- Synthesis and characterization of nano-cellulose immobilized phenanthroline-copper (I) complex as a recyclable and efficient catalyst for preparation of diaryl ethers, N-aryl amides and N-aryl heterocycles
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Functionalized nanocellulose was prepared and employed for immobilization of phenanthroline-copper(I) complex to afford cellulose nanofibril grafted heterogeneous copper catalyst [CNF-phen-Cu(I)]. This nanocatalyst was well characterized using FT-IR, NMR, XRD, CHNS, AAS, TGA, EDX and SEM. The activities of the synthesized catalyst were examined in the synthesis of diaryl ethers via C-O cross-coupling of phenols and aryl iodides, as well as, the preparation of N-aryl amides and N-aryl heterocycles through C-N cross-coupling of amides and N-H heterocycle compounds with aryl halides. In this trend, various substrates containing electron-donating and electron-withdrawing groups were exploited to evaluate the generality of this catalytic protocol. Accordingly, the catalyst demonstrated remarkable catalytic efficiency for both C-N and C-O cross-coupling reactions, thereby resulting in good to excellent yields of the desired products. Furthermore, the recoverability experiments of the catalyst showed that it can be readily retrieved by simple filtration and successfully reused several times with negligible loss of its catalytic activity.
- Aghili, Nora,Hosseinzadeh, Rahman,Mavvaji, Mohammad
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- Suzuki?Miyaura coupling and O?arylation reactions catalysed by palladium(II) complexes of bulky ligands bearing naphthalene core, Schiff base functionality and biarylphosphine moiety
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Schiff bases L1 [i.e., 2-(diphenylphosphino)-N-(naphthalen-1-ylmethylene)ethanamine], L2 [i.e., 2- (diphenylphosphino)-N-(naphthalen-2-ylmethylene)ethanamine], L3 [i.e., 2-(1-(2-(diphenylphosphino)ethylim- ino)ethyl)naphthalen-1-ol] and L4 [i.e., 2-((2-(diphenylphosphino)ethylimino)methyl)naphthalen-1-ol] have been synthesized using a straightforward methodology which involves a condensation reaction between H2N?CH2?CH2?PPh2 and appropriate carbonyl compound. Due to the presence of diphenylphosphine (?PPh2) moiety and >C = N? functionality, these compounds behave as ligands and undergo complexation reaction with palladium on treatment with Na2PdCl4 to yield the palladium(II) complexes (1–4). Ligands as well as complexes have been characterized using standard NMR spectroscopic techniques. ESI?MS and single crystal X?ray diffraction studies corroborate the structures of complexes. Crystal structures of complexes 1?3 reveal clearly that the geometry around Pd centre is distorted square planar. Ligands L1 and L2 are coordinated to Pd centre in bidentate (P, N type) mode, however, L3 and L4 act as a tridentate (P,N,O type) ligand and bind with metal in anionic mode. The Pd P and Pd N bond distances in complexes 1?3 are in the ranges 2.204?2.212 ? and 2.023?2.072 ?, respectively. Complex 3 [i.e., PdCl(L3?H)] also has a Pd-O bond, the length of which is found to be 2.009(3) ?. All the complexes have potential for catalysing O-arylation (C-O coupling) of phenol and Suzuki-Miyaura coupling (SMC) reactions. Both bromoarenes and chloroarenes can be used as substrates in Suzuki coupling and converted into biaryl derivatives. For O-arylation reactions of phenol, bromoarenes are used as arylating agents. For catalysis of such reactions (i.e., C-O coupling), high (0.1 mol%) catalyst loading is required. However, Suzuki reactions require low (0.001 mol%) loading of catalysts to occur with bromoarenes and give the products. The high potential of the complexes is also evident from the fact that they also convert different aryl chlorides into the coupled products in Suzuki coupling. 31P{1H} NMR data reveal that the electronic environments of nuclei of phosphorous donors are closely similar in all the four ligands. Similar magnitude of deshielding of the 31P{1H} signals in all the complexes indicate that, while forming the dative bond, the P donor of all the ligands transfer the electron density to the palladium to a similar extent. Hence, the electronic effects created by the ligands through the phosphorous donor are similar in all the complexes. Therefore, it is inferred that variation in their catalytic performance is because of difference in the binding mode of the ligand and/or minor alteration in the architecture of organic ligand. Amongst them, complex 2 shows the highest catalytic activity, and the least active catalyst is complex 3 for C-C coupling reactions. For C-O coupling reactions, the efficiencies of complexes 1 and 2 are slightly higher than those of complexes 3 and 4.
- Arora, Aayushi,Kaushal, Jolly,Kumar, Arun,Nautiyal, Divyanshu,Oswal, Preeti,Singh, Siddhant
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- Diarylation of N- and O-nucleophiles through a metal-free cascade reaction
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The arylation of heteroatom nucleophiles is a central strategy to reach diarylated compounds that are key building blocks in agrochemicals, materials, and pharmaceuticals. Nucleophilic aromatic substitution is a classical tool for such arylations, and recent developments in hypervalent iodine-mediated arylations allow a wider scope of products. Herein, we combine the benefits of these strategies to enable an efficient and transition-metal-free difunctionalization of N- and O-nucleophiles with two structurally different aryl groups and to provide di- and triarylamines and diaryl ethers in one single step (>100 examples). The core of this strategy is the unique reactivity discovered with specifically designed fluorinated diaryliodonium salts, which unveils novel reaction pathways in hypervalent iodine chemistry. The methodology is suitable for diarylation of aliphatic amines, anilines, ammonia, and even water. It tolerates a wide variety of functional and protecting groups, with the retained iodine substituent easily accessible for derivatization of the products.
- Bulfield, David,Kervefors, Gabriella,Linde, Erika,Olofsson, Berit,Purkait, Nibadita
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p. 850 - 865
(2022/03/14)
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- Ligand- and Counterion-Assisted Phenol O-Arylation with TMP-Iodonium(III) Acetates
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High reactivity of trimethoxyphenyl (TMP)-iodonium(III) acetate for phenol O-arylation was achieved. It was first determined that the TMP ligand and acetate anion cooperatively enhance the electrophilic reactivity toward phenol oxygen atoms. The proposed method provides access to various diaryl ethers in significantly higher yields than the previously reported techniques. Various functional groups, including aliphatic alcohol, boronic ester, and sterically hindered groups, were tolerated during O-arylation, verifying the applicability of this ligand- and counterion-assisted strategy.
- Kikushima, Kotaro,Miyamoto, Naoki,Watanabe, Kazuma,Koseki, Daichi,Kita, Yasuyuki,Dohi, Toshifumi
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supporting information
p. 1924 - 1928
(2022/03/27)
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- L-Proline N-oxide dihydrazides as an efficient ligand for cross-coupling reactions of aryl iodides and bromides with amines and phenols
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A novel catalytic system based on L-proline N-oxide/CuI was developed and applied to the cross-coupling reactions of various N- and O- nucleophilic reagents with aryl iodides and bromides. This strategy featured in the employment of an-proline derived dihydrazides N-oxide compound as the superior supporting ligand. By using this protocol, a variety of products, including N-arylimidazoles, N-arylpyrazoles, N-arylpyrroles, N-arylamines, and aryl ethers, were synthesized with up to 99% yield.
- Ding, Zhiqiang,Nie, Nan,Chen, Tian,Meng, Lingxin,Wang, Gongshu,Chen, Zhangpei,Hu, Jianshe
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supporting information
(2020/12/21)
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- Copper nanoparticle anchored biguanidine-modified Zr-UiO-66 MOFs: a competent heterogeneous and reusable nanocatalyst in Buchwald-Hartwig and Ullmann type coupling reactions
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We have designed a functionalized metal-organic framework (MOF) of UiO topology as a support, with an extremely high surface area, adjustable pore sizes and stable crystalline coordination polymeric structure and implanted copper (Cu) nanoparticles thereon. The core three dimensional Zr-derived MOF (UiO-66-NH2) was modified with a biguanidine moiety following a covalent post-functionalization approach. The morphological and physicochemical features of the material were determined using analytical methods such as FT-IR, SEM, TEM, EDX, atomic mapping, XRD and ICP-OES. The SEM and XRD results justified the unaffected morphology of Zr-MOF after structural modifications. The as-synthesized UiO-66-biguanidine/Cu nanocomposite was catalytically explored in the aryl and heteroaryl Buchwald-Hartwig C-N and Ullmann type C-O cross coupling reactions with excellent yields. A library of biaryl amine and biaryl ethers was synthesized over the catalyst under mild and green conditions. Furthermore, the catalyst was isolated by centrifugation and recycled 11 times with no significant copper leaching or change in its activity.
- Veisi, Hojat,Neyestani, Narges,Pirhayati, Mozhgan,Ahany Kamangar, Sheida,Lotfi, Shahram,Tamoradi, Taiebeh,Karmakar, Bikash
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p. 22278 - 22286
(2021/07/02)
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- Fe-MIL-101 modified by isatin-Schiff-base-Co: a heterogeneous catalyst for C-C, C-O, C-N, and C-P cross coupling reactions
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A metal-organic framework functionalized with a cobalt-complex is preparedviapost-synthetic modification of Fe-MIL-101-NH2. Initially, Fe-MIL-101-NH2reacted with isatin to produce Fe-MIL-101-isatin-Schiff-base, which can anchor the cobalt by the addition of cobalt acetate. The resulting MOF-Co catalyst is characterized by employing multiple techniques. This new modified MOF acts as a heterogeneous and recyclable catalyst for efficient Ullmann, Buchwald-Hartwig, Hirao, Hiyama and Mizoroki-Heck cross-coupling reactions of several aryl halides/phenylboronic acid/phenyltosylate with phenols, anilines/heterocyclic amines, triethyl phosphite, triethoxyphenylsilane and alkenes and generates the expected coupling products in good to high yields.
- Farrokhi, Alireza,Rouzifar, Majid,Sansano, José Miguel,Sobhani, Sara
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p. 19963 - 19976
(2021/11/12)
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- Preparation and characterization of Cu based on 5,5'-bistetrazole as a recyclable metal-organic framework and application in synthesis of diaryl ether by the Ullmann coupling reaction
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Cu based on 5,5′-bistetrazole ([Cu2BT · 2H2O] n) as a recyclable metal-organic framework (MOF) heterogeneous catalyst was characterized by FT-IR, 13C NMR, XRD, SEM, EDX, BET, BJH, and ICP-AES analysis. The catalytic activity of the catalyst was probed through the Ullmann reaction for synthesis of diaryl ether derivatives from two component reactions of aromatic arylhalides and phenol derivatives in DMSO. Simple procedure, high yields, short reaction time, and environmentally benign methods are advantages of this protocol. The catalyst was readily separated by simple filtration and reusable without significant loss of its catalytic efficiency.
- Noorpoor, Zeinab,Tavangar, Saeed
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p. 1651 - 1662
(2021/05/10)
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- Magnetization of graphene oxide nanosheets using nickel magnetic nanoparticles as a novel support for the fabrication of copper as a practical, selective, and reusable nanocatalyst in C-C and C-O coupling reactions
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Catalyst species are an important class of materials in chemistry, industry, medicine, and biotechnology. Moreover, waste recycling is an important process in green chemistry and is economically efficient. Herein, magnetic graphene oxide was synthesized using nickel magnetic nanoparticles and further applied as a novel support for the fabrication of a copper catalyst. The catalytic activity of supported copper on magnetic graphene oxide (Cu-ninhydrin@GO-Ni MNPs) was investigated as a selective, practical, and reusable nanocatalyst in the synthesis of diaryl ethers and biphenyls. Some of the obtained products were identified by NMR spectroscopy. This nanocatalyst has been characterized by atomic absorption spectroscopy (AAS), scanning electron microscopy (SEM), wavelength dispersive X-ray spectroscopy (WDX), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), and vibrating sample magnetometer (VSM) techniques. The results obtained from SEM shown that this catalyst has a nanosheet structure. Also, XRD and FT-IR analysis show that the structure of graphene oxide and nickel magnetic nanoparticles is stable during the modification of the nanoparticles and synthesis of the catalyst. The VSM curve of the catalyst shows that this catalyst can be recovered using an external magnet; therefore, it can be reused several times without a significant loss of its catalytic efficiency. The heterogeneity and stability of this nanocatalyst during organic reactions was confirmed by the hot filtration test and AAS technique.
- Hajjami, Maryam,Moradi, Parisa
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p. 25867 - 25879
(2021/08/09)
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- Thermally stable and robust gadolinium-based metal-organic framework: Synthesis, structure and heterogeneous catalytic O-arylation reaction
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Hydrothermal treatment of gadolinium nitrate and 2,6-naphthalenedicarboxylic acid (H2NDC) afforded a new metal-organic framework compound, {[Gd4(NDC)6(H2O)6]·2H2O}n(1). Compound 1 has been characterized by single-crystal X-ray crystallography, elemental analysis, FT-IR spectroscopy, therrmogravimetric analysis (TGA) and powder X-ray diffraction analysis. It is crystallized in the monoclinic system with the P21/n space group. Four crystallographically distinct Gd (III) centres are interconnected with each other through bridged carboxylato oxygen atoms and water molecules to form tetranuclear secondary building units, which are further connected through the carboxylato ligand and the network propagates along the crystallographic ac plane to form a 2D structure. Subsequent reinforcement from the remaining carboxylato oxygen atoms gives rise to a robust 3D framework structure. Thermogravimetric analysis demonstrates that compound 1 is fairly stable after dehydration under a nitrogen atmosphere. Notably, compound 1 is capable of catalyzing the O-arylation reaction efficiently between substituted phenols and bromoarene under heterogeneous conditions at 80 °C to afford unsymmetrical diarylethers.
- Ghosh, Pameli,Maity, Tanmoy,Biswas, Saptarshi,Debnath, Rakesh,Koner, Subratanath
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- Solvent-free palladium-catalyzed C–O cross-coupling of aryl bromides with phenols
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A new solvent-free procedure for C–O cross-coupling between phenols and aryl bromides comprising of Pd2(dba)3/ButBrettPhos catalytic system is efficient for substrates bearing donor or acceptor, as well as bulky substituents.
- Asachenko, Andrey F.,Bogachev, Vasilii N.,Cherkashchenko, Ilia R.,Lavrov, Konstantin V.,Minaeva, Lidiya I.,Nechaev, Mikhail S.,Rzhevskiy, Sergey A.,Sterligov, Grigorii K.,Topchiy, Maxim A.
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p. 409 - 411
(2021/06/07)
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- Structural Development of Salicylanilide-Based SPAK Inhibitors as Candidate Antihypertensive Agents
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Hypertension is an important target for drug discovery. We have focused on the with-no-lysine kinase (WNK)-oxidative stress-responsive 1 (OSR1) and STE20/SPS1-related proline-alanine-rich protein kinase (SPAK)-NaCl cotransporter (NCC) signal cascade as a potential target, and we previously developed a screening system for inhibitors of WNK-OSR1/SPAK-NCC signaling. Herein we used this system to examine the structure-activity relationship (SAR) of salicylanilide derivatives as SPAK kinase inhibitors. Structural design and development based on our previous hit compound, aryloxybenzanilide derivative 2, and the veterinary anthelmintic closantel (3) led to the discovery of compound 10 a as a potent SPAK inhibitor with reduced toxicity. Compound 10 a decreased the phosphorylation level of NCC in mouse kidney in vivo, and appears to be a promising lead compound for a new class of antihypertensive drugs.
- Fujii, Shinya,Kikuchi, Eriko,Suzuyama, Honoka,Watanabe, Yuko,Ishigami-Yuasa, Mari,Masuno, Hiroyuki,Mori, Takayasu,Isobe, Kiyoshi,Uchida, Shinichi,Kagechika, Hiroyuki
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supporting information
p. 2817 - 2822
(2021/07/12)
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- Light-Assisted Ullmann Coupling of Phenols and Aryl Halides: The Synergetic Effect Between Plasmonic Copper Nanoparticles and Carbon Nanotubes from Various Sources
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Utilizing light and plastic wastes as resources to turn the wasted phenols and hazardous aryl halides into value added chemicals seems to be an attractive idea for alleviating the energy crisis and environmental problems. In this work, plasmonic copper nanoparticles (Cu NPs) were loaded onto carbon nanotubes (CNTs) from various sources including commercial CNTs and those derived from plastic wastes. Under visible-light irradiation, the catalyst could efficiently convert phenols and aryl halides to diaryl ethers. Similar with commercial CNTs, excellent activity is also achieved when utilizing CNTs derived from different kinds of plastic wastes as support for the system. Further investigation shows that the visible-light irradiation and light-excited plasmonic Cu NPs are necessary to inhibit the phenol degradation on CNTs and in turn promote the cross-coupling of phenol and aryl halides. Compared with metal oxides and other carbon materials, the excellent capability of CNTs to absorb light, to convert light to heat, and to adsorb both two reactants simultaneously are critical to enhance the activity of Cu NPs, achieving high yields of diaryl ethers. This study could provide a novel strategy for catalyst design and generate a more economically sustainable process.
- Ji, Rongrong,Jie, Xiangyu,Li, Bing,Liu, Xuguang,Wang, Yuanhui,Zhao, Jian,Zhou, Yiwei
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- Photoinduced Iron-Catalyzed ipso-Nitration of Aryl Halides via Single-Electron Transfer
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A photoinduced iron-catalyzed ipso-nitration of aryl halides with KNO2 has been developed, in which aryl iodides, bromides, and some of aryl chlorides are feasible. The mechanism investigations show that the in situ formed iron complex by FeSO4, KNO2, and 1,10-phenanthroline acts as the light-harvesting photocatalyst with a longer lifetime of the excited state, and the reaction undergoes a photoinduced single-electron transfer (SET) process. This work represents an example for the photoinduced iron-catalyzed Ullmann-type couplings.
- Wu, Cunluo,Bian, Qilong,Ding, Tao,Tang, Mingming,Zhang, Wenkai,Xu, Yuanqing,Liu, Baoying,Xu, Hao,Li, Hai-Bei,Fu, Hua
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p. 9561 - 9568
(2021/08/06)
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- Catalysis with magnetically retrievable and recyclable nanoparticles layered with Pd(0) for C-C/C-O coupling in water
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Nanoparticles layered with palladium(0) were prepared from nano-sized magnetic Fe3O4 by coating it with silica and then reacting sequentially with phenylselenyl chloride under an N2 atmosphere and palladium(ii) chloride in water. The resulting Fe3O4?SiO2?SePh?Pd(0) NPs are magnetically retrievable and the first example of NPs in which the outermost layer of Pd(0) is mainly held by selenium. The weight percentage of Pd in the NPs was found to be 1.96 by ICP-AES. The NPs were authenticated via TEM, SEM-EDX, XPS, and powder XRD and found to be efficient as catalysts for the C-O and C-C (Suzuki-Miyaura) coupling reactions of ArBr/Cl in water. The oxidation state of Pd in the NPs having size distribution from ～12 to 18 nm was inferred as zero by XPS. They can be recycled more than seven times. The main features of the proposed protocols are their mild reaction conditions, simplicity, and efficiency as the catalyst can be separated easily from the reaction mixture by an external magnet and reused for a new reaction cycle. The optimum loading (in mol% of Pd) was found to be 0.1-1.0 and 0.01-1.0 for O-arylation and Suzuki-Miyaura coupling, respectively. For ArCl, the required amount of NPs was more as compared to that needed for ArBr. The nature of catalysis is largely heterogeneous.
- Joshi, Hemant,Sharma, Alpesh K.,Singh, Ajai K.
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p. 6452 - 6459
(2020/02/25)
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- CoII Immobilized on Aminated Magnetic-Based Metal–Organic Framework: An Efficient Heterogeneous Nanostructured Catalyst for the C–O Cross-Coupling Reaction in Solvent-Free Conditions
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Abstract: In this paper, we report the synthesis of Fe3O4?AMCA-MIL53(Al)-NH2-CoII NPs based on the metal–organic framework structures as a magnetically separable and environmentally friendly heterogeneous nanocatalyst. The prepared nanostructured catalyst efficiently promotes the C–O cross-coupling reaction in solvent-free conditions without the need for using toxic solvents and/or expensive palladium catalyst. Graphic Abstract: [Figure not available: see fulltext.].
- Mohammadinezhad, Arezou,Akhlaghinia, Batool
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p. 332 - 352
(2020/01/11)
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- Pd based on 2-Aminopyrimidine and 1H-benzo[d]imidazol-2-amine functionalizedFe3O4 nanoparticles as novel recyclable magnetic nanocatalysts for Ullmann coupling reaction
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In this study, Pd based on 2-Aminopyrimidine and 1H-benzo[d]imidazol-2-amine functionalized Fe3O4 magnetic nanoparticles [(Pd-APM-PSi-Fe3O4) and (Pd-BIA-PSi-Fe3O4)] was designed and used for the synthesis of di aryl ether by Ulmann cross-coupling reactions. Ulmann reaction performed with mixing of the arylhalides and phenol derivatives in DMF solvent. The prepared catalysts were characterized with various analytical techniques such as FT-IR, XRD, TGA, SEM, TEM, EDX, ICP and VSM. Pd-APM-PSi-Fe3O4 and Pd-BIA-PSi-Fe3O4 catalysts demonstrated good to excellent yields catalytic efficiency for Ulmann reactions in comparison with to commercial palladium catalysts. The catalyst is easily recycled and reused without loss of the catalytic activity. The combined merits of reusable catalyst conditions make the condensation with safe operation, no leaching of pd into environment, low pollution, rapid access to products and simple workup. Also, these novel magnetic nanocatalysts are superior to the industry standard Pd in every relevant aspect. They feature a way higher initial activity, a much more convenient separation, better recycling, and less contamination of the products. Last but not least, they can be very easily prepared from commercially available Fe3O4 nanoparticles using standard laboratory equipment.
- Chen, Jin,Dai, Linfang,Li, Jiayu,Mohammadnia, Majid
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- Palladium complexes of chalcogenoethanamine (S/Se) bidentate ligands: Applications in catalytic arylation of C[sbnd]H and O[sbnd]H bonds
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This report describes the syntheses of N,E (E = S, Se) coordinated bidentate palladium complexes, by the reaction of N-(2-bromobenzyl)-2-(phenylthio/selanyl)ethanamine (3, 4) with [PdCl2(CH3CN)2]. The new ligands and palladium complexes were characterized by techniques like 1H, 13C{1H} NMR, IR, and elemental analysis. The coordination modes of ligand with palladium precursor in complexes 5 and 6 were authenticated by single crystal X-ray diffraction. The complexes possess distorted square planar geometry around palladium center. Thermally robust and air stable complexes 5 and 6 were used as catalyst for regioselective arylation of imidazole and O-arylation of phenol. In case of regioselective arylation of imidazole, the reaction proceeds smoothly under mild reaction conditions, only 2.0 mol% of catalyst loading is required to achieve high yield (76–92%). This protocol is applicable to a broad substrate scope showing excellent tolerance towards different functional groups. Whereas for O-arylation of phenol also only 2.0 mol% catalyst loading is sufficient to give good yield (71–92%) with excellent tolerance towards a broad range of functional groups. Among sulfur and selenium coordinated ligands, selenium ligand coordinated complex, was found to outperform the catalytic reactions in both cases as compare to sulfur ligand. The mercury and triphenylphosphine poisoning tests suggest homogeneous nature of catalysis.
- Bhatt, Ramprasad,Bhuvanesh, Nattamai,Himanshi,Joshi, Hemant,Sharma, Alpesh K.
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- Ni(II) complexes of tripodal N4 ligands as catalysts for alkane hydroxylation and O-arylation of phenol: Structural and reactivity effects induced by fluoro substitution
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Nickel(II) complexes [NiII(L1-2)(OAc)(H2O)][BPh4] (1–2) and [NiII(L3)(OAc)][BPh4] (3) derived from fluorinated tripodal ligands viz. N-((6-fluoropyridin-2-yl)methyl)(pyridin-2-yl)-N-(pyridin-2-ylmethyl)methanamine (L1 or FTPA), N,N′-bis((6-fluoropyridin-2-yl)methyl)(pyridin-2-yl)methanamine (L2 or F2TPA) and tris((6-fluoropyridin-2-yl)methyl)amine (L3 or F3TPA) have been synthesized and characterized by spectroscopic (UV–visible, FT-IR, paramagnetic NMR), elemental analysis, electrochemistry and X-ray diffraction techniques. In structurally similar complexes 1 and 2, Ni(II) center has a distorted octahedral coordination geometry constituted by all the four N atoms of the ligands, one acetate group and a water molecule. Complex 3 has different structural aspects. It does not have the water molecule in the coordination sphere and contains one acetate group bound with metal center in a bidentate mode. All the complexes exhibit a one-electron oxidation corresponding to the NiII/NiIII redox couple, the potential of which is influenced by the donor functionalities of ligand. These complexes catalyze the oxidation of cyclohexane efficiently (turn over number: 586–698) and selectively (alcohol to ketone ratio: 7.9:1 to 8.4:1). The study also includes the catalysis of adamantane oxidation to a mixture of ketones and alcohols. Catalytic potential of all the three complexes (1–3) has also been screened for C–O coupling reactions of phenol with aryl halides. Among them, complex 1 is more efficient than 2 and 3 for such reactions.
- Kerbib, Wissame,Kumar, Arun,Kumar, Sushil,Nautiyal, Divyanshu,Singh, Siddhant
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- Aryl Ether Syntheses via Aromatic Substitution Proceeding under Mild Conditions
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In this study, mild conditions for aromatic substitutions during the syntheses of aryl ethers were developed. In the reaction conditions, the choices of solvent, base, and the sequence for the addition of the reagents proved important. A wide variety of alcohols were used directly as nucleophiles and smoothly reacted with aryl chlorides that possessed either a nitro or a cyano group at either the ortho- or para-position. Controlled experiments we performed suggested that the reaction underwent a charge-transfer process mediated by a combination of DMF and tert-BuOK.
- Ando, Shin,Tsuzaki, Marina,Ishizuka, Tadao
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p. 11181 - 11189
(2020/10/12)
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- A novel magnetic polyacrylonotrile-based palladium Core?Shell complex: A highly efficientcatalyst for Synthesis of Diaryl ethers
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The present article describes the synthesis of a new magnetic polyacrylonitrile-based Pd catalyst involving polyacrylonitrile modified via 2-aminopyridine as an efficient support to immobilize Pd nanoparticles. The simple reusability, easy separation and high stability of this Pd complex make it an excellent candidate to generate a C–O bond via Ph-X activation which is a really important subject in achieving biologically active compounds. It is worth to note access to good and high yields as well as broad substrate scope have resulted from superior reactivity of this catalyst complex. Furthermore, the structure of the magnetic polyacrylonitrile-based heterogeneous catalyst was characterized by fourier transmission infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM), X-ray diffraction (XRD). Also, its thermal properties were studied by thermogravimetric analysis (TGA).
- Eslami, Mohammad,Jarahiyan, Atefeh,Moghaddam, Firouz Matloubi,Pourjavadi, Ali
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- Structural development of N-(4-phenoxyphenyl)benzamide derivatives as novel SPAK inhibitors blocking WNK kinase signaling
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We report here structural development of N-(4-phenoxyphenyl)benzamide derivatives as novel SPAK (STE20/SPS1-related proline/alanine-rich kinase) inhibitors. Abnormal activation of the signal cascade of with-no-lysine kinase (WNK) with OSR1 (oxidative stress-responsive kinase 1)/SPAK and NCC (NaCl cotransporter) results in characteristic salt-sensitive hypertension, and therefore inhibitors of the WNK-OSR1/SPAK-NCC cascade are candidates for antihypertensive drugs. Based on the structure of lead compound 2, we examined the SAR of N-(4-phenoxyphenyl)benzamide derivatives, and developed compound 20l as a potent SPAK inhibitor. Compounds 20l is a promising candidate for a new class of antihypertensive drugs.
- Fujii, Shinya,Ishigami-Yuasa, Mari,Isobe, Kiyoshi,Kagechika, Hiroyuki,Kikuchi, Eriko,Mori, Takayasu,Suzuyama, Honoka,Uchida, Shinichi,Watanabe, Yuko
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supporting information
(2020/07/21)
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- Targeting Her2-insYVMA with Covalent Inhibitors - A Focused Compound Screening and Structure-Based Design Approach
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Mutated or amplified Her2 serves as a driver of non-small cell lung cancer or mediates resistance toward the inhibition of its family member epidermal growth factor receptor with small-molecule inhibitors. To date, small-molecule inhibitors targeting Her2 which can be used in clinical routine are lacking, and therefore, the development of novel inhibitors was undertaken. In this study, the well-established pyrrolopyrimidine scaffold was modified with structural motifs identified from a screening campaign with more than 1600 compounds, which were applied against wild-type Her2 and its mutant variant Her2-A775_G776insYVMA. The resulting inhibitors were designed to covalently target a reactive cysteine in the binding site of Her2 and were further optimized by means of structure-based drug design utilizing a set of obtained complex crystal structures. In addition, the analysis of binding kinetics and absorption, distribution, metabolism, and excretion parameters as well as mass spectrometry experiments and western blot analysis substantiated our approach.
- Lategahn, Jonas,Hardick, Julia,Grabe, Tobias,Niggenaber, Janina,Jeyakumar, Kirujan,Keul, Marina,Tumbrink, Hannah L.,Becker, Christian,Hodson, Luke,Kirschner, Tonia,Kl?vekorn, Philip,Ketzer, Julia,Baumann, Matthias,Terheyden, Susanne,Unger, Anke,Weisner, J?rn,Müller, Matthias P.,Van Otterlo, Willem A. L.,Bauer, Sebastian,Rauh, Daniel
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p. 11725 - 11755
(2020/11/26)
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- Copper(I)–creatine complex on magnetic nanoparticles as a green catalyst for N- and O-arylation in deep eutectic solvent
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Immobilization of copper(I) ions on magnetic nanoparticles was performed using surface modification of Fe3O4 with creatine. Fe3O4?creatine-Cu(I) magnetic catalyst was synthesized and applied in C&bond;X cross-coupling reactions with aryl halides in a deep eutectic as a green solvent. The results indicate the Fe3O4?creatine-Cu(I) magnetic nanoparticles showed excellent activity and high stability. In addition, it was revealed that this catalyst can be recycled five times without significant loss in catalytic activity.
- Bagheri, Sepideh,Heydari, Akbar,Pazoki, Farzane,Radfar, Iman
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- Diaza crown-type macromocycle (kryptofix 22) functionalised carbon nanotube for efficient Ni2+ loading; A unique catalyst for cross-coupling reactions
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Raising the capability of supporting and suppressing the leaching possibility to a very insignificant level has still remained challenging for some class of transition metals, i.e. Ni2+. Here we present the covalent functionalisation of macrocyclic ligand, 4,13-diaza-18-crown-6 (kryptofix 22), on the surface of carbon nanotube (CNT), leading to a unique adsorptive capability for supporting Ni2+. This material was incorporated as a promising catalyst in coupling reactions including C[sbnd]C, CN, and CO[sbnd][sbnd] cross-coupling reactions. We demonstrate that the kryptofix 22 functionalisation on the surface of CNT has a key role in the enhancement of the adsorption capability Ni2+ and subsequent catalytic activity. We further prove that this ligand causes a significant boost in the recyclability of the reactions due to the extremely trivial Ni2+ leaching from the CNT's surface during the reactions.
- Aalinejad, Michael,Doustkhah, Esmail,Pesyan, Nader Noroozi
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- Novel cobalt-valine catalyzed O-arylation of phenols with electron deficient aryl iodides
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Abstract: A Novel cobalt-catalyzed O-arylation of phenols with electron deficient aryl iodides is described. The reaction employs cheap and easy-to-handle cobalt acetate tetrahydrate as the catalyst precursor and naturally occurring l-valine as the ligand without the use of any transmetallating or reducing agents. The new protocol offers a wide scope for a variety of phenols towards O-arylation with moderate to excellent yields with electron deficient aryl iodides.
- Ujwaldev, Sankuviruthiyil M.,Saranya, Salim,Harry, Nissy Ann,Anilkumar, Gopinathan
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p. 339 - 346
(2019/01/18)
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- A new strategy to design a graphene oxide supported palladium complex as a new heterogeneous nanocatalyst and application in carbon–carbon and carbon-heteroatom cross-coupling reactions
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The palladium nanoparticles were successfully stabilized with an average diameter of 6–7?nm through the coordination of palladium and terpyridine-based ligands grafted on graphene oxide surface. The graphene oxide supported palladium nanoparticles were thoroughly characterized and applied as an efficient heterogeneous catalyst in carbon–carbon (Suzuki-Miyaura, Mizoroki-Heck coupling reactions) and carbon–heteroatom (C-N and C-O) bond-forming reactions. The catalyst was simply recycled from the reaction mixture and was reused consecutive four times with small drop in catalytic activity.
- Bahrami, Kiumars,Targhan, Homa
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- Preparation and characterization of isatin complexed with Cu supported on 4-(aminomethyl) benzoic acid-functionalized Fe3O4 nanoparticles as a novel magnetic catalyst for the Ullmann coupling reaction
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Isatin complexed with Cu supported on 4-(aminomethyl) benzoic acid-functionalized Fe3O4 nanoparticles (Cu-IS-AMBA-MNPs) as a new catalyst was designed, prepared and characterized by appropriate analyses. The heterogeneous reusable catalyst was successfully used for the efficient and widespread syntheses of diaryl ethers and diarylamines via the Ullmann coupling reaction. This green catalyst was easily removed, reused several times with no significant loss of its activity, and provided a clean synthesis with excellent yield and reduced time.
- Khodaei, Mohammad Mehdi,Alizadeh, Abdolhamid,Haghipour, Maryam
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p. 2727 - 2747
(2019/02/13)
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- Cell-Based Optimization of Covalent Reversible Ketoamide Inhibitors Bridging the Unprimed to the Primed Site of the Proteasome β5 Subunit
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The ubiquitin-proteasome system (UPS) is an established therapeutic target for approved drugs to treat selected hematologic malignancies. While drug discovery targeting the UPS focuses on irreversibly binding epoxyketones and slowly-reversibly binding boronates, optimization of novel covalent-reversibly binding warheads remains largely unattended. We previously reported α-ketoamides to be a promising reversible lead motif, yet the cytotoxic activity required further optimization. This work focuses on the lead optimization of phenoxy-substituted α-ketoamides combining the structure-activity relationships from the primed and the non-primed site of the proteasome β5 subunit. Our optimization strategy is accompanied by molecular modeling, suggesting occupation of P1′ by a 3-phenoxy group to increase β5 inhibition and cytotoxic activity in leukemia cell lines. Key compounds were further profiled for time-dependent inhibition of cellular substrate conversion. Furthermore, the α-ketoamide lead structure 27 does not affect escape response behavior in Danio rerio embryos, in contrast to bortezomib, which suggests increased target specificity.
- Stubba, Daniel,Bensinger, Dennis,Steinbacher, Janika,Proskurjakov, Lilia,Salcedo Gómez, álvaro,Schmidt, Uwe,Roth, Stefan,Schmitz, Katja,Schmidt, Boris
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supporting information
p. 2005 - 2022
(2019/11/22)
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- Diaryl ether compound, preparation method and application thereof
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The invention relates to a diaryl ether compound , a preparation method and application thereof, wherein the diaryl ether compound has the following structural formula: (the formula is shown in the description), wherein, -X- is CH- or -N-; =R1,-R2,-R3 are independently selected from one kind of H-,-F,-Cl,-Br, alkoxy, aryl, aryloxy, N, N-Dialkylamino, N-Alkyl-N-Acylamino, pyridyl, imidazolyl, pyrazolyl, furyl, pyrrolyl, morpholinyl, N-Alkyl piperazinyl, piperidinyl and tetrahydropyrrolyl. The diaryl ether compound has the advantage of inhibiting the activity of a PFKFB3 in the tumor cells, effectively blocking the activation of the key enzyme during the glycolysis process, thereby blocking energy supply from the energy source of the tumor cells, and providing a new medicament for the effective treatment of the tumor diseases.
- -
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Paragraph 0107-0109; 0116
(2019/01/23)
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- Novel Deazaflavin Analogues Potently Inhibited Tyrosyl DNA Phosphodiesterase 2 (TDP2) and Strongly Sensitized Cancer Cells toward Treatment with Topoisomerase II (TOP2) Poison Etoposide
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Topoisomerase II (TOP2) poisons as anticancer drugs work by trapping TOP2 cleavage complexes (TOP2cc) to generate DNA damage. Repair of such damage by tyrosyl DNA phosphodiesterase 2 (TDP2) could render cancer cells resistant to TOP2 poisons. Inhibiting TDP2, thus, represents an attractive mechanism-based chemosensitization approach. Currently known TDP2 inhibitors lack cellular potency and/or permeability. We report herein two novel subtypes of the deazaflavin TDP2 inhibitor core. By introducing an additional phenyl ring to the N-10 phenyl ring (subtype 11) or to the N-3 site of the deazaflavin scaffold (subtype 12), we have generated novel analogues with considerably improved biochemical potency and/or permeability. Importantly, many analogues of both subtypes, particularly compounds 11a, 11e, 12a, 12b, and 12h, exhibited much stronger cancer cell sensitizing effect than the best previous analogue 4a toward the treatment with etoposide, suggesting that these analogues could serve as effective cellular probes.
- Kankanala, Jayakanth,Ribeiro, Carlos J. A.,Kiselev, Evgeny,Ravji, Azhar,Williams, Jessica,Xie, Jiashu,Aihara, Hideki,Pommier, Yves,Wang, Zhengqiang
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p. 4669 - 4682
(2019/05/17)
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- Structural optimization and structure–activity relationship of 4-thiazolidinone derivatives as novel inhibitors of human dihydroorotate dehydrogenase
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Human dihydroorotate dehydrogenase (hDHODH), one of the attractive targets for the development of immunosuppressive drugs, is also a potential target of anticancer drugs and anti-leukemic drugs. The development of promising hDHODH inhibitors is in high demand. Based on the unique binding mode of our previous reported 4-thiazolidinone derivatives, via molecular docking method, three new series 4-thiazolidinone derivatives were designed and synthesized as hDHODH inhibitors. The preliminary structure–activity relationship was investigated. Compound 9 of biphenyl series and compound 37 of amide series displayed IC50 values of 1.32 μM and 1.45 μM, respectively. This research will provide valuable reference for the research of new structures of hDHODH inhibitors.
- Zeng, Fanxun,Quan, Lina,Yang, Guantian,Qi, Tiantian,Zhang, Letian,Li, Shiliang,Li, Honglin,Zhu, Lili,Xu, Xiaoyong
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- 3-(Ethoxycarbonyl)-1-(5-methyl-5-(nitrosooxy)hexyl)pyridin-1-ium cation: A green alternative to tert-butyl nitrite for synthesis of nitro-group-containing arenes and drugs at room temperature
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Due to their remarkable properties, task-specific ionic liquids have turned out to be progressively popular over the last few years in the field of green organic synthesis. Herein, for the first time, we report that a new task-specific nitrite-based ionic liquid such as 3-(ethoxycarbonyl)-1-(5-methyl-5-(nitrosooxy)hexyl)pyridin-1-ium bis(trifluoromethanesulfonyl)imides (TS-N-IL) derived from biodegradable ethyl nicotinate indeed acted as an efficient and eco-friendly reagent for the synthesis of highly valuable nitroaromatic compounds and drugs including nitroxynil, tolcapone, niclofolan, flutamide, niclosamide and nitrazepam. The bridging of an ionic liquid with nitrite group not only increases the yield and rate of direct C[sbnd]N bond formation reaction but also allows easy product separation and recyclability of a byproduct. Nonvolatile nature, easy synthesis, merely stoichiometric need and mildness are a portion of the extra focal points of TS-N-IL while contrasted with tert-butyl nitrite an outstanding and highly-flammable reagent utilized largely in organic synthesis.
- Chaudhary, Renu,Natarajan, Palani,Rani, Neetu,Sakshi,Venugopalan, Paloth
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supporting information
(2019/12/30)
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- URJC-1-MOF as New Heterogeneous Recyclable Catalyst for C-Heteroatom Coupling Reactions
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Guillermo Calleja and co-workers from @urjc describe URJC-1-MOF as a new heterogeneous recyclable catalyst for c-heteroatom coupling reactions. The capacity of copper-based URJC-1-MOF as a MOF catalyst in cross-coupling reactions has been evaluated, focusing on the Chan-Lam-Evans arylation-type reactions on amines and alcohols without extra additives or ligands. The extraordinary chemical and structural stability of URJC-1-MOF and its good specific surface, make this material a promising alternative to homogeneous Cu (II) catalysts for cross-coupling reactions. URJC-1-MOF showed a remarkable catalytic activity for cross-coupling C?N and C?O reactions, higher than other heterogeneous and homogeneous copper-based catalyst, such as CuO, HKUST-1, Cu?MOF-74, Cu(OAc)2 and CuSO4?5H2O. Moreover, its easy recovery by simple filtration and reusability in successive runs without any loss of activity and stability, demonstrates the potential of URJC-1-MOF as an alternative catalyst for this kind of reactions in different chemical media of industrial interest.
- Mu?oz, Antonio,Leo, Pedro,Orcajo, Gisela,Martínez, Fernando,Calleja, Guillermo
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p. 3376 - 3380
(2019/07/04)
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- Fe3O4@SiO2-copper sucrose xanthate as a green nanocatalyst for N-, O- and S-arylation
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Formation of C(sp2)–X bonds was carried out using a Fe3O4@SiO2-copper(I) sucrose xanthate nanoparticle catalyst with the aid of the copper(I) xanthate moiety in the catalyst which was prepared from the reaction between sucrose and carbon disulfide through an alkaline medium via the traditional Zeise approach. Various techniques were employed for the characterization of these novel nanoparticles. Three sorts of heteroatoms, N, O and S, successfully underwent heteroatom arylation to produce secondary or tertiary amines, ethers and thioethers, respectively.
- Radfar, Iman,Kazemi Miraki, Maryam,Esfandiary, Naghmeh,Ghandi, Leila,Heydari, Akbar
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- Design of BNPs-TAPC Palladium Complex as a Reusable Heterogeneous Nanocatalyst for the O-Arylation of Phenols and N-Arylation of Amines
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The thermally stable new heterogenous nanocatalyst BNPs@SiO2(CH2)3-TAPC-O-CH2CH2NH2-Pd(0) was synthesized, characterized and successfully applied in carbon-heteroatom (C–O and C–N) coupling reactions of aryl halides with phenols and amines. The formation of resultant nanocatalyst was approved by FT-IR, XRD, TGA, XPS and EDX techniques. The morphology of BNPs@SiO2(CH2)3-TAPC-O-CH2CH2NH2-Pd(0) was characterized using scanning and transmission electron microscopes. The leaching of palladium from the surface of the catalyst was studid by ICP-OES technique. Noteworthy, the highly active BNPs@SiO2(CH2)3-TAPC-O-CH2CH2NH2-Pd(0) can be easily recycled and reused for six times with negligible loss in its activity. Some remarkable advantages of this method are the shorter reaction times, milder conditions, no needs for an inert atmosphere, high yields and easy separation. Graphical Abstract: [Figure not available: see fulltext.].
- Bahrami, Kiumars,Khodamorady, Minoo
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p. 688 - 698
(2019/01/04)
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- Zirconium oxide complex anchored on boehmite nanoparticles as highly reusable organometallic catalyst for C–S and C–O coupling reactions
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Boehmite nanoparticles were prepared by a simple and inexpensive procedure in water using commercially available materials without inert atmosphere. Then, the surface of the boehmite nanoparticles was modified using 3-mercaptopropyltrimethoxysilane and subsequently zirconium oxide was supported on the modified surface. Zirconium oxide supported on boehmite nanoparticles (Pr.S-ZrO@boehmite) was characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and inductively coupled plasma technique. The catalytic application of Pr.S-ZrO@boehmite was studied in C–O and C–S coupling reactions for synthesis of valuable compounds such as ether and sulfide derivatives. All products were obtained in good to excellent yields and the catalyst could be recovered and reused several times without significant loss of catalytic efficiency. Furthermore, zirconium oxide is rarely used as catalyst for cross-coupling reactions.
- Ghorbani-Choghamarani, Arash,Seydyosefi, Zeinab,Tahmasbi, Bahman
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- Immobilized palladium nanoparticles on MNPs@A-N-AEB as an efficient catalyst for C-O bond formation in water as a green Solvent
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Palladium nanoparticles immobilized on the magnetic nanoparticles@2-amino-N-(2-aminoethyl) benzamide (MNPs@A-N-AEB.Pd0) have been presented as an efficient, and reusable magnetically heterogeneous catalyst for the C-O coupling reaction, namely Ullmann condensation reactions in an aqueous medium. This heterogeneous catalyst shows superior reactivity for the C-O arylation of different aryl halide (chloride, bromide, and iodide) with phenol derivatives to afford the desired products in good to excellent yields within short reaction time. Moreover, the catalyst can be easily recovered and reused for seven runs without loss of catalytic activity. The catalyst was characterized by several techniques, such as FT-IR, SEM, TEM, EDS, XRD, TGA and ICP-OES.
- Moghaddam, Firouz Matloubi,Eslami, Mohammad
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- The First C?Cl Activation in Ullmann C?O Coupling by MOFs
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It was found that introduction of only 0.03 mol % Ag(I) into the framework of Cu3(BTC)2 ? xH2O in maghemite anchored CuBTC activated the inert CuBTC astonishingly to exhibit unexpected high catalytic activity for C?Cl activation in coupling of chloroarenes with phenols without the use of expensive ligands. This is the first application of mixed-metal MOFs in the C?X activation. Putting reusability and activity together, a TON over 15000 was obtained which is the highest TON compared with all its precedents even better than the results by Pd catalysts.
- Ramezani, Leila,Yahyazadeh, Asieh,Sheykhan, Mehdi
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p. 4636 - 4651
(2018/09/21)
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- Synthesis and characterization of MCM-41-Biurea-Pd as a heterogeneous nanocatalyst and using its catalytic efficacy in C–C, C–N and C–O coupling reactions
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MCM-41-Biurea-Pd is introduced as a new, heterogeneous and reusable catalyst for C–C and C–heteroatom bond formation between various aryl halides, phenols and amines, in the presence of Ph3SnCl (Stille reaction) in PEG-400 as a green solvent at room temperature. The structure of the functionalized MCM-41 was analysed using various techniques.
- Batmani, Hana,Noroozi Pesyan, Nader,Havasi, Forugh
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- Cu2O/SiC as efficient catalyst for Ullmann coupling of phenols with aryl halides
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A Cu2O/SiC heterogeneous catalyst was prepared via a two-step liquid-phase method using diethylene glycol as both the solvent and the reducing agent. The catalyst was characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and H2 temperature-programmed reduction. All the results indicate that Cu is present on the SiC support primarily as Cu2O. The SEM and TEM results show that cubic Cu2O nanoparticles are uniformly dispersed on the β-SiC surface. The reaction conditions, namely the temperature, reaction time, and amounts of base and catalyst used, for the Ullmann-type C–O cross-coupling reaction were optimized. A model reaction was performed using iodobenzene (14.0 mmol) and phenol (14.0 mmol) with Cu2O/SiC (5 wt% Cu) as the catalyst, Cs2CO3 (1.0 equiv.) as the base, and tetrahydrofuran as the solvent at 150 °C for 3 h; a yield of 97% was obtained and the turnover frequency (TOF) was 1136 h?1. The Cu2O/SiC catalyst has a broad substrate scope and can be used in Ullmann-type C–O cross-coupling reactions of aryl halides and phenols bearing a variety of different substituents. The catalyst also showed high activity in the Ullmann-type C–S cross-coupling of thiophenol with iodobenzene and substituted iodobenzenes; a TOF of 1186 h?1 was achieved. The recyclability of the Cu2O/SiC catalyst in the O-arylation of phenol with iodobenzene was investigated under the optimum conditions. The yield decreased from 97% to 64% after five cycles. The main reason for the decrease in the catalyst activity is loss of the active component, i.e., Cu2O.
- Wang, Yibing,Guo, Xiaoning,Lü, Manqian,Zhai, Zhaoyang,Wang, Yingyong,Guo, Xiangyun
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p. 658 - 664
(2017/04/24)
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- A green approach for arylation of phenols using iron catalysis in water under aerobic conditions
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The first efficient iron-catalyzed coupling of aryl iodides with phenols was developed exclusively with water as solvent. The reaction is performed with low cost and readily available FeCl3·6H2O and DMEDA catalytic system providing diaryl ethers in good to excellent yields. The effectiveness of this reaction was further revealed by compatibility with a wide range of functional groups. Moreover, the procedure is rendered simple as this transformation is carried out in the presence of air. Thus, the protocol represents a facile, economical and eco-friendly procedure to access diaryl ethers.
- Sindhu, Kallikkakam S.,Ujwaldev, Sankuviruthiyil M.,Keerthi Krishnan,Anilkumar, Gopinathan
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p. 146 - 150
(2017/03/17)
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- N-Picolinamides as ligands in Ullman type C–O coupling reactions
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Copper-catalyzed modified Ullmann coupling reactions creating C–O bonds, including diaryl ethers or phenols, are vital to organic synthesis. Synthesized N-phenyl-2-pyridinecarboxamide and its derivatives were used as ligands in conjunction with catalytic copper sources in the formation of various diaryl ethers and phenols. Various aryl and heteroaryl halides with electron donating and withdrawing groups were reacted with various phenols under mild reaction conditions providing moderate to excellent yields.
- Damkaci, Fehmi,Sigindere, Cihad,Sobiech, Thomas,Vik, Erik,Malone, Joshua
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supporting information
p. 3559 - 3564
(2017/10/05)
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- Ullmann Reaction Catalyzed by Heterogeneous Mesoporous Copper/Manganese Oxide: A Kinetic and Mechanistic Analysis
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A heterogeneous copper oxide supported on mesoporous manganese oxide (meso Cu/MnOx) was explored for Ullmann-type cross-coupling reactions. An inverse micelle-templated evaporation-induced self-assembly method with in situ addition of copper was adopted to synthesize the mesoporous catalyst. Broad substrate scope and excellent functional group tolerability in C-O, C-N, and C-S bond formation reactions were observed using the optimized reaction conditions. The catalytic protocol was ligand free, and the catalyst was reusable without any significant loss of activity. The kinetic and Hammett analyses provided evidence for oxidative addition to a Cu(I) reaction center followed by nucleophilic addition and reductive elimination at the active copper oxide surface. Rate acceleration was observed for aryl halides with electron-withdrawing groups. The Hammett analysis determined ρ = +1.0, indicative of an oxidative addition, whereas the electronic effect in the phenol ring (ρ = -2.9) was indicative of coordination to a metal ion. Theoretically, the oxidative addition of the aryl halides is assisted by the ligand environment of the copper center. Relevant mechanistic implications are discussed on the basis of the experimental and computational results.
- Mullick, Kankana,Biswas, Sourav,Kim, Chiho,Ramprasad, Ramamurthy,Angeles-Boza, Alfredo M.,Suib, Steven L.
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p. 10290 - 10297
(2017/09/12)
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- Palladium(II) complexes of N, N-diphenylacetamide based thio/selenoethers and flower shaped Pd16S7 and prismatic Pd17Se15 nano-particles tailored as catalysts for C-C and C-O coupling
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2-Bromo-N,N-diphenylacetamide (P1) prepared by reacting diphenylamine with α-bromoacetyl bromide, on treatment with Na2S and Na2Se generated in situ, has resulted in thio and selenoether ligands, L1 ((Ph2NCOCH2)2S) and L2 ((Ph2NCOCH2)2Se), respectively. Reacting these ligands with Na2PdCl4 in ethanol at room temperature resulted in their complexes [Pd(L1/L2)2Cl2] (C1/C2). P1, L1, L2, C1 and C2 were characterized by 1H, 13C{1H} and 77Se{1H} NMR spectroscopy, IR spectroscopy and High resolution mass spectrometry (HR-MS). Single crystal structures of all the five compounds were determined by X-ray diffraction. In both C1 and C2 the geometry of Pd is nearly square planar. Flower shaped Pd16S7 (size 26-50 nm) and prismatic Pd17Se15 NPs (size 20-55 nm) were synthesized by a single source precursor route (thermolysis at ～280 °C in trioctylphosphine) from air and moisture insensitive C1 and C2, respectively. These shapes of the two nanophases were unknown hitherto. They were characterized by powder X-ray diffraction (PXRD), SEM-EDX and HR-TEM and found to show good catalytic activity for Suzuki-Miyaura (Pd loading 0.5 mol%; yield up to 96%) and C-O (Pd loading 0.5 mol%; yield up to 96%) coupling reactions (at 100 °C) of aryl bromides with phenylboronic acid and phenol, respectively. The complexes C1 and C2 were found very efficient for Suzuki-Miyaura and C-O coupling as revealed by their optimum loading of 0.0001-0.01 and 0.1 mol% of Pd, respectively, for the two reactions. The reuse of the complexes or NPs as a catalyst is demonstrated.
- Singh, Poornima,Singh, Ajai K.
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supporting information
p. 10037 - 10049
(2017/08/10)
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- Copper immobilized on magnetite nanoparticles coated with ascorbic acid: An efficient and reusable catalyst for C─N and C─O cross-coupling reactions
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In a continuation of using magnetic nanoparticle (MNP)-supported catalysts, ascorbic acid (readily available, very safe and with strong affinity to MNPs) was used instead of the commonly used silica layer coating. This hybrid was used for immobilizing copper nanoparticles to produce Cu/ascorbic acid@MNPs catalyst. The catalyst was characterized and used in carbon–oxygen and carbon–nitrogen (various substrates) cross-coupling reactions in aqueous media and at room temperature with excellent product yields. Furthermore, the catalyst could be quickly and completely recovered using an external magnetic field and reused for six reaction cycles without significant change in catalytic activity.
- Hajipour, Abdol R.,Check, Maryam,Khorsandi, Zahra
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- Palladacycles of sulfated and selenated Schiff bases of ferrocene-carboxaldehyde as catalysts for O-arylation and Suzuki-Miyaura coupling
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Schiff base ligands (L1: sulfated and L2: selenated) having a ferrocene core synthesized by reacting ferrocene-carboxaldehyde with 2-(phenylthio/seleno)ethylamine on treatment with Na2PdCl4 in the presence of NaOAc give cyclopalladated complexes [Pd(L1/L2-H)Cl] (1/2). Complex 1 of a sulfated Schiff base L1, on reacting with one equivalent of triphenylphosphine gives complex [Pd(L1-H)PPh3Cl] (3), formed due to cleavage of a Pd-S bond. With 2 such a reaction does not occur, as a Pd-Se bond being stronger than that of its sulfur analogue does not get cleaved. L1, L2 and their complexes 1-3 were authenticated with HR-MS, 1H, 13C{1H} and 77Se{1H} NMR spectroscopy. The single crystal structures of 1-3 were determined with X-ray diffraction. Palladium in all three complexes has nearly a square planar geometry. The Pd-S, Pd-Se and Pd-P bond distances are 2.4249(12), 2.5058(14) and 2.2445(17) ? respectively. The catalytic activity of complexes 1-3 was explored for O-arylation of phenol and Suzuki-Miyaura coupling (SMC) of phenylboronic acid with aryl bromides and chlorides. The optimum reaction time for SMC of ArBr is 3 h whereas for ArCl it is 6 h. The TON values of O-arylation catalyzed with complexes 1-3 are up to ～170 (TOF, 28 h?1) and SMC ～9300 (TOF, 3100 h?1) for the reaction time of the order of 3 and 6 h respectively. The catalytic process is somewhat more efficient with 2 (Pd bonded with a selenoether group), than 3, followed by 1.
- Sharma, Alpesh K.,Joshi, Hemant,Bhaskar, Renu,Kumar, Satyendra,Singh, Ajai K.
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p. 2485 - 2496
(2017/03/08)
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- Cellulose-supported N-heterocyclic carbene silver complex with pendant ferrocenyl group for diaryl ether synthesis
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A cellulose-supported N-heterocyclic carbene Ag(I) complex has been synthesized by covalent grafting of ferrocenyl ionic liquid in the matrix of cellulose followed by metallation with silver oxide. The complex was employed as a heterogeneous catalyst in the synthesis of diaryl ethers. Reactions of a variety of phenols with aryl halides afford corresponding diaryl ethers in moderate to good yields. Recyclability experiments were executed successfully for five consecutive runs.
- Jagadale, Megha,Salunkhe, Rajashri,Kumbhar, Arjun,Gajare, Shivanand,Rajmane, Mohan,Rashinkar, Gajanan
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- The Suzuki-Miyaura Coupling of Nitroarenes
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Synthesis of biaryls via the Suzuki-Miyaura coupling (SMC) reaction using nitroarenes as an electrophilic coupling partners is described. Mechanistic studies have revealed that the catalytic cycle of this reaction is initiated by the cleavage of the aryl-nitro (Ar-NO2) bond by palladium, which represents an unprecedented elemental reaction.
- Yadav, M. Ramu,Nagaoka, Masahiro,Kashihara, Myuto,Zhong, Rong-Lin,Miyazaki, Takanori,Sakaki, Shigeyoshi,Nakao, Yoshiaki
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supporting information
p. 9423 - 9426
(2017/07/24)
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- Synthesis, SAR and molecular docking study of novel non-β-lactam inhibitors of TEM type β-lactamase
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The novel classes of acylated phenoxyanilide and thiourea compounds were investigated for their ability to inhibit TEM type β-lactamase enzyme. Two compounds 4g and 5c reveal the inhibition potency in micromolar range and show their action by non-covalent binding in the vicinity of the TEM-171 active site. The structure activity relationship around carbon chain length and different substituents in ortho- and para-positions of acylated phenoxyanilide as well as molecular modelling study has been performed.
- Antipin, Roman L.,Beshnova, Daria A.,Petrov, Rostislav A.,Shiryaeva, Anna S.,Andreeva, Irina P.,Grigorenko, Vitaly G.,Rubtsova, Maya Yu.,Majouga, Alexander G.,Lamzin, Victor S.,Egorov, Alexey M.
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supporting information
p. 1588 - 1592
(2017/03/17)
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