104013-25-4Relevant academic research and scientific papers
STEREOCHEMICAL CONTROL IN YEAST REDUCTION
Nakamura, Kaoru,Ushio, Kazutoshi,Oka, Shinzaburo,Ohno, Atsuyoshi,Yasui, Shinro
, p. 3979 - 3982 (1984)
A substrate which is subjected to yeast reduction has been modified by iodination or phenylsulfonylation.Both substituents improves chemical and optical yields and control the stereochemical course of the reduction.
Cyclopentadienyl-ruthenium(II) complexes as efficient catalysts for the reduction of carbonyl compounds
Cabrita, Ivania R.,Florindo, Pedro R.,Fernandes, Ana C.
, p. 1511 - 1516 (2017)
This work reports the reduction of a large variety of aldehydes and ketones with the system PhSiH3/[CpRu(PPh3)2Cl] in good to excellent yields and high chemoselectivity. The catalyst [CpRu(PPh3)2Cl] can be used in at least 12 catalytic cycles with excellent catalytic activity and several substrates were reduced under solvent free conditions.
Catalytic hydrogenation of carbonyl and nitro compounds using an [: N, O] -chelate half-sandwich ruthenium catalyst
Yao, Zi-Jian,Zhu, Jing-Wei,Lin, Nan,Qiao, Xin-Chao,Deng, Wei
, p. 7158 - 7166 (2019)
A series of N,O-chelate half-sandwich ruthenium complexes for both carbonyl and nitro compound hydrogenation have been synthesized based on β-ketoamino ligands. All complexes exhibited high activity for the catalytic hydrogenation of a series of ketones and nitroarenes with molecular H2 as the reducing reagent in aqueous medium. Consequently, the catalytic system showed the catalytic TON values of 950 for 1-phenylethanol in acetophenone hydrogenation and 1960 for 1-chloro-4-nitrobenzene in p-chloroaniline hydrogenation. Good catalytic activity was displayed for various kinds of substrates with either electron-donating or electron-withdrawing groups. The neutral ruthenium complexes 1-4 were fully characterized using NMR, IR, and elemental analysis. Molecular structures of complexes 2 and 4 were further confirmed using single-crystal X-ray diffraction analysis.
Highly dispersed Ni nanoparticles on mesoporous silica nanospheres by melt infiltration for transfer hydrogenation of aryl ketones
Kweon, Hyemin,Jang, Sanha,Bereketova, Akerke,Chan Park, Ji,Park, Kang Hyun
, p. 14154 - 14159 (2019)
Nickel-based catalysts have been applied to the catalytic reactions for transfer hydrogenation of carbonyl compounds. In the present work, highly dispersed nickel particles located at the pores of mesoporous silica spheres (Ni@mSiO2) were prepared via an optimized melt infiltration route. The nickel nanoparticles of 10 wt% in the Ni@mSiO2 catalyst could be uniformly loaded with high dispersion of 36.3%, resulting excellent performance for catalytic transfer hydrogenation of aryl ketones.
Chiral ruthenium catalyst immobilized within magnetically retrievable mesoporous silica microcapsules for aqueous asymmetric transfer hydrogenations
Zoabi, Amani,Omar, Suheir,Abu-Reziq, Raed
, p. 2101 - 2109 (2015)
The preparation of magnetically separable silica microcapsules that incorporate in their inner shell a chiral catalyst and their application in asymmetric transfer hydrogenation reactions are described. The preparation method is based on the emulsification of an oil phase containing chloroform, a modified Noyori Ru-TsDPEN catalyst, tetraethoxysilane (TEOS), and hydrophobic magnetic nanoparticles in water in the presence of an appropriate surfactant, followed by an interfacial polycondensation process under basic conditions to generate a silica shell around the oil droplets. The resulting catalytic microreactors can be considered a "quasi-homogeneous" system because the immobilized chiral catalyst reacts in a homogeneous zone, the microcapsule core filled with an organic solvent. The catalytic activity was tested in the asymmetric transfer hydrogenation of ketones in an aqueous medium. The catalytic reactions took place only in the presence of surfactants. In addition, the judicious selection of the surfactant plays a crucial role in enhancing the reaction progress through the emulsion-solid transfer (EST) approach. The catalytic activity of the Ru-TsDPEN catalyst immobilized within the silica microcapsules was superior to the same catalyst supported on silica microspheres or linked to the backbone of a silica sol-gel matrix, which indicates the importance of the homogeneous zones for the reactions. We report the design of a "quasi-homogeneous" catalytic system, based on a modified Noyori Ru-TsDPEN catalyst confined within mesoporous silica-based microreactors, for the efficient asymmetric transfer hydrogenation of ketones in water. The new system demonstrates excellent reactivity and enantioselectivity characteristic of homogeneous catalysts, but can be easily recovered.
Transfer hydrogenation of ketones catalyzed by a trinuclear Ni(II) complex of a Schiff base functionalized N-heterocyclic carbene ligand
Abubakar, Samaila,Ibrahim, Halliru,Bala, Muhammad D.
, p. 276 - 282 (2019)
A new Schiff base-functionalized N-heterocyclic carbene ligand precursor 3-benzyl-1-[2-((2-hydroxy-benzylidene)-amino]-ethyl-3H-imidazol-1-ium bromide (3), and its trinuclear Ni(II) complex [LNiL-Ni-LNiL].2Br (4) where L = 2-[2-(3-benzylimidazol-1-yl) ethyliminomethyl]phenol, were synthesized via the solventless and free carbene routes respectively. Both compounds were characterized by spectroscopic and X-ray diffraction techniques. Single crystal XRD analysis of 4 showed that it is composed of a central square planar Ni(II) ion symmetrically linked to two distorted square planar Ni(II) ions via two bridging ligands. The central Ni(II) ion is only bound to the Schiff base moieties of the bridging ligands via the phenolate oxygen donor (O1) and imine nitrogen donor (N1) atoms in a trans [N^O^(Ni2+)^N^O] mode, whilst the carbene moieties of each bridging ligand and a tridentate L are coordinated in a distorted square planar CNHC-(Ni2+)^N^O^CNHC mode to stabilise each of the terminal Ni(II) ions. Complex 4 showed significant activity as a catalyst in the transfer hydrogenation of a range of aliphatic and aromatic ketones, at a catalyst concentration of 0.1 mol%. An excellent conversion up to 100% was achieved for aromatic ketones after 4 h.
Controlled synthesis of a hexagonal-shaped NiO nanocatalyst with highly reactive facets {1-1-0} and its catalytic activity
Patra, Astam K.,Kundu, Sudipta K.,Kim, Dukjoon,Bhaumik, Asim
, p. 791 - 798 (2015)
A new facile chemical approach has been developed to produce hexagonal-shaped NiO nanocrystals with high-energy facets {1-1-0} under hydrothermal synthesis followed by annealing in the presence of air. The phase purity, crystallinity, shape/size, and mesostructure of NiO nanocrystals were investigated by powder XRD and high-resolution transmission electron microscopy. The size, shape, and exposed crystal facets of the nanocrystals are the key factor for their physical and chemical properties. Herein, the chemical properties of hexagonal-shaped NiO nanocrystals have been tested for the reduction of carbonyl compounds in comparison with NiO nanoparticles and bulk NiO materials. The reactivity of the NiO nanocrystals is enhanced dramatically through morphology evolution. In particular, hexagonal-shaped NiO nanocrystals with highly reactive {1-1-0} facets exhibit approximately 12 and 25-% higher catalytic activity than NiO nanoparticles and bulk NiO, respectively. These hexagonal-shaped NiO nanocrystals are active over several cycles for the reduction of carbonyl compounds to their respective alcohol in the presence of 2-propanol. Effect of the crystal shape: Hexagonal-shaped NiO nanocrystals with highly reactive {1-1-0} facets show approximately 12 and 25-% higher catalytic activity than NiO nanoparticles and bulk NiO, respectively, in the catalytic reduction of benzaldehyde with 2-propanol as a solvent and hydride-donating agent.
Ketone Hydrogenation by Using ZnO?Cu(OH)Cl/MCM-41 with a Splash of Water: An Environmentally Benign Approach
Choudhary, Neha,Ghosh, Topi,Mobin, Shaikh M.
, p. 1339 - 1348 (2020)
MCM-41-supported ZnO?Cu(OH)Cl nanoparticles were synthesized via an incipient wetness impregnation technique using zinc chloride and copper chloride salts as well as water at room temperature. The catalyst was characterized by powder X-ray diffraction (PXRD), infrared spectroscopy (IR), and TGA, whereas surface and morphological studies were performed by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The above studies revealed the incorporation of metal species into the pores of MCM-41, leading to a decrease in surface area of the nanoparticles that was found to be 239.079 m2/g. The substituents attached to the ketone determine the rate of the reaction, and the utilization of the green solvent ‘water’ astonishingly completes the hydrogenation reaction in 45 minutes at 40 °C with 100% conversion and 100% selectivity as analyzed by gas chromatography-mass spectrometry. Hence, ZnO?Cu(OH)Cl/MCM-41 nanoparticles with 2.46 wt% zinc and 6.39 wt% copper were demonstrated as an active catalyst for the reduction of ketones without using any gaseous hydrogen source making it highly efficient as well as environmentally and economically benign.
Rhenium and manganese complexes bearing amino-bis(phosphinite) ligands: Synthesis, characterization, and catalytic activity in hydrogenation of ketones
Li, Haoran,Wei, Duo,Bruneau-Voisine, Antoine,Ducamp, Maxime,Henrion, Micka?l,Roisnel, Thierry,Dorcet, Vincent,Darcel, Christophe,Carpentier, Jean-Fran?ois,Soulé, Jean-Fran?ois,Sortais, Jean-Baptiste
, p. 1271 - 1279 (2018)
A series of rhenium and manganese complexes supported by easily accessible and easily tunable amino-bisphosphinite ligands was prepared and characterized by NMR and IR spectroscopy, HR mass spectrometry, elemental analysis, and X-ray diffraction studies. These complexes have been tested in the hydrogenation of ketones. Notably, one of the rhenium complexes, bearing an NH moiety, proved significantly more active than the rest of the series. The reaction proceeds well at 120 °C, under 50 bar of H2, in the presence of 0.5 mol % of catalyst and 1 mol % of tBuOK. Interestingly, activation of the precatalyst could be followed stepwise by NMR and a rhenium hydride was characterized by X-ray diffraction studies.
Reduction of acetophenones using Borohydride Exchange Resins (BER) and a BER-Lithium salt system
Fernandes, Jane Luiza Nogueira,De Souza, Marcos Costa,Brenelli, Eugenia Cristina Souza,Brenelli, Jose Afranio
, p. 4058 - 4062 (2009)
Borohydride reduction of acetophenones was carried out with the borohydride-form of an anion exchange polystyrene-divinylbenzene resin. High yields were achieved and reaction rates were significantly increased by the addition of LiNO3, LiCl, LiBr or LiI without decreasing yield.
