- Generation of Oxidoreductases with Dual Alcohol Dehydrogenase and Amine Dehydrogenase Activity
-
The l-lysine-?-dehydrogenase (LysEDH) from Geobacillus stearothermophilus naturally catalyzes the oxidative deamination of the ?-amino group of l-lysine. We previously engineered this enzyme to create amine dehydrogenase (AmDH) variants that possess a new hydrophobic cavity in their active site such that aromatic ketones can bind and be converted into α-chiral amines with excellent enantioselectivity. We also recently observed that LysEDH was capable of reducing aromatic aldehydes into primary alcohols. Herein, we harnessed the promiscuous alcohol dehydrogenase (ADH) activity of LysEDH to create new variants that exhibited enhanced catalytic activity for the reduction of substituted benzaldehydes and arylaliphatic aldehydes to primary alcohols. Notably, these novel engineered dehydrogenases also catalyzed the reductive amination of a variety of aldehydes and ketones with excellent enantioselectivity, thus exhibiting a dual AmDH/ADH activity. We envisioned that the catalytic bi-functionality of these enzymes could be applied for the direct conversion of alcohols into amines. As a proof-of-principle, we performed an unprecedented one-pot “hydrogen-borrowing” cascade to convert benzyl alcohol to benzylamine using a single enzyme. Conducting the same biocatalytic cascade in the presence of cofactor recycling enzymes (i.e., NADH-oxidase and formate dehydrogenase) increased the reaction yields. In summary, this work provides the first examples of enzymes showing “alcohol aminase” activity.
- Tseliou, Vasilis,Schilder, Don,Masman, Marcelo F.,Knaus, Tanja,Mutti, Francesco G.
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supporting information
p. 3315 - 3325
(2020/12/11)
-
- Efficient and chemoselective hydrogenation of aldehydes catalyzed by well-defined PN3-pincer manganese(ii) catalyst precursors: An application in furfural conversion
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Well-defined and air-stable PN3-pincer manganese(ii) complexes were synthesized and used for the hydrogenation of aldehydes into alcohols under mild conditions using MeOH as a solvent. This protocol is applicable for a wide range of aldehydes containing various functional groups. Importantly, α,β-unsaturated aldehydes, including ynals, are hydrogenated with the CC double bond/CC triple bond intact. Our methodology was demonstrated for the conversion of biomass derived feedstocks such as furfural and 5-formylfurfural to furfuryl alcohol and 5-(hydroxymethyl)furfuryl alcohol respectively.
- Gholap, Sandeep Suryabhan,Dakhil, Abdullah Al,Chakraborty, Priyanka,Li, Huaifeng,Dutta, Indranil,Das, Pradip K.,Huang, Kuo-Wei
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supporting information
p. 11815 - 11818
(2021/11/30)
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- Disproportionation of aliphatic and aromatic aldehydes through Cannizzaro, Tishchenko, and Meerwein–Ponndorf–Verley reactions
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Disproportionation of aldehydes through Cannizzaro, Tishchenko, and Meerwein–Ponndorf–Verley reactions often requires the application of high temperatures, equimolar or excess quantities of strong bases, and is mostly limited to the aldehydes with no CH2 or CH3 adjacent to the carbonyl group. Herein, we developed an efficient, mild, and multifunctional catalytic system consisting AlCl3/Et3N in CH2Cl2, that can selectively convert a wide range of not only aliphatic, but also aromatic aldehydes to the corresponding alcohols, acids, and dimerized esters at room temperature, and in high yields, without formation of the side products that are generally observed. We have also shown that higher AlCl3 content favors the reaction towards Cannizzaro reaction, yet lower content favors Tishchenko reaction. Moreover, the presence of hydride donor alcohols in the reaction mixture completely directs the reaction towards the Meerwein–Ponndorf–Verley reaction. Graphic abstract: [Figure not available: see fulltext.].
- Sharifi, Sina,Sharifi, Hannah,Koza, Darrell,Aminkhani, Ali
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p. 803 - 808
(2021/07/20)
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- Synthesis, Docking, and Biological activities of novel Metacetamol embedded [1,2,3]-triazole derivatives
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ERα controls the breast tissue development and progression of breast cancer. In our search for novel compounds to target Estrogen Receptor Alpha Ligand-Binding Domain, we identified “N-(3-((1H-1,2,3-triazol-4-yl)methoxy)phenyl)acetamide” derivatives as lead compounds. The Docking studies indicated good docking score for Metacetamol derivatives when docked into the 1XP6. A series of metacetamol derivatives have been synthesized, characterized and evaluated for cytotoxicity, anti bacterial and anti oxidant activities. Among the tested twelve hybrid compounds, “7a, 7g, 7h and 7i” derivatives showed promising cytotoxicity with IC50 value of 50 value of 30 μM, whereas Compounds “7a, 7b, 7c, 7d, 7g, 7j, 7k and 7l” showed moderate anti bacterial activity with the MIC value of 300 μM.
- Battu, Satyanarayana,Joolakanti, Hima Bindhu,Kamepalli, Ramanjaneyulu,Miryala, Jeevanreddy
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-
- Bimetallic Bis-NHC-Ir(III) Complex Bearing 2-Arylbenzo[d]oxazolyl Ligand: Synthesis, Catalysis, and Bimetallic Effects
-
Herein, an unprecedented bimetallic bis-NHC Cp*Ir complex 1 bearing 2-arylbenzo[d]oxazolyl and NHC ligands is reported. A significant increase in activity was observed for N-methylation of amines and reduction of aldehydes with MeOH catalyzed by 1 compared to the monometallic analogues (2-11). Under the optimal conditions, it showed to be highly effective in N-methylation of nitroarenes with MeOH as both C1 and H2 source. Substrates, including aromatic amines, ketones, and nitro compounds with various functional groups, can be well-tolerated. Mechanistic studies and DFT calculation highlight the significance of bimetallic centers cooperativity.
- Huang, Shuang,Hong, Xi,Cui, He-Zhen,Zhan, Bing,Li, Zhi-Ming,Hou, Xiu-Feng
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p. 3514 - 3523
(2020/10/09)
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- Cerium(IV) Carboxylate Photocatalyst for Catalytic Radical Formation from Carboxylic Acids: Decarboxylative Oxygenation of Aliphatic Carboxylic Acids and Lactonization of Aromatic Carboxylic Acids
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We found that in situ generated cerium(IV) carboxylate generated by mixing the precursor Ce(OtBu)4 with the corresponding carboxylic acids served as efficient photocatalysts for the direct formation of carboxyl radicals from carboxylic acids under blue light-emitting diodes (blue LEDs) irradiation and air, resulting in catalytic decarboxylative oxygenation of aliphatic carboxylic acids to give C-O bond-forming products such as aldehydes and ketones. Control experiments revealed that hexanuclear Ce(IV) carboxylate clusters initially formed in the reaction mixture and the ligand-to-metal charge transfer nature of the Ce(IV) carboxylate clusters was responsible for the high catalytic performance to transform the carboxylate ligands to the carboxyl radical. In addition, the Ce(IV) carboxylate cluster catalyzed direct lactonization of 2-isopropylbenzoic acid to produce the corresponding peroxy lactone and ?3-lactone via intramolecular 1,5-hydrogen atom transfer (1,5-HAT).
- Hirosawa, Keishi,Mashima, Kazushi,Satoh, Tetsuya,Shinohara, Koichi,Shirase, Satoru,Tamaki, Sota,Tsurugi, Hayato
-
supporting information
(2020/03/25)
-
- One-Pot Cascade Biotransformation for Efficient Synthesis of Benzyl Alcohol and Its Analogs
-
Benzyl alcohol is a naturally occurring aromatic alcohol and has been widely used in the cosmetics and flavor/fragrance industries. The whole-cell biotransformation for synthesis of benzyl alcohol directly from bio-based L-phenylalanine (L-Phe) was herein explored using an artificial enzyme cascade in Escherichia coli. Benzaldehyde was first produced from L-Phe via four heterologous enzymatic steps that comprises L-amino acid deaminase (LAAD), hydroxymandelate synthase (HmaS), (S)-mandelate dehydrogenase (SMDH) and benzoylformate decarboxylase (BFD). The subsequent reduction of benzaldehyde to benzyl alcohol was achieved by a broad substrate specificity phenylacetaldehyde reductase (PAR) from Solanum lycopersicum. We found the designed enzyme cascade could efficiently convert L-Phe into benzyl alcohol with conversion above 99%. In addition, we also examined L-tyrosine (L-Tyr) and m-fluoro-phenylalanine (m-f-Phe) as substrates, the cascade biotransformation could also efficiently produce p-hydroxybenzyl alcohol and m-fluoro-benzyl alcohol. In summary, the developed biocatalytic pathway has great potential to produce various high-valued fine chemicals.
- Liu, Lijun,Zhu, Yuling,Chen, Yufen,Chen, Huiyu,Fan, Cong,Mo, Qiwen,Yuan, Jifeng
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supporting information
p. 1018 - 1021
(2020/03/04)
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- Polypyridyl iridium(III) based catalysts for highly chemoselective hydrogenation of aldehydes
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Iridium-catalyzed transfer hydrogenation (TH) of carbonyl compounds using HCOOR (R = H, Na, NH4) as a hydrogen source is a pivotal process as it provides the clean process and is easy to execute. However, the existing highly efficient iridium catalysts work at a narrow pH; thus, does not apply to a wide variety of substrates. Therefore, the development of a new catalyst which works at a broad pH range is essential as it can gain a broader scope of utilization. Here we report highly efficient polypyridyl iridium(III) catalysts, [Ir(tpy)(L)Cl](PF6)2 {where tpy = 2,2′:6′,2′'-Terpyridine, L = phen (1,10-Phenanthroline), Me2phen (4,7-Dimethyl-1,10-phenanthroline), Me4phen (3,4,7,8-Tetramethyl-1,10-phenanthroline), Me2bpy (4,4′-Dimethyl-2–2′-dipyridyl)} for the chemoselective reduction of aldehydes to alcohols in aqueous ethanol and sodium formate as the hydride source. The reaction can be carried out efficiently in broad pH ranges, from pH 6 to 11. These catalysts are air stable, easy to prepare using commercially available starting materials, and are highly applicable for a wide range of substrates, such as electron-rich or deficient (hetero)arenes, halogens, phenols, alkoxy, ketones, esters, carboxylic acids, cyano, and nitro groups. Particularly, acid and hydroxy groups containing aldehydes were reduced successfully in basic and acidic reaction conditions, demonstrating the efficiency of the catalyst in a broad pH range with high conversion rates under microwave irradiation.
- Pandrala, Mallesh,Resendez, Angel,Malhotra, Sanjay V.
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p. 283 - 288
(2019/09/30)
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- A new anthraquinoid ligand for the iron-catalyzed hydrosilylation of carbonyl compounds at room temperature: New insights and kinetics
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The reaction of 1-((2-(pyridin-2-yl)ethyl)amino)anthraquinone with either Fe(HMDS)2 or Li(HMDS)/FeCl2 allowed the preparation of a new anthraquinoid-based iron(ii) complex active in the hydrosilylations of carbonyls. The new complex Fe(2)2 was characterized by single-crystal X-ray diffraction, infrared spectroscopy, NMR, and high resolution mass spectrometry (electrospray ionization). Superconducting quantum interference device (SQUID) magnetometry established no spin crossover behavior with an S = 2 state at room temperature. This complex was determined to be an effective catalyst for the hydrosilylation of aldehydes and ketones, exhibiting turnover frequencies of up to 63 min-1 with a broad functional group tolerance by just using 0.25 mol% of the catalyst at room temperature, and even under solvent-free conditions. The aldehyde hydrosilylation makes it one of the most efficient first-row transition metal catalysts for this transformation. Kinetic studies have proven first-order dependences with respect to acetophenone and Ph2SiH2 and a fractional order in the case of the catalyst.
- Raya-Barón, álvaro,Galdeano-Ruano, Carmen P.,O?a-Burgos, Pascual,Rodríguez-Diéguez, Antonio,Langer, Robert,López-Ruiz, Rosalía,Romero-González, Roberto,Kuzu, Istemi,Fernández, Ignacio
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p. 7272 - 7281
(2018/06/04)
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- Transfer hydrogenation and hydration of aromatic aldehydes and nitriles using heterogeneous NiO nanofibers as a catalyst
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A simple and efficient hydrogen transfer reaction of aldehydes and hydration of nitriles using nickel oxide nanofibers (NiO NFs) as a heterogeneous catalyst is reported. NiO NFs prepared by electrospinning technique was cubic (confirmed by XRD) with an average diameter of 80 nm (obtained from HR-TEM) and utilized as a nanocatalyst for heterogeneous transfer hydrogenation of aromatic aldehydes and hydration of aromatic nitriles. All the reaction products produced with minimum reaction time and maximum yield were confirmed using GC-MS with NIST library. Furthermore, heterogeneity of the catalyst was confirmed with ICP-MS analysis. The as-prepared catalyst was reused for six cycles and was found to be efficient. Hence, the present catalytic synthesis of alcohols and amides may be an economically viable process.
- Thenmozhi,Kadirvelu
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p. 15572 - 15577
(2018/10/04)
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- Cooperative interplay between a flexible PNN-Ru(II) complex and a NaBH4 additive in the efficient catalytic hydrogenation of esters
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A catalyst loading of between 0.001-0.05 mol% of the PNN-bearing ruthenium(II) complex [fac-PNN]RuH(PPh3)(CO) (PNN = 8-(2-diphenylphosphinoethyl)amidotrihydroquinoline), in combination with 5 mol% NaBH4, efficiently catalyzes the hydrogenation of esters to their corresponding alcohols under mild pressures of hydrogen. Both aromatic and aliphatic esters can be converted with high values of TON or TOF achievable. Mechanistic investigations using both DFT calculations and labeling experiments highlight the cooperative role of NaBH4 in the catalysis while the catalytically active species has been established as trans-dihydride [mer-PNHN]RuH2(CO) (PNHN = 8-(2-diphenylphosphinoethyl)aminotrihydroquinoline). The stereo-structure of the PNHN-ruthenium species greatly affects the activity of the catalyst, and indeed the cis-dihydride isomer [fac-PNHN]RuH2(CO) is unable to catalyze the hydrogenation of esters until ligand reorganization occurs to give the trans isomer.
- Wang, Zheng,Chen, Xiangyang,Liu, Bo,Liu, Qing-Bin,Solan, Gregory A.,Yang, Xinzheng,Sun, Wen-Hua
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p. 1297 - 1304
(2017/05/05)
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- Synthesis and biological evaluation of curcumin inspired indole analogues as tubulin polymerization inhibitors
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In our endeavour towards the development of potent cytotoxic agents, a series of some new curcumin inspired indole analogues, in which indole and phenyl moieties are linked on either sides of 1,5-diaryl-1,4-pentadien-3-one system have been synthesized and characterized by spectral data. All the newly synthesized analogues were tested for their cytotoxic potential against a panel of eight cancer cell lines namely, lung (A549), breast (MDA-MB-231, BT549 and 4T1), prostate (PC-3, DU145), gastric (HGC-27) and cervical (HeLa). Notably, among all the compounds tested, compounds 11c, 11d and 11f showed potent growth inhibition on PC-3 and BT549 with IC50values in the range of 3.12–6.34?μM and 4.69–8.72?μM respectively. The most active compound (11c) was also tested on RWPE-1 (normal prostate) cells and was found to be safe compared to the PC-3?cells. In tubulin polymerization assay, compounds 11c and 11f effectively inhibited microtubule assembly with IC50values of 10.21?±?0.10 and 8.83?±?0.06?μM respectively. The results from molecular modelling studies revealed that these compounds bind at the colchicine binding site of the tubulin. Moreover, DAPI and acridine orange/ethidium bromide staining studies indicated that compounds 11c and 11f can induce apoptosis in PC-3?cells. Further flow-cytometry analysis revealed that compound 11c arrests PC-3?cells in G2/M phase of the cell cycle while compound 11f treatment resulted in moderate increase in the G2/M population. Additionally, the treatment by these compounds led to the impairment of mitochondrial membrane potential (DΨm) in PC-3?cells.
- Sri Ramya,Angapelly, Srinivas,Guntuku, Lalita,Singh Digwal, Chander,Nagendra Babu, Bathini,Naidu,Kamal, Ahmed
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p. 100 - 114
(2016/12/30)
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- COMPOSITIONS AND METHODS FOR REDUCTION OF KETONES, ALDEHYDES AND IMINIUMS, AND PRODUCTS PRODUCED THEREBY
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A method of producing an alcohol, comprises reducing an aldehyde or a ketone with a hydridosilatrane. The reducing is carried out with an activator.
- -
-
Paragraph 0076-0077
(2018/01/20)
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- Silatrane as a Practical and Selective Reagent for the Reduction of Aryl Aldehydes to Benzylic Alcohols
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Hydrosilanes are cheap, readily available substrates, yet they do not see as extensive use for simple carbonyl reductions as borohydrides. Hydrosilane reducing agents broadly fall into one of two general categories: either a) they are easy to handle and require expensive and/or hazardous additives, or b) they are difficult and/or dangerous to handle. This work details the discovery of mild and functional group compatible conditions utilizing hydrosilatrane for the selective reduction of aryl aldehydes to benzylic alcohols without unwanted formation of ethers or deoxygenated products. This method offers significant advances in silane reductions as silatrane is an air- and moisture-stable yet relatively reactive reducing agent that can be used in benchtop open air reactions.
- Skrypai, Vladislav,Hurley, Joseph J. M.,Adler, Marc J.
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supporting information
p. 2207 - 2211
(2016/05/09)
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- Combined production method for substituted benzaldehyde, substituted benzyl alcohol and substituted benzoic acid
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The invention discloses a combined production method for substituted benzaldehyde, substituted benzyl alcohol and substituted benzoic acid. The method comprises the following steps: (1) oxidation: a step of continuously introducing substituted toluene, a catalyst and oxygen-contained gas into an oxidation reactor and carrying out reaction so as to obtain oxidation reaction liquid; (2) hydrolyzation: a step of allowing the oxidation reaction liquid to continuously enter a hydrolysis reactor, and continuously adding water into the hydrolysis reactor and carrying out reaction so as to obtain a hydrolysis reaction mixture; (3) liquid-liquid layering: a step of layering the hydrolysis reaction mixture so as to obtain an oil phase and an aqueous phase; and (4) separation of products: a step of subjecting the oil phase to distillation so as to respectively obtain incompletely-reacted substituted toluene, substituted benzyl alcohol and substituted benzaldehyde, and subjecting the aqueous phase to cooling, crystallizing and filtering so as to obtain filtrate and substituted benzoic acid. The combined production method provided by the invention has the advantages of high raw material conversion rate, few by-products, good selectivity of target products, greenness and environmental protection.
- -
-
Paragraph 0085; 0086
(2017/01/31)
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- Method for preparing alcohol through catalytic hydrogenation reduction of carboxylate
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The invention discloses a method for preparing alcohol through catalytic hydrogenation reduction of a carboxylate compound with 2-(diphenylphosphinoethyl)-(5,6,7,8-tetrahydroquinolyl)amine as a ruthenium complex catalyst of ligand. The catalyst has high-efficiency catalysis activity on alkyl benzoate, aromatic esters and fatty esters. The preparation method is simple and has good stability, the catalysis activity of the catalyst is high, and the dosage of the catalyst is 0.025-0.005% of the mole of a substrate. The method can be used for producing alcohols, and has the advantages of simplicity, small pollution to environment, high yield and low cost. Most of carboxylate can be hydrogenated and reduced to form alcohols by using a complex represented by formula (1) with sodium borohydride as an additive, and the conversion number TOC can reach 50000; and a cocaalyst sodium borohydride is used to substitute most of alcoholic alkalis used as a catalyst in especially used in aromatic esters with electron-withdrawing substituent, so the cost is reduced, operation is simple, and industrial production is easy.
- -
-
Paragraph 0023; 0025; 0028; 0040
(2016/12/07)
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- Unexpectedly fast catalytic transfer hydrogenation of aldehydes by formate in 2-propanol-water mixtures under mild conditions
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Unsaturated aldehydes were efficiently reduced by transfer hydrogenation from sodium formate in water-2-propanol mixtures using a water-soluble Ru(II)-tertiary phosphine catalyst. The reaction yielded unsaturated alcohols with complete selectivity and without hydrogenation or isomerization of CC bonds of the substrates. Very high reaction rate was observed in the transfer hydrogenation of cinnamaldehyde already at 30 °C with turnover frequency of 160 h-1 and this increased to 3800 h-1 at 70 °C. Consequently, the method is applicable to the synthesis of unsaturated alcohols in case of heat sensitive or highly volatile aldehydes, too. Based on multinuclear NMR investigations, trans-[RuH2(H2O)(mtppms)3] is suggested as the key catalytic species.
- Szatmári, Imre,Papp, Gábor,Joó, Ferenc,Kathó, ágnes
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- Pt nanoparticles entrapped in mesoporous metal-organic frameworks MIL-101 as an efficient catalyst for liquid-phase hydrogenation of benzaldehydes and nitrobenzenes
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Metal organic-framework MIL-101 and inorganic mesoporous composites Al2O3@SBA-15 supported Pt catalysts, Pt/MIL-101 and Pt/Al2O3@SBA-15 catalysts, were prepared and characterized by means of X-ray diffraction (XRD), N2 adsorption-desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), CO chemisorption and thermo-gravimetric (TG) analysis. Pt nanoparticles were highly dispersed on both supports. In liquid-phase hydrogenation of nitrobenzene, benzaldehyde and their derivatives, the Pt/MIL-101 catalyst was superior to the Pt/Al2O3@SBA-15 catalyst in water. For liquid-phase hydrogenation of nitrobenzene with the Pt/MIL-101 catalyst, owing to high solubility of nitrobenzene in ethanol, the reaction in ethanol went much faster than that in water, furnishing a turnover frequency (TOF) in ethanol up to 18,053 h-1, almost triple of that obtained in water under similar conditions. The highest TOF of 25,438 h-1 was obtained in ethanol for hydrogenation of 3-chloro-nitrobenzene with the Pt/MIL-101 catalyst. As for hydrogenation of benzaldehyde series, 2-fluoro-benzaldehyde and 3-fluoro-benzaldehyde gave the highest TOFs of 5146 h-1 and 3165 h-1 in water with the Pt/MIL-101 and Pt/Al2O3@SBA-15 catalysts, respectively. We deduce that surface property of MIL-101 with high hydrophobicity is helpful to enrich reactants around the Pt/MIL-101 catalyst in water, where nitrobenzene or benzaldehyde and its derivatives have a limited solubility, so that high catalytic performance was achieved with the Pt/MIL-101 catalyst in water. Of particular note is that the Pt/MIL-101 catalyst can be reused at least four times without loss in activity or selectivity.
- Pan, Huiyan,Li, Xiaohong,Yu, Yin,Li, Junrui,Hu, Jun,Guan, Yejun,Wu, Peng
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- Hydrosilylation of aldehydes and ketones catalyzed by half-sandwich manganese(I) N-heterocyclic carbene complexes
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Easily available manganese(I) N-heterocyclic carbene (NHC) complexes, Cp(CO)2Mn(NHC), obtained in one step from industrially produced cymantrene, were evaluated as pre-catalysts in the hydrosilylation of carbonyl compounds under UV irradiation. Complexes with NHC ligands incorporating at least one mesityl group led to the most active and selective catalytic systems. A variety of aldehydes (13 examples) and ketones (11 examples) were efficiently reduced under mild conditions [Cp(CO)2Mn(IMes) (1 mol%), Ph 2SiH2 (1.5 equiv.), hν (350 nm), toluene, 25 °C, 1-24 h] with good functional group tolerance.
- Zheng, Jianxia,Elangovan, Saravanakumar,Valyaev, Dmitry A.,Brousses, Remy,Cesar, Vincent,Sortais, Jean-Baptiste,Darcel, Christophe,Lugan, Noel,Lavigne, Guy
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supporting information
p. 1093 - 1097
(2014/04/03)
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- Ru nanoparticles entrapped in ordered mesoporous carbons: An efficient and reusable catalyst for liquid-phase hydrogenation
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Ru nanoparticles entrapped in ordered mesoporous carbons (CMK-3) served as an efficient and reusable catalyst for liquid-phase hydrogenation of benzaldehyde and its derivatives under our tested conditions (medium hydrogen pressure, room temperature, water as solvent). The Ru nanoparticles can be well stabilized by CMK-3 ordered mesoporous carbons so that the Ru leaching was below the detection limit of ICP-AES. Therefore, the Ru/CMK-3 catalyst can be used for at least five times without distinct loss in activity or selectivity for the hydrogenation of benzaldehyde. It is worthy of note that the Ru/CMK-3 catalyst was more efficient than the commercial Ru/C and homemade Ru/AC catalyst for the liquid-phase hydrogenation of benzaldehyde. The Ru/ CMK-3 catalyst can also catalyze the liquid-phase hydrogenation of nitrobenzene and its derivatives with high conversions and excellent selectivities under optimal conditions. Springer Science+Business Media New York 2013.
- Ding, Yue,Li, Xiaohong,Pan, Huiyan,Wu, Peng
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p. 268 - 277
(2014/05/06)
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- Electrophilicity and nucleophilicity of commonly used aldehydes
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The present approach for determining the electrophilicity (E) and nucleophilicity (N) of aldehydes includes a kinetic study of KMNO4 oxidation and NaBH4 reduction of aldehydes. A transition state analysis of the KMNO4 promoted aldehyde oxidation reaction has been performed, which shows a very good correlation with experimental results. The validity of the experimental method has been tested using the experimental activation parameters of the two reactions. The utility of the present approach is further demonstrated by the theoretical versus experimental relationship, which provides easy access to E and N values for various aldehydes and offers an at-a-glance assessment of the chemical reactivity of aldehydes in various reactions. the Partner Organisations 2014.
- Pratihar, Sanjay
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p. 5781 - 5788
(2014/07/22)
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- Discovery of potent and specific dihydroisoxazole inhibitors of human transglutaminase 2
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Transglutaminase 2 (TG2) is a ubiquitously expressed enzyme that catalyzes the posttranslational modification of glutamine residues on protein or peptide substrates. A growing body of literature has implicated aberrantly regulated activity of TG2 in the pathogenesis of various human inflammatory, fibrotic, and other diseases. Taken together with the fact that TG2 knockout mice are developmentally and reproductively normal, there is growing interest in the potential use of TG2 inhibitors in the treatment of these conditions. Targeted-covalent inhibitors based on the weakly electrophilic 3-bromo-4,5-dihydroisoxazole (DHI) scaffold have been widely used to study TG2 biology and are well tolerated in vivo, but these compounds have only modest potency, and their selectivity toward other transglutaminase homologues is largely unknown. In the present work, we first profiled the selectivity of existing inhibitors against the most pertinent TG isoforms (TG1, TG3, and FXIIIa). Significant cross-reactivity of these small molecules with TG1 was observed. Structure-activity and -selectivity analyses led to the identification of modifications that improved potency and isoform selectivity. Preliminary pharmacokinetic analysis of the most promising analogues was also undertaken. Our new data provides a clear basis for the rational selection of dihydroisoxazole inhibitors as tools for in vivo biological investigation.
- Kl?ck, Cornelius,Herrera, Zachary,Albertelli, Megan,Khosla, Chaitan
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supporting information
p. 9042 - 9064
(2015/03/14)
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- Metal-free, visible-light photoredox catalysis: Transformation of arylmethyl bromides to alcohols and aldehydes
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A mild, simple, and controllable metal-free photocatalytic system for the transformation of arylmethyl bromides to corresponding alcohols and aldehydes in high yields with visible-light irradiation has been achieved. Eosin Y was found to be an efficient promoter for this oxidative dehalogenation reaction under photo irradiation conditions.
- Li, Jian,Wang, Hongni,Liu, Li,Sun, Jiangtao
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p. 49974 - 49978
(2014/12/10)
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- Benzylic hydroxylation of aromatic compounds by P450 BM3
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Cytochrome P450 BM3 monooxygenase from Bacillus megaterium and its variants are promising catalysts for organic synthesis. Aiming at the identification of variants for selective hydroxylation of functionalised aromatic compounds, the double mutant F87A L188C showed remarkably improved catalytic activity towards a set of tested toluene derivatives. The apparent catalytic efficiency of this variant towards the model substrate methyl 2-methoxy-3-methylbenzoate was 63.6 s-1 M-1, which is 535-fold higher compared to that of wild-type BM3. Furthermore, the double mutant selectively catalysed the benzylic hydroxylation of numerous toluene derivatives, especially in the presence of carbonyl- or carboxyl-functions that are directly attached to the aromatic ring. Preparative scale conversion resulted in efficient production of methyl 3-(hydroxymethyl)-2-methoxybenzoate (73% yield) which proved that F87A L188C is a suitable, efficient and sustainable catalyst for the introduction of benzylic hydroxyl groups in general.
- Neufeld, Katharina,Marienhagen, Jan,Schwaneberg, Ulrich,Pietruszka, Joerg
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p. 2408 - 2421
(2013/09/12)
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- Pt nanoparticles supported on highly dispersed TiO2 coated on SBA-15 as an efficient and recyclable catalyst for liquid-phase hydrogenation
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A series of TiO2@SBA-15 composites with different TiO 2 loadings have been synthesized through hydrolysis of tetrabutyl orthotitanate via a facile sol-gel method in the presence of SBA-15 mesoporous silica. The TiO2@SBA-15 composites retain the mesostructure of the SBA-15 host, and TiO2 is highly dispersed and uniformly coated. The TiO2@SBA-15 composites serve as remarkable supports for Pt nanoparticles, which can be applied efficiently to the liquid-phase hydrogenation of benzaldehyde, its derivatives, and other unsaturated compounds under mild conditions. Of particular note is that the Pt/TiO2@SBA-15 catalysts can be reused several times without distinct loss in activity or selectivity. The more electron-deficient surface state, together with the structural and physicochemical features of Pt/TiO2@SBA-15 catalysts, would improve the catalytic activity and reusability toward the liquid-phase hydrogenation of unsaturated compounds.
- Li, Xiaohong,Zheng, Wenli,Pan, Huiyan,Yu, Yin,Chen, Li,Wu, Peng
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supporting information
p. 9 - 19
(2013/04/23)
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- PROCESS FOR PRODUCTION OF AROMATIC ALCOHOL OR HETEROCYCLIC AROMATIC ALCOHOL
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A process of production of an aromatic alcohol or a heterocyclic aromatic alcohol, containing a step of reacting an aromatic amine or a heterocyclic aromatic amine having an aromatic ring or a heterocyclic aromatic ring having thereon at least one substituent -CHR1NR2R3 (wherein R1, R2 and R3 each independently represent hydrogen, an alkyl group having from 1 to 4 carbon atoms, or a benzyl group), with an alcohol, in the presence of a basic catalyst.
- -
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Paragraph 0033-0034
(2013/11/19)
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- Pt nanoparticles entrapped in ordered mesoporous carbons for liquid-phase hydrogenation of unsaturated compounds
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Pt nanoparticles entrapped in ordered mesoporous carbons were proved effective for liquid-phase hydrogenation of benzaldehyde and its derivatives in water. Due to higher hydrophobicity, Pt/CMK-3 catalyst was slightly superior to Pt/CMK-8 catalyst towards benzaldehyde hydrogenation. Nevertheless, the larger pore volume of Pt/CMK-8 catalyst is more beneficial for mass transfer of benzaldehyde derivatives. In addition, the surface electronic state of Pt particles deposited on CMK-8 is helpful for the activation of carbonyl compounds. Therefore, the Pt/CMK-8 and Pt/CMK-3 catalysts showed tiny differences in most cases. The Pt catalysts can also catalyze the hydrogenation of olefins and other carbonyl compounds.
- Ding, Yue,Li, Xiaohong,Li, Bo,Wang, Haihong,Wu, Peng
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p. 147 - 151
(2013/01/14)
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- SUBSTITUTED AROMATIC CARBOXAMIDE AND UREA DERIVATIVES AS VANILLOID RECEPTOR LIGANDS
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The invention relates to substituted aromatic carboxamide and urea derivatives, to processes for the preparation thereof, to pharmaceutical compositions containing these compounds and also to the use of these compounds for preparing pharmaceutical compositions (formula (I)).
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Page/Page column 131
(2010/11/18)
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- Revisiting the Meerwein-Ponndorf-Verley reduction: A sustainable protocol for transfer hydrogenation of aldehydes and ketones
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An economical and sustainable transfer hydrogenation for aldehydes and ketones is described. The general protocol is mild, chemo-selective and, importantly, uses neither precious nor non-precious metals and even no ligands. The Royal Society of Chemistry 2009.
- Polshettiwar, Vivek,Varma, Rajender S.
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experimental part
p. 1313 - 1316
(2010/05/02)
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- Efficient hydrogenation of benzaldehydes over mesopolymer-entrapped pt nanoparticles in water
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Pt nanoparticles entrapped in the matrices of FDU-14 periodic mesoporous organic polymer (abbreviated as mesopolymer), prepared by a simple nd facile method, serve as an efficient catalyst for the liquid-phase hydrogenation of benzaldehydes under mild conditions. Water was confirmed to be a better choice of solvent for the hydrogenation of benzaldehydes on the Pt/FDU-14 catalyst. The highest activity (turnover frequency) was about 5700 mol-1mol -1h-1 for 3-fluorobenzaldehyde hydrogenation in water and no distinct loss of activity or selectivity was observed after the catalyst was recycled nine times. For the para-substituted benzaldehydes, the catalytic performance of Pt/FDU-14 was superior to the commercial Pt/alumina catalyst owing to the more hydrophobic nature of the FDU-based catalyst.
- Li, Xiaohong,Shen, Yali,Song, Liying,Wang, Hongna,Wu, Haihong,Liu, Yueming,Wu, Peng
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experimental part
p. 699 - 706
(2011/06/26)
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- Self-modulated highly chemoselective direct-reductive-amination (DRA) of benzaldehydes straightforward to N-monosubstituted benzylamine hydrochlorides
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An unprecedented efficient and chemoselective DRA of benzaldehydes and primary amines was developed to directly yield N-monosubstituted benzylamine hydrochlorides as single products in practically quantitative yields. The method was characterized by simply adding a few milliliters of CHCl3 in the conventional Pd-C catalytic hydrogenation system at atmospheric pressure and room temperature. A self-modulated system and a four-stage cyclic pathway were proposed.
- Xing, Lixin,Cheng, Chuanjie,Zhu, Rui,Zhang, Boyang,Wang, Xinyan,Hu, Yuefei
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scheme or table
p. 11783 - 11788
(2009/04/05)
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- Enzyme-catalysed synthesis and reactions of benzene oxide/oxepine derivatives of methyl benzoates
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A series of twelve benzoate esters was metabolised, by species of the Phellinus genus of wood-rotting fungi, to yield the corresponding benzyl alcohol derivatives and eight salicylates. The isolation of a stable oxepine metabolite, from methyl benzoate, allied to evidence of the migration and retention of a carbomethoxy group (the NIH Shift), during enzyme-catalysed ortho-hydroxylation of alkyl benzoates to form salicylates, is consistent with a mechanism involving an initial arene epoxidation step. This mechanism was confirmed by the isolation of a remarkably stable, optically active, substituted benzene oxide metabolite of methyl 2-(trifluoromethyl)benzoate, which slowly converted into the racemic form. The arene oxide was found to undergo a cycloaddition reaction with 4-phenyl-1,2,4-triazoline-3,5-dione to yield a crystalline cycloadduct whose structure and racemic nature was established by X-ray crystallography. The metabolite was also found to undergo some novel benzene oxide reactions, including epoxidation to give an anti-diepoxide, base-catalysed hydrolysis to form a trans-dihydrodiol and acid-catalysed aromatisation to yield a salicylate derivative via the NIH Shift of a carbomethoxy group. This journal is The Royal Society of Chemistry.
- Boyd, Derek R.,Sharma, Narain D.,Harrison, John S.,Malone, John. F.,McRoberts, W. Colin,Hamilton, John T. G.,Harper, David B.
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experimental part
p. 1251 - 1259
(2008/10/09)
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- Lithium bromide as a flexible, mild, and recyclable reagent for solvent-free cannizzaro, tishchenko, and meerwein-ponndorf-verley reactions
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A room temperature convenient disproportionation or reduction of aldehydes prompted by lithium bromide and triethylamine is described in a solvent-free environment. Distribution of the products to selectively direct the process toward Cannizzaro or Tishchenko reactions is controlled by the type of workup selection. The presence of hydrogen donor alcohols in the mixture completely diverts the process toward the MeerweinPonndorf-Verley reaction.
- Mojtahedi, Mohammad M.,Akbarzadeh, Elahe,Sharifi, Roholah,Abaee, M. Saeed
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p. 2791 - 2793
(2008/02/05)
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- A convenient and general iron-catalyzed hydrosilylation of aldehydes
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A general and highly chemoselective hydrosilylation of aldehydes using iron catalysts is reported. Fe(OAc)2 in the presence of tricyclohexylphosphine as ligand and polymethylhydrosiloxane (PMHS) as an economical hydride source forms an efficient catalyst system for the hydrosilylation of a variety of aldehydes. Aryl, heteroaryl, alkyl and α,β-unsaturated aldehydes are successfully reduced to the corresponding primary alcohols. Broad substrate scope and high tolerance against several functional groups make the process synthetically useful.
- Shaikh, Nadim S.,Junge, Kathrin,Beller, Matthias
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p. 5429 - 5432
(2008/09/19)
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- A simple reduction of methyl aromatic esters to alcohols using sodium borohydride-methanol system
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Several aromatic esters were reduced to the corresponding alcohol by using sodium borohydride-methanol system. The reduction was completed within 2.0-4.0h after refluxing in THF. The alcohol products were isolated after aqueous workup in good yields (88-97%).
- Boechat, Núbia,Santos Da Costa, Jorge Carlos,De Souza Mendon?a, Jorge,Mello De Oliveira, Pedro Santos,Nora De Souza, Marcus Vinícius
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p. 6021 - 6022
(2007/10/03)
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- On the Mechanism of the Oxidation of Toluenes in Artificial P450 Model Systems: Formation of Benzyl Alcohols, Benzaldehydes and Phenols
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Systems with pentafluoroiodosylbenzene (PFIB) and hemin (FeTPPCl8Cl) in dichloromethane were adopted to study the activities of the model system using toluenes as substrates for P450 enzymes. The oxidation products were mainly corresponding benzyl alcohols and benzaldehydes. Previously reported suspension systems were extended to homogeneous mixed solution systems of CH2Cl2/CH3OH/H2O to study the oxidation of benzyl alcohols to the corresponding benzaldehydes: the Hammett relation with ρ = -0.86 against ?+. As benzaldehydes were scarcely observed in natural P450 systems, the formation of benzaldehyde seemed characteristic only of the "open" model systems. In suspension systems, the product ratios between corresponding benzaldehydes and benzyl alcohols (ald/alc) were about 0.1-0.4, specific to the substituents and conditions applied. Curiously, the ratios (ald/alc) increased with the electronegativity of the substituents on the phenyl rings of the toluene derivatives. Time course experiments in suspension systems indicated that benzyl alcohols and benzaldehydes were formed not stepwise, but simultaneously from toluene. Separate experiments indicated that the reaction of benzyl alcohol to benzaldehyde was four-fold faster than that of toluene to benzyl alcohol. The rate was not enough to elucidate the amount of benzaldehyde. We suggest that the benzyl radical is formed by hydrogen abstraction and is attacked by the second oxidant, PFIB. Rebounding of the hydroxyl radical and the reaction with the oxidant were competitive depending on the conditions. Additionally, small amounts of phenols were formed from toluenes with electron-donating substituents. This was a minor reaction on which the aromatic hydroxylation occurred via epoxidation under the present conditions.
- Nakano, Taku,Kawabata, Sally,Sugihara, Tamami,Agatsuma, Noriko,Kakuda, Hiroko,Mori, Yoshihiro
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p. 2353 - 2360
(2007/10/03)
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- Synthesis of Primary Amines: First Homogeneously Catalyzed Reductive Amination with Ammonia
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(Matrix Presented) The synthesis of primary amines via reductive amination of the corresponding carbonyl compounds with aqueous ammonia is achieved for the first time with soluble transition metal complexes. Up to an 86% yield and a 97% selectivity for benzylamines were obtained in the case of various benzaldehydes by using a Rh-catalyst together with water-soluble phosphine and ammonium acetate. In the case of aliphatic aldehydes, a bimetallic catalyst based on Rh/Ir gave improved results.
- Gross, Thoralf,Seayad, Abdul Majeed,Ahmad, Moballigh,Beller, Matthias
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p. 2055 - 2058
(2007/10/03)
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- Magnesium-mediated carbon-carbon bond formation in aqueous media: Barbier-Grignard allylation and pinacol coupling of aldehydes
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Magnesium-mediated Barbier-Grignard type alkylation of aldehydes with alkyl halides was studied in aqueous media. The reaction of aromatic aldehydes with allyl halides is highly effective with either THF or water as the reaction solvent but poor in a mixture of THF/water. It was found that the magnesium-mediated allylation of aldehydes with allyl bromide and iodide proceeds effectively in aqueous 0.1 N HCl or 0.1 N NH4Cl. Aromatic aldehydes reacted chemoselectively in the presence of aliphatic aldehydes. An exclusive selectivity was also observed when both aliphatic and aromatic aldehyde functionalities are present in the same molecule. In the absence of allyl halides, aldehydes and ketones reacted with magnesium in aqueous 0.1 N NH4Cl to form the corresponding pinacol coupling products in high yields. The effectiveness of the pinacol reaction was strongly influenced by the steric environment surrounding the carbonyl group. Aliphatic aldehydes and simple alkyl halides appear inert under the reaction conditions for either alkylation or the pinacol coupling reaction.
- Zhang, Wen-Chun,Li, Chao-Jun
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p. 3230 - 3236
(2007/10/03)
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- Magnesium in water: Simple and effective for pinacol-coupling
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A simple and effective pinacol-coupling has been carried out with magnesium. The reaction is highly effective in water in the presence of a catalytic amount of ammonium chloride. Under these conditions, various aromatic aldehydes and ketones undergo carbonyl coupling, generating 1,2-diols in good yields. The effectiveness of the reaction is strongly influenced by the steric environment surrounding the carbonyl group. Aliphatic aldehydes appear inert under the reaction conditions.
- Zhang, Wen-Chun,Li, Chao-Jun
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p. 3131 - 3132
(2007/10/03)
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- Correlation Analysis of Reactivity in the Oxidation of Substituted Benzyl Alcohols by Pyridinium Hydrobromide Perbromide
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Oxidation of monosubstituted benzyl alcohols by pyridinium hydrobromide perbromide (PHPB) leads to the formation of the corresponding benzaldehydes.The reaction is first order with respect to PHPB.Michaelis-Menten-type kinetics were observed with respect to he alcohol.The oxidation of α,α-dideuteriobenzyl alcohol indicated the presence of a substantial kinetic isotope effect.The rates of oxidation of meta- and para-substituted benzyl alcohols were correlated in terms of Taft's and Swain's dual substituent-parameter equations.The rates of the meta compounds correlated best with Taft's ?1 and ?0R values whereas the para-compounds showed an excellent correlation with Taft's ?1 and ?R + constants.The rates of the otho-substituted alcohols showed very good correlation with Charton's triparametric equation.The rate increased with an increase in the polarity of the solvent.A mechanism involving a rapid reversible formation of an intermediate complex and its subsequent decomposition in the rate-determining step has been proposed.
- Suri, Deepa,Banerji, Kalyan K.,Kothari, Seema
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p. 1734 - 1758
(2007/10/03)
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- Group 6 anionic ·-hydride complexes [HM2(CO)10]- (M = Cr, Mo, W): New catalysts for hydrogenation and hydrosilylation
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Group 6 anionic ·-hydride complexes catalyze hydrogenation of conjugated olefins, aldehydes, ketoesters, and alkynes, and hydrosilylation of aldehydes and conjugated olefins with high regio- and stereoselectivity. Ketones are converted into silyl ethers and silyl enol ethers with monohydrosilanes and dihydrosilanes, respectively.
- Fuchikami, Takamasa,Ubukata, Yumiko,Tanaka, Yasutaka
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p. 1199 - 1202
(2007/10/02)
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- The Hammett Relationship in the Reduction of Aldehydes with 2-Propanol by Catalysis with Hydrous Zirconium Oxide
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A linear correlation of the Hammett relationship was obtained for a catalytic reduction of substituted benzaldehydes with 2-propanol with hydrous zirconium oxide.The reaction constant p was 1.35, indicating that the electronic effect on the reaction is larger than on the standard one.
- Shibagaki, Makoto,Kuno, Hideyuki,Takahashi, Kyoko,Matsushita, Hajime
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p. 4153 - 4154
(2007/10/02)
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- Reductive C2-Homologation of Substituted Benzaldehydes by Fermenting Baker's Yeast
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Reduction of benzaldehyde and substituted benzaldehydes with actively fermenting baker's yeast afforded optically active 1-arylpropane-1,2-diols in fairly good yields, as well as benzylic alcohols.It was revealed that benzaldehydes substituted with electron-withdrawing groups, which were previously reported to result only corresponding benzylic alcohols, were also reduced to give propanediol compounds in moderate yields.The reaction was shown to be highly diastereo-selective for erythro diols (>97percent d.e.).The optical purities of the erythro isomers (1R,2S) were also extremely high (>97percent e.e.), and single recrystallization of dibenzoates gave optically pure diol derivatives within the limits of HPLC analysis.
- Ohta, Hiromichi,Ozaki, Kazuhiko,Konishi, Jin,Tsuchihashi, Gen-ichi
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p. 1261 - 1266
(2007/10/02)
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- SUBSTITUENT EFFECTS IN THE PHOTOSOLVOLYSIS OF BENZYL DERIVATIVES. GENERAL STRUCTURE-REACTIVITY RELATIONSHIPS.
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The relative reactivity of photosolvolysis of a number of substituted benzyl acetates is in the order ortho > meta > para, these substitutent effects being apparently additive, as suggested by the relative reactivity of photomethanolysis of several dimethoxy-susbstituted benzyl alcohols.
- Wan, Peter,Chak, Becky,Li, Carrier
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p. 2937 - 2940
(2007/10/02)
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- Photochemical Transformations. 26. Sensitized and Unsensitized Photoreactions of Some Benzyl Chlorides in tert-Butyl Alcohol
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Benzyl chloride and a variety of meta- and para-substituted derivatives have been irradiated in tert-butylalcohol at 254 nm or in acetone-tert-butyl alcohol mixtures at 300 nm.Quantum and chemical yields of photosolvolysis products (benzyl tert-butyl ether and/or benzyl alcohol), photohomolysis products (bibenzyl and 4-phenyl-2-methyl-2-butanol), and corresponding products from substituted benzylchlorides have been measured as functions of substrate concentration and medium composition.Sensitized reactions favor bond heterolysis, but direct irradiations favor homolysis, although reactions are not clean in either case.There is no correlation between quantum yields for photosolvolysis and Hammett ? or Brown ?+ constants, and no salt effects of added lithium perchlorate were observed, in either direct or sensitized reactions.
- Cristol, Stanley J.,Bindel, Thomas H.
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p. 951 - 957
(2007/10/02)
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