scholarly journals Switchable Access to Amines and Imines from Reductive Coupling of Nitroarenes with Alcohols Catalyzed by Biomass-Derived Cobalt Nanoparticles

Catalysts ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 116 ◽  
Author(s):  
Tao Song ◽  
Yanan Duan ◽  
Xiufang Chen ◽  
Yong Yang
Keyword(s):  
Heterogeneous Catalyst ◽  
Reaction System ◽  
Reaction Medium ◽  
Cobalt Nanoparticles ◽  
Significant Loss ◽  
Reductive Coupling ◽  
Hierarchical Porous ◽  
Borrowing Hydrogen ◽  
High Yields ◽  
First Time

Cobalt nanoparticles modified with N-doped hierarchical porous carbon derived from biomass are found to be a highly efficient, reusable heterogeneous catalyst for the coupling of nitroarenes with alcohols, selectively affording imines and amines via the borrowing hydrogen strategy for the first time. The product selectivity between imine and amine may be precisely tuned by simple alteration of the reaction conditions without changing the catalyst in one reaction system. In this study, a broad set of complex imines and amines was successfully synthesized in good to high yields with various functional groups tolerated for both nitroarenes and alcohols, highlighting the potentially practical utility of the protocol. This heterogeneous catalyst can be easily removed from the reaction medium by external magnet and can be reused at least four times without significant loss in activity and selectivity.

An Expeditious One-Pot Three-Component Synthesis of 4-Aryl-3,4-dihydrobenzo[g] quinoline-2,5,10(1H)-triones under Green Conditions

2020 ◽  
Vol 23 (23) ◽  
pp. 2626-2634
Author(s):  
Saiedeh Kamalifar ◽  
Hamzeh Kiyani
Keyword(s):  
Reaction Medium ◽  
Meldrum's Acid ◽  
Meldrum’S Acid ◽  
One Pot ◽  
One Pot Synthesis ◽  
Substituted Benzaldehydes ◽  
High Yields ◽  
First Time ◽  
Green Conditions

: An efficient and facial one-pot synthesis of 4-aryl-3,4-dihydrobenzo[g]quinoline- 2,5,10(1H)-triones was developed for the first time. The process proceeded via the three-component cyclocondensation of 2-amino-1,4-naphthoquinone with Meldrum’s acid and substituted benzaldehydes under green conditions. The fused 3,4-dihydropyridin-2(1H)- one-ring naphthoquinones have been synthesized with good to high yields in refluxing ethanol as a green reaction medium. This protocol is simple and effective as well as does not involve the assistance of the catalyst, additive, or hazardous solvents.

scholarly journals A nickel phosphide nanoalloy catalyst for the C-3 alkylation of oxindoles with alcohols

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shu Fujita ◽  
Kohei Imagawa ◽  
Sho Yamaguchi ◽  
Jun Yamasaki ◽  
Seiji Yamazoe ◽  
...  
Keyword(s):  
Precious Metal ◽  
Cerium Dioxide ◽  
Catalytic Performance ◽  
Significant Loss ◽  
Nickel Phosphide ◽  
Cooperative Catalysis ◽  
Metal Phosphides ◽  
Borrowing Hydrogen ◽  
High Yields ◽  
Transition Metal Phosphides

AbstractAlthough transition metal phosphides are well studied as electrocatalysts and hydrotreating catalysts, the application of metal phosphides in organic synthesis is rare, and cooperative catalysis between metal phosphides and supports remains unexplored. Herein, we report that a cerium dioxide-supported nickel phosphide nanoalloy (nano-Ni2P/CeO2) efficiently promoted the C-3 alkylation of oxindoles with alcohols without any additives through the borrowing hydrogen methodology. Oxindoles were alkylated with various alcohols to provide the corresponding C-3 alkylated oxindoles in high yields. This is the first catalytic system for the C-3 alkylation of oxindoles with alcohols using a non-precious metal-based heterogeneous catalyst. The catalytic activity of nano-Ni2P/CeO2 was comparable to that reported for precious metal-based catalysts. Moreover, nano-Ni2P/CeO2 was easily recoverable and reusable without any significant loss of activity. Control experiments revealed that the Ni2P nanoalloy and the CeO2 support functioned cooperatively, leading to a high catalytic performance.

Cobalt Used as a Novel and Reusable Catalyst: A New and One-Pot Synthesis of Isatin-Derived N,S-Acetals Using Substituted Isatins and Thiols

Synthesis ◽  
2019 ◽  
Vol 51 (21) ◽  
pp. 4014-4022
Author(s):  
Caren D. G. da Silva ◽  
Ramesh Katla ◽  
Beatriz F. dos Santos ◽  
José M. C. Tavares Junior ◽  
Tábata B. Albuquerque ◽  
...  
Keyword(s):  
Heterogeneous Catalyst ◽  
Continuous Flow ◽  
High Conversion ◽  
Reusable Catalyst ◽  
One Pot ◽  
One Pot Synthesis ◽  
High Yields ◽  
Recyclable Heterogeneous Catalyst ◽  
First Time

The synthesis of isatin-derived N,S-acetals using cobalt as a recyclable heterogeneous catalyst in batch and continuous flow is reported for the first time. The present protocol produced high yields, which can be observed from the reaction between ketimines and thiols. Such reactions can also be applied to a gram-scale. In addition, the catalyst is recyclable, economically-viable, and nontoxic as well as easy to prepare. The remarkable features of this new methodology are high conversion and cleaner reaction profiles.

scholarly journals Coupling photocatalytic water oxidation with organic reduction: strategy for using water to reduce organic molecules

2021 ◽  
Author(s):  
Xinzhe Tian ◽  
Yinggang Guo ◽  
Wenbo Liu ◽  
Yi Zheng ◽  
Yun-Lai Ren ◽  
...  
Keyword(s):  
Water Splitting ◽  
Water Oxidation ◽  
Organic Molecules ◽  
Reductive Coupling ◽  
Aryl Bromides ◽  
Mechanistic Investigation ◽  
Reaction Proceeds ◽  
Novel Method ◽  
High Yields ◽  
First Time

Abstract The utilization of readily available and non-toxic water by photocatalytic water splitting is highly attractive in green chemistry. Herein we report that light-induced oxidative half-reaction of water splitting is effectively coupled with reduction of organic compounds, which opens up, for the first time, an avenue to use water as an electron donor to enable reductive transformations of organic substances. The used photocatalyst (Pd/g-C3N4*) was synthetized by a novel method where Pd/g-C3N4 was irradiated by light in the presence of Na2CO3 and H2O. The present strategy allowed a series of aryl bromides to undergo the reductive coupling to provide biaryl products in low to high yields. Preliminary mechanistic investigation suggests that the reaction proceeds through the single electron transfer from Pd to aryl bromides. This work will guide chemists to use water as a reducing agent to develop green procedures for various organic reactions.

scholarly journals Palladium Nanocatalysts on Hydroxyapatite: Green Oxidation of Alcohols and Reduction of Nitroarenes in Water

2019 ◽  
Vol 9 (19) ◽  
pp. 4183 ◽  
Author(s):  
Shokouhimehr ◽  
Yek ◽  
Nasrollahzadeh
Keyword(s):  
Electron Microscopy ◽  
Heterogeneous Catalyst ◽  
Photoelectron Spectroscopy ◽  
Pd Nanoparticles ◽  
Structural Features ◽  
Significant Loss ◽  
X Ray ◽  
Transmission Electron ◽  
Palladium Nanocatalysts ◽  
High Yields

A green procedure is described for supporting Pd nanoparticles on hydroxyapatite (HAP), which serves as a highly-stable heterogeneous catalyst displaying excellent activity for the aqueous expeditious reduction of nitroaromatics to the corresponding amines with sodium borohydride, and oxidation of primary and secondary alcohols by hydrogen peroxide with high yields and selectivities. The structural features of the prepared catalyst are confirmed by latest techniques including field emission scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The reusability of the heterogeneous catalyst was affirmed in the aqueous reduction of nitrobenzene and oxidation of cycloheptanol for six consecutive runs without significant loss of catalytic activity.

Synthesis of Chalcone Derivatives by Phthalhydrazide-Functionalized TiO2-Coated Nano-Fe3O4 as a New Heterogeneous Catalyst

2020 ◽  
Vol 17 ◽  
Author(s):  
Forough Motamedi Nia ◽  
Mahnaz Farahi ◽  
Bahador Karami ◽  
Raziyeh Keshavarz
Keyword(s):  
Heterogeneous Catalyst ◽  
Significant Loss ◽  
Magnetic Nanocatalyst ◽  
Chalcone Derivatives ◽  
Ft Ir ◽  
Nano Fe3o4

Abstract:: Phthalhydrazide immobilized on TiO2-coated nano Fe3O4 (Fe3O4-P) was synthesized and characterized by FT-IR, XRD, SEM, EDS and VSM analysis. The resulting magnetic nanocatalyst was used as a catalyst for the synthesis of chalcone derivatives which affords the desired products in good to excellent yields. This catalyst can be isolated readily after completion of the reaction by an external magnetite field and reused several times without significant loss of activity.

scholarly journals Synthesis, Characterization of Chitosan-Aluminum Oxide Nanocomposite for Green Synthesis of Annulated Imidazopyrazol Thione Derivatives

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1160
Author(s):  
Abir S. Abdel-Naby ◽  
Sara Nabil ◽  
Sarah Aldulaijan ◽  
Ibtisam M. Ababutain ◽  
Azzah I. Alghamdi ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Aluminum Oxide ◽  
Reaction Medium ◽  
Thiol Group ◽  
Docking Studies ◽  
Significant Loss ◽  
Gram Negative Bacteria ◽  
Organic Catalyst ◽  
Group 1

Chitosan-aluminum oxide nanocomposite was synthesized, characterized, and used as a green heterogeneous catalyst to synthesize novel imidazopyrazolylthione derivatives. Nanocomposite polymeric material was characterized by EDS-SEM and XRD. The powerful catalytic activity, and its base character of the nanocomposite, was used to synthesize imidazopyrazolylthione (1) in a good yield compared to traditional cyclocondensation synthesis. Using the nanocomposite catalyst, substitution of the thiol group (1) afforded the corresponding thiourea (2) and the corresponding ester (3). The efficiency of the nanocomposite over the traditional base organic catalyst, Et3N and NaOH, makes it an effective, economic, and reproducible nontoxic catalyst. Moreover, the heterogeneous nanocomposite polymeric film was easily isolated from the reaction medium, and recycled up to four times, without a significant loss of its catalytic activity. The newly synthesized derivatives were screened as antibacterial agents and showed high potency. Molecular docking was also performed for a more in-depth investigation. The results of the docking studies have demonstrated that the docked compounds have strong interaction energies with both Gram-positive and Gram-negative bacteria.

scholarly journals Au Modified F-TiO2 for Efficient Photocatalytic Synthesis of Hydrogen Peroxide

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3844
Author(s):  
Lijuan Li ◽  
Bingdong Li ◽  
Liwei Feng ◽  
Xiaoqiu Zhang ◽  
Yuqian Zhang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction System ◽  
Reaction Medium ◽  
Pure Tio2 ◽  
H2o2 Production ◽  
Tio2 Photocatalyst ◽  
H2o2 Decomposition ◽  
Spin Resonance ◽  
Photocatalytic Synthesis

In this work, Au-modified F-TiO2 is developed as a simple and efficient photocatalyst for H2O2 production under ultraviolet light. The Au/F-TiO2 photocatalyst avoids the necessity of adding fluoride into the reaction medium for enhancing H2O2 synthesis, as in a pure TiO2 reaction system. The F− modification inhibits the H2O2 decomposition through the formation of the ≡Ti–F complex. Au is an active cocatalyst for photocatalytic H2O2 production. We compared the activity of TiO2 with F− modification and without F− modification in the presence of Au, and found that the H2O2 production rate over Au/F-TiO2 reaches four times that of Au/TiO2. In situ electron spin resonance studies have shown that H2O2 is produced by stepwise single-electron oxygen reduction on the Au/F-TiO2 photocatalyst.

TRANSMISSION ELECTRON MICROSCOPY OF SURFACE AND INTERFACIAL STEPS

1997 ◽  
Vol 04 (03) ◽  
pp. 559-566 ◽  
Author(s):  
J. M. GIBSON ◽  
X. CHEN ◽  
O. POHLAND
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Free Surface ◽  
Significant Loss ◽  
Stress Fields ◽  
Preliminary Results ◽  
Surface Steps ◽  
Transmission Electron ◽  
First Time

Transmission electron microscopy is uniquely able to extend techniques for imaging free surface steps to the buried interface regime, without significant loss of detail. Two mechanisms for imaging surface and interfacial steps by transmission electron microscopy are described. They are thickness contrast and strain contrast. The former reveals the position and approximate height of steps, whereas the latter detects stress fields which are commonly associated with steps. The basis for each of these methods is elaborated, and preliminary results are shown for step images at Si/SiO2 interfaces, where measurable stress fields have been directly detected for the first time.

Gold(I) Complexes Bearing P∩N-Ligands: An Unprecedented Twelve-membered Ring Structure Stabilized by Aurophilic Interactions

2009 ◽  
Vol 64 (11-12) ◽  
pp. 1513-1524 ◽  
Author(s):  
Uwe Monkowius ◽  
Manfred Zabel ◽  
Michel Fleck ◽  
Hartmut Yersin
Keyword(s):  
Solid State ◽  
Ring Structure ◽  
Phosphine Ligands ◽  
X Ray Crystallography ◽  
Aggregation Pattern ◽  
Elemental Analyses ◽  
High Yields ◽  
First Time ◽  
Solid State Structures ◽  
Aurophilic Interactions

The P∩N-ligands Ph2Pqn, 1, Ph2 Piqn, 2, Ph2 Ppym, 3, and the As∩N-ligands Ph2Asqn, 4, Ph2Asiqn, 5, (Ph = phenyl, qn = 8-quinoline, iqn = 1-isoquinoline, pym = 2-pyrimidine) have been synthesized, the ligands 2 and 5 for the first time. Their ligand properties were probed by the synthesis of gold(I) complexes. Reaction with (tht)AuCl (tht = tetrahydrothiophene) yielded the chlorogold complexes Ph2RP-Au-Cl (R = qn, 6; iqn, 7; pym, 8) and Ph2RAs-Au-Cl (R = qn, 9; iqn, 10) in high yields. Further treatment of 7 and 8 with one equivalent of AgBF4 provided the complexes [(Ph2Piqn)Au]BF4, 11, [(Ph2Ppym)Au]BF4, 12, and [(Ph2Piqn)Au(tht)]BF4, 14. For comparison, the previously reported complex [(Ph2Ppy)Au]BF4 (py = pyridine), 13, was re-investigated. The compounds were characterized by elemental analyses, mass spectrometry and NMR spectroscopy. In addition, the solid-state structures of 2, 3, 6, 7, 9 - 14 have been determined by X-ray crystallography. The chloro-gold compounds crystallize in the common rod-like structure known from R3EAuCl (R = aryl, E = P, As) complexes without further aggregation via aurophilic interactions. In all cases the phosphine acts as a monodentate ligand. In the solid state compounds 11 - 13 feature an unprecedented cyclic trinuclear aggregation pattern, in which the Au(I) atoms are linearly coordinated by the bridging phosphine ligands forming a cyclic (P-Au-N)3 arrangement. The resulting twelvemembered ring is further stabilized by Au · · · Au interactions. Due to the presence of these Au · · · Au contacts, 11 - 13 are emissive in the solid state but not in solution

Sign in / Sign up

Export Citation Format

Share Document