V3O32]6-and [Ru(PMo6V3O32)2]14-, and their use as heterogeneous catalysts for oxidation of alcohols
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Self-assembly of cis-[RuCl2(dmso)4], NaVO3, Na2MoO4 and NaH2PO4 in a molar ratio of 1?:?3?:?6?:?1 in HOAc-NaOAc buffer (pH = 4-5) in the presence of CsCl gave a ruthenium(ii)-supported phosphovanadomolybdate [RuII(dmso)3PMoVI6VV3O32]6- (1). While a similar reaction with the reactants in a molar ratio of 1?:?6?:?12?:?2 afforded a ruthenium substituted "sandwich"type polyoxometalate [RuII(PMoVI6VV3O32)2]14- (2). Clusters 1 and 2 were well characterized by single-crystal X-ray diffraction. Their use as heterogeneous catalysts for oxidation of alcohols in the presence of molecular oxygen was also investigated.
- Shi, Hao-Yu,Zhou, Wen-Yan,Song, Xiao-Ming,Jia, Ai-Quan,Shi, Hua-Tian,Zhang, Qian-Feng
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p. 1551 - 1555
(2021/02/06)
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- Membrane transport inspired hydrolysis of non-activated esters at near physiological pH
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A positively charged micelle loaded with substrates was transported selectively to the reaction site (cathode) to promote the proximity and localization of the reactants (ester and hydroxide). The guided vehicular delivery coupled with electrolysis allows the hydrolysis of non-activated esters at near physiological pH with significant yields along with recyclability.
- Mandal, Raki,Mahanty, Kingshuk,Mandal, Subhendu,De Sarkar, Suman,Tarafdar, Pradip K.
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p. 11088 - 11091
(2021/10/30)
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- The effects of metals and ligands on the oxidation of n-octane using iridium and rhodium “PNP” aminodiphosphine complexes
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Ir and Rh “PNP” complexes with different ligands are utilized for the oxidation of n-octane. Based on the obtained conversion, selectivity, and the characterized recovered catalysts, it is found that the combination of Ir and the studied ligands does not promote the redox mechanism that is known to result in selective formation of oxo and peroxo compounds [desired species for C(1) activation]. Instead, they support a deeper oxidation mechanism, and thus higher selectivity for ketones and acids is obtained. In contrast, these ligands seem to tune the electron density around the Rh (in the Rh-PNP complexes), and thus result in a higher n-octane conversion and improved selectivity for the C(1) activated products, with minimized deeper oxidation, in comparison to Ir-PNP catalysts.
- Naicker, Dunesha,Alapour, Saba,Friedrich, Holger B
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p. 282 - 289
(2020/12/01)
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- Flexible pincer backbone revisited: CuSNS complexes as efficient catalysts in paraffin oxidation
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New Cu(II) complexes containing a set of tridentate hybrid SNS ligands were synthesised and fully characterised by IR, HRMS, elemental analysis and single-crystal X-ray diffraction. The complexes with the general formula Cu[bis(Rthioethyl)phenylamine]Cl2 (1); [R = methyl (a); ethyl (b); butyl (c); cyclohexyl (d) and t-butyl (e)] exhibited five-coordinate trigonal bipyramidal geometry around each Cu(II) centre in the solid-state with the S-donor atoms occupying the axial positions. However, complex 1b crystallised as a dimer bridged through a cuprate anion denoted as [1b(μ-CuCl4)1b]. Their application as catalysts in the oxidation of n-octane with hydrogen peroxide (H2O2) as an oxidant gave high substrate conversions to C-8 oxygenate products, mainly octanols, after reduction with PPh3. Notably, complex 1d produced the highest yield of 57% in 1 h reaction time at a catalyst concentration of 1 mol%. In general, high turnover numbers (2830–3180) were recorded for the 1/H2O2 catalytic systems with substantially high combined selectivity of 22–27% to 1-octanol and octanoic acid, which are the more desired products of n-octane oxidation resulting from its terminal carbon (C(1)) activation. The high activity of the catalysts is attributed to metal–ligand cooperative catalysis involving CuII-OOH intermediates as the active species modulated by the tridentate SNS ligands. In comparison with related complexes bearing N-donor atoms, the excellent catalytic performance of these series of CuSNS complexes highlights the critical role of the phenylamine N-donor atom.
- Bala, Muhammad D.,Friedrich, Holger B.,Soobramoney, Lynette
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supporting information
(2021/07/16)
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- Transformations of Peroxide Products of Non-1-ene Ozonolysis by the Action of Carboxylic Acid Hydrazides
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Abstract: The behavior of aliphatic (cyclohexanecarboxylic) and aromatic (salicylic and isonicotinic) carboxylic acid hydrazides toward peroxide products of ozonolysis of a terminal alkene, non-1-ene, in protic (methanol) and aprotic solvents (THF, methylene chloride) has been studied. These hydrazides are capable of acting as reducing agents or decomposing intermediate peroxides. For the synthesis of N′-octylidene isoniazid derivative, it is advisable to carry out the reaction in methanol, whereas the use of THF as solvent favors formation of N′-octylidenecyclohexane-1-carbonydrazide. Salicylic acid hydrazide showed a low efficiency; in this case, mixtures of the corresponding hydrazone with octanoic acid or its methyl ester were formed in a low yield.
- Myasoedova, Yu. V.,Nurieva,Garifullina,Ishmuratova,Ishmuratov, G. Yu.
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p. 113 - 116
(2021/03/03)
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- A Mild, General, Metal-Free Method for Desulfurization of Thiols and Disulfides Induced by Visible-Light
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A visible-light-induced metal-free desulfurization method for thiols and disulfides has been explored. This radical desulfurization features mild conditions, robustness, and excellent functionality compatibility. It was successfully applied not only to the desulfurization of small molecules, but also to peptides.
- Qiu, Wenting,Shi, Shuai,Li, Ruining,Lin, Xianfeng,Rao, Liangming,Sun, Zhankui
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supporting information
p. 1255 - 1258
(2021/05/05)
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- A study of the mechanism of triglyceride hydrodeoxygenation over alumina-supported and phosphatized-alumina-supported Pd catalysts
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The mechanism of catalytic hydrodeoxygenation (HDO) of fats, vegetable oils, and fatty acids was studied using alumina-supported Pd catalysts and tricaprylin and valeric acid as model reactants. The chemistry of fatty acid/catalyst interaction was studied by quasi-operando Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). The Pd/γ–Al2O3 catalyst showed good activity in the hydrogenolysis reaction of the ester bonds to convert tricaprylin to caprylic acid, but they were of poor activity in the consecutive hydrodeoxygenation (HDO) of the acid to paraffin. The surface modification of the support alumina by phosphate groups significantly increased the HDO activity of the Pd catalyst and, consequently, the paraffin yield. The activity change was accounted partly for the partial replacement of the weak base Al–OH groups by weak acid P–OH groups but mainly for the partial elimination of Lewis acid (Al⊕) – Lewis base (O?) pair sites on the surface of the support. Both surface Al–OH and P–OH groups were shown to participate in the reaction with carboxylic acid and formed bidentate surface carboxylate species, which further reacted with hydrogen to give paraffin. Carboxylates of less basic surface sites were found to be more prone to HDO reaction than those of strong base sites. Monodentate carboxylates, formed on Al⊕ O? pair sites were of low reactivity. Phosphatizing eliminated most of the Lewis type acid-base pair sites, therefore, reactive bidentate carboxylates represented the most abundant surface intermediate (MASI) during the HDO reaction of triglyceride. The hydroxyl coverage of the carboxylated surface was shown to become somewhat higher under steady-state reaction conditions. The increased hydroxyl coverage implies that C–O bond hydrogenolysis of the surface carboxylate proceeds, regenerating OH groups and forming aldehyde that could be intermediate of paraffin formation.
- Barthos, Róbert,Domján, Attila,Hancsók, Jen?,Lónyi, Ferenc,Mihályi, Magdolna R.,Novodárszki, Gyula,Solt, Hanna E.,Valyon, József,Vikár, Anna
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- Method for preparing carboxylic acid by catalyzing aldehyde oxidation with N-heterocyclic carbene
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The invention discloses a method for preparing carboxylic acid by catalyzing aldehyde oxidation with N-heterocyclic carbene, and relates to the field of catalytic technology. The method comprises thefollowing steps: taking deionized water as a solvent and aldehyde as a reaction substrate, adding alkali into a reaction system, taking air as an oxidant and N-heterocyclic carbene as a catalyst required by the reaction, and carrying out catalytic oxidation on aldehyde at room temperature to 80 DEG C to generate a corresponding reaction product. The method has the beneficial effects that the N-heterocyclic carbene is used as the catalyst, no organic solvent is needed in the reaction process, the reaction process is green and safe, and the reaction yield is high.
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Paragraph 0039-0043; 0052-0055
(2020/11/25)
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- Selective Oxidation of Alcohols to Carbonyl Compounds over Small Size Colloidal Ru Nanoparticles
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The selective oxidation of alcohols to corresponding aldehydes is one of the most challenging problems in modern chemistry due to over-oxidation of these products further into corresponding acids and esters. Herein, we report an efficient and eco-friendly method for selective oxidation of aliphatic, unsaturated and aromatic alcohols to aldehydes (>90 %) using small size (2 nm) non-supported colloidal Ru nanoparticles. The selectivity rapidly decreases with increase of the size of nanoparticles (from 2 to 10 nm) or after their deposition over support. X-ray photoelectron spectroscopy suggests that this catalytic performance can be attributed to high content Ru?O species on the surface of small size Ru nanoparticles, which undergo reduction with formation of water and aldehyde and easy oxidation cycles during the reaction according to the Mars-van Krevelen mechanism. The presence of surface oxide layer over small size Ru nanoparticles suppresses over-oxidation of aldehydes to acids.
- Zhao, JingPeng,Hernández, Willinton Y.,Zhou, WenJuan,Yang, Yong,Vovk, Evgeny I.,Capron, Mickael,Ordomsky, Vitaly
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p. 238 - 247
(2019/11/14)
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- Preparation method of bimetallic catalyst oxidation aldehyde synthetic carboxylic acid (by machine translation)
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The method is, in a reaction solvent: under normal pressure oxygen condition, under the action of a bimetallic catalyst under the action of a bimetallic catalyst under the action of a bimetallic catalyst under the action of a bimetallic catalyst, at, DEG, under stirring . under a stirring condition with an aldehyde compound as a substrate 10-90 °C in a reaction solvent under, a stirring condition under the action of a bimetallic catalyst . The reaction solution is stirred, for. 1-12h, hours at; room temperature, under, the action, of a bimetallic 1:1 catalyst Cu(OAc) under the action of a bimetallic catalyst under the action of a bimetallic catalyst under the action of a double-metal catalyst. 2 · H2 O And Co(OAc)2 · 44H2 O As the bimetallic catalyst, can achieve the highest yield of the carboxylic acid product, in high yield, by adjusting the reaction temperature, solvent, catalyst amount, for different types of the raw material aldehyde 98%. (by machine translation)
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Paragraph 0052-0053
(2020/05/30)
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- Oxidation of aromatic and aliphatic aldehydes to carboxylic acids by Geotrichum candidum aldehyde dehydrogenase
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Oxidation reaction is one of the most important and indispensable organic reactions, so that green and sustainable catalysts for oxidation are necessary to be developed. Herein, biocatalytic oxidation of aldehydes was investigated, resulted in the synthesis of both aromatic and aliphatic carboxylic acids using a Geotrichum candidum aldehyde dehydrogenase (GcALDH). Moreover, selective oxidation of dialdehydes to aldehydic acids by GcALDH was also successful.
- Hoshino, Tomoyasu,Yamabe, Emi,Hawari, Muhammad Arisyi,Tamura, Mayumi,Kanamaru, Shuji,Yoshida, Keisuke,Koesoema, Afifa Ayu,Matsuda, Tomoko
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- The plant pathogen enzyme AldC is a long-chain aliphatic aldehyde dehydrogenase
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Aldehyde dehydrogenases are versatile enzymes that serve a range of biochemical functions. Although traditionally considered metabolic housekeeping enzymes because of their ability to detoxify reactive aldehydes, like those generated from lipid peroxidation damage, the contributions of these enzymes to other biological processes are widespread. For example, the plant pathogen Pseudomonas syringae strain PtoDC3000 uses an indole-3-acetaldehyde dehydrogenase to synthesize the phytohormone indole-3-acetic acid to elude host responses. Here we investigate the biochemical function of AldC from PtoDC3000. Analysis of the substrate profile of AldC suggests that this enzyme functions as a long-chain aliphatic aldehyde dehydrogenase. The 2.5 ? resolution X-ray crystal of the AldC C291A mutant in a dead-end complex with octanal and NAD1 reveals an apolar binding site primed for aliphatic aldehyde substrate recognition. Functional characterization of site-directed mutants targeting the substrate- and NAD(H)-binding sites identifies key residues in the active site for ligand interactions, including those in the “aromatic box” that define the aldehyde-binding site. Overall, this study provides molecular insight for understanding the evolution of the prokaryotic aldehyde dehydrogenase superfamily and their diversity of function.
- Lee, Soon Goo,Harline, Kate,Abar, Orchid,Akadri, Sakirat O.,Bastian, Alexander G.,Chen, Hui-Yuan S.,Duan, Michael,Focht, Caroline M.,Groziak, Amanda R.,Kao, Jesse,Kottapalli, Jagdeesh S.,Leong, Matthew C.,Lin, Joy J.,Liu, Regina,Luo, Joanna E.,Meyer, Christine M.,Mo, Albert F.,Pahng, Seong Ho,Penna, Vinay,Raciti, Chris D.,Srinath, Abhinav,Sudhakar, Shwetha,Tang, Joseph D.,Cox, Brian R.,Holland, Cynthia K.,Cascella, Barrie,Cruz, Wilhelm,McClerkin, Sheri A.,Kunkel, Barbara N.,Jez, Joseph M.
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p. 13914 - 13926
(2020/12/09)
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- Selective TEMPO-Oxidation of Alcohols to Aldehydes in Alternative Organic Solvents
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The TEMPO-catalyzed oxidation of alcohols to aldehydes has emerged to one of the most widely applied methodologies for such transformations. Advantages are the utilization of sodium hypochlorite, a component of household bleach, as an oxidation agent and the use of water as a co-solvent. However, a major drawback of this method is the often occurring strict limitation to use dichloromethane as an organic solvent in a biphasic reaction medium with water. Previous studies show that dichloromethane cannot easily be substituted because a decrease of selectivity or inhibition of the reaction is observed by using alternative organic solvents. Thus, up to now, only a few examples are known in which after a tedious optimization of the reaction dichloromethane could be replaced. In order to overcome the current limitations, we were interested in finding a TEMPO-oxidation method in alternative organic solvents, which is applicable for various alcohol oxidations. As a result, we found a method for N-oxyl radical-catalyzed oxidation using sodium hypochlorite as an oxidation agent in nitriles as an organic solvent component instead of dichloromethane. Besides the oxidation of aromatic primary alcohols also aliphatic primary alcohols, secondary alcohols as well as dialcohols were successfully converted when using this method, showing high selectivity towards the carbonyl compound and low amounts of the acid side-product.
- Hinzmann, Alessa,Stricker, Michael,Busch, Jasmin,Glinski, Sylvia,Oike, Keiko,Gr?ger, Harald
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p. 2399 - 2408
(2020/04/29)
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- METHOD FOR PRODUCING CARBONYL COMPOUND
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PROBLEM TO BE SOLVED: To allow a method that oxidizes a first or second alcohol compound to obtain a carbonyl compound to be conducted with a higher yield than that of a method that uses sodium hypochlorite as an oxidizer. SOLUTION: A first or second alcohol compound is oxidized, in the presence of tetraalkylammonium hypochlorite and, preferably, in coexistence with a nitroxy radical catalyst and a metal halide cocatalyst, to produce a carbonyl compound composed of an aldehyde compound, a carboxylic acid compound, and a ketone compound. SELECTED DRAWING: None COPYRIGHT: (C)2021,JPO&INPIT
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Paragraph 0062; 0065
(2021/02/04)
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- Carbon dots as photocatalysts for organic synthesis: Metal-free methylene-oxygen-bond photocleavage
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We report for the first time that irradiation of four different citric acid-derived carbon dots (CDs), in the absence of any other redox mediators, promotes an organic reaction. In this proof-of-concept study methylene-oxygen bond reductive photocleavage in N-methyl-4-picolinium esters is demonstrated. Cyclic voltammetry and UV-Vis spectra of the CDs and of the esters indicate that photocleavage reactivity correlates with the redox properties and the relative energies expressed in the Fermi scale. A photo-fragmentation mechanism is proposed. This study offers a new possibility to employ inexpensive and readily available CDs to promote photo-organic reactions.
- Cailotto, Simone,Negrato, Matteo,Daniele, Salvatore,Luque, Rafael,Selva, Maurizio,Amadio, Emanuele,Perosa, Alvise
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p. 1145 - 1149
(2020/03/11)
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- Palladium supported on a novel ordered mesoporous polypyrrole/carbon nanocomposite as a powerful heterogeneous catalyst for the aerobic oxidation of alcohols to carboxylic acids and ketones on water
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Preparation of an ordered mesoporous polypyrrole/carbon (PPy/OMC) composite has been described through a two-step nanocasting process using KIT-6 as a template. Characterization of the PPy/OMC nanocomposite by various analysis methods such as TEM, XRD, TGA, SEM and N2 sorption confirmed the preparation of a material with ordered mesoporous structure, uniform pore size distribution, high surface area and high stability. This nanocomposite was then used for the immobilization of palladium nanoparticles. The nanoparticles were almost uniformly distributed on the support with a narrow particle size of 20-25 nm, confirmed by various analysis methods. Performance of the Pd?PPy/OMC catalyst was evaluated in the aerobic oxidation of various primary and secondary alcohols on water as a green solvent, giving the corresponding carboxylic acids and ketones in high yields and excellent selectivity. The catalyst could also be reused for at least 10 reaction runs without losing its catalytic activity and selectivity. High catalytic efficiency of the catalyst can be attributed to a strong synergism between the PPy/OMC and that of supported Pd nanoparticles.
- Ganji, Nasim,Karimi, Babak,Najafvand-Derikvandi, Sepideh,Vali, Hojatollah
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p. 13616 - 13631
(2020/04/24)
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- A sodium trifluoromethanesulfinate-mediated photocatalytic strategy for aerobic oxidation of alcohols
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A sodium trifluoromethanesulfinate-mediated photocatalytic strategy for the aerobic oxidation of alcohols has been developed for the first time, and the photoredox aerobic oxidation of secondary and primary alcohols provided the corresponding ketones and carboxylic acids, respectively, in high to excellent yields.
- Zhu, Xianjin,Liu, Can,Liu, Yong,Yang, Haijun,Fu, Hua
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p. 12443 - 12446
(2020/10/30)
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- Substrate hydrophobicity and enzyme modifiers play a major role in the activity of lipase from: Thermomyces lanuginosus
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Lipase from Thermomyces lanuginosus (TL) displays high affinity for long-chain substrates, such as triolein and other long-chain triacylglycerols. Aiming to broaden the substrate chain-length specificity, different aldehydes (naphthaldehyde, butyraldehyde, hexyl aldehyde and dodecyl aldehyde) and naphthyl isothiocyanate were grafted onto lipase TL through lysine coupling. The catalytic activity of the modified lipases was investigated by reaction with substrates differing in the aliphatic chain size (p-nitrophenyl benzoate, p-nitrophenyl acetate, p-nitrophenyl butyrate, p-nitrophenyl hexanoate, p-nitrophenyl octanoate, p-nitrophenyl laurate and p-nitrophenyl palmitate). The enzymes modified with aldehydes revealed higher activity than the enzymes modified with the isothiocyanate. The most notable results were achieved for lipase TL grafted with 4 units of a dodecyl chain (TL5), which revealed the highest activity against all the tested substrates, being 10-fold more active than the native enzyme for smaller substrates (acetate and butyrate chains) and 2-fold for longer substrates (laurate and palmitate chains). The kinetic parameters evaluated (Vmax, KM and kcat/KM) also confirmed the significant catalytic performance of TL5 compared to the native enzyme. The increase in activity revealed by the modified lipases was directly proportional to the size and hydrophobicity of the linkers' aliphatic chain. Small conformational changes, either on the enzyme's lid or on the cavity of the active site were suggested by molecular dynamics simulations, circular dichroism and fluorescence spectroscopy. Moreover, the grafting with aldehydes or with the isothiocyanate conferred higher thermostability to the lipase. The chemical surface modification developed efficiently improved the activity of lipase TL, broadening the substrate's chain-length specificity, increasing thereafter the substrate possibilities for industrial reactions. This journal is
- Castro, Tarsila G.,Cavaco-Paulo, Artur,Noro, Jennifer,Silva, Carla
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p. 5913 - 5924
(2020/10/08)
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- Process for the preparation of fatty acids
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The invention discloses a method for preparing fatty acid. The method comprises the following steps: providing a first reactant which is a furan compound containing an carbonyl group; providing a second reactant which is a compound containing a carboxyl group, an ester group or an anhydride group and can participate in a condensation reaction with the carbonyl group of the first reactant; allowingthe first reactant and the second reactant to participate in a first condensation reaction, and allowing a C=O bond of the carbonyl group of the first reactant to be connected with alpha carbon of the carbonyl group of the second reactant and to be converted into a C=C bond so as to form a condensation product; and carrying out a second-step reaction under hydrogen pressure in the presence of a co-catalytic system of a hydrogenation catalyst and Lewis acid, opening a furan ring of the condensation product, carrying out hydrodeoxygenation at the same time, removing all oxygen except for oxygenin the carboxyl group, and allowing a carbon chain to be saturated so as to obtain the fatty acid.
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Paragraph 0179-0206; 0219-0221
(2020/09/04)
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- Nickel-Catalyzed Formal Aminocarbonylation of Unactivated Alkyl Iodides with Isocyanides
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Herein, we disclose a Ni-catalyzed formal aminocarbonylation of primary and secondary unactivated aliphatic iodides with isocyanides to afford alkyl amide, which proceeds via the selective monomigratory insertion of isocyanides with alkyl iodides, subsequent β-hydride elimination, and hydrolysis process. The reaction features wide functional group tolerance under mild conditions. Additionally, the selective, one-pot hydrolysis of reaction mixture under acid conditions allows for expedient synthesis of the corresponding alkyl carboxylic acid.
- Chen, Yifeng,Huang, Wenyi,Qu, Jingping,Shrestha, Mohini,Wang, Yun,Weng, Yangyang
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p. 3245 - 3250
(2020/04/21)
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- Ni(I)-Alkyl Complexes Bearing Phenanthroline Ligands: Experimental Evidence for CO2Insertion at Ni(I) Centers
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Although the catalytic carboxylation of unactivated alkyl electrophiles has reached remarkable levels of sophistication, the intermediacy of (phenanthroline)Ni(I)-alkyl species - complexes proposed in numerous Ni-catalyzed reductive cross-coupling reactions - has been subject to speculation. Herein we report the synthesis of such elusive (phenanthroline)Ni(I) species and their reactivity with CO2, allowing us to address a long-standing question related to Ni-catalyzed carboxylation reactions.
- Hazari, Nilay,Hopmann, Kathrin H.,Martin, Ruben,Obst, Marc F.,Odena, Carlota,Somerville, Rosie J.
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supporting information
p. 10936 - 10941
(2020/07/08)
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- Lessons in Strain and Stability: Enantioselective Synthesis of (+)-[5]-Ladderanoic Acid
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The synthesis of structurally complex and highly strained natural products provides unique challenges and unexpected opportunities for the development of new reactions and strategies. Herein, the synthesis of (+)-[5]-ladderanoic acid is reported. En route to the target, unusual and unexpected strain release driven transformations were uncovered. This occurrence required a drastic revision of the synthetic design that ultimately led to the development of a novel stepwise cyclobutane assembly by an allylboration/Zweifel olefination sequence.
- Hancock, Erin N.,Kuker, Erin L.,Tantillo, Dean J.,Brown, M. Kevin
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supporting information
p. 436 - 441
(2019/11/25)
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- Oxidation of Alkynyl Boronates to Carboxylic Acids, Esters, and Amides
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A general efficient protocol was developed for the synthesis of carboxylic acids, esters, and amides through oxidation of alkynyl boronates, generated directly from terminal alkynes. This protocol represents the first example of C(sp)?B bond oxidation. This approach displays a broad substrate scope, including aryl and alkyl alkynes, and exhibits excellent functional group tolerance. Water, primary and secondary alcohols, and amines are suitable nucleophiles for this transformation. Notably, amino acids and peptides can be used as nucleophiles, providing an efficient method for the synthesis and modification of peptides. The practicability of this methodology was further highlighted by the preparation of pharmaceutical molecules.
- Li, Chenchen,Li, Ruoling,Zhang, Bing,Zhao, Pei,Zhao, Wanxiang
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supporting information
p. 10913 - 10917
(2020/05/25)
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- PRODUCTION METHOD OF AMIDE COMPOUND
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PROBLEM TO BE SOLVED: To provide a production method of an amide compound, which can use a variety of carboxylic acid halides and can produce a desired amide compound at a yield higher than a batch process by suppressing a side reaction. SOLUTION: Provided is a production method of an amide compound using a flow type reactor, in which the flow type reactor includes: a first flow path; a second flow path; a first mixing means provided at a confluent part of the first flow path and the second flow path; and a third flow path that is connected to the first mixing means and arranged on a down stream side of the first mixing means, the production method comprising: a mixing step of obtaining a mixed liquid by circulating a first liquid containing the carboxylic acid halide in the first flow path, circulating a second liquid containing an amine compound having a molecular weight of 1,000 or less, an inorganic alkali and water in the second flow path, and mixing the first liquid and the second liquid by the first mixing means to obtain a mixture; and a reaction step of obtaining an amide compound by circulating the mixed liquid in the third flow path and reacting the carboxylic acid halide and the amine compound in the third flow path. SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2020,JPO&INPIT
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Paragraph 0134-0137
(2020/10/08)
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- Method for catalytically oxidizing primary alcohol into corresponding carboxylic acid and simultaneously co-producing corresponding alpha olefin
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The invention relates to a method for catalytically oxidizing primary alcohol into corresponding carboxylic acid and simultaneously co-producing corresponding alpha olefin. The method comprises the following steps: mixing primary alcohol shown as a substrate (I), a catalyst cobalt salt, a nitrogen-containing ligand and a solvent, refluxing and stirring for 4-48 hours in an oxygen or air atmospherewith a certain pressure, and distilling and separating the reacted liquid to obtain carboxylic acid shown as (II) and alpha olefin in a certain proportion. The cobalt salt catalyst used in the methodis cheap and easy to obtain, the used nitrogen-containing ligand is a commercial nitrogen-containing compound, the used oxidant is oxygen or air, the reaction condition is mild, and various primary alcohols can be converted into corresponding carboxylic acids and alpha olefins at a high conversion rate under the condition of low cost.
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Paragraph 0030-0031
(2020/12/30)
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- Catalytic Oxidative Deamination by Water with H2Liberation
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Selective oxidative deamination has long been considered to be an important but challenging transformation, although it is a common critical process in the metabolism of bioactive amino compounds. Most of the synthetic methods developed so far rely on the use of stoichiometric amounts of strong and toxic oxidants. Here we present a green and efficient method for oxidative deamination, using water as the oxidant, catalyzed by a ruthenium pincer complex. This unprecedented reaction protocol liberates hydrogen gas and avoids the use of sacrificial oxidants. A wide variety of primary amines are selectively transformed to carboxylates or ketones in good to high yields. It is noteworthy that mechanistic experiments and DFT calculations indicate that in addition to serving as the oxidant, water also plays an important role in assisting the hydrogen liberation steps involved in amine dehydrogenation.
- Tang, Shan,Rauch, Michael,Montag, Michael,Diskin-Posner, Yael,Ben-David, Yehoshoa,Milstein, David
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supporting information
p. 20875 - 20882
(2020/12/23)
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- Quantitative Evaluation of the Effect of the Hydrophobicity of the Environment Surrounding Br?nsted Acid Sites on Their Catalytic Activity for the Hydrolysis of Organic Molecules
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Sulfo-functionalized siloxane gels with a variety of surface hydrophobicities were fabricated to elucidate the effect of the environment surrounding the Br?nsted acid site on their catalytic activity for the hydrolysis of organic molecules. A detailed structural analysis of these siloxane gels by elemental analysis, X-ray photoelectron spectroscopy, Fourier-transformed infrared (FT-IR), and 29Si MAS NMR revealed the formation of gel catalysts with a highly condensed siloxane network, which enabled us to quantitatively evaluate the hydrophobicity of the environment surrounding the catalytically active sulfo-functionality. A sulfo group in a highly hydrophobic environment exhibited excellent catalytic turnover frequency for the hydrolysis of acetate esters with a long alkyl chain, whereas not only conventional solid acid catalysts but also liquid acids showed quite low catalytic activity. Detailed kinetic studies corroborated that the adsorption of oleophilic esters at the Br?nsted acid site was facilitated by the surrounding hydrophobic environment, thus significantly promoting hydrolysis under aqueous conditions. Furthermore, sulfo-functionalized siloxane gels with a highly hydrophobic surface showed excellent catalytic activity for the hydrolytic deprotection of silyl ethers.
- Miura, Hiroki,Kameyama, Shutaro,Komori, Daiki,Shishido, Tetsuya
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supporting information
p. 1636 - 1645
(2019/01/21)
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- Efficient Oxidation of Benzylic and Aliphatic Alcohols Using a Bioinspired Cross-Bridged Cyclam Manganese Complex with H2O2
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The cross-bridged cyclam manganese complex Mn(Me2EBC)Cl2 efficiently catalyzes the oxidation of benzylic and aliphatic alcohols at pH 3 in a mixture of acetonitrile and water at room temperature. The environmentally benign and high oxygen content oxidant H2O2 was adopted. Conversions of the alcohols to the corresponding carbonyl compounds reached 98 % with good to excellent selectivity. In addition, several lignin model compounds were also catalytically oxidized under these conditions, with excellent conversion (up to 96 %) and selectivity (up to 99 %).
- Zhang, Zhan,Khrouz, Lhoussain,Yin, Guochuan,Andrioletti, Bruno
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supporting information
p. 323 - 327
(2018/11/27)
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- Highly efficient and practical aerobic oxidation of alcohols by inorganic-ligand supported copper catalysis
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The oxidation of alcohols to aldehydes or ketones is a highly relevant conversion for the pharmaceutical and fine-chemical industries, and for biomass conversion, and is commonly performed using stoichiometric amounts of highly hazardous oxidants. The aerobic oxidation of alcohols with transition metal complex catalysts previously required complicated organic ligands and/or nitroxyl radicals as co-catalysts. Herein, we report an efficient and eco-friendly method to promote the aerobic oxidation of alcohols using an inorganic-ligand supported copper catalyst 1, (NH4)4[CuMo6O18(OH)6], with O2 (1 atm) as the sole oxidant. Catalyst 1 is synthesized directly from cheap and commonly available (NH4)6Mo7O24·4H2O and CuSO4, which consists of a pure inorganic framework built from a central CuII core supported by six MoVIO6 inorganic scaffolds. The copper catalyst 1 exhibits excellent selectivity and activity towards a wide range of substrates in the catalytic oxidation of alcohols, and can avoid the use of toxic oxidants, nitroxyl radicals, and potentially air/moisture sensitive and complicated organic ligands that are not commercially available. Owing to its robust inorganic framework, catalyst 1 shows good stability and reusability, and the catalytic oxidation of alcohols with catalyst 1 could be readily scaled up to gram scale with little loss of catalytic activity, demonstrating great potential of the inorganic-ligand supported Cu catalysts in catalytic chemical transformations.
- Wei, Zheyu,Ru, Shi,Zhao, Qixin,Yu, Han,Zhang, Gang,Wei, Yongge
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supporting information
p. 4069 - 4075
(2019/08/07)
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- Synthesis of Carboxylic Acids by Palladium-Catalyzed Hydroxycarbonylation
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The synthesis of carboxylic acids is of fundamental importance in the chemical industry and the corresponding products find numerous applications for polymers, cosmetics, pharmaceuticals, agrochemicals, and other manufactured chemicals. Although hydroxycarbonylations of olefins have been known for more than 60 years, currently known catalyst systems for this transformation do not fulfill industrial requirements, for example, stability. Presented herein for the first time is an aqueous-phase protocol that allows conversion of various olefins, including sterically hindered and demanding tetra-, tri-, and 1,1-disubstituted systems, as well as terminal alkenes, into the corresponding carboxylic acids in excellent yields. The outstanding stability of the catalyst system (26 recycling runs in 32 days without measurable loss of activity), is showcased in the preparation of an industrially relevant fatty acid. Key-to-success is the use of a built-in-base ligand under acidic aqueous conditions. This catalytic system is expected to provide a basis for new cost-competitive processes for the industrial production of carboxylic acids.
- Sang, Rui,Kucmierczyk, Peter,Dühren, Ricarda,Razzaq, Rauf,Dong, Kaiwu,Liu, Jie,Franke, Robert,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 14365 - 14373
(2019/09/06)
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- Aerobic Oxidation of Secondary Alcohols with Nitric Acid and Iron(III) Chloride as Catalysts in Fluorinated Alcohol
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Fluorinated alcohols as solvents strongly influence and direct chemical reaction through donation of strong hydrogen bonds while being weak acceptors. We used 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as the activating solvent for a nitric acid and FeCl3-catalyzed aerobic oxidation of secondary alcohols to ketones. Reaction proceeded selectively with excellent yields with no reaction on the primary alcohol group. Oxidation of benzyl alcohols proceeds selectively to aldehydes with only HNO3 as the catalyst, while reaction on tertiary alcohols proceeds through dehydration and dimerization. A mechanistic study showed in situ formation of NOCl that converts alcohol into alkyl nitrite, which in the presence of Fe3+ ions and fluorinated alcohol decomposes into ketone. The study indicates that iron(III) acts also as the single-electron transfer catalyst in regeneration of NOCl reactive species.
- Mo?ina, ?tefan,Iskra, Jernej
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p. 14579 - 14586
(2019/11/14)
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- Dehydrogenation of Alcohols to Carboxylic Acid Catalyzed by in Situ-Generated Facial Ruthenium- CPP Complex
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A selective catalytic system for the dehydrogenation of primary alcohols to carboxylic acids using a facial ruthenium complex generated in situ from the [Ru(COD)Cl2]n and a hybrid N-heterocyclic carbene (NHC)-phosphine-phosphine ligand (CPP) has been first reported. The facial coordination model was unveiled by NMR analysis of the reaction mixture. Such a fac-ruthenium catalyst system exhibited high catalytic activity and stability, and a high turnover number of 20 000 could be achieved with catalyst loading as low as 0.002 mol %. The exceedingly high catalyst stability was tentatively attributed to both the anchoring role of NHC and the hemi-lability of phosphines. The catalytic system also features a wide substrate scope. In particular, the facial coordination of CPP ligands was found to be beneficial for sterically hindered alcohols, and ortho-substituted benzylic alcohols and bulky adamantanyl methanol as well as cholesterol were all found to be viable dehydrogenation substrates.
- Liu, Hui-Min,Jian, Lei,Li, Chao,Zhang, Chun-Chun,Fu, Hai-Yan,Zheng, Xue-Li,Chen, Hua,Li, Rui-Xiang
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p. 9151 - 9160
(2019/08/12)
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- Highly active bidentate N-heterocyclic carbene/ruthenium complexes performing dehydrogenative coupling of alcohols and hydroxides in open air
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Eight bidentate NHC/Ru complexes, namely [Ru]-1-[Ru]-8, were designed and prepared. In particular, [Ru]-2 displayed extraordinary performance even in open air for the dehydrogenative coupling of alcohols and hydroxides. Notably, an unprecedentedly low catalyst loading of 250 ppm and the highest TON of 32 800 and TOF of 3200 until now were obtained.
- Wang, Zhi-Qin,Tang, Xiao-Sheng,Yang, Zhao-Qi,Yu, Bao-Yi,Wang, Hua-Jing,Sang, Wei,Yuan, Ye,Chen, Cheng,Verpoort, Francis
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supporting information
p. 8591 - 8594
(2019/07/25)
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- Direct oxidative esterification of primary alcohols and oxidation of secondary alcohols over mesoporous spherical silica encapsulated MnO2 nanoparticles
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In this work, a simple and efficient strategy for the fabrication of novel encapsulated MnO2 nanoparticles inside spherical mesoporous silica hollow-nanoparticles was described. They were synthesized by consecutively anchoring MnO2 nanoparticles on poly(styrene-co-methacrylic acid) particles, coating with a mesoporous silica shell, and subsequently removing the polymeric core by dissolving in acetone. The catalytic activity of the nanoparticles was examined in the aerobic oxidation of various primary and secondary alcohols, which showed good activity and selectivity for the transformation of primary alcohols to the corresponding esters through the oxidative esterification process and secondary alcohols to ketones in short reaction times under mild reaction conditions. In addition, the catalyst system was utilized for the oxidation of primary alcohols to aldehydes using tert-butyl hydroperoxide (TBHP) as an oxidant under mild conditions and produced an excellent product yield.
- Hosseinzadeh, Shahram Zare,Babazadeh, Mirzaagha,Shahverdizadeh, Gholam Hossein,Hosseinzadeh-Khanmiri, Rahim
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p. 9491 - 9499
(2019/06/21)
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- A Diaminopropane Diolefin Ru(0) Complex Catalyzes Hydrogenation and Dehydrogenation Reactions
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New ruthenium (0) complexes with a cooperative diolefin diaminopropane (DAP) or the dehydrogenated iminopropenamide ligand (IPA) were synthesized for comparison with their diaminoethane (DAE)/ diazadiene (DAD) ruthenium analogues. These DAP/IPA complexes are efficient catalysts in dehydrogenation reactions of alkaline aqueous methanol which proceeds under mild conditions (T=70 °C) and of higher alcohols, forming the corresponding carbonate and carboxylates, respectively. The scope of the reaction includes an example of a 1,2-diol as model for biomass derived alcohols. Their catalytic applications are extended to the atom-efficient dehydrogenative coupling of alcohols and amines to amides. The reaction proceeds without any additives and is applicable to the synthesis of formamides from methanol. Moreover, DAP/IPA complexes catalyze the hydrogenation of a series of esters, lactone, ketone, activated olefin, aldehyde and imine substrates. The diaminopropane Ru catalyst exhibits higher activity compared to the dehydrogenated β-ketiminate (IPA) and previously studied DAD/DAE based catalysts. We present studies on their stoichiometric reactivity with relevance to their possible catalytic mechanisms and the isolation and full characterization of key reaction intermediates.
- Casas, Fernando,Trincado, Monica,Rodriguez-Lugo, Rafael,Baneerje, Dipshikha,Grützmacher, Hansj?rg
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p. 5241 - 5251
(2019/11/16)
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- Characterization of one novel microbial esterase WDEst9 and its use to make l-methyl lactate
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Chiral lactic acids and their ester derivatives are crucial building blocks and intermediates for the synthesis of a great variety of valuable functional materials and pharmaceuticals. Before our study, the reports about the enantioselective preparation of pure L-lactic acid and its ester derivatives through direct hydrolysis of racemic substrate were quite rare. Herein, we heterologously expressed and functionally characterized one novel microbial esterase WDEst9 from Dactylosporangium aurantiacum, which exhibited high resistance to diverse metal ions, organic solvents, surfactants, NaCl and KCl. We further utilized WDEst9 as a green biocatalyst in the kinetic resolution of (±)-methyl lactate through direct hydrolysis and generated L-methyl lactate with high enantiomeric excess (e.e. >99%) and high yield (>86%) after process optimization. Notably, the enantioselectivity of WDEst9 was opposite than that of two previously reported esterases PHE14 and BSE01701 that can generate D-methyl lactate though kinetic resolution of (±)-methyl lactate. Microbial esterase WDEst9 is a promising green biocatalyst in the preparation of valuable chiral chemicals and opens the door for the identification of useful industrial enzymes and biocatalysts from the genus Dactylosporangium.
- Wang, Yilong,Xu, Shan,Li, Renqiang,Sun, Aijun,Zhang, Yun,Sai, Ke,Hu, Yunfeng
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p. 190 - 200
(2018/12/11)
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- Length-Selective Synthesis of Acylglycerol-Phosphates through Energy-Dissipative Cycling
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The main aim of origins of life research is to find a plausible sequence of transitions from prebiotic chemistry to nascent biology. In this context, understanding how and when phospholipid membranes appeared on early Earth is critical to elucidating the prebiotic pathways that led to the emergence of primitive cells. Here we show that exposing glycerol-2-phosphate to acylating agents leads to the formation of a library of acylglycerol-phosphates. Medium-chain acylglycerol-phosphates were found to self-assemble into vesicles stable across a wide range of conditions and capable of retaining mono- and oligonucleotides. Starting with a mixture of activated carboxylic acids of different lengths, iterative cycling of acylation and hydrolysis steps allowed for the selection of longer-chain acylglycerol-phosphates. Our results suggest that a selection pathway based on energy-dissipative cycling could have driven the selective synthesis of phospholipids on early Earth.
- Bonfio, Claudia,Caumes, Cécile,Duffy, Colm D.,Patel, Bhavesh H.,Percivalle, Claudia,Tsanakopoulou, Maria,Sutherland, John D.
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p. 3934 - 3939
(2019/03/08)
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- Preparation method of acid with different substituent groups
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The invention discloses a preparation method of an acid with different substituent groups. A terminal alkyne is lithiated with n-butyllithium, and then reacts with isopropoxyboronic acid pinacol ester, hydrogen chloride is added to achieve quenching, then the obtained reaction product is oxidized by an oxidizing agent, and the oxidized reaction product is separated and purified to obtain the acid.The method of the invention has the advantages of simplicity in operation, one-pot process preparation, no metal catalysis, nontoxic reagents, greenness, environmental friendliness and high atomic utilization rate, and provides a novel and quick way for preparing the acid with different substituent groups; and the obtained acid is an important fine chemical product, and can be widely used in fields of medicines, pesticides, spices and other industries.
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Paragraph 0038-0042
(2019/10/23)
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- Symmetric triazolylidene Ni(II) complexes applied as oxidation catalysts
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A set of related Ni(II) complexes of N-heterocyclic carbene ligands (NHC) [trans-X2Ni(NHC)2] (X = Cl, I) bearing linear straight chain alkyl wingtip substituents have been synthesised and fully characterised. Single crystal XRD data revealed symmetrically aligned Ni(II) centres within square planar coordination of trans halide, trans NHC ligands. The complexes were used for the catalytic oxidation of alkanes under mild conditions in conjunction with tert-butyl hydroperoxide as an oxidant. Under optimised reaction conditions, the catalytic results pointed to good activities of circa 15% and 19% for cyclohexane and n-octane respectively. Furthermore, the catalytic systems are shown to be very efficient for the oxidation of linear alcohols to corresponding ketones.
- Mncube, Siyabonga G.,Bala, Muhammad D.
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p. 467 - 473
(2018/11/06)
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- Flexible SNS pincer complexes of copper: Synthesis, structural characterisation and application in n-octane oxidation
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Two new tridentate SNS ligands based on a flexible, straight chain amine backbone were prepared and in combination with three related but previously reported ligands were reacted with CuCl2 to yield new tridentate pincer-type copper(II) complexes. The molecular structures of the new ligands bis(cyclohexylthioethyl)methylamine (L1d), bis(t-butylthioethyl)methylamine (L1e), and all the complexes Cu[bis(Rthioethyl)methylamine]Cl2 (1) where R = methyl (a); ethyl (b); butyl (c); cyclohexyl (d) and t-butyl (e); were confirmed by a range of spectroscopic and analytical techniques. Single crystal X-ray diffraction analysis determined the solid-state structures of the salt of L1e and the complexes. Complexes 1a-e all exhibited five-coordinate ligand geometry around each Cu(II) centre defined by the tridentate SNS and two chlorido donors. The complexes were applied as catalysts in the oxidation of n-octane using t-butyl hydroperoxide and hydrogen peroxide (H2O2) as oxidants. The H2O2 based systems yielded up to 36% conversion of n-octane to C-8 oxygenates with very high alcohol selectivity of up to 78%.
- Soobramoney, Lynette,Bala, Muhammad D.,Friedrich, Holger B.,Pillay, Michael N.
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- Site-Selective, Remote sp3 C?H Carboxylation Enabled by the Merger of Photoredox and Nickel Catalysis
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A photoinduced carboxylation of alkyl halides with CO2 at remote sp3 C?H sites enabled by the merger of photoredox and Ni catalysis is described. This protocol features a predictable reactivity and site selectivity that can be modulated by the ligand backbone. Preliminary studies reinforce a rationale based on a dynamic displacement of the catalyst throughout the alkyl side chain.
- Sahoo, Basudev,Bellotti, Peter,Juliá-Hernández, Francisco,Meng, Qing-Yuan,Crespi, Stefano,K?nig, Burkhard,Martin, Ruben
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supporting information
p. 9001 - 9005
(2019/06/24)
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- Biocatalytic N-Alkylation of Amines Using Either Primary Alcohols or Carboxylic Acids via Reductive Aminase Cascades
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The alkylation of amines with either alcohols or carboxylic acids represents a mild and safe alternative to the use of genotoxic alkyl halides and sulfonate esters. Here we report two complementary one-pot systems in which the reductive aminase (RedAm) from Aspergillus oryzae is combined with either (i) a 1° alcohol/alcohol oxidase (AO) or (ii) carboxylic acid/carboxylic acid reductase (CAR) to affect N-alkylation reactions. The application of both approaches has been exemplified with respect to substrate scope and also preparative scale synthesis. These new biocatalytic methods address issues facing alternative traditional synthetic protocols such as harsh conditions, overalkylation and complicated workup procedures.
- Ramsden, Jeremy I.,Heath, Rachel S.,Derrington, Sasha R.,Montgomery, Sarah L.,Mangas-Sanchez, Juan,Mulholland, Keith R.,Turner, Nicholas J.
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p. 1201 - 1206
(2019/01/21)
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