- Metal-free organic dyes containing thiadiazole unit for dye-sensitized solar cells: A combined experimental and theoretical study
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We have designed and synthesized four new metal free D-A-π-A type dyes (9-12) with variations in their acceptor/anchor groups. The four dyes carry tert-butyl substituted triphenylamine as donor, thiadiazole as acceptor and bithiophene as π-spacer. Cyanoacetic acid, rhodanine-3-acetic acid, 2-(4-methoxyphenyl)acetic acid and 2-phenylacetic acid are used as acceptor/anchor groups, respectively in the dyes 9-12. The acceptor/anchor effect on their photophysical, electrochemical and photovoltaic properties was investigated. The dyes exhibited good power conversion efficiency ranging from 1.95-4.12%. Among the four dyes, 9 showed the best photovoltaic performance: short-circuit current density (Jsc) of 8.50 mA cm-2, open-circuit voltage (Voc) of 645 mV and fill factor (FF) of 0.75, corresponding to an overall conversion efficiency of 4.12% under standard global AM 1.5 solar light conditions. This journal is the Partner Organisations 2014.
- Siva Kumar, Gangala,Srinivas, Kola,Shanigaram, Balaiah,Bharath, Dyaga,Singh, Surya Prakash,Bhanuprakash,Rao, V. Jayathirtha,Islam, Ashraful,Han, Liyuan
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Read Online
- Hydrogenation of ethyl p-nitrobenzoate on carbon-supported palladium-triphenylphosphine catalyst
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Hydrogenation of ethyl p-nitrobenzoate on carbon-supported palladium-triphenylphosphine catalyst at 40°C and atmospheric pressure of H2 was studied.
- Obraztsova,Efimov
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Read Online
- Kinetics of the reduction of p-nitrobenzoic acid esters in nanoreactors on the basis of sulfonated polymers
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The kinetics of the reduction of p-nitrobenzoic acid esters in nanoreactors based on sulfonated network polymers containing nanodispersed palladium was studied. The kinetic characteristics of the hydrogenation of aromatic nitro compounds were calculated.
- Al'Tshuler,Shkurenko,Gorlov
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Read Online
- Nickel Boride Catalyzed Reductions of Nitro Compounds and Azides: Nanocellulose-Supported Catalysts in Tandem Reactions
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Nickel boride catalyst prepared in situ from NiCl2 and sodium borohydride allowed, in the presence of an aqueous solution of TEMPO-oxidized nanocellulose (0.01 wt%), the reduction of a wide range of nitroarenes and aliphatic nitro compounds. Here we describe how the modified nanocellulose has a stabilizing effect on the catalyst that enables low loading of the nickel salt pre-catalyst. Ni-B prepared in situ from a methanolic solution was also used to develop a greener and facile reduction of organic azides, offering a substantially lowered catalyst loading with respect to reported methods in the literature. Both aromatic and aliphatic azides were reduced, and the protocol is compatible with a one-pot Boc-protection of the obtained amine yielding the corresponding carbamates. Finally, bacterial crystalline nanocellulose was chosen as a support for the Ni-B catalyst to allow an easy recovery step of the catalyst and its recyclability for new reduction cycles.
- Proietti, Giampiero,Prathap, Kaniraj Jeya,Ye, Xinchen,Olsson, Richard T.,Dinér, Peter
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p. 133 - 146
(2021/11/04)
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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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- Iridium-Triggered Allylcarbamate Uncaging in Living Cells
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Designing a metal catalyst that addresses the major issues of solubility, stability, toxicity, cell uptake, and reactivity within complex biological milieu for bioorthogonal controlled transformation reactions is a highly formidable challenge. Herein, we report an organoiridium complex that is nontoxic and capable of the uncaging of allyloxycarbonyl-protected amines under biologically relevant conditions and within living cells. The potential applications of this uncaging chemistry have been demonstrated by the generation of diagnostic and therapeutic agents upon the activation of profluorophore and prodrug in a controlled fashion within HeLa cells, providing a valuable tool for numerous potential biological and therapeutic applications.
- Gupta, Ajay,Gupta, Shalini,Mahawar, Pritam,Prasad, Puja,Sasmal, Pijus K.,Singh, Neelu
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supporting information
p. 12644 - 12650
(2021/09/06)
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- Pleuromutilin derivative with 1, 3, 4-oxadiazole side chain and preparation and application thereof
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The invention belongs to the field of medicinal chemistry, and particularly relates to a pleuromutilin derivative with a 1, 3, 4-oxadiazole side chain and preparation and application thereof The pleuromutilin derivative with the 1, 3, 4-oxadiazole side chain is a compound shown in a formula 2 or a pharmaceutically acceptable salt thereof, and a solvent compound, an enantiomer, a diastereoisomer and a tautomer of the compound shown in the formula 2 or the pharmaceutically acceptable salt thereof or a mixture of the solvent compound, the enantiomer, the diastereoisomer and the tautomer in any proportion, including a racemic mixture. The pleuromutilin derivative has good antibacterial activity, is especially suitable for being used as a novel antibacterial agent for systemic system infection of animals or human beings, and has good water solubility.
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Paragraph 0055-0056; 0070; 0090; 0092; 0095; 0103
(2021/07/24)
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- Highly efficient N-doped carbon supported FeSx-Fe2O3 catalyst for hydrogenation of nitroarenes via pyrolysis of sulfurized N,Fe-containing MOFs
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Integrating MOFs as precursor, especially for employing N-containing organic linkers, with sulfides is an effective method to prepare the highly efficient N-doped carbon supported metal-based catalysts for hydrogenation of nitroarenes. In this work, a N,Fe-containing metal organic frameworks (MOFs; termed as MIL88-HMTA) with spindle-like structure was prepared via self-assembly method, in which hexamethylenetetramine (HMTA) linker was introduced as N source. Subsequently, N-doped carbon supported FeSx-Fe2O3 catalyst (named FeSx-Fe2O3@CN) was fabricated upon the pyrolysis of sulfurized MIL88-HMTA. Catalytic experiments reveal that the FeSx-Fe2O3@CN delivered excellent performance for hydrogenation of nitroarenes in comparison with those of catalyst without sulfidation process (Fe2O3@CN) and conventional MIL88 derived catalyst (Fe2O3@C). The XRD, TEM, SEM/EDX, Raman, UV, and XPS analyses have revealed that the developed FeSx-Fe2O3@CN catalyst exhibited outstanding catalytic efficiency was ascribed to synergistic effect between FeSx and Fe2O3 species, abundant structural defects, more Fe-Nx species, and strengthened decomposition ability of hydrazine hydrate (N2H4?H2O). Furthermore, the effect of sulfidation ratio (the mass ratio between thioacetamide and MIL88-HMTA) towards preparation of the developed FeSx-Fe2O3@CN on the catalytic activity of hydrogenation reaction was also systematically performed. Notably, the optimized catalyst (denoted as FeSx-Fe2O3@CN-8) exhibited unexpected performance and recyclability for hydrogenation of nitroarenes under mild condition. The pyrolysis of sulfurized N-containing MOFs may present a facile approach for fabricating MOFs-derived N-doped carbon supported catalysts, which provides a potential application in heterogeneous catalytic reactions.
- Li, Xuewei,She, Wei,Wang, Jing,Li, Weizuo,Li, Guangming
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- Biorenewable carbon-supported Ru catalyst for: N -alkylation of amines with alcohols and selective hydrogenation of nitroarenes
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Herein, we developed a renewable carbon-supported Ru catalyst (Ru/PNC-700), which was facilely prepared via simple impregnation followed by the pyrolysis process. The prepared Ru/PNC-700 catalyst demonstrated remarkable catalytic activity in terms of conversion and selectivity towards N-alkylation of anilines with benzyl alcohol and chemoselective hydrogenation of aromatic nitro compounds. In addition, local anesthetic pharmaceutical agents (e.g., butamben and benzocaine), including key drug intermediates, were synthesized in excellent yields under mild conditions and in the presence of water as a green solvent. Moreover, the prepared Ru/PNC-700 catalyst could be easily recovered and reused up to five times without any apparent loss in activity and selectivity.
- Goyal, Vishakha,Narani, Anand,Natte, Kishore,Poddar, Mukesh Kumar,Ray, Anjan,Sarki, Naina,Tripathi, Deependra
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p. 14687 - 14694
(2021/08/23)
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- Yeast supported gold nanoparticles: an efficient catalyst for the synthesis of commercially important aryl amines
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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
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supporting information
p. 1915 - 1923
(2021/02/06)
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- Simple RuCl3-catalyzed N-Methylation of Amines and Transfer Hydrogenation of Nitroarenes using Methanol
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Methanol is a potential hydrogen source and C1 synthon, which finds interesting applications in both chemical synthesis and energy technologies. The effective utilization of this simple alcohol in organic synthesis is of central importance and attracts scientific interest. Herein, we report a clean and cost-competitive method with the use of methanol as both C1 synthon and H2 source for selective N-methylation of amines by employing relatively cheap RuCl3.xH2O as a ligand-free catalyst. This readily available catalyst tolerates various amines comprising electron-deficient and electron-donating groups and allows them to transform into corresponding N-methylated products in moderate to excellent yields. In addition, few marketed pharmaceutical agents (e. g., venlafaxine and imipramine) were also successfully synthesized via late-stage functionalization from readily available feedstock chemicals, highlighting synthetic value of this advanced N-methylation reaction. Using this platform, we also attempted tandem reactions with selected nitroarenes to convert them into corresponding N-methylated amines using MeOH under H2-free conditions including transfer hydrogenation of nitroarenes-to-anilines and prepared drug molecules (e. g., benzocaine and butamben) as well as key pharmaceutical intermediates. We further enable one-shot selective and green syntheses of 1-methylbenzimidazole using ortho-phenylenediamine (OPDA) and methanol as coupling partners.
- Sarki, Naina,Goyal, Vishakha,Tyagi, Nitin Kumar,Puttaswamy,Narani, Anand,Ray, Anjan,Natte, Kishore
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p. 1722 - 1729
(2021/04/19)
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- Selective primary aniline synthesis through supported Pd-catalyzed acceptorless dehydrogenative aromatization by utilizing hydrazine
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By utilizing hydrazine (N2H4) as the nitrogen source in the presence of a hydroxyapatite-supported Pd nanoparticle catalyst (Pd/HAP), various primary anilines can be selectively synthesized from cyclohexanonesviaacceptorless dehydrogenative aromatization. The strong nucleophilicity of N2H4and the stability of the hydrazone intermediates can effectively suppress the formation of the undesired secondary aniline byproducts.
- Lin, Wei-Chen,Yamaguchi, Kazuya,Yatabe, Takafumi
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supporting information
p. 6530 - 6533
(2021/07/07)
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- Cyclic (Alkyl)(amino)carbene Ligand-Promoted Nitro Deoxygenative Hydroboration with Chromium Catalysis: Scope, Mechanism, and Applications
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Transition metal catalysis that utilizes N-heterocyclic carbenes as noninnocent ligands in promoting transformations has not been well studied. We report here a cyclic (alkyl)(amino)carbene (CAAC) ligand-promoted nitro deoxygenative hydroboration with cost-effective chromium catalysis. Using 1 mol % of CAAC-Cr precatalyst, the addition of HBpin to nitro scaffolds leads to deoxygenation, allowing for the retention of various reducible functionalities and the compatibility of sensitive groups toward hydroboration, thereby providing a mild, chemoselective, and facile strategy to form anilines, as well as heteroaryl and aliphatic amine derivatives, with broad scope and particularly high turnover numbers (up to 1.8 × 106). Mechanistic studies, based on theoretical calculations, indicate that the CAAC ligand plays an important role in promoting polarity reversal of hydride of HBpin; it serves as an H-shuttle to facilitate deoxygenative hydroboration. The preparation of several commercially available pharmaceuticals by means of this strategy highlights its potential application in medicinal chemistry.
- Zhao, Lixing,Hu, Chenyang,Cong, Xuefeng,Deng, Gongda,Liu, Liu Leo,Luo, Meiming,Zeng, Xiaoming
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p. 1618 - 1629
(2021/01/25)
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- Optimizing the structure of (salicylideneamino)benzoic acids: Towards selective antifungal and anti-staphylococcal agents
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An increasing resistance of human pathogenic bacteria and fungi has become a global health problem. Based on previous reports of 4-(salicylideneamino)benzoic acids, we designed, synthesised and evaluated their me-too analogues as potential antimicrobial agents. Forty imines derived from substituted salicylaldehydes and aminobenzoic acids, 4-aminobenzoic acid esters and 4-amino-N-phenylbenzamide were designed using molecular hybridization and prodrug strategies. The target compounds were synthesized with high yields and characterized by spectral methods. They were investigated against a panel of Gram-positive and Gram-negative bacteria, mycobacteria, yeasts and moulds. The most active imines were tested to determine their cytotoxicity and selectivity in HepG2 cells. Dihalogenosalicylaldehydes-based derivatives showed potent broad-spectrum antimicrobial properties, particularly against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (minimum inhibitory concentrations, MIC, from 7.81 μM) and Enterococcus faecalis (MIC of ≥15.62 μM), yeasts (MIC from 7.81 μM) and Trichophyton interdigitale mould (MIC of ≥3.90 μM). Methyl 4-[(2-hydroxy-3,5-diiodobenzylidene)amino]benzoate 4h exhibited excellent in vitro activity along with low toxicity to mammalian cells. This compound is selective for staphylococci, Candida spp. and Trichophyton interdigitale. In addition, this imine was evaluated as a potential inhibitor of Gram-positive biofilms. The successful approach used provided some promising derivatives with more advantageous properties than the parent 4-(salicylideneamino)benzoic acids.
- Krátky, Martin,Kone?ná, Klára,Broke?ová, Kate?ina,Maixnerová, Jana,Trejtnar, Franti?ek,Vin?ová, Jarmila
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- Design, synthesis, in vitro and in vivo evaluation against MRSA and molecular docking studies of novel pleuromutilin derivatives bearing 1, 3, 4-oxadiazole linker
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A class of pleuromutilin derivatives containing 1, 3, 4-oxadiazole were designed and synthesized as potential antibacterial agents against Methicillin-resistant staphylococcus aureus (MRSA). The ultrasound-assisted reaction was proposed as a green chemistry method to synthesize 1, 3, 4-oxadiazole derivatives (intermediates 85–110). Among these pleuromutilin derivatives, compound 133 was found to be the strongest antibacterial derivative against MRSA (MIC = 0.125 μg/mL). Furthermore, the result of the time-kill curves displayed that compound 133 could inhibit the growth of MRSA in vitro quickly (- 4.36 log10 CFU/mL reduction). Then, compound 133 (- 1.82 log10 CFU/mL) displayed superior in vivo antibacterial efficacy than tiamulin (- 0.82 log10 CFU/mL) in reducing MRSA load in mice thigh model. Besides, compound 133 exhibited low cytotoxicity to RAW 264.7 cells. Molecular docking studies revealed that compound 133 was successfully localized in the binding pocket of 50S ribosomal subunit (ΔGb = -10.50 kcal/mol). The results indicated that these pleuromutilin derivatives containing 1, 3, 4-oxadiazole might be further developed into novel antibiotics against MRSA.
- Liu, Jie,Zhang, Guang-Yu,Zhang, Zhe,Li, Bo,Chai, Fei,Wang, Qi,Zhou, Zi-Dan,Xu, Ling-Ling,Wang, Shou-Kai,Jin, Zhen,Tang, You-Zhi
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- Design, Synthesis, and Study of the Insecticidal Activity of Novel Steroidal 1,3,4-Oxadiazoles
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A series of novel steroidal derivatives with a substituted 1,3,4-oxadiazole structure was designed and synthesized, and the target compounds were evaluated for their insecticidal activity against five aphid species. Most of the tested compounds exhibited potent insecticidal activity against Eriosoma lanigerum (Hausmann), Myzus persicae, and Aphis citricola. Compounds 20g and 24g displayed the highest activity against E. lanigerum, showing LC50 values of 27.6 and 30.4 μg/mL, respectively. Ultrastructural changes in the midgut cells of E. lanigerum were detected by transmission electron microscopy, indicating that these steroidal oxazole derivatives might exert their insecticidal activity by destroying the mitochondria and nuclear membranes in insect midgut cells. Furthermore, a field trial showed that compound 20g exhibited effects similar to those of the positive controls chlorpyrifos and thiamethoxam against E. lanigerum, reaching a control rate of 89.5% at a dose of 200 μg/mL after 21 days. We also investigated the hydrolysis and metabolism of the target compounds in E. lanigerum by assaying the activities of three insecticide-detoxifying enzymes. Compound 20g at 50 μg/mL exhibited inhibitory action on carboxylesterase similar to the known inhibitor triphenyl phosphate. The above results demonstrate the potential of these steroidal oxazole derivatives to be developed as novel pesticides.
- Bai, Hangyu,Jiang, Weiqi,Li, Qi,Li, Tian,Ma, Shichuang,Shi, Baojun,Wu, Wenjun
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p. 11572 - 11581
(2021/10/12)
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- Catalytic production of anilines by nitro-compounds hydrogenation over highly recyclable platinum nanoparticles supported on halloysite nanotubes
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Pt-nanoparticles supported on halloysite-nanotubes (HNTs) were selectively deposited onto the inner (Pt(IN)/HNT) or outer (Pt(OUT)/HNT) surface of the support to evaluate their operational stability on the cleaner and efficient hydrogenation of nitro compounds to produce their corresponding anilines. The formation of Pt0-aggregates on the inner or outer surfaces was observed, with mean particles sizes of 2.4–2.9 nm. The catalysts were evaluated using ethanol as solvent and nitrobenzene as a model substrate at a temperature of 298 K, under 1 bar of H2 pressure. The Pt(IN)/HNT catalyst showed better catalytic performance than Pt(OUT)/HNT, which was mainly attributed to the confinement effect of the Pt-nanoparticles inside the HNTs. However, the operational stability showed that Pt(OUT)/HNT retained its catalytic performance after 15 cycles, while the Pt(IN)/HNT catalyst suffered deactivation after the 5th cycle. The best catalytic system showed a moderate-to-high efficiency in the efficient hydrogenation of 7 nitro compounds used to produce their corresponding anilines, which are important pharmaceutical building blocks.
- Aepuru, Radhamanohar,Bustamante, Tatiana M.,Campos, Cristian H.,Leal-Villarroel, Edgardo,Mangalaraja, Ramalinga Viswanathan,Shanmugaraj, Krishnamoorthy,Torres, Cecilia C.,Vinoth, Victor
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- Sulfonated covalent triazine polymer loaded with Pd nanoparticles as a bifunctional catalyst for one pot hydrogenation esterification reaction
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Highly dispersed Pd nanoparticles over covalent triazine polymer functionalized with sulfonic acid groups (CTP-SO3H/Pd) were prepared by facile Friedel-Crafts reaction, post synthetic sulfonation and Pd immobilization method. The prepared catalyst was characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption-desorption, inductively coupled plasma - optical emission spectrometry (ICP-OES), elemental analysis and X-ray photoelectron spectroscopy (XPS). The sulfonic acid groups were grafted into the terphenyl backbone and the presence of triazine functionality within the framework enabled the uniform dispersion of palladium nanoparticles over the polymer network. When used as a bifunctional catalyst in one pot hydrogenation-esterification (OHE) reaction, the CTP-SO3H/Pd exhibited good activity and stability. The performance of CTP-SO3H/Pd is due to the surface-active acid/metal sites and was evident from the yield of the product in the reaction. The catalyst was easily recovered by filtration and recycle tests showed that it could be re-used for at least five repetitive runs with minor loss of catalytic activity suggesting its potential utility in OHE reaction. A plausible mechanistic pathway for OHE reaction over CTP-SO3H/Pd was also proposed.
- Ravi, S.,Raza, A. Ahmed,Sheriff, A. K. Ibrahim,Tajudeen, S. Syed
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- Preparation method of 4-aminobenzoic acid and derivatives thereof
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The invention discloses a preparation method of 4-aminobenzoic acid and derivatives thereof. The method comprises the following steps: (1) reacting an acid ester raw material, namely 1, 4-phthalic acid monoester or 1, 4-phthalic acid diester or 1, 4-phthalic acid monoester monoamide, with hydroxylamine to obtain a 4-carboxyl benzoyl hydroxamic acid inorganic salt, a 4-alkoxyacyl benzoyl hydroxamic acid inorganic salt and a 4-carbamoyl benzoyl hydroxamic acid inorganic salt respectively; and (2), enabling the 4-carboxyl benzoyl hydroxamic acid inorganic salt, the 4-alkoxyacyl benzoyl hydroxamic acid inorganic salt or the 4-carbamoyl benzoyl hydroxamic acid inorganic salt to be subjected to rearrangement reaction, so as to obtain the 4-aminobenzoate, the 4-aminobenzoate ester and the 4-aminobenzamide; and acidifying the 4-aminobenzoate to obtain the 4-aminobenzoic acid. Nitrification and reduction reactions are not used, and hidden dangers of waste acid pollution and explosive polynitrobenzene are eliminated.
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Paragraph 0027; 0053-0054
(2021/05/05)
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- Chemoselective electrochemical reduction of nitroarenes with gaseous ammonia
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Valuable aromatic nitrogen compounds can be synthesized by reduction of nitroarenes. Herein, we report electrochemical reduction of nitroarenes by a protocol that uses inert graphite felt as electrodes and ammonia as a reductant. Depending on the cell voltage and the solvent, the protocol can be used to obtain aromatic azoxy, azo, and hydrazo compounds, as well as aniline derivatives with high chemoselectivities. The protocol can be readily scaled up to >10 g with no decrease in yield, demonstrating its potential synthetic utility. A stepwise cathodic reduction pathway was proposed to account for the generations of products in turn.
- Chang, Liu,Li, Jin,Wu, Na,Cheng, Xu
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supporting information
p. 2468 - 2472
(2021/04/02)
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- Synthesis of Substituted Anilines from Cyclohexanones Using Pd/C-Ethylene System and Its Application to Indole Synthesis
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The synthesis of anilines and indoles from cyclohexanones using a Pd/C-ethylene system is reported. A simple combination of NH4OAc and K2CO3 under nonaerobic conditions was found to be the most suitable to perform this reaction. Hydrogen transfer between cyclohexanone and ethylene generates the desired products. The reaction tolerates a variety of substitutions on the starting cyclohexanones.
- Maeda, Katsumi,Matsubara, Ryosuke,Hayashi, Masahiko
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supporting information
p. 1530 - 1534
(2021/03/08)
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- Benzo imidazo [2, 1-b] thiazole compound and application thereof (by machine translation)
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The invention discloses a benzoimidazo [2, 1-b] thiazole compound and application thereof, and belongs to the technical field of medicines. The inhibitory activity of the synthesized benzimidazo [2, 1-b] thiazole analogues on FLTT3 is more than 90%, wherein the compounds (compounds 2 , 4, 6, 8 and 10) are IC of FLTT3-ITD kinase. 50 Lower value, in particular compound 2, IC IC50 The value is only 5.60 nm, and therefore the compound of the present invention may be used as an inhibitor FLTT3, or for preparing a drug capable of modulating or suppressing diseases associated with abnormal cell proliferation by affecting the enzymatic activity of one or more tyrosine kinases and interfering with aberrant cell proliferation, having a wide application prospect. (by machine translation)
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Paragraph 0105-0110
(2020/07/15)
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- Cycloglutaramide-based ligand, synthetic method of ligand, application of ligand in coupling reaction for synthesizing arylamine derivative and catalytic system
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The invention discloses a cycloglutaramide-based ligand having a general formula I shown in the specification, a synthetic method of the ligand, an application of the ligand in a coupling reaction forsynthesizing an arylamine derivative, and a catalytic system. The compounds represented by the formula I can be used as a ligand in the coupling reaction of synthesizing the arylamine derivative by using an aryl halide under catalysis of copper, especially the coupling reaction of aryl halide and an amine source to form a C-N bond under catalysis. Under mild reaction conditions, the high-yield arylamine derivative is obtained, and the ligand has a simple structure, convenient preparation and a less use amount.
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Paragraph 0106; 0107; 0108; 0109; 0110
(2020/03/12)
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- Palladium Supported on Carbon Nanoglobules as a Promising Catalyst for Selective Hydrogenation of Nitroarenes
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The catalysts 1?wt% palladium supported on carbon nanoglobules (CNGs) were shown to be highly active in the liquid-phase hydrogenation of various nitroarenes and provided nearly 100% selectivity to aromatic amines at complete conversion under mild conditions (323?K, 0.5?MPa, 1?h). The catalytic activity (in terms of turnover frequency and substrate conversion) and selectivity depend on the kind of CNGs support, catalyst preparation method and the reaction conditions (solvent nature). The Pd/CNGs catalyst can be repeatedly used while maintaining the same catalytic performance. The excellent performances of Pd/CNGs catalysts can be due to the globular morphology of the supports as well as the absence of micropores and pronounced surface defects. Graphic Abstract: [Figure not available: see fulltext.]
- Mironenko,Belskaya,Stepanova,Gulyaeva,Trenikhin,Likholobov
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p. 888 - 900
(2019/11/11)
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- Palladium nanoparticles embedded in mesoporous carbons as efficient, green and reusable catalysts for mild hydrogenations of nitroarenes
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The reduction of nitroarenes is the most efficient route for the preparation of aromatic primary amines. These reductions are generally performed in the presence of heterogeneous transition metal catalysts, which are rather efficient but long and tedious to prepare. In addition, they contain very expensive metals that are in most cases difficult to reuse. Therefore, the development of efficient, easily accessible and reusable Pd catalysts obtained rapidly from safe and non-toxic starting materials was implemented in this report. Two bottom-up synthesis methods were used, the first consisted in the impregnation of a micro/mesoporous carbon support with a Pd salt solution, followed by thermal reduction (at 300, 450 or 600 °C) while the second involved a direct synthesis based on the co-assembly and pyrolysis (600 °C) of a mixture of a phenolic precursor, glyoxal, a surfactant and a Pd salt. The obtained composites possess Pd nanoparticles (NPs) of tunable sizes (ranging from 1-2 to 7.0 nm) and homogeneously distributed in the carbon framework (pores/walls). It turned out that they were successfully used for mild and environment-friendly hydrogenations of nitroarenes at room temperature under H2(1 atm) in EtOH in the presence of only 5 mequiv. of supported Pd. The determinations of the optimal characteristics of the catalysts constituted a second objective of this study. It was found that the activity of the catalysts was strongly dependent on the Pd NPs sizes,i.e., catalysts bearing small Pd NPs (1.2 nm obtained at 300 °C and 3.4 nm obtained at 450 °C) exhibited an excellent activity, while those containing larger Pd NPs (6.4 nm and 7.0 nm obtained at 600 °C, either by indirect or direct methods) were not active. Moreover, the possibility to reuse the catalysts was shown to be dependent on the surface chemistry of the Pd NPs: the smallest Pd NPs are prone to oxidation by air and their surface was gradually covered by a PdO shell decreasing their activity during reuse. A good compromise between intrinsic catalytic activity (i.e. during first use) and possibility of reuse was found in the catalyst made by impregnation followed by reduction at 450 °C since the hydrogenation could be performed in only 2 h in EtOH or even in water. The catalyst was quantitatively recovered after reaction by filtration, used at least 7 times with no loss of efficiency. Advantageously, almost Pd-free primary aromatic amines were obtained since the Pd leaching was very low (0.1% of the introduced amount). Compared to numerous reports from the literature, the catalysts described here were both easily accessible from eco-friendly precursors and very active for hydrogenations under mild and “green” reaction conditions.
- Becht, Jean-Michel,Enneiymy, Mohamed,Fioux, Philippe,Le Drian, Claude,Matei Ghimbeu, Camelia
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p. 36741 - 36750
(2020/10/19)
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- Preparation method of arylamine compound
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The invention belongs to the technical field of natural compounds, pharmaceutical and chemical intermediates and related chemistry, and provides a preparation method of arylamine compounds. The methoduses aromatic nitro compounds as raw materials, a nano porous platinum-iron catalyst as a catalyst and hydrogen as a hydrogen source to prepare arylamine through selective hydrogenation. The adoptedcatalyst is the nano porous platinum-iron catalyst, the pore size is 1nm-50nm, and the molar ratio of the aromatic nitro compound to the catalyst is 1:0.01-1:0.5; the pressure of the hydrogen is 0.1-20.0 MPa; and the molar concentration of the nitro compound in the solvent is 0.01-2 mmol/mL. The method has the beneficial effects that the reaction conditions are very mild, the product selectivity is high, the operation and post-treatment are simple, the catalyst activity is high, the property is stable, the price is low, the reproducibility is good, the catalytic effect is not obviously reducedafter repeated use for multiple times, and the possibility is provided for industrialization.
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Paragraph 0052-0059
(2020/12/10)
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- Commercially Available CuO Catalyzed Hydrogenation of Nitroarenes Using Ammonia Borane as a Hydrogen Source
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Tandem ammonia borane dehydrogenation and nitroarenes hydrogenation has been reported as a novel strategy for the preparation of aromatic amines. However, the practical application of this strategy is subjected to the high-cost and tedious preparation of supported noble metal nanocatalysts. The commercially available CuO powder is herein demonstrated to be a robust catalyst for hydrogenation of nitroarenes using ammonia borane as a hydrogen source under mild conditions. Numerous amines (even sterically hindered, halogenated, and diamines) could be obtained through this method. This monometallic catalyst is characteristic of support-free, excellent chemoselectivity, low-cost, and high recyclability, which will favor its future utilization in preparative reduction chemistry. Mechanistic studies are also carried out to clarify that diazene and azoxybenzene are key intermediates of this heterogeneous reduction.
- Du, Jialei,Chen, Jie,Xia, Hehuan,Zhao, Yiwei,Wang, Fang,Liu, Hong,Zhou, Weijia,Wang, Bin
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p. 2426 - 2430
(2020/03/30)
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- Synthesis of Some Aromatic and Aliphatic Esters Using WO3/ZrO2 Solid Acid Catalyst under Solvent Free Conditions
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A simple method is delineated for the synthesis of substituted ester products in superior yields by esterification reaction under solvent unbound condition using tungsten upgraded ZrO2 solid acid catalyst at 353 K. The WO3/ZrO2 catalyst has been prepared by using impregnation method followed by calcination at 923 K over a period of 6 h in air atmosphere. SEM, XRD, FTIR, and BET surface area techniques were used to categorize this catalyst. Zirconia has both acidic and basic possessions which can be changed by incorporating suitable promoter atom like tungsten which in turn increases the surface area thereby enhancing the surface acidity. Impregnation of W6+ ions exhibits a strong influence on phase modification of zirconia from thermodynamically solid monoclinic to metastable tetragonal phase. Amalgamation of promoter W6+ will stabilize tetragonal phase which is active in catalyzing reactions. In esterification reaction WO3/ZrO2 catalyst was found to be stable, efficient and environmental friendly, effortlessly recovered by filtration, excellent yield of product and can be reusable efficiently.
- Guguloth, Vijaya Charan,Battu, Satyanarayana
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p. 2153 - 2157
(2020/09/16)
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- PTG-0861: A novel HDAC6-selective inhibitor as a therapeutic strategy in acute myeloid leukaemia
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Dysregulated Histone Deacetylase (HDAC) activity across multiple human pathologies have highlighted this family of epigenetic enzymes as critical druggable targets, amenable to small molecule intervention. While efficacious, current approaches using non-selective HDAC inhibitors (HDACi) have been shown to cause a range of undesirable clinical toxicities. To circumvent this, recent efforts have focused on the design of highly selective HDACi as a novel therapeutic strategy. Beyond roles in regulating transcription, the unique HDAC6 (with two catalytic domains) regulates the deacetylation of α-tubulin; promoting growth factor-controlled cell motility, cell division, and metastatic hallmarks. Recent studies have linked aberrant HDAC6 function in various hematological cancers including acute myeloid leukaemia and multiple myeloma. Herein, we report the discovery, in vitro characterization, and biological evaluation of PTG-0861 (JG-265), a novel HDAC6-selective inhibitor with strong isozyme-selectivity (~36× ) and low nanomolar potency (IC50 = 5.92 nM) against HDAC6. This selectivity profile was rationalized via in silico docking studies and also observed in cellulo through cellular target engagement. Moreover, PTG-0861 achieved relevant potency against several blood cancer cell lines (e.g. MV4-11, MM1S), whilst showing limited cytotoxicity against non-malignant cells (e.g. NHF, HUVEC) and CD-1 mice. In examining compound stability and cellular permeability, PTG-0861 revealed a promising in vitro pharmacokinetic (PK) profile. Altogether, in this study we identified a novel and potent HDAC6-selective inhibitor (~4× more selective than current clinical standards – citarinostat, ricolinostat), which achieves cellular target engagement, efficacy in hematological cancer cells with a promising safety profile and in vitro PK.
- Bukhari, Shazreh,Cabral, Aaron D.,Gawel, Justyna M.,Gunning, Patrick T.,Israelian, Johan,Manaswiyoungkul, Pimyupa,Nawar, Nabanita,Olaoye, Olasunkanmi O.,Radu, Tudor B.,Raouf, Yasir S.,Sedighi, Abootaleb,Shouksmith, Andrew E.,Sina, Diana,Toutah, Krimo,de Araujo, Elvin D.
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- Design, synthesis, biological evaluation and molecular dynamics studies of 4-thiazolinone derivatives as protein tyrosine phosphatase 1B (PTP1B) inhibitors
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Protein tyrosine phosphatase 1B (PTP1B) is a key negative regulator of insulin signaling pathway, and more and more studies have shown that it is a potential target for the treatment of type 2 diabetes mellitus (T2DM). In this study, 17 new 4-thiazolinone derivatives were designed and synthesized as novel PTP1B inhibitors, and ADMET prediction confirmed that these compounds were to be drug-like. In vitro enzyme activity experiments were performed on these compounds, and it was found that a plurality of compounds had good inhibitory activity and high selectivity against PTP1B protein. Among them, compound 7p exhibited the best inhibitory activity with an IC50 of 0.92 μM. The binding mode of compound 7p and PTP1B protein was explored, revealing the reason for its high efficiency. In addition, molecular dynamics simulations for the PTP1BWT and PTP1Bcomp#7p systems revealed the effects of compound 7p on PTP1B protein at the molecular level. In summary, the study reported for the first time that 4-thiazolinone derivatives as a novel PTP1B inhibitor had good inhibitory activity and selectivity for the treatment of T2DM, providing more options for the development of PTP1B inhibitors. AbbreviationsBBB blood-brain barrierCDC25B cell division cycle 25 homolog BCYP2D6 Cytochrome P450 2D6 bindingDCCM dynamic cross-correlation mapDS Discovery StudioH bond hydrogen bondHIA human intestinal absorptionLAR leukocyte antigen-related phosphataseMD molecular dynamicsMEG-2 maternal-effect germ-cell defective 2MM-PBSA molecular mechanics Poisson Boltzmann surface area)PCA principal component analysisPDB Protein Data BankpNPP p–nitrophenyl phosphatePPB plasma protein bindingPTP1B protein tyrosine phosphotase 1BRMSD root mean square deviationRMSF root mean square fluctuationSHP-1 src homologous phosphatase-1SHP-2 src homologous phosphatase-2SPC single-point chargeTCPTP T cell protein tyrosine phosphataseT2DM Type 2 diabetes mellitusVDW van der Waals Communicated by Ramaswamy H. Sarma.
- Liu, Wen-Shan,Wang, Rui-Rui,Yue, Hai,Zheng, Zhi-Hui,Lu, Xin-Hua,Wang, Shu-Qing,Dong, Wei-Li,Wang, Run-Ling
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p. 3814 - 3824
(2019/11/03)
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- Characterization of Conformationally Constrained Benzanilide Scaffolds for Potent and Selective HDAC8 Targeting
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Histone deacetylases (HDACs) are an attractive therapeutic target for a variety of human diseases. Currently, all four FDA-approved HDAC-targeting drugs are nonselective, pan-HDAC inhibitors, exhibiting adverse side effects at therapeutic doses. Although selective HDAC inhibition has been proposed to mitigate toxicity, the targeted catalytic domains are highly conserved. Herein, we describe a series of rationally designed, conformationally constrained, benzanilide foldamers which selectively bind the catalytic tunnel of HDAC8. The series includes benzanilides, MMH371, MMH409, and MMH410, which exhibit potent in vitro HDAC8 activity (IC50 = 66, 23, and 66 nM, respectively) and up to 410-fold selectivity for HDAC8 over the next targeted HDAC. Experimental and computational analyses of the benzanilide structure docked with human HDAC8 enzyme showed the adoption of a low-energy L-shaped conformer that favors HDAC8 selectivity. The conformationally constrained HDAC8 inhibitors present an alternative biological probe for further determining the clinical utility and safety of pharmacological knockdown of HDAC8 in diseased cells.
- Hassan, Muhammad Murtaza,Israelian, Johan,Nawar, Nabanita,Ganda, Giovanni,Manaswiyoungkul, Pimyupa,Raouf, Yasir S.,Armstrong, David,Sedighi, Abootaleb,Olaoye, Olasunkanmi O.,Erdogan, Fettah,Cabral, Aaron D.,Angeles, Fabrizio,Altintas, Rabia,De Araujo, Elvin D.,Gunning, Patrick T.
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p. 8634 - 8648
(2020/09/21)
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- Discovery and characterization of an acridine radical photoreductant
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Photoinduced electron transfer (PET) is a phenomenon whereby the absorption of light by a chemical species provides an energetic driving force for an electron-transfer reaction1–4. This mechanism is relevant in many areas of chemistry, including the study of natural and artificial photosynthesis, photovoltaics and photosensitive materials. In recent years, research in the area of photoredox catalysis has enabled the use of PET for the catalytic generation of both neutral and charged organic free-radical species. These technologies have enabled previously inaccessible chemical transformations and have been widely used in both academic and industrial settings. Such reactions are often catalysed by visible-light-absorbing organic molecules or transition-metal complexes of ruthenium, iridium, chromium or copper5,6. Although various closed-shell organic molecules have been shown to behave as competent electron-transfer catalysts in photoredox reactions, there are only limited reports of PET reactions involving neutral organic radicals as excited-state donors or acceptors. This is unsurprising because the lifetimes of doublet excited states of neutral organic radicals are typically several orders of magnitude shorter than the singlet lifetimes of known transition-metal photoredox catalysts7–11. Here we document the discovery, characterization and reactivity of a neutral acridine radical with a maximum excited-state oxidation potential of ?3.36 volts versus a saturated calomel electrode, which is similarly reducing to elemental lithium, making this radical one of the most potent chemical reductants reported12. Spectroscopic, computational and chemical studies indicate that the formation of a twisted intramolecular charge-transfer species enables the population of higher-energy doublet excited states, leading to the observed potent photoreducing behaviour. We demonstrate that this catalytically generated PET catalyst facilitates several chemical reactions that typically require alkali metal reductants and can be used in other organic transformations that require dissolving metal reductants.
- MacKenzie, Ian A.,Wang, Leifeng,Onuska, Nicholas P. R.,Williams, Olivia F.,Begam, Khadiza,Moran, Andrew M.,Dunietz, Barry D.,Nicewicz, David A.
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- Preparation method of ethyl p-aminobenzoate
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The invention relates to the technical field of fine chemical engineering, in particular to a preparation method of ethyl p-aminobenzoate. The invention relates to a preparation method of ethyl p-aminobenzoate, which is characterized by comprising the following steps: (1) adding p-nitrobenzoic acid, ethanol and a composite catalyst into a reaction kettle; (2) carrying out a reaction for 6-8 h under a reflux condition to obtain ethyl p-aminobenzoate, an intermediate p-aminobenzoic acid and p-nitrobenzoic acid which is not completely reacted; and (3) carrying out post-treatment to obtain the ethyl p-aminobenzoate finished product. The composite catalyst is composed of sulfate, an inorganic reducing agent, a diatomite and an amine accelerator.
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Paragraph 0032-0040; 0051-0055
(2020/10/14)
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- Green synthesis of zinc oxide particles with apple-derived compounds and their application as catalysts in the transesterification of methyl benzoates
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ZnO nanoparticles (ZnONPs) were successfully synthesized using bravo-de-esmolfe apple extract in aqueous medium at room temperature. ZnO microparticles, prepared with a pure apple phytochemical, quercetin (ZnOq), or without phytochemicals (ZnO) were studied for comparative purposes. The re-use of apple waste for highly efficient catalyst production, based on green synthetic routes, can be added to the concept of a circular economy. The synthesized ZnO particles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N2adsorption/desorption Brunauer-Emmett-Teller (BET) theory. The XRD patterns indicated the formation of a hexagonal wurtzite phase with high purity and SEM and TEM analyses revealed the morphology of the particles. The apple extract produced spherical ZnONPs composed of round lamina-like structures, similar to the micro sized lamina-like shape of ZnOq and dissimilar to the flower-like shape of ZnO. The green synthesized ZnO nanoparticles (ZnONPs) led to a high product yield ofca. 96% within 24 h of reaction time in the transesterification reaction of different carboxylic esters.
- Alegria, Elisabete C. B. A.,Alves, Marta M.,Fátima Montemor, M.,Pombeiro, Armando J. L.,Ribeiro, Ana P. C.,Saraiva, Marta S.,Soliman, Mohamed M. A.
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p. 6488 - 6494
(2020/06/03)
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- A new ligand for copper-catalyzed amination of aryl halides to primary(hetero)aryl amines
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N,N′-Bis(3,5-dimethoxyphenyl)cyclopentane-1,1-dicarboxamide was found as a new ligand for copper-catalyzed amination of aryl iodides, bromides and chlorides to afford various primary (hetero)aryl amines. These reactions proceeded efficiently under mild conditions when inexpensive aqueous ammonia (28% NH3 in H2O) was used as the amino source.
- Chen, Dong,Dong, Xinrui,Jiang, Shang,Jiang, Sheng,Qiu, Yatao,Wu, Xiaoxing
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supporting information
(2020/02/11)
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- Bifunctional Pincer Catalysts for Chemoselective Transfer Hydrogenation and Related Reactions
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A comparative study on the chemoselective transfer hydrogenation of nitroarenes to anilines and related processes using FA as the hydrogen source is described; these processes are catalyzed by a series of pincer catalysts equipped with different functional groups in the secondary coordination sphere. Some new (4 and 5) as well as previously reported (1–3) catalysts belonging to the family of bifunctional PC(sp3)P pincer complexes were employed in this study The reported compounds exhibited remarkably different catalytic activity behavior, depending on the nature of the functional groups. Transfer hydrogenation of nitrobenzene with FA as a hydrogen source was probed using iridium complexes 3 or 4 as a catalyst. Under the same conditions, the analogous palladium complex was found to be useful for the selective amidation of aniline with light carboxylic acids.
- Cohen, Shirel,Bilyachenko, Alexey N.,Gelman, Dmitri
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p. 3203 - 3209
(2019/02/09)
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- Green reusable Pd nanoparticles embedded in phytochemical resins for mild hydrogenations of nitroarenes
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A green chemical preparation of Pd nanoparticles (NPs) embedded in phytochemical resins using a plant extract from Pulicaria odora L. and PdCl2 under ambiant conditions is reported. Two batches of Pd NPs have been prepared: they present homogeneous sizes of respectively 2.2 nm and 3.2 nm depending on the preparation conditions. The Pd NPs were characterized by different techniques (TEM, HRTEM, XRD, XPS and BET) and have been successfully used for the reduction of nitroarenes in EtOH under H2 at atmospheric pressure at rt in the presence of only 5 mequiv. of Pd. Finally the Pd NPs embedded in resin particles were easily recovered by filtration and used at least seven times without significant loss in efficiency. The residual amount of palladium found in the reaction product is very low (0.6% of the initial amount). Therefore both preparation of the Pd NPs and their use for hydrogenations of nitroarenes are environmentally benign.
- Enneiymy, Mohamed,Le Drian, Claude,Becht, Jean-Michel
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supporting information
p. 17383 - 17389
(2019/11/20)
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- Process for preparing benzocaine through solvent-free hydrogenation
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The invention relates to a process for preparing benzocaine (ethyl p-aminobenzoate) through solvent-free hydrogenation, and belongs to the field of chemical engineering. The process comprises: (1) heating ethyl p-nitrobenzoate for more than 1 h at a tempe
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Paragraph 0014-0024
(2020/01/03)
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- Reduction of Nitroarenes to Anilines with a Benzothiazoline: Application to Enantioselective Synthesis of 2-Arylquinoline Derivatives
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The metal-free reduction of nitroarenes to aniline derivatives was accomplished in a short time by using a benzothiazoline as the hydrogen donor in combination with a Bronsted acid. An enantioselective synthesis of 2-arylquinolines was achieved by using 1-aryl-3-(2-nitrophenyl)propan-1-ones as starting materials and a combination of a benzothiazoline and a chiral phosphoric acid.
- Miyagawa, Masamichi,Yamamoto, Ryota,Kobayashi, Nanako,Akiyama, Takahiko
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supporting information
p. 499 - 502
(2019/02/26)
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- Metal-free chemoselective reduction of nitroaromatics to anilines via hydrogen transfer strategy
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A novel protocol for chemoselective reduction of aromatic nitro compounds to aromatic amines has been established. The metal-free reduction goes through a hydrogen transfer process. Various easily reducible functional groups can be well tolerated under the optimized reaction conditions.
- Shuai, Qi,Li, Jun,Zhao, Feng,Su, Weike,Deng, Guojun
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p. 965 - 975
(2019/04/13)
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- Copper-catalyzed demethylative esterification of arylmethylketones: a new route for the synthesis of benzocaine
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An efficient method for oxidative cleavage of C(CO)–C bonds of ketones has been developed. This procedure enables activated methyl ketones to react with tetraethyl orthosilicate for generation of the corresponding methyl esters using copper as the catalyst. Primary mechanistic studies revealed that in contrary to other related studies, the involvement of the aldehyde as the intermediate of this reaction is highly probable. Interestingly, this study provides an unprecedented positive effect of the elemental sulfur upon this oxidative esterification reaction. As an application of our method, we have reported a two-step procedure for the synthesis of benzocaine. The second step of this procedure involves a highly selective reduction in nitro group in the presence of ester functionality.
- Roodan, Sajedeh Maddah,Ghaderi, Arash
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p. 2327 - 2332
(2019/06/27)
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- Effect of particle restructuring during reduction processes over polydopamine-supported Pd nanoparticles
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The effect of catalyst restructuring on the polydopamine-supported Pd catalyzed transfer hydrogenation of ethyl 4-nitrobenzoate and the catalytic hydrogenation of (E)-2-methyl-2-butenoic acid is reported. Transmission electron microscopy investigation of different catalyst pre-treatment and reaction conditions revealed high catalytic activity in both reactions unless drastic aggregation of the active metal occurred. In the transfer hydrogenation reaction aggregation was primarily dependent on the H-source used, while in the catalytic hydrogenation additives in combination with the reductive environment led to extensive Pd aggregation and thus decreased catalytic activity. The enantioselective hydrogenation of (E)-2-methyl-2-butenoic acid showed increased enantioselectivity and decreased conversion with increased particle size.
- Gazdag, Tamás,Baróthi, ádám,Juhász, Koppány Levente,Kunfi, Attila,Németh, Péter,Sápi, András,Kukovecz, ákos,Kónya, Zoltán,Szori, Kornél,London, Gábor
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p. 484 - 491
(2018/12/13)
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- Selective Synthesis of Primary Anilines from NH3 and Cyclohexanones by Utilizing Preferential Adsorption of Styrene on the Pd Nanoparticle Surface
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Dehydrogenative aromatization is one of the attractive alternative methods for directly synthesizing primary anilines from NH3 and cyclohexanones. However, the selective synthesis of primary anilines is quite difficult because the desired primary aniline products and the cyclohexanone substrates readily undergo condensation affording the corresponding imines (i.e., N-cyclohexylidene-anilines), followed by hydrogenation to produce N-cyclohexylanilines as the major products. In this study, primary anilines were selectively synthesized in the presence of supported Pd nanoparticle catalysts (e.g., Pd/HAP, HAP=hydroxyapatite, Ca10(PO4)6(OH)2) by utilizing competitive adsorption unique to heterogeneous catalysis; in other words, when styrene was used as a hydrogen acceptor, which preferentially adsorbs on the Pd nanoparticle surface in the presence of N-cyclohexylidene-anilines, various structurally diverse primary anilines were selectively synthesized from readily accessible NH3 and cyclohexanones. The Pd/HAP catalyst was reused several times though its catalytic performance gradually declined.
- Koizumi, Yu,Jin, Xiongjie,Yatabe, Takafumi,Miyazaki, Ray,Hasegawa, Jun-ya,Nozaki, Kyoko,Mizuno, Noritaka,Yamaguchi, Kazuya
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supporting information
p. 10893 - 10897
(2019/07/12)
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- Synthesis of Nitrogen-Containing Goniothalamin Analogues with Higher Cytotoxic Activity and Selectivity against Cancer Cells
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Two series of racemic goniothalamin analogues displaying nitrogen-containing groups were designed and synthesized. A total of 19 novel analogues were evaluated against a panel of four different cancer cell lines, along with the normal prostate cell line PNT2 to determine their selectivity. Among them, goniothalamin chloroacrylamide 13 e displayed the lowest IC50 values for both MCF-7 (0.5 μm) and PC3 (0.3 μm) cells, about 26-fold more potent than goniothalamin (1). Besides its higher potency, compound 13 e also displayed much higher selectivity than goniothalamin. In contrast, goniothalamin isobutyramide 13 c was the most potent analogue against Caco-2 cells (IC50=0.8 μm), about 10-fold more potent and 17-fold more selective than 1. These results reveal the potential of compounds 13 c and 13 e for further in vivo studies, representing the first goniothalamin analogues with IC50 values in the low micromolar range and high selectivity against MCF-7, Caco-2, and PC3 cancer cell lines.
- Meirelles, Matheus A.,Braga, Carolyne B.,Ornelas, Catia,Pilli, Ronaldo A.
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supporting information
p. 1403 - 1417
(2019/08/01)
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- Synthesis, chemical characterization and antimicrobial activity of new acylhydrazones derived from carbohydrates
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A new series of glycosylated acylhydrazones was synthesized and all the chemical structures were confirmed by High Resolution Mass Spectrometry (HRMS), 1H and 13C Nuclear Magnetic Resonance (1H-NMR; 13C-NMR) and Fourier Transform Infrared (FTIR) spectroscopy methods. The mass accuracy between the calculated and found values observed in HRMS analyses were near or lower than 5 ppm, which are acceptable for proposing a molecular formula using this technique. All of the synthesized compounds were screened for their antibacterial, antifungal and antiviral activities. Five compounds (12, 13, 14, 16 and 19) exerted a modest antifungal activity against the strains evaluated. Derivative 14 showed fungicidal activity against Candida glabrata at 173.8 μM and saccharide unit contributed to the increase of the antifungal potential against this strain. New chemical manipulation of derivative 14 can make it possible to obtain new potentially antimicrobial agents.
- Guilherme, Fernanda Dias,Simonetti, Julia évelin,Folquitto, Lais Regina Santos,Reis, Adriana Cotta Cardoso,Oliver, Josidel Concei??o,Dias, Amanda Latércia Tranches,Dias, Danielle Ferreira,Carvalho, Diogo Teixeira,Brand?o, Geraldo Célio,Souza, Thiago Belarmino de
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p. 349 - 356
(2019/03/04)
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- Synthesis and biological evaluation of novel disulfides incorporating 1,3,4-thiadiazole scaffold as promising antitumor agents
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In the present study, fourteen 2,5-disubstituted 1,3,4-thiadiazole derivatives containing disulfide group were prepared. The resulting compounds 7a–7n were identified by IR, NMR, MS, and elemental analysis. Their antiproliferative properties in vitro were studied employing standard CCK-8 assay against SMMC-7721, MCF-7, and A549 lines. Bioassay indicated that some compounds showed stronger antitumor effects than reference drugs PX-12 and 5-fluorouracil. Among these screened compounds, compound 7h showed excellent biological activities in inhibiting SMMC-7721 cell proliferation with IC50 at 1.93 ± 0.08 μM. Compounds 7k and 7i manifested highly effective growth inhibitory activity versus MCF-7 cells, with IC50 at 3.04 ± 0.09 and 3.54 ± 0.17 μM, respectively. For A549 cells, compound 7m was found to have the highest antitumor potency with IC50 at 3.67 ± 0.13 μM.
- Li, Sha,Wang, Hai-Xin,Liu, Hai-Ying,Jing, Fen,Fu, Xiao-Yun,Li, Cai-Wen,Shi, Yan-Ping,Chen, Bao-Quan
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p. 1502 - 1508
(2019/07/30)
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- Synthesis, characterization and assessment of local anesthetic activity of some benzohydroxamic acids
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In the present investigation, 6 compounds (E1-E6) were synthesized by reaction of ethyl esters of p-substituted benzoic acid with hydroxylamine. The chemical structures of the synthesized hydroxamic acids were verified on the basis of spectral analysis (IR, 1H NMR, 13C NMR and mass spectra). The benzohydroxamic acids were examined for potential local anesthetic activity using foot withdrawal reflex of the frog and benzocaine was used as standard drug. Compounds were tested at two different solvents; 5 % DMSO and 0.65 % NaOH, each solution was tested at three different concentration levels (40, 100 and 200 μg/mL). Local anesthetic activity of the compounds differed according to the concentration level and selected solvent. Compounds E4 and E5 were found to be the most active and were comparable to the standard drug in tested solvents at all investigated concentrations. All compounds displayed an enhanced activity in the the aqueous basic solutions.
- Aldeen, Ekhlas Sheakh,Elsaman, Tilal,Mohamed, Malik Suliman,Adam, Mohamed E.,Mohamed, Magdi Awadalla
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p. 181 - 185
(2018/12/11)
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- Synthesis of novel indole derivatives containing double 1,3,4-oxadiazole moiety as efficient bactericides against phytopathogenic bacterium Xanthomonas oryzae
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Abstract: A series of novel indole derivatives containing double 1,3,4-oxadiazole moiety was designed, synthesized and evaluated for their antibacterial activities in vitro. These compounds were fully characterized by 1H NMR, 13C NMR, and HRMS. Bioassay results indicated that most of title compounds exhibited excellent antibacterial activities against rice bacterial pathogen Xanthomonas oryzae (Xoo). For example, compounds 7d, 7h, 7i, 7j, 7k, 7l and 7m had the half-maximal effective concentration (EC50) values of 52.31, 54.12, 40.65, 38.80, 51.13, 52.75 and 50.66?μg/mL, respectively, which was better than that of commercial product bismerthiazol (BMT) (85.18?μg/mL). The experimental results proved that indole derivatives bearing double 1,3,4-oxadiazole unit are promising candidates for the development of new agricultural bactericides against pathogenic bacterium Xoo. Graphical abstract: [Figure not available: see fulltext.].
- Tian, Kun,Li, Xiao-Qin,Zhang, Li,Gan, Yi-Yuan,Meng, Jiao,Wu, Shou-Qun,Wan, Jin-Lin,Xu, Yang,Cai, Chao-Ting,Ouyang, Gui-Ping,Wang, Zhen-Chao
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- Direct conversion of phenols into primary anilines with hydrazine catalyzed by palladium
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Primary anilines are essential building blocks to synthesize various pharmaceuticals, agrochemicals, pigments, electronic materials, and others. To date, the syntheses of primary anilines mostly rely on the reduction of nitroarenes or the transition-metal-catalyzed Ullmann, Buchwald-Hartwig and Chan-Lam cross-coupling reactions with ammonia, in which non-renewable petroleum-based chemicals are typically used as feedstocks via multiple step syntheses. A long-standing scientific challenge is to synthesize various primary anilines directly from renewable sources. Herein, we report a general method to directly convert a broad range of phenols into the corresponding primary anilines with the cheap and widely available hydrazine as both amine and hydride sources with simple Pd/C as the catalyst.
- Qiu, Zihang,Lv, Leiyang,Li, Jianbin,Li, Chen-Chen,Li, Chao-Jun
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p. 4775 - 4781
(2019/05/16)
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- ZnO nanoparticles: An efficient catalyst for transesterification reaction of α-keto carboxylic esters
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Pure ZnO nanoparticles were synthesized by a sustainable precipitation method using zinc nitrate and sodium hydroxide in aqueous medium at room temperature. They were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM-EDX), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV–vis) spectroscopy and Brunauer-Emmett-Teller (BET) analysis. The XRD patterns indicate the formation of the hexagonal wurtzite phase with high purity and SEM-EDS analysis confirm the purity and a homogenous distribution of the nanostructures. The ZnO nanostructures present plate-like agglomerates, resulting in a quasi-spherical morphology. The catalytic activity of the formed ZnO nanoparticles was evaluated towards the transesterification reaction of different carboxylic esters in the presence of various alcohols. This catalyst is highly selective for the transesterification of α-keto carboxylic ester (methyl benzoylformate) and leads to ca. 97percent of product yield within 24 h of reaction time.
- Alegria, Elisabete C. B. A.,Karmakar, Anirban,Pombeiro, Armando J. L.,Rúbio, Guilherme M. D. M.,Ribeir, Ana P. C.,Saraiva, Marta S.,Soliman, Mohamed M. A.,da Silva, M. Fátima C. Guedes
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- Cobalt-Catalyzed Electrophilic Amination of Aryl- and Heteroarylzinc Pivalates with N-Hydroxylamine Benzoates
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Aryl- and heteroarylzinc pivalates can be aminated with O-benzoylhydroxylamines at 25 °C within 2–4 h in the presence of 2.5–5.0 % CoCl2?2 LiCl to furnish the corresponding tertiary arylated or heteroarylated amines in good yields. This electrophilic amination also provides access to diarylamines and aryl(heteroaryl)amines. A new tuberculosis drug candidate (Q203) was prepared in six steps and 56 % overall yield by using this cobalt-catalyzed amination as the key step.
- Chen, Yi-Hung,Gra?l, Simon,Knochel, Paul
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supporting information
p. 1108 - 1111
(2018/01/01)
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- Copper-mediated reduction of azides under seemingly oxidising conditions: Catalytic and computational studies
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The reduction of aryl azides in the absence of an obvious reducing agent is reported. Careful catalyst design led to the production of anilines in the presence of water and air. The reaction medium (toluene/water) is crucial for the success of the reaction, as DFT calculations support the formation of benzyl alcohol as the oxidation product. A singular catalytic cycle is presented for this transformation based on four key steps: nitrene formation through nitrogen extrusion, formal oxidative addition of water, C(sp3)-H activation of toluene and reductive elimination.
- Zelenay, Benjamin,Besora, Maria,Monasterio, Zaira,Ventura-Espinosa, David,White, Andrew J. P.,Maseras, Feliu,Díez-González, Silvia
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p. 5763 - 5773
(2018/11/24)
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- A highly efficient Ga(OTf)3/KI-catalysed transformation of aryl azides to aryl amines using low catalyst loading
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A highly proficient transformation of aryl azides to aryl amines under Ga(OTf)3/KI catalysis is described.
- Hassan, Hani Mutlak A.
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p. 572 - 574
(2018/11/27)
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