- Photochemical substitution of polyhalogenothiophene and halogenothiazole derivatives
-
The irradiation of 2,3-diodo-5-nitrothiophene in the presence of aromatic and heteroaromatic compounds gave the corresponding 2-aryl derivatives in high yields. The irradiation of 2,4-diiodo-5-nitrothiophene under the same conditions gave the corresponding 2-aryl derivatives in low yields. The observed difference in the reactivity can be explained on the basis of the hypothesis that the homolytic cleavage of the carbon-iodine bond occurred in a π,π* triplet state. Computational results showed that the lowest triplet state of the 2,3-diiodo isomer is π,π*, while that of the 2,4-isomer is π,π*. The irradiation of 2-bromo-5-nitrothiazole in the presence of benzene or indene gave the corresponding 2-bromo-5-arylthiazole. This behaviour can be explained by considering that the lowest excited triplet state cannot allow the cleavage of the carbon-bromine bond thus electron transfer occurs and leads to the substitution of the nitro group. The photochemical substitution reactions on 2,3-diiodo-5-nitrothiophene can be carried out in large scale using a new flow reactor using a PFTE pipe.
- D'Auria, Maurizio,Distefano, Claudio,D'Onofrio, Franco,Mauriello, Giacomo,Racioppi, Rocco
-
-
Read Online
- Chemoselective (Hetero)Arene Electroreduction Enabled by Rapid Alternating Polarity
-
Conventional chemical and even electrochemical Birch-type reductions suffer from a lack of chemoselectivity due to a reliance on alkali metals or harshly reducing conditions. This study reveals that a simpler avenue is available for such reductions by simply altering the waveform of current delivery, namely rapid alternating polarity (rAP). The developed method solves these issues, proceeding in a protic solvent, and can be easily scaled up without any metal additives or stringently anhydrous conditions.
- Hayashi, Kyohei,Griffin, Jeremy,Harper, Kaid C.,Kawamata, Yu,Baran, Phil S.
-
p. 5762 - 5768
(2022/04/15)
-
- Hydroboration Reaction and Mechanism of Carboxylic Acids using NaNH2(BH3)2, a Hydroboration Reagent with Reducing Capability between NaBH4and LiAlH4
-
Hydroboration reactions of carboxylic acids using sodium aminodiboranate (NaNH2[BH3]2, NaADBH) to form primary alcohols were systematically investigated, and the reduction mechanism was elucidated experimentally and computationally. The transfer of hydride ions from B atoms to C atoms, the key step in the mechanism, was theoretically illustrated and supported by experimental results. The intermediates of NH2B2H5, PhCH= CHCOOBH2NH2BH3-, PhCH= CHCH2OBO, and the byproducts of BH4-, NH2BH2, and NH2BH3- were identified and characterized by 11B and 1H NMR. The reducing capacity of NaADBH was found between that of NaBH4 and LiAlH4. We have thus found that NaADBH is a promising reducing agent for hydroboration because of its stability and easy handling. These reactions exhibit excellent yields and good selectivity, therefore providing alternative synthetic approaches for the conversion of carboxylic acids to primary alcohols with a wide range of functional group tolerance.
- Wang, Jin,Ju, Ming-Yue,Wang, Xinghua,Ma, Yan-Na,Wei, Donghui,Chen, Xuenian
-
p. 5305 - 5316
(2021/04/12)
-
- 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.
-
supporting information
p. 3315 - 3325
(2020/12/11)
-
- Reaction of Diisobutylaluminum Borohydride, a Binary Hydride, with Selected Organic Compounds Containing Representative Functional Groups
-
The binary hydride, diisobutylaluminum borohydride [(iBu)2AlBH4], synthesized from diisobutylaluminum hydride (DIBAL) and borane dimethyl sulfide (BMS) has shown great potential in reducing a variety of organic functional groups. This unique binary hydride, (iBu)2AlBH4, is readily synthesized, versatile, and simple to use. Aldehydes, ketones, esters, and epoxides are reduced very fast to the corresponding alcohols in essentially quantitative yields. This binary hydride can reduce tertiary amides rapidly to the corresponding amines at 25 °C in an efficient manner. Furthermore, nitriles are converted into the corresponding amines in essentially quantitative yields. These reactions occur under ambient conditions and are completed in an hour or less. The reduction products are isolated through a simple acid-base extraction and without the use of column chromatography. Further investigation showed that (iBu)2AlBH4 has the potential to be a selective hydride donor as shown through a series of competitive reactions. Similarities and differences between (iBu)2AlBH4, DIBAL, and BMS are discussed.
- Amberchan, Gabriella,Snelling, Rachel A.,Moya, Enrique,Landi, Madison,Lutz, Kyle,Gatihi, Roxanne,Singaram, Bakthan
-
supporting information
p. 6207 - 6227
(2021/05/06)
-
- Efficient and chemoselective hydrogenation of aldehydes catalyzed by well-defined PN3-pincer manganese(ii) catalyst precursors: An application in furfural conversion
-
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
-
supporting information
p. 11815 - 11818
(2021/11/30)
-
- Disproportionation of aliphatic and aromatic aldehydes through Cannizzaro, Tishchenko, and Meerwein–Ponndorf–Verley reactions
-
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
-
p. 803 - 808
(2021/07/20)
-
- Scope and limitations of biocatalytic carbonyl reduction with white-rot fungi
-
The reductive activity of various basidiomycetous fungi towards carbonyl compounds was screened on an analytical level. Some strains displayed high reductive activities toward aromatic carbonyls and aliphatic ketones. Utilizing growing whole-cell cultures of Dichomitus albidofuscus, the reactions were up-scaled to a preparative level in an aqueous system. The reactions showed excellent selectivities and gave the respective alcohols in high yields. Carboxylic acids were also reduced to aldehydes and alcohols under the same conditions. In particular, benzoic, vanillic, ferulic, and p-coumaric acid were reduced to benzyl alcohol, vanillin, dihydroconiferyl alcohol and 1-hydroxy-3-(4-hydroxyphenyl)propan, respectively.
- Zhuk, Tatyana S.,Skorobohatko, Oleksandra S.,Albuquerque, Wendell,Zorn, Holger
-
supporting information
(2021/02/02)
-
- Synthesis, Docking, and Biological activities of novel Metacetamol embedded [1,2,3]-triazole derivatives
-
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
-
-
- Sodium Aminodiboranate, a New Reagent for Chemoselective Reduction of Aldehydes and Ketones to Alcohols
-
Sodium aminodiboranate (NaNH 2(BH 3) 2, NaADBH) is a new member of the old borane family, which exhibits superior performance in chemoselective reduction. Experimental results show that NaADBH can rapidly reduce aldehydes and ketones to the corresponding alcohols in high efficiency and selectivity under mild conditions. There are little steric and electronic effects on this reduction.
- Wang, Jin,Guo, Yu,Li, Shouhu,Chen, Xuenian
-
supporting information
p. 1104 - 1108
(2021/05/25)
-
- Experimental and density functional theory studies on hydroxymethylation of phenylboronic acids with paraformaldehyde over a Rh-PPh3 catalyst
-
The synthesis of benzyl alcohols (BAs) is highly vital for their wide applications in organic synthesis and pharmaceuticals. Herein, BAs was efficiently synthesized via hydroxymethylation of phenylboronic acids (PBAs) and paraformaldehyde over a simple Rh-PPh3 catalyst combined with an inorganic base (NaOH). A variety of BAs with the groups of CH3?, CH3O?, Cl?, Br?, and so on were obtained with moderate to good yields, indicating that the protocol had a good universality. Density functional theory (DFT) calculations proposed the Hayashi-type arylation mechanism involved the arylation step of PBA and Rh(OH)(PPh3)2 catalyst to form Rh(I)-bound aryl intermediates and the hydrolysis step of Rh(I)-bound aryl intermediates and HCHO to generate BA product (the rate-determining step). The present route provides a valuable and direct method for the synthesis of BAs and expands the application range of paraformaldehyde.
- Wang, Kuan,Lan, Jie,He, Zhen-Hong,Cao, Zhe,Wang, Weitao,Yang, Yang,Liu, Zhao-Tie
-
-
- Microwave-heated γ-Alumina Applied to the Reduction of Aldehydes to Alcohols
-
The development of cheap and robust heterogeneous catalysts for the Meerwein-Ponndorf-Verley (MPV) reduction is desirable due to the difficulties in product isolation and catalyst recovery associated with the traditional use of homogeneous catalysts for MPV. Herein, we show that microwave heated γ-Al2O3 can be used for the reduction of aldehydes to alcohols. The reaction is efficient and has a broad substrates scope (19 entries). The products can be isolated by simple filtration, and the catalyst can be regenerated. With the use of microwave heating, we can direct the heating to the catalyst rather than to the whole reaction medium. Furthermore, DFT was used to study the reaction mechanism, and we can conclude that a dual-site mechanism is operative where the aldehyde and 2-propoxide are situated on two adjacent Al sites during the reduction. Additionally, volcano plots were used to rationalize the reactivity of Al2O3 in comparison to other metal oxides.
- Dhokale, Bhausaheb,Susarrey-Arce, Arturo,Pekkari, Anna,Runemark, August,Moth-Poulsen, Kasper,Langhammer, Christoph,H?relind, Hanna,Busch, Michael,Vandichel, Matthias,Sundén, Henrik
-
p. 6344 - 6355
(2020/10/28)
-
- Potassium Fluoride-Catalyzed Hydroboration of Aldehydes and Ketones: Facile Reduction to Primary and Secondary Alcohols
-
A catalytic hydroboration of various ketones and aldehydes can be achieved in the presence of inexpensive and commercially available inorganic salts containing fluoride anion. As a result, the reduction of carbonyl moieties to the corresponding primary and secondary alcohols can be achieved at room temperature under mild conditions.
- Kuciński, Krzysztof,Hreczycho, Grzegorz
-
p. 552 - 555
(2020/02/04)
-
- Group 6 Metal Carbonyl Complexes Supported by a Bidentate PN Ligand: Syntheses, Characterization, and Catalytic Hydrogenation Activity
-
We report on the preparation of a series of phosphorus-nitrogen donor ligand complexes [M(CO)4(PN)], where M = Cr, Mo, W and PN is 2-(diphenylphosphino)ethylamine. The organometallic compounds were readily obtained upon reacting the respective metal hexacarbonyls with equimolar amounts of the pertinent ligand in the presence of tetraethylammonium bromide. The PN-ligated metal carbonyls were fully characterized by standard spectroscopic techniques and X-ray crystallography. The ability of the title compounds to function as homogeneous hydrogenation catalysts was probed in the reduction of acetophenone and benzaldehyde derivatives to yield the corresponding alcohols. The reaction setup was easily assembled by simply combining the components in the autoclave on the bench outside an inert-gas-operated glovebox system.
- Faust, Kirill,Topf, Christoph,Vielhaber, Thomas
-
p. 4535 - 4543
(2020/12/23)
-
- Linear β-amino alcohol catalyst anchored on functionalized magnetite nanoparticles for enantioselective addition of dialkylzinc to aromatic aldehydes
-
A linear β-amino alcohol ligand, previously found to be a very efficient catalyst for enantioselective addition of dialkylzinc to aromatic aldehydes, has been anchored on differently functionalized superparamagnetic core-shell magnetite-silica nanoparticles (1a and 1b). Its catalytic activity in the addition of dialkylzinc to aldehydes has been evaluated, leading to promising results, especially in the case of 1b for which the recovery by simple magnetic decantation and reuse was successfully verified. This journal is
- Ciprioti, Stefano Vecchio,De Angelis, Martina,Di Pietro, Federica,Iannoni, Marika,Pilloni, Luciano,Primitivo, Ludovica,Ricelli, Alessandra,Righi, Francesco,Righi, Giuliana,Sappino, Carla,Suber, Lorenza
-
p. 29688 - 29695
(2020/10/26)
-
- Selective hydrogenation of primary amides and cyclic di-peptides under Ru-catalysis
-
A ruthenium(II)-catalyzed selective hydrogenation of challenging primary amides and cyclic di-peptides to their corresponding primary alcohols and amino alcohols, respectively, is reported. The hydrogenation reaction operates under mild and eco-benign conditions and can be scaled-up.
- Subaramanian, Murugan,Sivakumar, Ganesan,Babu, Jessin K.,Balaraman, Ekambaram
-
supporting information
p. 12411 - 12414
(2020/10/30)
-
- Storing redox equivalent in the phenalenyl backbone towards catalytic multi-electron reduction
-
Storing and transferring electrons for multi-electron reduction processes are considered to be the key steps in various important chemical and biological transformations. In this work, we accomplished multi-electron reduction of a carboxylic acid via a hydrosilylation pathway where a redox-active phenalenyl backbone in Co(PLY-O,O)2(THF)2, stores electrons and plays a preponderant role in the entire process. This reduction proceeds by single electron transfer (SET) from the mono-reduced ligand backbone leading to the cleavage of the Si-H bond. Several important intermediates along the catalytic reduction reaction have been isolated and well characterized to prove that the redox equivalent is stored in the form of a C-H bond in the PLY backbone via a ligand dearomatization process. The ligand's extensive participation in storing a hydride equivalent has been conclusively elucidated via a deuterium labelling experiment. This is a rare example where the ligand orchestrates the multielectron reduction process leaving only the metal to maintain the conformational requirements and fine tunes the electronics of the catalyst.
- Bhunia, Mrinal,Sahoo, Sumeet Ranjan,Shaw, Bikash Kumar,Vaidya, Shefali,Pariyar, Anand,Vijaykumar, Gonela,Adhikari, Debashis,Mandal, Swadhin K.
-
p. 7433 - 7441
(2019/08/15)
-
- A method of synthesis of primary alcohol (by machine translation)
-
The invention discloses a method for synthesizing a primary alcohol, using transition metal catalysis, the use of isopropanol as a hydrogen source to synthesize primary alcohol, the reaction not only using a cheap, environmental protection of isopropanol as a hydrogen source and solvent, and has high yield, environmental protection and the like, so that the reaction has broad prospects for development. (by machine translation)
- -
-
Paragraph 0035; 0036; 0037; 0038; 0039
(2019/03/17)
-
- Ambient-pressure hydrogenation of ketones and aldehydes by a metal-ligand bifunctional catalyst [Cp*Ir(2,2′-bpyO)(H2O)] without using base
-
An efficient catalytic system for hydrogenation of ketones and aldehydes using a Cp*Ir complex [Cp*Ir(2,2′-bpyO)(H2O)] bearing a bipyridine-based functional ligand as catalyst has been developed. A wide variety of secondary and primary alcohols were synthesized by the catalyzed hydrogenation of ketones and aldehydes under facile atmospheric-pressure without a base. The catalyst also displays an excellent chemoselectivity towards other carbonyl functionalities and unsaturated motifs. This catalytic system exhibits high activity for hydrogenation of ketones and aldehydes with H2 gas.
- Wang, Rongzhou,Qi, Jipeng,Yue, Yuancheng,Lian, Zhe,Xiao, Haibin,Zhuo, Shuping,Xing, Lingbao
-
-
- Manganese(I)-Catalyzed Transfer Hydrogenation and Acceptorless Dehydrogenative Condensation: Promotional Influence of the Uncoordinated N-Heterocycle
-
The four bidentate manganese(I) complexes [(C5H4N-C5H3N-OH)Mn(CO)3Br] (1), [(C9H6N-C5H3N-OH)Mn(CO)3Br] (2), [(C8H5N2-C5H3N-OH)Mn(CO)3Br] (3), and [(C8H5N2-C5H3N-OCH3)Mn(CO)3Br] (4) were synthesized. These complexes were tested as catalysts for the transfer hydrogenation of ketones, and 3 showed the highest activity. The reactions proceeded well with 0.5 mol % of catalyst loading and 20 mol % of t-BuOK at 85 °C for 24 h. Furthermore, 3 was also used as a catalyst for the synthesis of primary alcohols via transfer hydrogenation of aldehydes and the synthesis of 1,2-disubstituted benzimidazoles and quinolines via acceptorless dehydrogenative condensations.
- Zhang, Chong,Hu, Bowen,Chen, Dafa,Xia, Haiping
-
p. 3218 - 3226
(2019/09/13)
-
- n-Butyllithium (1 mol %)-catalyzed Hydroboration of Aldehydes and Ketones with Pinacolborane
-
A practical and efficient protocol for the hydroboration of aldehydes and ketones using a pinacolborane and alkyl lithium system is demonstrated. A systematic evaluation showed that 1 mol % n-butyllithium afforded catalyzed hydroboration of aldehydes and ketones in a short reaction time under ambient conditions. Excellent yield, functional group tolerance, short reaction time, low catalyst loading, and gram-scale synthesis are the salient features of the proposed protocol.
- Yang, Su Jin,Jaladi, Ashok Kumar,Kim, Jea Ho,Gundeti, Shankaraiah,An, Duk Keun
-
-
- Mild palladium-catalysed highly efficient hydrogenation of CN, C-NO2, and CO bonds using H2 of 1 atm in H2O
-
Here we present the first example of a mild and high-efficiency protocol enabling a process in water using 1 atm of H2 for the efficient and selective hydrogenation of nitriles, nitro compounds, ketones, and aldehydes to yield primary amines and alcohols with satisfactory yields of up to >99%. Several palladium-based nanoparticle catalysts were prepared from K2PdCl4 and ligands, and one of them was found to be the best and most suitable for the hydrogenation of CN, C-NO2, and CO bonds. In addition, the catalyst Pd-NPs can be easily recycled and reused without losing their activity and selectivity. A plausible mechanism for the hydrogenation of a CN bond was also proposed, representing the first example that possesses great potential for sustainable industrial purposes.
- Liu, Yaxu,He, Shaopo,Quan, Ziyi,Cai, Huizhuo,Zhao, Yang,Wang, Bo
-
supporting information
p. 830 - 838
(2019/02/27)
-
- Lithium triethylborohydride as catalyst for solvent-free hydroboration of aldehydes and ketones
-
Commercially available and inexpensive lithium triethylborohydride (LiHBEt3) acts as efficient catalyst for the solvent-free hydroboration of a wide range of aldehydes and ketones, which were subsequently transformed to corresponding 1° and 2° alcohols in one-pot procedure at room temperature (rt).
- Kuciński, Krzysztof,Hreczycho, Grzegorz
-
p. 1912 - 1915
(2019/04/27)
-
- Biphenyl tridentate ligand ruthenium complex and production method and application thereof
-
The invention relates to production methods of a novel biphenyl tridentate ligand and a ruthenium complex of the novel biphenyl tridentate ligand and application of the ruthenium complex of the novelbiphenyl tridentate ligand in reaction of hydrogenation of an ester compound to an alcohol compound. A method for using the biphenyl tridentate ligand ruthenium complex for catalyzing hydrogenation ofthe ester compound to the alcohol compound is characterized by comprising the steps of using the biphenyl tridentate ligand ruthenium complex which is 0.001-0.1 mol% of the amount of substance of theester compound as a catalyst, adding alkali which is 1-10 mol% of the amount of substance of the ester compound, and catalyzing hydrogenation of the ester compound to the corresponding alcohol compound under conditions of 60-100 DEG C and 30-70 MPa hydrogen pressure. The biphenyl tridentate ligand and the ruthenium complex of the biphenyl tridentate ligand are convenient to produce and stable instructure, and the ruthenium complex of the biphenyl tridentate ligand shows excellent catalytic activity in the hydrogenation reaction of the ester compound. The defects of rigorous reaction conditions of high temperature, high pressure and the like needed by existing homogeneous or heterogeneous catalytic system hydrogenated fat compounds and high dosages of catalysts are overcome, the dosage ofthe catalyst is little, the reaction conditions are mild, the selectivity of the reaction is good, and the economical efficiency and the safety of the production system are improved.
- -
-
Paragraph 0108-0114
(2019/07/17)
-
- DMSO-Triggered Complete Oxygen Transfer Leading to Accelerated Aqueous Hydrolysis of Organohalides under Mild Conditions
-
Addition of DMSO is found to greatly accelerate the aqueous hydrolysis of organohalides to alcohols, providing a neutral, more efficient, milder and more economic process. Mechanistic studies using 18O-DMSO and 18O-H2O showed that, contrary to the opinion that DMSO works as a dipolar solvent to enhance water's nucleophilicity, the accelerating effect comes from a complete oxygen transfer from DMSO to organohalides through generation of ROS+Me2?X? salts through C?O bond formation, followed by O?S bond disassociative hydrolysis of ROS+Me2?X? with water. This method is applicable to a wide range of organohalides and thus may have potential for practical industrial application, owing to easy recovery of DMSO from the H2O/DMSO mixture by regular vacuum rectification.
- Liu, Haicheng,Liu, Jianping,Cheng, Xiaokai,Jia, Xiaojuan,Yu, Lei,Xu, Qing
-
p. 2994 - 2998
(2019/01/04)
-
- Palladium doping of In2O3 towards a general and selective catalytic hydrogenation of amides to amines and alcohols
-
Herein, the first general heterogeneous catalytic protocol for the hydrogenation of primary, secondary and tertiary amides to their corresponding amines and alcohols is described. Advantageously, this catalytic protocol works under additive-free conditions and is compatible with the presence of aromatic rings, which are fully retained in the final products. This hydrogenative C-N bond cleavage methodology is catalyzed by a Pd-doped In2O3 catalyst prepared by a microwave hydrothermal-assisted method followed by calcination. This catalyst displays highly dispersed Pd2+ ionic species in the oxide matrix of In2O3 that have appeared to be essential for its high catalytic performance.
- Sorribes, Iván,Lemos, Samantha C. S.,Martín, Santiago,Mayoral, Alvaro,Lima, Renata C.,Andrés, Juan
-
p. 6965 - 6976
(2019/12/26)
-
- Cu(II) complexes of N-rich aroylhydrazone: Magnetism and catalytic activity towards microwave-assisted oxidation of xylenes
-
The new aroylhydrazone N-(di(pyridin-2-yl)methylene)pyrazine-2-carbohydrazide (HL) species, rich in N-donor sites, has been used to synthesize Cu(ii) compounds with different nuclearities, viz. the binuclear [Cu2(μ-1κN3,2κN2O-L)(Cl)3(MeOH)] (1), the octanuclear [Cu4(μ-1κN3,2κN2O-L)2(μ-Cl)3(Cl)3]2 (2) and the 1D coordination polymer [Cu3(μ3-1κN3,2κN2O,3κN-L)(μ-NO3)(NO3)3(H2O)3]n·nNO3 (3). They have been characterized by elemental analysis, FT-IR and single crystal X-ray diffraction. The magnetic properties of 2 and 3 have been explored using variable temperature magnetic measurements. The catalytic performances of the compounds were evaluated towards the peroxidative oxidation of o-, p- A nd m-xylenes under microwave irradiation, leading to the formation of the corresponding methyl benzyl alcohol, tolualdehyde and toluic acid as the major products. Complex 3 exhibits the best catalytic activity towards the oxidation of p-xylene with a total yield of 37% (4-methylbenzyl alcohol + p-tolualdehyde + p-toluic acid).
- Sutradhar, Manas,Roy Barman, Tannistha,Alegria, Elisabete C. B. A.,Guedes Da Silva, M. Fátima C.,Liu, Cai-Ming,Kou, Hui-Zhong,Pombeiro, Armando J. L.
-
p. 12839 - 12849
(2019/09/07)
-
- Multi-phase catalytic hydrogenation reduction method of unsaturated compound
-
The invention discloses a multi-phase catalytic hydrogenation reduction method of an unsaturated compound. The method comprises a step of carrying out multi-phase catalytic hydrogenation reaction to reduce the unsaturated compound; the multi-phase catalytic hydrogenation reaction takes water as a solvent and a hydrophobic and atmophile material as a catalyst. According to the multi-phase catalytichydrogenation reduction method, hydrophobic and atmophile properties of the catalyst are utilized, so that hydrogen gas can be rapidly adsorbed and spread on the surface of the catalyst, the surfacehydrogen concentration of the catalyst is improved, and the hydrogenation reaction speed is improved; a conventional pressurizing method is changed, so that requirements on equipment and dangerousnessare reduced. The atmophile catalyst Pd/GA can be used for hydrogenation of double bonds, nitryl and an aldehyde group under normal pressure, and is applicable to wide types. The method provided by the invention has a wide application potential in other fields needing gas to react.
- -
-
Paragraph 0055; 0056; 0057; 0058; 0059
(2019/04/26)
-
- Transfer Hydrogenation of Aldehydes and Ketones with Isopropanol under Neutral Conditions Catalyzed by a Metal-Ligand Bifunctional Catalyst [Cp?Ir(2,2′-bpyO)(H2O)]
-
A Cp?Ir complex bearing a functional bipyridonate ligand [Cp?Ir(2,2′-bpyO)(H2O)] was found to be a highly efficient and general catalyst for transfer hydrogenation of aldehydes and chemoselective transfer hydrogenation of unsaturated aldehydes with isopropanol under neutral conditions. It was noteworthy that many readily reducible or labile functional groups such as nitro, cyano, ester, and halide did not undergo any change under the reaction conditions. Furthermore, this catalytic system exhibited high activity for transfer hydrogenation of ketones with isopropanol. Notably, this research exhibited new potential of metal-ligand bifunctional catalysts for transfer hydrogenation.
- Wang, Rongzhou,Tang, Yawen,Xu, Meng,Meng, Chong,Li, Feng
-
p. 2274 - 2281
(2018/02/23)
-
- A Pseudodearomatized PN3P?Ni-H Complex as a Ligand and σ-Nucleophilic Catalyst
-
In contrast to the conventional strategy of modifying the reactivities and selectivities of the transition metal and organocatalysts by varying the steric and electronic properties of organic substituent groups, we hereby demonstrate a novel approach that the sigma (σ) nucleophilicity of the imine arm can be significantly enhanced in a pseudodearomatized PN3P? pincer ligand platform to reach unprecedented N-heterocyclic carbene-like reactivity. Accordingly, the imine arm of the PN3P?Ni-H pincer complex efficiently catalyzes the hydrosilylation of aldehydes, cycloaddition of carbon dioxide (CO2) to epoxides, and serves as a ligand in the Ru-catalyzed dehydrogenative acylation of amines with alcohols.
- Li, Huaifeng,Gon?alves, Théo P.,Hu, Jinsong,Zhao, Qianyi,Gong, Dirong,Lai, Zhiping,Wang, Zhixiang,Zheng, Junrong,Huang, Kuo-Wei
-
p. 14969 - 14977
(2019/01/03)
-
- Novel leucine ureido derivatives as aminopeptidase N inhibitors using click chemistry
-
The over-expression of aminopeptidase N on diverse malignant cells is associated with the tumor angiogenesis and metastasis. In this report, one new series of leucine ureido derivatives containing the triazole moiety was designed, synthesized and evaluated as APN inhibitors. Among them, compound 13v showed the best APN inhibition with an IC50 value of 0.089 ± 0.007 μM, which was two orders of magnitude lower than that of bestatin (IC50 = 9.4 ± 0.5 μM). Compound 13v also showed dose-dependent anti-angiogenesis activities. Even at the lower concentration (10 μM), compound 13v presented similar anti-angiogenesis activity compared with bestatin at 100 μM in both the human umbilical vein endothelial cells (HUVECs) capillary tube formation assay and the rat thoracic aorta rings test. Moreover, compared with bestatin, 13v exhibited comparable, if not better in vivo anti-metastasis activity in a mouse H22 pulmonary metastasis model.
- Cao, Jiangying,Ma, Chunhua,Zang, Jie,Gao, Shuai,Gao, Qianwen,Kong, Xiujie,Yan, Yugang,Liang, Xuewu,Ding, Qin'ge,Zhao, Chunlong,Wang, Binghe,Xu, Wenfang,Zhang, Yingjie
-
p. 3145 - 3157
(2018/06/01)
-
- Low-Valent Titanium-Mediated Radical Conjugate Addition Using Benzyl Alcohols as Benzyl Radical Sources
-
A concise method to directly generate benzyl radicals from benzyl alcohol derivatives has been developed. The simple and inexpensive combination of TiCl4(collidine) (collidine = 2,4,6-collidine) and manganese powder afforded a low-valent titanium reagent, which facilitated homolytic cleavage of benzylic C-OH bonds. The application to radical conjugate addition reactions demonstrated the broad scope of this method. The reaction of various benzyl alcohol derivatives with electron-deficient alkenes furnished the corresponding radical adducts.
- Suga, Takuya,Shimazu, Shoma,Ukaji, Yutaka
-
supporting information
p. 5389 - 5392
(2018/09/12)
-
- Transfer hydrogenation and hydration of aromatic aldehydes and nitriles using heterogeneous NiO nanofibers as a catalyst
-
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
-
p. 15572 - 15577
(2018/10/04)
-
- Highly dispersed ultrafine palladium nanoparticles encapsulated in a triazinyl functionalized porous organic polymer as a highly efficient catalyst for transfer hydrogenation of aldehydes
-
Fabrication of highly dispersed ultrafine noble metal nanoparticle (NMNP) based catalysts with high stability and excellent catalytic performance is a challenging issue for heterogeneous catalysis. As an alternative complement to existing solutions, herein, we designed and synthesized a stable triazinyl-pentaerythritol porous organic polymer (TP-POP) through a facile polycondensation between cyanuric chloride and pentaerythritol. The obtained TP-POP material has a three-dimensional folded structure, rich triazinyl groups, abundant hydrophobic pores and high thermal stability. Ultrafine Pd NPs with a narrow size distribution (1.4-2.8 nm) are then successfully confined in the organic pores of the TP-POP, through a reversed double solvent approach (RDSA). It is worth noting that the current strategy can effectively confine Pd NPs in the inner space of the TP-POP, and successfully avoids the agglomeration of Pd NPs as compared with the common impregnation-reduction method. The as-prepared Pd@TP-POP catalyst shows excellent catalytic activity in the reduction of 4-nitrophenol and transfer hydrogenation of aromatic aldehydes under very mild conditions. The excellent performance of the Pd@TP-POP catalyst is attributed to the abundant mesopores of the TP-POP which can enhance the accessibility of the highly dispersed ultrafine Pd NP active sites that are confined in the organic pores. More importantly, the Pd@TP-POP catalyst is easily recycled and highly stable without loss of its catalytic activity even after ten reaction cycles. Therefore, this study provides a new platform for designing and fabricating stable POP materials to confine size-controlled NMNPs with superior catalytic performance for various potential catalysis applications.
- Yang, Jin,Yuan, Man,Xu, Dan,Zhao, Hong,Zhu, Yangyang,Fan, Menying,Zhang, Fengwei,Dong, Zhengping
-
p. 18242 - 18251
(2018/10/02)
-
- Chemoselective reduction of aldehydes and ketones by potassium diisobutyl-t-butoxy aluminum hydride (PDBBA)
-
t-Butoxy derivatives of DIBALH [lithium diisobutyl-t-butoxyaluminum hydride (LDBBA), sodium diisobutyl-t-butoxyaluminum hydride (SDBBA), and potassium diisobutyl-t-butoxyaluminum hydride (PDBBA)] were examined as chemoselective reducing agents of carbonyl compounds. Among them, PDBBA was found to be the most efficient for the reduction of aldehydes and ketones to the corresponding alcohols in the presence of ester, amide, and nitrile substituents at ambient temperature. In addition, the optimal conditions gave higher chemoselectivity for aldehydes in the presence of ketones.
- Kim, Joo Yeon,Shin, Won Kyu,Jaladi, Ashok Kumar,An, Duk Keun
-
p. 4236 - 4241
(2018/06/30)
-
- Chemoselective continuous-flow hydrogenation of aldehydes catalyzed by platinum nanoparticles dispersed in an amphiphilic resin
-
A chemoselective continuous-flow hydrogenation of aldehydes catalyzed by a dispersion of platinum nanoparticles in an amphiphilic polymer (ARP-Pt) has been developed. Aromatic and aliphatic aldehydes bearing various reducible functional groups, such as keto, ester, or amide groups, readily underwent flow hydrogenation in aqueous solutions within 22 s in a continuous-flow system containing ARP-Pt to give the corresponding primary benzylic or aliphatic alcohols in ≤99% yield with excellent chemoselectivity. Moreover, the long-term continuous-flow hydrogenation of benzaldehyde for 8 days was realized, and the total turnover number of the catalyst reached 997. The flow hydrogenation system provides an efficient and practical method for the chemoselective hydrogenation of aldehydes bearing reducible functional groups.
- Osako, Takao,Torii, Kaoru,Hirata, Shuichi,Uozumi, Yasuhiro
-
p. 7371 - 7377
(2017/11/09)
-
- Synthesis of Phenanthridines through Palladium-Catalyzed Cascade Reaction of 2-Halo-N-Ms-arylamines with Benzyl Halides/Sulfonates
-
An efficient palladium-catalyzed nucleophilic substitution/C–H activation/aromatization cascade reaction between readily available 2-halo-N-Ms-arylamines (Ms = methanesulfonyl) and benzyl halides/sulfonates has been described. A wide variety of phenanthridines were synthesized in a one-pot fashion in moderate to high yields (37–86 %). Notably, this method provides a straightforward, facile approach for the synthesis of phenanthridines. The practicality was further substantiated by successfully carrying out a gram-scale preparation.
- Yang, Si-Yi,Han, Wen-Yong,Zhang, Ding-Lei,Zhou, Xiao-Jian,Bai, Mei,Cui, Bao-Dong,Wan, Nan-Wei,Yuan, Wei-Cheng,Chen, Yong-Zheng
-
p. 996 - 1003
(2017/02/15)
-
- Selective One-Pot Three-Step Cascade Reaction: From Aromatic Aldehydes to 2,2-Diphenylethanol Derivatives
-
We report herein a green and scalable one-pot, three-step, pinacol-coupling-rearrangement-reduction cascade reaction useful for the formation of 2,2-diphenylethanol derivatives. The reaction is carried out in water in the presence of a commercially available and regenerable supported acid under moderate pressure. A dozen of aromatic aldehydes have been successfully submitted to the standard protocol giving the target 2,2-diarylethanol derivatives in good yield (70-85%).
- Billamboz, Muriel,Imbs, Claire,Banaszak-Léonard, Estelle,Len, Christophe
-
p. 835 - 843
(2017/06/23)
-
- Method for preparing alcohol by hydrolyzing halogenated hydrocarbon
-
The invention provides a method for preparing alcohol by hydrolyzing halogenated hydrocarbon. According to the invention, the relatively low-cost halogenated hydrocarbon is used as a raw material, a low-toxic stable mixture of DMSO and water is used as a solvent, no additional catalyst is required, and the halogenated hydrocarbon can be directly hydrolyzed into corresponding alcohol by only adding little alkali or additive into low-activity halogenated hydrocarbon. According to method, the inert gas shielding is not required, the operation is simple and feasible, the requirement for the experimental equipment is low, the product yield is high, and the method is suitable for preparing different types of alcohol by hydrolyzing different types of halogenated hydrocarbon. Thus, the method has certain theoretical research values and potential application prospects.
- -
-
Paragraph 0030; 0031; 0032; 0033
(2017/10/22)
-
- Efficient carbon-supported heterogeneous molybdenum-dioxo catalyst for chemoselective reductive carbonyl coupling
-
Reductive coupling of various carbonyl compounds to the corresponding symmetric ethers with dimethylphenylsilane is reported using a carbon-supported dioxo-molybdenum catalyst. The catalyst is air- and moisture-stable and can be easily separated from the reaction mixture for recycling. In addition, the catalyst is chemoselective, thus enabling the synthesis of functionalized ethers without requiring sacrificial ligands or protecting groups.
- Liu, Shengsi,Li, Jiaqi,Jurca, Titel,Stair, Peter C.,Lohr, Tracy L.,Marks, Tobin J.
-
p. 2165 - 2169
(2017/07/22)
-
- Direct Catalytic Hydrogenation of Simple Amides: A Highly Efficient Approach from Amides to Amines and Alcohols
-
A highly chemoselective and reactive direct catalytic reduction of various amides to amines and alcohols was developed by using a tetradentate ruthenium complex. The catalytic system showed excellent activity (turnover numbers up to 19 600) and great functional group tolerance under mild reaction conditions, compared to several bidentate and tridentate ruthenium-catalyzed systems.
- Shi, Liyang,Tan, Xuefeng,Long, Jiao,Xiong, Xiong,Yang, Song,Xue, Peng,Lv, Hui,Zhang, Xumu
-
supporting information
p. 546 - 548
(2017/01/18)
-
- Ultrasonic-promoted selective reduction of aldehydes vs. ketones by NaBH4/PhCO2Na/H2O
-
In this study, we have investigated the selective reduction of aldehydes vs. ketones by NaBH4/PhCO2Na/H2O system under ultrasound irradiation. NaBH4 (1.25 equivalents) and PhCO2Na (2 equivalents) is optimized conditions for reduce a variety of aldehydes (1 mmol) in the presence of ketones (1 mmol) to their corresponding alcohols in water as green solvent in high to excellent yields of the product (90-95%). A benzoate-borane complex [PhCO2-H3B]Na is possibly the active reductant in the reaction mixture.
- Mirtaghizadeh, Mina,Setamdideh, Davood
-
p. 1539 - 1543
(2016/08/06)
-
- An Efficient, Stable and Reusable Palladium Nanocatalyst: Chemoselective Reduction of Aldehydes with Molecular Hydrogen in Water
-
Palladium nanoparticles (Pd-BNP) stabilized by a binaphthyl-backbone can be efficiently used for the chemoselective reduction of aldehydes in the presence of hydrogen at room temperature in water. The Pd-BNP catalyst is easily recovered and reused for five catalytic cycles. (Figure presented.).
- Kotha, Surya Srinivas,Sharma, Nidhi,Sekar, Govindasamy
-
supporting information
p. 1694 - 1698
(2016/10/13)
-
- Generation, Stability, and Utility of Lithium 4,4′-Di-tert-butylbiphenylide (LiDBB)
-
Several procedures were evaluated for the preparation of lithium 4,4′-di-tert-butylbiphenylide (LiDBB, Freeman's reagent) from lithium metal and 4,4′-di-tert-butylbiphenyl (DBB) in THF. Solutions with nominal concentration of 0.4 and 1.0 M were formed. The stability of LiDBB solutions was evaluated over time, and the gradual uptake of lithium metal was observed. At 0 °C the LiDBB solutions were stable for over a week in THF. At 20 °C the LiDBB solution underwent various decomposition pathways, which led to uptake of more lithium metal and the accumulation of side products. These decomposition pathways were studied, and the importance of ethene in the destruction of THF by LiDBB was observed. On a practical note, LiDBB solutions in THF were stable and effective for over a week at 0 °C or for more than 37 weeks when stored under argon at -25 °C. These observations will extend the utility of LiDBB as a reagent in organic synthesis.
- Hill, Richard R.,Rychnovsky, Scott D.
-
p. 10707 - 10714
(2016/11/29)
-
- Size Specific Activity of Polymer Stabilized Gold Nanoparticles for Transfer Hydrogenation Catalysis
-
Abstract: [Poly (N-Vinyl Pyrrollidone)] (PVP) (K30, average Mol. Wt., 40?kDa) stabilized gold nanoparticles with four different size (mean diameter) of 1.4?±?0.2, 3.8?±?0.4, 5.5?±?0.8 and 7.8?±?1?nm were synthesized using solution based chemical reduction method and used as catalysts for transfer hydrogenation reaction. Transfer hydrogenation of several organic functional groups (>C=O, –CH=O, –NO2, –CH=CH2, –C≡C–H, –C≡N) were studied using potassium formate (HCOOK) as hydrogen source in water. The major focus of this work was on catalytic activity, product selectivity and recycling ability of Au:PVP nanoparticles as a transfer hydrogenation catalyst. The size specific catalytic activity showed that up to 3.8?nm sized gold nanoparticles are highly active catalyst and afterwards its activity diminishes sharply with increasing particle size. Mechanistic insight showed that formate ions are activated on gold surface and produced bound hydride species, which is the active intermediate for this catalytic transformation. Graphical Abstract: [Figure not available: see fulltext.]
- Chavda, Nikeshsinh,Trivedi, Abhishek,Thakarda, Jaydev,Agrawal, Yadvendra K.,Maity, Prasenjit
-
p. 1331 - 1339
(2016/07/06)
-
- Liquid-phase oxidation with hydrogen peroxide of benzyl alcohol and xylenes on Ca10(PO4)6(OH)2 – CaWO4
-
A W-containing apatite (W/HAp) catalyst was prepared following a hydrothermal synthesis route and served as a model catalyst. Crystallographic analysis indicated that the resulting material contained hydroxyapatite, Ca10?3xWx(PO4)6(OH)2, W-hydroxyapatite, calcium tungstate, CaWO4, and tricalcium phosphate, Ca3(PO4)2. The catalyst was investigated in liquid phase oxidation of benzyl alcohol and xylenes using hydrogen peroxide as an oxidant. For comparison, commercial calcium phosphate, hydroxyapatite and CaWO4 were tested in the same reaction. Calcium phosphate and hydroxyapatite appeared as inactive and decomposed hydrogen peroxide non-selectively. A moderate activity but low hydrogen peroxide efficiency was observed for the CaWO4 phase. In contrast, the W/HAp catalyst showed a reasonable activity and a better hydrogen peroxide efficiency in the oxidation of benzyl alcohol and xylenes. This new W/HAp catalyst showed, after six cycles, losses of the activity below 15% compared to the fresh catalyst with no effect on the selectivity. It is noteworthy that ICP-OES analyses showed no tungsten leaching that is the main advantage of this catalyst.
- Domínguez, María Isabel,Cojocaru, Bogdan,Tudorache, Madalina,Odriozola, José Antonio,Centeno, Miguel Angel,Parvulescu, Vasile I.
-
p. 1156 - 1165
(2016/10/13)
-
- NOVEL IMINES WITH TUNABLE NUCLEOPHILICITY AND STERIC PROPERTIES THROUGH METAL COORDINATION: APPLICATIONS AS LIGANDS AND METALLOORGANOCATALYSTS
-
The invention describes phospho-amino pincer-type ligands, metal complexes thereof, and catalytic methods comprising such metal complexes for conversion of carbon dioxide to methanol, conversion of aldehydes into alcohols, conversion of aldehydes in the presence of a trifluoromethylation agent into trifluorinated secondary alcohols, cycloaddition of carbon dioxide to an epoxide to provide cyclic carbonates or preparation of an amide from the combination of an alcohol and an amine.
- -
-
Paragraph 0179; 0187
(2016/04/20)
-
- Coproduction method of methyl benzyl alcohol, methyl benzaldehyde, and methyl benzoic acid
-
The invention discloses a coproduction method of methyl benzyl alcohol, methyl benzaldehyde, and methyl benzoic acid. The coproduction method comprises the following steps: mixing xylene, a co-oxidization agent (a C8 oxygen-containing compound), and a catalyst, and continuously introducing oxygen-containing gas to carry out reactions. By controlling the amount of the added oxygen-containing gas, the content of oxygen gas in tail gas is not more than 5%. The mass ratio of the co-oxidization agent (a C8 oxygen-containing compound) to xylene is 0.003-0.2:1, and the using amount of the catalyst is 10-10000 ppm of the weight of the xylene. The reaction temperature is 105 to 200 DEG C, the reaction pressure is 0.2 to 2.5 MPa, the reaction time is 0.4 to 5 hours, and the xylene is oxidized into a mixture of methyl benzyl alcohol, methyl benzaldehyde, and methyl benzoic acid in one step. The method has the advantages of mild reaction conditions, high product yield, good selectivity, green, and environment-friendliness.
- -
-
Paragraph 0070; 0071
(2017/01/12)
-
- Combined production method for substituted benzaldehyde, substituted benzyl alcohol and substituted benzoic acid
-
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 0101; 0102
(2017/01/31)
-
- Preparation and characterization of a RHA/TiO2 nanocomposite: Introduction of an efficient and reusable catalyst for chemoselective trimethylsilyl protection and deprotection of alcohols and phenols
-
In this work, rice husk ash (RHA), as a natural source of amorphous silica, was used as a support for the synthesis of anatase-phase titania nanoparticles leading to the RHA/TiO2 nanocomposite. This nanocomposite was used as an efficient catalyst for the chemoselective trimethylsilylation of various alcohols and phenols and deprotection of the obtained trimethylsilyl ethers. The procedure gave the products in excellent yields in very short reaction times. Also this catalyst can be reused at least six times without loss of its catalytic activity.
- Seddighi, Mohadeseh,Shirini, Farhad,Goli-Jolodar, Omid
-
p. 23564 - 23570
(2016/03/12)
-
- Highly chemoselective hydrogenation of active benzaldehydes to benzyl alcohols catalyzed by bimetallic nanoparticles
-
By using novel Pd/Ni bimetallic nanoparticles as a catalyst, the active benzaldehydes were hydrogenated to the corresponding benzyl alcohols as unique products in practical quantitative yields. The undesired catalytic hydrogenolysis of the benzyl alcohol was inhibited completely. By using this hydrogenation as a key step, the total synthesis of the natural product gastrodin was achieved with less total steps and a higher total yield.
- Liu, Chulong,Bao, Hailin,Wang, Dingsheng,Wang, Xinyan,Li, Yadong,Hu, Yuefei
-
p. 6460 - 6462
(2015/11/16)
-