- Reduction of carbonyl compounds via hydrosilylation catalyzed by well-defined PNP-Mn(I) hydride complexes
-
Reduction reactions of unsaturated compounds are fundamental transformations in synthetic chemistry. In this context, the reduction of polarized double bonds such as carbonyl or C=C motifs can be achieved by hydrogenation reactions. We describe here a highly chemoselective Mn(I)-based PNP pincer catalyst for the hydrosilylation of aldehydes and ketones employing polymethylhydrosiloxane (PMHS) as inexpensive hydrogen donor. Graphic abstract: [Figure not available: see fulltext.]
- Weber, Stefan,Iebed, Dina,Glatz, Mathias,Kirchner, Karl
-
p. 635 - 639
(2021/06/17)
-
- Practical Chemoselective Acylation: Organocatalytic Chemodivergent Esterification and Amidation of Amino Alcohols with N-Carbonylimidazoles
-
Chemoselective transformations are a cornerstone of efficient organic synthesis; however, achieving this goal for even simple transformations, such as acylation reactions, is often a challenge. We report that N-carbonylimidazoles enable catalytic chemodivergent aniline or alcohol acylation in the presence of pyridinium ions or 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), respectively. Both acylation reactions display high and broad chemoselectivity for the target group. Unprecedented levels of chemoselectivity were observed in the DBU-catalyzed esterification: A single esterification product was obtained from a molecule containing primary aniline, alcohol, phenol, secondary amide, and N?H indole groups. These acylation reactions are highly practical as they involve only readily available, inexpensive, and relatively safe reagents; can be performed on a multigram scale; and can be used on carboxylic acids directly by in situ formation of the acylimidazole electrophile.
- Brown, Hailee,Heller, Stephen T.,Light, Christina,Medlin, Abigail,Nelson, Hope,Richard, William
-
supporting information
p. 22818 - 22825
(2021/09/13)
-
- Rhodium-Catalyzed Regiodivergent Synthesis of Alkylboronates via Deoxygenative Hydroboration of Aryl Ketones: Mechanism and Origin of Selectivities
-
Here, we report an efficient rhodium-catalyzed deoxygenative borylation of ketones to synthesize alkylboronates, in which the regioselectivity can be switched by the choice of the ligand. The linear alkylboronates were obtained exclusively in the presence of P(nBu)3, and PPh2Me favored the formation of branched alkylboronates. The protocol also allows access to 1,1,2-triboronates from the readily available ketones. Mechanistic studies suggest that this Rh-catalyzed deoxygenative borylation of ketones goes through an alkene intermediate, which undergoes regiodivergent hydroboration to afford linear and branched alkylboronates. The different steric effects of PPh2Me and P(nBu)3 were found to be responsible for product selectivity by density functional theory calculations. The alkene intermediate can alternatively undergo sequential dehydrogenative borylation and hydroboration to deliver the triboronates.
- Zhang, Bing,Xu, Xin,Tao, Lei,Lin, Zhenyang,Zhao, Wanxiang
-
p. 9495 - 9505
(2021/08/04)
-
- Effect of solvent in the hydrogenation of acetophenone catalyzed by Pd/S-DVB
-
A solvent effect was found in the hydrogenation of acetophenone catalyzed by a new Pd/S-DVB catalyst, immobilized on a styrene (S)/divinylbenzene (DVB) copolymer containing phosphinic groups. The porous structure of the catalyst was characterized by a specific surface area of 94.7 m2g?1. The presence of Pd(ii) and Pd(0) in Pd/S-DVB was evidenced by XPS and TEM. Pd/S-DVB catalyzes the hydrogenation of acetophenone (APh) to 1-phenylethanol (PhE) and ethylbenzene (EtB). The highest conversion of APh was obtained in methanol (MeOH) and in 2-propanol (2-PrOH), while in water it was lower. The conversion of APh correlates well with the hydrogen-bond-acceptance (HBA) capacity of the solvent. However, in all binary mixtures of alcohol and water the APh conversion and the yield of products significantly decreased. The observed inhibiting effect can be explained by the microheterogeneity of these mixtures and the blocking of the catalyst surface restricting access of the substrates to the Pd centers.
- Bereta, Tomasz,Mieczyńska, Ewa,Ronka, Sylwia,Tylus, W?odzimierz,Trzeciak, Anna M.
-
p. 5023 - 5028
(2021/03/26)
-
- Highly selective hydrogenation of aromatic ketones to alcohols in water: effect of PdO and ZrO2
-
Pd/ZrO2and PdO/ZrO2composites, containing Pd or PdO nanoparticles, were prepared using an original one-step methodology. These nanocomposites catalyze the hydrogenation of acetophenone (AP) at 1 bar and 10 bar of H2in an aqueous solution. Compared to unsupported Pd or PdO nanoparticles, a remarkable increase in their activity was achieved as a result of interaction with zirconia. An unsupported PdO hydrogenated AP mainly to ethylbenzene (EB), while excellent regioselectivity towards 1-phenylethanol (PE) was obtained with PdO/ZrO2and it was preserved during recycling. Similarly, regioselectivity to PE was higher with Pd/ZrO2compared to unsupported Pd NPs. PdO and zirconia resulted in high selectivity to alcohols in the hydrogenation of substituted acetophenones.
- Alsalahi, W.,Trzeciak, A. M.,Tylus, W.
-
p. 10386 - 10393
(2021/08/09)
-
- Mixed-metal MOFs as efficient catalysts for transfer hydrogenation of furfural, levulinic acid and other carbonyl compounds
-
Crystalline, porous Fe-Ni mixed-metal metal-organic frameworks (MOFs), namely MIL-88B(Fe2Ni) and NH2-MIL-88B(Fe2Ni), were synthesized and characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, atomic absorption spectrophotometry (AAS) and nitrogen physisorption measurements. The MOFs were then employed as catalysts for transfer hydrogenation (TH) of biomass derivatives such as furfural and levulinic acid, and various other carbonyl compounds using 2-propanol as a sacrificial hydrogen donor. These heterogeneous catalysts are deemed to be environmentally benign, efficient and recyclable. NH2-MIL-88B(Fe2Ni) showcased good catalytic activity with low catalyst loading in short reaction time. The catalysts were recovered and reused several times without significant degradation in catalytic activity. A mechanism for the TH reaction was also proposed. As far as we are aware, this is the first report on the synthesis of furfuryl alcohol and γ-valerolactone (GVL) via TH reaction in just 60 min using a MOF catalyst.
- Karvembu, Ramasamy,Raja, Duraisamy Senthil,Sindhuja, Dharmalingam,Swaminathan, Srividya,Vasanthakumar, Punitharaj
-
-
- Yeast supported gold nanoparticles: an efficient catalyst for the synthesis of commercially important aryl amines
-
Candida parapsilosisATCC 7330 supported gold nanoparticles (CpGNP), prepared by a simple and green method can selectively reduce nitroarenes and substituted nitroarenes with different functional groups like halides (-F, -Cl, -Br), olefins, esters and nitriles using sodium borohydride. The product aryl amines which are useful for the preparation of pharmaceuticals, polymers and agrochemicals were obtained in good yields (up to >95%) using CpGNP catalyst under mild conditions. The catalyst showed high recyclability (≥10 cycles) and is a robust free flowing powder, stored and used after eight months without any loss in catalytic activity.
- Krishnan, Saravanan,Patel, Paresh N.,Balasubramanian, Kalpattu K.,Chadha, Anju
-
supporting information
p. 1915 - 1923
(2021/02/06)
-
- Chemoselective reduction of nitroarenes, N-acetylation of arylamines, and one-pot reductive acetylation of nitroarenes using carbon-supported palladium catalytic system in water
-
Developing and/or modifying fundamental chemical reactions using chemical industry-favorite heterogeneous recoverable catalytic systems in the water solvent is very important. In this paper, we developed convenient, green, and efficient approaches for the chemoselective reduction of nitroarenes, N-acetylation of arylamines, and one-pot reductive acetylation of nitroarenes in the presence of the recoverable heterogeneous carbon-supported palladium (Pd/C) catalytic system in water. The utilize of the simple, effective, and recoverable catalyst and also using of water as an entirely green solvent along with relatively short reaction times and good-to-excellent yields of the desired products are some of the noticeable features of the presented synthetic protocols. Graphic abstract: [Figure not available: see fulltext.].
- Zeynizadeh, Behzad,Mohammad Aminzadeh, Farkhondeh,Mousavi, Hossein
-
p. 3289 - 3312
(2021/05/11)
-
- Adhesive functionalized ascorbic acid on CoFe2O4: A core-shell nanomagnetic heterostructure for the synthesis of aldoximes and amines
-
This paper reports on the simple synthesis of novel green magnetic nanoparticles (MNPs) with effective catalytic properties and reusability. These heterogeneous nanocatalysts were prepared by the anchoring of Co and V on the surface of CoFe2O4 nanoparticles coated with ascorbic acid (AA) as a green linker. The prepared nanocatalysts have been identified by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray atomic mapping, thermogravimetric analysis, X-ray powder diffraction, vibrating sample magnetometer analysis, coupled plasma optical emission spectrometry and Fourier transform infrared spectroscopy. The impact of CoFe2O4@AA-M (Co, V) was carefully examined for NH2OH·HCl oximation of aldehyde derivatives first and then for the reduction of diverse nitro compounds with sodium borohydride (NaBH4) to the corresponding amines under green conditions. The catalytic efficiency of magnetic CoFe2O4@AA-M (Co, V) nanocatalysts was investigated in production of different aldoximes and amines with high turnover numbers (TON) and turnover frequencies (TOF) through oximation and reduction reactions respectively. Furthermore, the developed environment-friendly method offers a number of advantages such as high turnover frequency, mild reaction conditions, high activity, simple procedure, low cost and easy isolation of the products from the reaction mixture by an external magnetic field and the catalyst can be reused for several consecutive runs without any remarkable decrease in catalytic efficiency.
- Sorkhabi, Serve,Ghadermazi, Mohammad,Mozafari, Roya
-
p. 41336 - 41352
(2020/11/30)
-
- The immobilized Cu nanoparticles on magnetic montmorillonite (MMT?Fe3O4?Cu): As an efficient and reusable nanocatalyst for reduction and reductive-acetylation of nitroarenes with NaBH4
-
In this study, the immobilization of copper nanoparticles on superparamagnetic montmorillonite, MMT?Fe3O4?Cu, was studied. Magnetically nanoparticles (MNPs) of iron oxide (Fe3O4) were primarily prepared by a chemical co-precipitation method. Next, the prepared Fe3O4 MNPs were intercalated within the interlamellar spaces and external surface of sodium-exchanged montmorillonite. Finally, Cu NPs were immobilized on magnetic montmorillonite by a simply mixing of an aqueous solution of CuCl2·2H2O with MMT?Fe3O4 followed by the reduction with NaBH4. Characterization of MMT?Fe3O4 clay system represented that through the immobilization of Fe3O4 MNPs, disordered-layers structure of MMT was easily reorganized to an ordered-layers arrangement. The synthesized composite systems were characterized using FT-IR, SEM, EDX, XRD, VSM, BET and ICP-OES analyses. SEM analysis exhibited that dispersion of Cu NPs, with the size distribution of 15–25 nm, on the surface of magnetic clay was taken place perfectly. BET surface analysis indicated that after the immobilization of Fe3O4 and Cu species, the surface area and total pore volume of MMT?Fe3O4?Cu system was decreased. Next, the Cu-clay nanocomposite system showed a perfect catalytic activity towards reduction of nitroarenes to anilines as well as reductive-acetylation of nitroarenes to acetanilides using NaBH4 and Ac2O in water as a green and economic solvent. The copper magnetic clay catalyst can be easily separated from the reaction mixture by an external magnetic field and reused for six consecutive cycles without the significant loss of its catalytic activity.
- Zeynizadeh, Behzad,Rahmani, Soleiman,Tizhoush, Hengameh
-
-
- The immobilized copper species on nickel ferrite (NiFe2O4@Cu): a magnetically reusable nanocatalyst for one-pot and quick reductive acetylation of nitroarenes to N-arylacetamides
-
In this study, a green protocol for synthesis of N-arylacetamides was introduced. Magnetically, nanoparticles of the immobilized copper species on nickel ferrite, NiFe2O4@Cu, were synthesized and then characterized using SEM, EDX, XRD, VSM, ICP-OES, BET and XPS analyses. The XPS analysis approved that the immobilized copper species on NiFe2O4 only contain Cu(0) and its oxide form as CuO. The prepared nanocomposite system represented a perfect catalytic activity toward one-pot and quick reductive acetylation of various nitroarenes to the corresponding N-arylacetamides. All reactions were carried out in a mixture of H2O–EtOH (1.5–0.5) within 2–10?min using the combination system of NaBH4 and Ac2O in a one-pot approach and via a two-step procedure. The utilized Cu nanocomposite was magnetically separated from the reaction mixture and reused for 5 consecutive cycles without the significant loss of its catalytic activity.
- Zeynizadeh, Behzad,Shokri, Zahra,Mohammadzadeh, Iman
-
p. 859 - 870
(2019/12/24)
-
- Enantioselective Reduction of α,β-Unsaturated Ketones and Aryl Ketones by Perakine Reductase
-
This report describes the enantioselective reduction of structurally diverse α,β-unsaturated ketones and aryl ketones by perakine reductase (PR) from Rauvolfia. This enzymatic reduction produces α-chiral allylic and aryl alcohols with excellent enantioselectivity and most of the products in satisfactory yields. Furthermore, the work demonstrates 1 mmol scale reactions for product delivery without any detrimental effect on yield and enantioselectivity. The catalytic mechanism, determined by 3D-structure-based modeling of PR and ligand complexes, is also described.
- Cai, Sheng,Shao, Nana,Chen, Yuanyuan,Li, Anbang,Pan, Jie,Zhu, Huajian,Zou, Hongbin,Zeng, Su,Sun, Lianli,Zhao, Jinhao
-
supporting information
p. 4411 - 4414
(2019/05/22)
-
- Synergistic Effects of ppm Levels of Palladium on Natural Clinochlore for Reduction of Nitroarenes
-
Augmenting the modified naturally occurring clay clinochlore with ppm amounts of palladium leads to a new and very effective reagent for the reduction of numerous aromatic nitro species. When palladium nanoparticles are supported on pyridyltriazole-modified clinochlore, iron within clinochlore acts synergistically with palladium to catalyze the reduction of a wide variety of nitroarenes at room temperature in aqueous media. Based on E-factor calculations, the catalyst system is found to be in line with green chemistry standards and can be recycled up to five times.
- Gholinejad, Mohammad,Oftadeh, Erfan,Shojafar, Mohammad,Sansano, José M.,Lipshutz, Bruce H.
-
p. 4240 - 4248
(2019/09/06)
-
- Au@zirconium-phosphonate nanoparticles as an effective catalytic system for the chemoselective and switchable reduction of nitroarenes
-
In the present paper, a novel inorganic-organic layered material, a zirconium phosphate aminoethyl phosphonate, ZP(AEP), bearing aminoethyl groups on the layer surface, was used to immobilize AuNPs by a two-step procedure. The gold-based catalyst, Au1@ZP(AEP), containing 1 wt% Au, was characterized in terms of physico-chemical properties and TEM analysis revealed that the AuNPs have a spherical shape and an average size of 7.8 (±2.4) nm. Au1@ZP(AEP) proved its high efficiency for the chemoselective reduction of nitroarenes under mild conditions. Both batch and flow condition protocols have been defined. The catalytic system has been proven to be able to easily switch chemoselectivity allowing the control of the reduction of a series of nitroaromatics towards their corresponding azoxyarenes (2a-k) or anilines (2a-l) in 96% EtOH or abs EtOH, respectively, by using NaBH4 as a reducing agent, in good to excellent yields. Recovery and reuse of the catalytic system has been investigated proving the benefits of the flow approach.
- Ferlin, Francesco,Cappelletti, Matteo,Vivani, Riccardo,Pica, Monica,Piermatti, Oriana,Vaccaro, Luigi
-
p. 614 - 626
(2019/02/13)
-
- Selective Room-Temperature Hydrogenation of Carbonyl Compounds under Atmospheric Pressure over Platinum Nanoparticles Supported on Ceria-Zirconia Mixed Oxide
-
A Pt/CeO2-ZrO2 catalytic system was able to initiate an extremely intense hydrogen spillover providing a huge amount of activated hydrogen (12 mol/mol Pt) at temperatures –50°C - +25°C, which was not observed before. The idea was to use this activated hydrogen for reduction of carbonyl compounds under ambient conditions. Thus, the efficient and selective heterogeneous hydrogenation of carbonyl compounds of different structure, including 5-hydroxymethylfurfural and cinnamaldehyde, to the corresponding alcohols with quantitative yields was successfully performed over the Pt/CeO2-ZrO2 catalysts at room-temperature and atmospheric pressure of H2. The proposed catalysts afforded hydrogenation under significantly milder conditions with a much higher activity and selectivity compared to the commercial catalysts and reported catalytic systems. Hydrogenation of the C=O bond in the presence of a C=C bond proceeded with a high regioselectivity.
- Redina, Elena A.,Vikanova, Kseniia V.,Kapustin, Gennady I.,Mishin, Igor V.,Tkachenko, Olga P.,Kustov, Leonid M.
-
supporting information
p. 4159 - 4170
(2019/07/12)
-
- Sustainable Protocol for the Reduction of Nitroarenes by Heterogeneous Au@SBA-15 with NaBH4 under Flow Conditions
-
A gold-incorporated SBA-15 catalyst was prepared by a solvent-free ball-milling approach. The catalyst showed high reactivity and selectivity in the reduction of a variety of nitroarenes to anilines operating in absolute EtOH with NaBH4 as reducing agent. The catalyst was reused in batch conditions over five consecutive runs without any losses of activity or selectivity. Considering the high chemical stability and reusability of the catalytic system, a continuous-flow protocol was also investigated and defined to minimize the generation of waste and optimize the continuous reuse of the catalyst. Benefits of flow conditions were proven by turnover numbers that increased from 47.5 to 1902 and also by the minimization of both leaching (9.5 vs. 1 ppm) and E-factor values (8 vs. 23 in batch).
- Ferlin, Francesco,Giannoni, Tommaso,Zuliani, Alessio,Piermatti, Oriana,Luque, Rafael,Vaccaro, Luigi
-
p. 3178 - 3184
(2019/02/19)
-
- Ultra-low-loading palladium nanoparticles stabilized on nanocrystalline Polyaniline (Pd@PANI): A efficient, green, and recyclable catalyst for the reduction of nitroarenes
-
Ultra-low-loading Pd@PANI nanocomposites (0.048 w.t% Pd) were synthesized via a method that combined interfacial polymerization and in situ composite with camphor sulfonic acid ((+)-CSA) as a dopant. Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectra, and X-ray photoelectron spectroscopy (XPS) were performed to characterize the structures. It can be used as an efficient catalyst for the reduction of nitroarenes in aqueous solution by using a smaller amount of NaBH4 (2.5 equiv.) at room temperature with high activity (TON?=?3.4?×?103), good stability (cycled eight times), as well as wide applicability (27 substrates). The catalyst also showed a marvelous activity in the gram-level reaction (yield?=?92%). UV–Visible spectrophotometry was used to investigate the reaction kinetics for the reduction of 4-nitrophenol to 4-aminophenol, and the results reconfirmed the excellent performance of the catalyst. The unique properties and superior performance of the prepared ultra-low-loading Pd@PANI nanocomposites lead it be an attractive alternative catalyst for conventional organic catalytic applications.
- Wang, Gang,Yuan, Shuo,Wu, Zhiqiang,Liu, Wanyi,Zhan, Haijuan,Liang, Yanping,Chen, Xiaoyan,Ma, Baojun,Bi, Shuxian
-
-
- Constructing reactive Fe and Co complexes from isolated picolyl-functionalized N-heterocyclic carbenes
-
We report the isolation of free picolyl-functionalized N-heterocyclic carbenes (NHCs), which serve as versatile precursors to access low coordinate iron and cobalt complexes. The reactivities of these new iron and cobalt complexes towards catalytic hydrosilylation of ketones have also been explored. For example, low loadings (0.05-1 mol%) of a four-coordinate iron complex bearing two deprotonated picolyl-NHC ligands can effect the fast catalytic reduction of ketones using the inexpensive industrial byproduct polymethylhydrosiloxane (PMHS) as the reductant at ambient temperature.
- Liang, Qiuming,Liu, Nina Jiabao,Song, Datong
-
supporting information
p. 9889 - 9896
(2018/08/06)
-
- Synthesis and evaluation of hemisalen type ligands based on chiral diamine and their use with ruthenium (II) as water-soluble catalysts for the ATH of aromatic ketones
-
We have developed a robust ruthenium (II) complex catalyst coordinated by chiral Schiff bases for the reduction of acetophenone by ATH in water. The results show a significant effect of the nature of the chiral entity on the reactivity and the selectivity of the catalytic system. The Schiff base synthesized from the chiral diamine is more reactive and selective than the Schiff base synthesized from chiral amino alcohol. The reduction of acetophenone by catalysts coordinated with hemisalen ligands synthesized from chiral cyclohexyl diamine (1–4) gives high asymmetric inductions with ee up to 84% and total conversion. The effectiveness of the best ligand has been evaluating on a set of aromatic/heterocyclic ketones and was resulted to the corresponding alcohols with high enantioselectivities and good yields. A multigram-scale of the reduction process was applied on chroman-4-one and giving access to (R)-(+)-chromanol-4-ol with 87% ee and yield of 79%.
- Boukachabia, Mourad,Aribi-Zouioueche, Louisa,Riant, Olivier
-
supporting information
p. 95 - 101
(2018/05/26)
-
- Synthesis of magnetic Fe3O4@SiO2@Cu–Ni–Fe–Cr LDH: an efficient and reusable mesoporous catalyst for reduction and one-pot reductive-acetylation of nitroarenes
-
Abstract: Magnetically recoverable Fe3O4@SiO2@Cu–Ni–Fe–Cr LDH was prepared under co-precipitation conditions. Characterization of the mesoporous catalyst was confirmed using Fourier-transformed infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, vibration sample magnetometer, Brunauer–Emmett–Teller, thermogravimetric, differential thermogravimetric analyses and transmission electron microscopy. Reduction of nitroarenes to the corresponding arylamines and one-pot reductive-acetylation of nitroarenes to acetanilides were carried out successfully by nanoparticles of the immobilized Cu–Ni–Fe–Cr layered double hydroxide on silica-coated Fe3O4 in water as a green solvent. All reactions were carried out within 6–22?min affording arylamines and N-arylacetamides in high-to-excellent yields. Reusability of the core–shell nanocatalyst was examined six times without significant loss of its catalytic activity.
- Gilanizadeh, Masumeh,Zeynizadeh, Behzad
-
p. 2821 - 2837
(2018/10/31)
-
- Highly Efficient Pt-Catalyst Supported on Mesoporous Ceria-Zirconia Oxide for Hydrogenation of Nitroaromatic Compounds to Anilines
-
Abstract: In this work, we have prepared a new catalytic system based on highly dispersed Pt nanoparticles supported on mesoporous ceria-zirconia oxide. The unique ability of the synthesized catalyst to activate hydrogen in the temperature range from –50 to 25°C allows us to provide selective hydrogenation of nitro-aromatic compounds to anilines at room temperature and atmospheric pressure of H2.
- Redina,Vikanova
-
p. 2374 - 2378
(2019/01/03)
-
- Extreme halophilic alcohol dehydrogenase mediated highly efficient syntheses of enantiopure aromatic alcohols
-
Enzymatic synthesis of enantiopure aromatic secondary alcohols (including substituted, hetero-aromatic and bicyclic structures) was carried out using halophilic alcohol dehydrogenase ADH2 from Haloferax volcanii (HvADH2). This enzyme showed an unprecedented substrate scope and absolute enatioselectivity. The cofactor NADPH was used catalytically and regenerated in situ by the biocatalyst, in the presence of 5% ethanol. The efficiency of HvADH2 for the conversion of aromatic ketones was markedly influenced by the steric and electronic factors as well as the solubility of ketones in the reaction medium. Furthermore, carbonyl stretching band frequencies ν (CO) have been measured for different ketones to understand the effect of electron withdrawing or donating properties of the ketone substituents on the reaction rate catalyzed by HvADH2. Good correlation was observed between ν (CO) of methyl aryl-ketones and the reaction rate catalyzed by HvADH2. The enzyme catalyzed the reductions of ketone substrates on the preparative scale, demonstrating that HvADH2 would be a valuable biocatalyst for the preparation of chiral aromatic alcohols of pharmaceutical interest.
- Alsafadi, Diya,Alsalman, Safaa,Paradisi, Francesca
-
p. 9169 - 9175
(2017/11/15)
-
- Magnetically nano core–shell Fe3O4@Cu(OH)x: a highly efficient and reusable catalyst for rapid and green reduction of nitro compounds
-
Magnetically separable nano core–shell Fe3O4@Cu(OH)x with 22?% Cu content was prepared by the addition of sodium hydroxide to a mixture of CuCl2·2H2O and nano Fe3O4 in water. Characterization of the impregnated copper hydroxide was carried out by X-ray fluorescence (XRF), X-ray diffraction (XRD) atomic absorption spectroscopy (AAS), scanning electron microscopy (SEM), value stream mapping (VSM) and Brunauer–Emmett–Teller (BET) analysis. The core–shell nanocatalyst exhibited the excellent catalytic activity toward reduction of various nitro compounds to the corresponding amines with NaBH4. All reactions were carried out in H2O (55–60?°C) within 3–15?min to afford amines in high to excellent yields. Reusability of core–shell Cu(OH)x catalyst was examined 9?times without significant loss of its catalytic activity.
- Shokri, Zahra,Zeynizadeh, Behzad,Hosseini, Seyed Ali,Azizi, Behrooz
-
p. 101 - 109
(2017/01/05)
-
- Synthesis and characterization of magnetically nanoparticles of Fe3O4@APTMS@ZrCp2 as a novel and reusable catalyst for convenient reduction of nitro compounds with glycerol
-
The present paper describes the synthesis of magnetically nanoparticles of zirconocene-modified magnetite, Fe3O4@APTMS@ZrCp2, as a new generation in heterogeneous and reusable type nanocatalysts. The prepared zirconocene nanocomposite was characterized using FT-IR, SEM, XRD, EDX, AGFM, ICP–OES, TGA and BET analyses. The core–shell nanocatalyst exhibited an excellent catalytic activity towards glycerol reduction of various nitro compounds to the corresponding amines. All reactions were carried out in H2O at room temperature (40–90?min) to afford amines in high to excellent yields. Reusability of the core–shell zirconocene was examined 5 times without significant loss of its catalytic activity.
- Zeynizadeh, Behzad,Sepehraddin, Farhad
-
p. 2649 - 2657
(2017/11/06)
-
- Enzymatic reduction of acetophenone derivatives with a benzil reductase from Pichia glucozyma (KRED1-Pglu): electronic and steric effects on activity and enantioselectivity
-
A recombinant ketoreductase from Pichia glucozyma (KRED1-Pglu) was used for the enantioselective reduction of various mono-substituted acetophenones. Reaction rates of meta- and para-derivatives were consistent with the electronic effects described by σ-Hammett coefficients; on the other hand, enantioselectivity was determined by an opposite orientation of the substrate in the binding pocket. Reduction of ortho-derivatives occurred only with substrates bearing substituents with low steric impact (i.e., F and CN). Reactivity was controlled by stereoelectronic features (C=O length and charge, shape of LUMO frontier molecular orbitals), which can be theoretically calculated.
- Contente, Martina L.,Serra, Immacolata,Palazzolo, Luca,Parravicini, Chiara,Gianazza, Elisabetta,Eberini, Ivano,Pinto, Andrea,Guidi, Benedetta,Molinari, Francesco,Romano, Diego
-
supporting information
p. 3404 - 3408
(2016/04/09)
-
- Cu nanoparticles: a highly efficient non-noble metal catalyst for rapid reduction of nitro compounds to amines with NaBH4 in water
-
The purely aqueous-phase reduction of a wide range of nitro compounds to the corresponding amines has been carried out with NaBH4 in the presence of inexpensive Cu nanoparticles as catalyst. The reactions were taken place in water (80?°C) within 4–15?min to give amines in high to excellent yields.
- Zeynizadeh, Behzad,Zabihzadeh, Mehdi,Shokri, Zahra
-
p. 1487 - 1492
(2016/07/06)
-
- Fast and efficient protocol for solvent-free reduction of nitro compounds to amines with NaBH4 in the presence of bis-thiourea complexes of bivalent cobalt nickel, copper and zinc chlorides
-
Reduction of nitro compounds to the corresponding amines has been carried out efficiently with NaBH4 in the presence of bis-thiourea complexes of bivalent cobalt, nickel, copper and zinc chlorides, [MII(tu)2Cl2]. The reactions were carried out under solvent-free conditions at room temperature to afford amines in high to excellent yields. Comparison of the results showed that the reducing capability of NaBH4 was influenced with bis-thiourea complexes as: Co(tu)2Cl2> Ni(tu)2Cl2> Cu(tu)2Cl2> Zn(tu)2Cl2.
- Zeynizadeh, Behzad,Sorkhabi, Serve
-
p. 679 - 684
(2016/10/30)
-
- Transfer hydrogenation of ketones, nitriles, and esters catalyzed by a half-sandwich complex of ruthenium
-
Half-sandwich complexes [Cp(PiPr3)Ru(CH3CN)2]PF6 (1; Cp = cyclopentadienyl) and [Cp(phen)Ru(CH3CN)]PF6 (2; Cp = pentamethylcyclopentadienyl, phen = phenanthroline) catalyse the transfer hydrogenation of ketones to alcohols, aldimines to amines, and nitriles to imines under mild conditions. In the latter process, the imine products come from the coupling of the amines formed initially with acetone derived from the reducing solvent (isopropanol). Among functionally substituted nitriles, the aldo and keto groups are reduced concomitantly with the cyano group, whereas ester and amido groups are tolerated. Amides and alkyl esters are not reduced under these conditions even upon heating to 70°C. However, phenylbenzoates and trifluoroacetates are reduced to alcohols. Kinetic studies on the reduction of acetophenone in isopropanol established that the reaction is first order in both the substrate and the alcohol. Stoichiometric mechanistic studies showed the formation of a hydride species. A hydride mechanism was proposed to account for these observations.
- Lee, Sun-Hwa,Nikonov, Georgii I.
-
p. 107 - 113
(2015/01/30)
-
- Rapid and green reduction of aromatic/aliphatic nitro compounds to amines with NaBH4 and additive Ni2B in H2O
-
Abstract NaBH4 with catalytic amounts of Ni2B as an additive reagent reduced aromatic and aliphatic nitro compounds to the corresponding amines in high to excellent yields. Reduction reactions were carried out in H2O within 3-30 min at room temperature or 75-80 °C. The catalytic activity of Ni2B as an additive reagent was superior to using the in situ precipitated one.
- Zeynizadeh, Behzad,Zabihzadeh, Mehdi
-
p. 1221 - 1226
(2015/06/02)
-
- Base-catalyzed hydrosilylation of ketones and esters and insight into the mechanism
-
Simple bases (KOtBu, KOH) catalyze the silane-promoted reduction of ketones and esters to alcohols and of aldimines to amines. The inexpensive silane PMHS (polymethylhydrosiloxane) can be used as the reducing reagent. Double and triple bonds, as well as nitro- and cyano-groups are tolerated. Careful dosing of the silane allows for chemoselective reduction of a more reactive group in the presence of a less reactive group (for example, aldehyde reduction in the presence of ketone/ketone reduction in the presence of ester group). Mechanistic studies showed that addition of base to silanes leads to silicate species, which are the acting reducing agents. Under basic conditions, hydrosiloxanes (tetramethyldisiloxane, TMDS; PMHS) convert into simple silanes (H 2SiMe2, H3SiMe), making this a practical method to generate these challenging silanes. Copyright
- Revunova, Kseniya,Nikonov, Georgii I.
-
supporting information
p. 839 - 845
(2014/01/23)
-
- Hydrogenation of 3-nitroacetophenone over rhodium/silica catalysts: Effect of metal dispersion and catalyst support
-
The effect of physical properties of rhodium/silica catalysts on the hydrogenation of 3-nitroacetophenone was investigated using a series of catalysts with different particle sizes, pore sizes and dispersions. The hydrogenation reaction was carried out in the liquid phase at different temperatures (313-343 K) and hydrogen pressures (2-5 barg). The hydrogenation of 3-nitroacetophenone was found to be a consecutive reaction with 3-aminoacetophenone, 1-(3-aminophenyl) ethanol, and 1-(3-aminocyclohexyl) ethanol the main products; traces of 3-aminoaniline were also detected. The reaction was zero order with respect to the concentration of 3-nitroacetophenone and half order with respect to hydrogen. The rate of formation and disappearance of intermediates increased with increasing temperature and hydrogen pressure. The rate of ring hydrogenation to form 1-(3-aminocyclohexyl) ethanol shows a marked increase at high temperatures. The catalytic activity varies with both the pore size of silica support and the rhodium dispersion with no significant influence of catalyst particle size. The turnover frequency increases with decreasing metal dispersion (or with increasing average metal crystallite size) revealing an antipathetic particle size effect. This behaviour can be related to changes in the electronic and structural make up of small metal crystallites but suggests that the reaction takes place on the plane face surface of the FCC close-pack structure of rhodium in which the number of face surface atoms increases at the expense of the edge and corner sites as the metal crystallite size increases.
- Abdul-Wahab, Majid I.,Jackson, S. David
-
p. 121 - 128
(2013/07/26)
-
- Asymmetric reduction of acetophenone derivatives by Lens culinaris
-
The enzymatic reduction of acetophenone derivatives has been evaluated using whole cells from the edible plant lentil (Lens culinaris) as biocatalyst to afford chiral (R) and (S)-alcohols in enantiomeric excess 68-99%. Acetophenone was selected as the model substrate for enantioselective bioreduction. The reaction was performed under a range of conditions in order to optimize the bioreduction procedure with respect to reaction time, media and optimal mass of lentil. With substituted (fluorine, chlorine, bromine, methyl, hydroxyl, methoxy, amino and nitro groups) acetophenones, electronic and steric influences on the course of the reaction were observed.
- Ferreira, Daniele Alves,Da Costa Assun??o, Jo?o Carlos,De Lemos, Telma Leda Gomes,Monte, Francisco José Queiroz
-
p. 469 - 475
(2013/02/23)
-
- Selective reduction of ketones using water as a hydrogen source under high hydrostatic pressure
-
A selective reduction of a broad variety of ketones is described. The method is based on the combination of a Ni-Al alloy and high hydrostatic pressure (HHP, 2.8 kbar) in an aqueous medium. The reaction of the Ni-Al alloy with water provides in situ hydrogen generation and the high pressure ensures that the H2 formed remains in the solution, thus the CO reduction readily occurs. The application of the HHP resulted in selective formation of the desired products and the common problem of non-selective overhydrogenation could be avoided. In most cases the reductions resulted in high yields and excellent selectivities without the use of any base.
- Tomin, Anna,Lazarev, Alexander,Bere, Matthew P.,Redjeb, Hana,T?r?k, Béla
-
experimental part
p. 7321 - 7326
(2012/09/22)
-
- NOVEL TRICYCLIC DERIVATIVE OR PHARMACEUTICALLY ACCEPTABLE SALTS THEREOF, PREPARATION METHOD THEREOF, AND PHARMACEUTICAL COMPOSITION CONTAINING THE SAME
-
The present invention relates to a novel tricyclic derivative with efficient inhibitory activity against poly(ADP-ribose)polymerases (PARP) or pharmaceutically acceptable salts thereof, a preparation method thereof, and a pharmaceutical composition containing the same. The tricyclic derivative of the invention is useful for the prevention or treatment of diseases caused by excess PARP activity, especially neuropathic pain, neurodegenerative diseases, cardiovascular diseases, diabetic nephropathy, inflammatory diseases, osteoporosis, and cancer, by inhibiting the activity of poly(ADP-ribose)polymerases.
- -
-
Page/Page column 53
(2011/10/04)
-
- NOVEL TRICYCLIC DERIVATIVE OR PHARMACEUTICALLY ACCEPTABLE SALTS THEREOF, PREPARATION METHOD THEREOF, AND PHARMACEUTICAL COMPOSITION CONTAINING THE SAME
-
The present invention relates to a novel tricyclic derivative with efficient inhibitory activity against poly(ADP-ribose)polymerases (PARP) or pharmaceutically acceptable salts thereof, a preparation method thereof, and a pharmaceutical composition containing the same. The tricyclic derivative of the invention is useful for the prevention or treatment of diseases caused by excess PARP activity, especially neuropathic pain, neurodegenerative diseases, cardiovascular diseases, diabetic nephropathy, inflammatory diseases, osteoporosis, and cancer, by inhibiting the activity of poly(ADP-ribose)polymerases.
- -
-
Page/Page column 43
(2011/10/02)
-
- Candida tenuis xylose reductase catalysed reduction of acetophenones: The effect of ring-substituents on catalytic efficiency
-
The catalytic efficiencies of Candida tenuis xylose reductase catalysed reductions of mono-substituted acetophenones are in reasonable correlation with the σ-Hammett coefficients of the substituted phenyl groups. Variations of the substrate transformation rates are hence mainly caused by mesomeric and inductive effects of the substituents, while differences in substrate binding have a secondary relevance. Some substrate 1H NMR chemical shifts and carbonyl IR absorption bands are in reasonable accordance with the catalytic activities and allow the estimation of the transformation rates with good accuracy. The resulting substituted (S)-1-phenyl ethanols are generated in very high enantiomeric excess.
- Vogl, Michael,Kratzer, Regina,Nidetzky, Bernd,Brecker, Lothar
-
experimental part
p. 5863 - 5870
(2011/09/30)
-
- Iron hydride complexes bearing phosphinite-based pincer ligands: Synthesis, reactivity, and catalytic application in hydrosilylation reactions
-
Treatment of resorcinol-derived bis(phosphinite) ligands 1,3-(R 2PO)2C6H4 (R = iPr and Ph) with Fe(PMe3)4 furnishes iron POCOP-pincer hydride complexes [2,6-(R2PO)2C6H3]Fe(H) (PMe3)2 (R = iPr, 1a; R = Ph, 1b) with two PMe3cis to each other. The isopropyl complex 1a undergoes ligand substitution upon mixing with CO to give [2,6-(iPr 2PO)2C6H3]Fe(H)(PMe 3)(CO). The kinetic product (2a) of this process contains a CO ligand trans to the hydride, whereas the thermodynamic product (2a′) has a CO ligand cis to the hydride. The displacement of PMe3 in 2a by CO takes place at an elevated temperature, resulting in the formation of [2,6-( iPr2PO)2C6H3]Fe(H)(CO) 2 (3a). These new iron POCOP-pincer hydride complexes catalyze the hydrosilylation of aldehydes and ketones with different functional groups, and 1a is the most efficient catalyst for this process. Isotopic labeling experiments rule out the hydride ligand being directly involved in the reduction. The hydrosilylation reactions are more likely to proceed via the activation of silanes or carbonyl substrates after ligand (PMe3, or CO in the case of 3a) dissociation from the iron center.
- Bhattacharya, Papri,Krause, Jeanette A.,Guan, Hairong
-
p. 4720 - 4729
(2011/11/13)
-
- Convenient reduction of nitro compounds to their corresponding amines with promotion of NaBH4/Ni(OAc)2.4H2O system in wet CH3CN
-
NaBH4 in the presence of catalytic amounts of Ni(OAc) 2.4H2O reduces varieties of nitro compounds to their corresponding amines. Reduction reactions were carried out in a mixture of CH3CN and H2O (3.0:0.3 ml) at room temperature with high to excellent yields of products.
- Setamdideh, Davood,Khezri, Behrooz,Mollapour, Manouchehr
-
experimental part
p. 991 - 996
(2012/03/27)
-
- Rapid and efficient reduction of nitroarenes to their corresponding amines with promotion of NaBH4/NiCl2·6H2O system in aqueous CH3CN
-
NaBH4 in the presence of catalytic amounts of NiCl2 6H2O reduces varieties of nitroarenes to their corresponding amines. Reduction reactions were carried out in a mixture of CH3CN and H 2O (3.0:0.3 mL) at room temperature with high to excellent yields of products.
- Setamdideh, Davood,Khezri, Behrooz
-
scheme or table
p. 5575 - 5580
(2012/07/31)
-
- A mild and convenient reduction of nitro compounds with NaBH 4/SbF3 system in wet CH3CN
-
NaBH4 in the presence of catalytic amounts of SbF3 reduces a range of nitro compounds to their corresponding amines in high to excellent yields. Reduction reactions were carried out in wet CH3CN within 2-30 minutes at room temperature.
- Zeynizadeh, Behzad,Ghasemi, Hamed
-
p. 542 - 544
(2007/10/03)
-
- Chemo- and regioselective reduction of nitroarenes, carbonyls and azo dyes over nickel-incorporated hexagonal mesoporous aluminophosphate molecular sieves
-
Nickel-incorporated hexagonal mesoporous aluminophosphate (NiHMA) molecular sieves were found to be highly efficient heterogeneous catalysts for the chemo- and regioselective reduction of nitroarenes and carbonyl compounds as well as the reductive cleavage of azo functions, including bulkier substrates, by the hydrogen transfer method.
- Selvam, Parasuraman,Mohapatra, Susanta K.,Sonavane, Sachin U.,Jayaram, Radha V.
-
p. 2003 - 2007
(2007/10/03)
-
- Selective reduction of alkenes, α,β-unsaturated carbonyl compounds, nitroarenes, nitroso compounds, N,N-hydrogenolysis of azo and hydrazo functions as well as simultaneous hydrodehalogenation and reduction of substituted aryl halides over PdMCM-41 catalyst under transfer hydrogen conditions
-
Chemoselective reductions of alkenes, α,β-unsaturated carbonyl compounds, nitro and nitroso compounds, N,N-hydrogenolysis of azo and hydrazo functions as well as simultaneous reduction and hydrodehalogenation of substituted aryl halides, including bulkier substrates, were achieved by catalytic transfer hydrogenation (CTH) using mesoporous PdMCM-41 catalyst. The yields were practically unaffected upon recycling of the catalyst. Further, the CTH process is accomplished without affecting the reduction of any other reducible functional group.
- Selvam, Parasuraman,Sonavane, Sachin U.,Mohapatra, Susanta K.,Jayaram, Radha V.
-
p. 3071 - 3075
(2007/10/03)
-
- SUBSTITUTED QUINAZOLINE DERIVATIVES AND THEIR USE AS INHIBITORS
-
The use of a compound of formula (I) 1 or a salt, ester or amide thereof; where X is O, or S, S(O) or S(O)2, or NR6 where R6 is hydrogen or C1-6 alkyl,; R5 is an optionally substituted 5-membered heteroaromatic ring, R1, R2 ,R3, R4 are independently selected from various specified moieties, in the preparation of a medicament for use in the inhibition of aurora 2 kinase. Certain compounds are novel and these, together with pharmaceutical compositions containing them are also described and claimed
- -
-
-
- Regio- and chemoselective catalytic transfer hydrogenation of aromatic nitro and carbonyl as well as reductive cleavage of azo compounds over novel mesoporous NiMCM-41 molecular sieves
-
(equation presented) Regio-and chemoselective reduction of nitroarenes and carbonyl compounds and reductive cleavage of azo compounds, including bulkier molecules, was achieved by the catalytic transfer hydrogenation method (CTH) using a novel nickel-containing mesoporous silicate (NiMCM-41) molecular sieve catalyst. In addition, the catalyst was also found to behave as a truly heterogeneous catalyst as the yield was practically unaffected.
- Mohapatra, Susanta K.,Sonavane, Sachin U.,Jayaram, Radha V.,Selvam, Parasuraman
-
p. 4297 - 4300
(2007/10/03)
-
- Hydrogen-transfer catalyzed by half-sandwich Ru(II) aminophosphine complexes
-
The syntheses of and catalytic studies on some Ru(II) complexes bearing the aminophosphine ligands N,N-dimethyl-2-diphenylphosphinoethylamine (PN), optically pure (RC,Spl)-2-{1-(N,N-dimethylamino)ethyl}-1- diphenylphosphinoferrocene(PPFA), and N,N-dimethyl-2-diphenylphosphinoaniline (DBD) are described, [RuCp(CH3CN)3]+ reacts with these ligands to give the cationic complexes [RuCp(PN-κN,κP)(CH3CN)]+ (1a), [(SRu,RC,Spl)-RuCp(PPFA-κN,κP) (CH3CN)]+ (1b), and [RuCp(DBD-κN,κP)(CH3CN)]+ (1c), respectively, in high yields. From these, in turn, the residual CH3CN ligand can be replaced by Br- upon addition of NEt4Br in CH2Cl2, resulting in the formation of the neutral complexes RuCp(PN)Br (2a), (SRu,RC,Spl)-RuCp(PPFA)Br (2b), and RuCp(DBD)Br (2c), again in good yields. Similarly, [Ru(η6-p-cymene)Cl2]2 reacts with 1 equiv. of PN or PPFA to give Ru(η6-p-cymene)(PN-κP)Cl2 (3a) and Ru(η6-p-cymene)(PPFA-κP)Cl2 (3b). Furthermore, treatment of 3 with TlCF3SO3 in THF at room temperature affords the cationic complexes [Ru(η6-p-cymene)(PN-κN,κP)Cl]CF3SO 3 (4a) and [(RRu,RC,Spl)-Ru (η6-p-cymene)-(PPFA-κN,κP)Cl]CF3SO 3 (4b). The absolute configuration at the metal center of 2b and 4b′ (BPh4- salt of 4b) was determined by X-ray crystallography. Catalytic studies were performed with the racemic complexes 1a, 2a, 2c, and 4a and the diastereopure complexes 1b, 2b, and 4b. All of these proved to be excellent precatalysts for the transfer hydrogenation of acetophenone and derivatives thereof, and cyclohexanone. With the enantiomerically pure systems 2b and 4b, only racemic products were obtained. This testifies to the hemilabile nature of the aforementioned aminophosphine ligands giving transient κ-P-bonding coordination. Since diastereoface selection of incoming substrates is based on the planar chirality of the ferrocene moiety, rather than the metal centered chirality, no enantioselective reaction takes place.
- Standfest-Hauser,Slugovc,Mereiter,Schmid,Kirchner,Xiaoc,Weissensteiner
-
p. 2989 - 2995
(2007/10/03)
-
- SELECTIVE REDUCTION OF KETONES WITH SODIUMBOROHYDRIDE-ACETIC ACID
-
Aliphatic ketones, and aromatic ketones having o-hydroxy or o-amino substituents are reduced rapidly to the alcohols by NaBH4 and acetic acid; other types of ketones react much more slowly.
- Nieminen, Tuula, E. A.,Hase, Tapio A.
-
p. 4725 - 4728
(2007/10/02)
-
- Preparation of m-amino-α-methylbenzyl alcohol
-
M-Amino-α-methylbenzyl alcohol is produced in a facile manner in a single step hydrogenation from m-nitroacetophenone under relatively mild conditions with a palladium catalyst, through the utilization of a strongly acidic aqueous medium.
- -
-
-
- Preparation of m-amino-α-methylbenzyl alcohol
-
M-Amino-α-methylbenzyl alcohol is produced in a facile manner in a single step hydrogenation from m-nitroacetophenone under relatively mild conditions with standard hydrogenation catalysts through the utilization of an aqueous reaction medium.
- -
-
-
