- Developments in Dynamic Covalent Chemistries from the Reaction of Thiols with Hexahydrotriazines
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Dynamic covalent chemistries have garnered significant attention for their potential to revolutionize technologies in the material fields (engineering, biomedical, and sensors) and synthetic design strategies as they provide access to stimuli responsiveness and adaptive behaviors. However, only a limited number of molecular motifs have been known to display this dynamic behavior under mild conditions. Here, we identified a dynamic covalent motif - thioaminals - that is produced from the reaction of hexahydrotriazines (HTs) with thiols. Furthermore, we report on the synthesis of a new family of step-growth polymers based on this motif. The condensation efficiently proceeds to quantitative yields within a short time frame and offers versatility in functional group tolerance; thus, it can be exploited to synthesize both small molecule thioaminals as well as high molecular weight polymers from the step-growth polymerization of HTs with dithiols. Careful evaluation of substituted HTs and organic thiols supported by DFT calculations led to a chemically diverse library of polymers based on this motif. Finally, dynamic substitution reactions were employed toward the facile preparation of functional oligomers and macromolecules. This dynamic covalent motif is particularly attractive for a range of applications that include material design and drug delivery due to the economic feasibility of synthesis.
- Wojtecki, Rudy J.,Jones, Gavin O.,Yuen, Alexander Y.,Chin, Willy,Boday, Dylan J.,Nelson, Alshakim,García, Jeannette M.,Yang, Yi Yan,Hedrick, James L.
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- 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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- Naphthalimide-Based Azo-Functionalized Supramolecular Vesicle in Hypoxia-Responsive Drug Delivery
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Supramolecular materials that respond to external triggers are being extensively utilized in developing spatiotemporal control in biomedical applications ranging from drug delivery to diagnostics. The present article describes the development of self-assembled vesicles in 1:9 (v/v), tetrahydrofuran (THF)-water by naphthalimide-based azo moiety containing amphiphile (NI-Azo) where azo moiety would act as the stimuli-responsive junction. The self-assembly of NI-Azo took place through H-type of aggregation. Microscopic and spectroscopic analyses confirmed the formation of supramolecular vesicles with a dimension of 200-250 nm. Azo (-N=N-) moiety is known to get reduced to amine derivatives in the presence of the azoreductase enzyme, which is overexpressed in the hypoxic microenvironment. The absorbance intensity of this characteristic azo (-N=N-) moiety of NI-Azo (1:9 (v/v), THF-water) at 458 nm got diminished in the presence of both extracellular and intracellular bacterial azoreductase extracted from Escherichia coli bacteria. The same observation was noted in the presence of sodium dithionite (mimic of azoreductase), indicating that azoreductase/sodium dithionite induced azo bond cleavage of NI-Azo, which was confirmed by matrix-assisted laser desorption ionization time-of-flight spectrometric data of the corresponding aromatic amine fragments. The anticancer drug, curcumin, was encapsulated inside NI-Azo vesicles that successfully killed B16F10 cells (cancer cells) in CoCl2-induced hypoxic environment owing to the azoreductase-responsive release of drug. The cancer cell killing efficiency by curcumin-loaded NI-Azo vesicles in the hypoxic condition was 2.15-fold higher than that of the normoxic environment and 2.4-fold higher compared to that of native curcumin in the hypoxic condition. Notably, cancer cell killing efficiency of curcumin-loaded NI-Azo vesicles was 4.5- and 1.9-fold higher than that of noncancerous NIH3T3 cells in normoxic and hypoxic environments, respectively. Cell killing was found to be primarily through the early apoptotic pathway.
- Sarkar, Deblina,Chowdhury, Monalisa,Das, Prasanta Kumar
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p. 3480 - 3492
(2022/03/27)
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- Development of sustainable and efficient nanocatalyst based on polyoxometalate/nickel oxide nanocomposite: A simple and recyclable catalyst for reduction of nitroaromatic compounds
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In this paper, we report the synthesis and characterization of NiO@PolyMo nanocomposite. The newly synthesized nanocomposite was characterized by transmission electronmicroscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and powder X-ray diffraction (XRD). The particle sizes of the NiO@PolyMo nanocatalyst are in the range of 10–20 nm. Powder XRD patterns show that the phase of NiO@PolyMo remains unaltered even after the functionalization of NiO. The lattice fringes of d = 0.20 nm were observed, which correspond to the (111) plane of NiO phase. The newly synthesized material shows excellent catalytic performance and good selectivity for reduction of nitroarenes. The advantages of the present protocols are mild, and can be carried out using water as a solvent, which is an eco-friendly benign.
- Kurbah, Sunshine Dominic
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p. 1487 - 1495
(2021/04/22)
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- Photocatalytic reduction of nitroaromatics into anilines using CeO2-TiO2 nanocomposite
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The reduction of nitro compounds into amines is an important approach for synthetic and pharmaceutical chemistry. The reduced compounds are used as synthetic intermediates in the synthesis of therapeutic molecules. In the present work, we have fabricated cerium dioxide decorated TiO2 nanoparticles using a sol-gel-hydrothermal method. The synthesized nanocomposite was effectively reduced various nitro-compounds, specifically aromatic nitro compounds, into amines in visible light. All the nitro compounds screened in the photoreduction reaction showed >90% conversion with >96% selectivity. Chromatographic techniques confirmed the products obtained. The nanocomposite photocatalyst has excellent stability under the experimental condition and exhibited up to five cycles with no loss of metal content. The nanomaterials were characterized using various spectroscopic techniques.
- Chen, Changdong,Lu, Caiyun,Sun, Chengxin,Wang, Fangfang,Yin, Zhengfeng
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- Rhodium-terpyridine Catalyzed Transfer Hydrogenation of Aromatic Nitro Compounds in Water
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A rhodium terpyridine complex catalyzed transfer hydrogenation of nitroarenes to anilines with i-PrOH as hydrogen source and water as solvent has been developed. The catalytic system can work at a substrate/catalyst (S/C) ratio of 2000, with a turnover frequency (TOF) up to 3360 h?1, which represents one of the most active catalytic transfer hydrogenation systems for nitroarene reduction. The catalytic system is operationally simple and the protocol could be scaled up to 20 gram scale. The water-soluble catalyst bearing a carboxyl group could be recycled 15 times without significant loss of activity.
- Liu, Yuxuan,Miao, Wang,Tang, Weijun,Xue, Dong,Xiao, Jianliang,Wang, Chao,Li, Changzhi
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supporting information
p. 1725 - 1729
(2021/06/01)
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- Optimization of WZ4003 as NUAK inhibitors against human colorectal cancer
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NUAK, the member of AMPK (AMP-activated protein kinase) family of protein kinases, is phosphorylated and activated by the LKB1 (liver kinase B1) tumor suppressor protein kinase. Recent work has indicated that NUAK1 is a key component of the antioxidant stress response pathway, and the inhibition of NUAK1 will suppress the growth and survival of colorectal tumors. As a promising target for anticancer drugs, few inhibitors of NUAK were developed. With this goal in mind, based on NUAK inhibitor WZ4003, a series of derivatives has been synthesized and evaluated for anticancer activity. Compound 9q, a derivative of WZ4003 by removing a methoxy group, was found to be the most potential one with stronger inhibitory against NUAK1/2 enzyme activity, tumor cell proliferation and inducing apoptosis of tumor cells. By in vivo efficacy evaluations of colorectal SW480 xenografts, 9q suppresses tumor growth more effectively with an excellent safety profile in vivo and is therefore seen as a suitable candidate for further investigation.
- Yang, Huali,Wang, Xiaobing,Wang, Cheng,Yin, Fucheng,Qu, Lailiang,Shi, Cunjian,Zhao, Jinhua,Li, Shang,Ji, Limei,Peng, Wan,Luo, Heng,Cheng, Maosheng,Kong, Lingyi
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- A Concise Route to Cyclic Amines from Nitroarenes and Ketoacids under Iron-Catalyzed Hydrosilylation Conditions
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Starting from nitroarenes, under hydrosilylation conditions, using a well-defined N-heterocyclic carbene iron(0) catalyst, (IMes)Fe(CO)4, the corresponding aniline derivatives were produced in 61–92% isolated yields. More impressively, a selective synthesis of cyclic amines such as pyrrolidines, piperidines and azepanes were conducted from levulinic acid, 1,5- and 1,6-keto acids, respectively. The sequential procedure proceeded under both visible light irradiation and thermal conditions with 20 examples in isolated yields up to 69%. (Figure presented.).
- Ammaiyappan, Yuvaraj,Darcel, Christophe,Tongdee, Satawat,Wu, Jiajun
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p. 3859 - 3865
(2021/07/12)
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- Efficient hydrogenation catalyst designing via preferential adsorption sites construction towards active copper
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Based on the experimental and DFT calculation results, here for the first time we built preferential adsorption sites for nitroarenes by modification of the supported Cu catalysts surface with 1,10-phenathroline (1,10-phen), by which the yield of aniline via reduction of nitroarene is enhanced three times. Moreover, a macromolecular layer was in-situ generated on supported Cu catalysts to form a stable macromolecule modified supported Cu catalyst, i.e., CuAlOx-M. By applying the CuAlOx-M, a wide variety of nitroarene substrates react smoothly to afford the desired products in up to > 99% yield with > 99% selectivity. The method tolerates a variety of functional groups, including halides, ketone, amide, and C = C bond moieties. The excellent catalytic performance of the CuAlOx-M can be attributed to that the 1,10-phen modification benefits the preferential adsorption of nitrobenzene and slightly weakens adsorption of aniline on the supported nano-Cu surface.
- Dai, Xingchao,He, Dongcheng,Li, Teng,Shi, Feng,Wang, Hongli,Wang, Tao,Wang, Xinzhi
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p. 397 - 406
(2021/07/21)
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- Green synthesized AgNPs decorated on Ketjen black for enhanced catalytic dye degradation
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The green synthesis of nanoparticles using plant-based materials as an alternative to chemical and physical routes provides economic and environmental benefits. In the present study, silver nanoparticles (AgNPs) were fabricated using Pseudocydonia sinensis fruit extract. The fabricated NPs were then decorated on commercial Ketjen black-300 (AgNPs@KB-300) and Ketjen black-600 (AgNPs@ KB-600). The synthesized materials were characterized via XRD, FTIR, XPS, SEM-EDX, and HR-TEM studies. The SEM and HR-TEM results revealed that the synthesized AgNPs were spherical and successfully decorated on KB-300 and KB-600. Additionally, the catalytic ability of the synthesized samples during the degradation of methyl orange in the presence of NaBH4 was studied. Notably, the catalytic activity of AgNPs@ KB-600 was higher than that of AgNPs@ KB-300.
- Ramaraghavulu, Rajavaram,Rao, V. Koteswara,Devarayapalli,Yoo, Kisoo,Nagajyothi,Shim, Jaesool
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p. 637 - 648
(2020/10/15)
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- Cu/CuxS-Embedded N,S-Doped Porous Carbon Derived in Situ from a MOF Designed for Efficient Catalysis
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The reasonable design of the precursor of a carbon-based nanocatalyst is an important pathway to improve catalytic performance. In this study, a simple solvothermal method was used to synthesize [Cu(TPT)(2,5-tdc)] ? 2H2O (Cu-MOF), which contains N and S atoms, in one step. Further in-situ carbonization of the Cu-MOF as the precursor was used to synthesize Cu/CuxS-embedded N,S-doped porous carbon (Cu/CuxS/NSC) composites. The catalytic activities of the prepared Cu/CuxS/NSC were investigated through catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The results show that the designed Cu/CuxS/NSC has exceptional catalytic activity and recycling stability, with a reaction rate constant of 0.0256 s?1, and the conversion rate still exceeds 90 % after 15 cycles. Meanwhile, the efficient catalytic reduction of dyes (CR, MO, MB and RhB) confirmed its versatility. Finally, the active sites of the Cu/CuxS/NSC catalysts were analyzed, and a possible multicomponent synergistic catalytic mechanism was proposed.
- Wang, Dongsheng,Fan, Mingyue,He, Tingyu,Zeng, Fanming,Hu, Xiaoli,Li, Chun,Su, Zhongmin
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supporting information
p. 11468 - 11476
(2021/06/14)
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- Manganese Catalyzed Hydrogenation of Azo (N=N) Bonds to Amines
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We report the first example of homogeneously catalyzed hydrogenation of the N=N bond of azo compounds using a complex of an earth-abundant-metal. The hydrogenation reaction is catalyzed by a manganese pincer complex, proceeds under mild conditions, and yields amines, which makes this methodology a sustainable alternative route for the conversion of azo compounds. A plausible mechanism involving metal-ligand cooperation and hydrazine intermediacy is proposed based on mechanistic studies. (Figure presented.).
- Ben-David, Yehoshoa,Das, Uttam Kumar,Diskin-Posner, Yael,Kar, Sayan,Milstein, David
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supporting information
p. 3744 - 3749
(2021/07/09)
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- Synthesis and characterization of polyaniline/nickel oxide composites for fuel additive and dyes reduction
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Polyaniline (PANI) and Polyaniline/Nickel oxide (PANI/NiO) composites are prepared to use as a potential catalyst, by Chemical oxidation method using ammonium persulfate (NH4)2S2O8)) as an oxidant. Nickel oxide (NiO) nanopartiles are prepared by Sol-gel method. The synthesized products were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction technique (XRD). The prepared PANI/NiO composites are used as additive with different concentrations in diesel to investigate their efficiency as fuel additive. The catalytic properties are studied by using the synthesized products as catalyst for reduction of dyes in aqueous media. Sodium borohydride (NaBH4) is used as reducing agent. Linear relationships are obtained between time and ln(A0/At) for Methyl orange and Methylene blue. Kapp values were obtained for three catalysts showed the increasing trend of reduction for both dyes as, PANI NiO PANI/NiO composites. Experimental data analysis proved PANI/NiO composites to be efficient catalysts and fuel additive as compared to PANI and NiO.
- Jamil, Saba,Ahmad, Zunaira,Ali, Muhammad,Rauf Khan, Shanza,Ali, Sarmed,Amen Hammami, Mohamed,Haroon, Muhammad,Saleh, Tawfik A.,Ramzan Saeed Ashraf Janjua, Muhammad
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- Cyan color-emitting nitrogen-functionalized carbon nanodots (NFCNDs) from Indigofera tinctoria and their catalytic reduction of organic dyes and fluorescent ink applications
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The present study reports the synthesis of nitrogen-functionalized carbon nanodots (NFCNDs) by a low-cost hydrothermal method using the leaf extract of Indigofera tinctoria as a novel carbon precursor. The synthesized NFCNDs were characterized by diverse spectroscopic techniques. The optical properties of N-CNDs were analyzed by UV-visible and fluorescence spectroscopic studies. The quantum yield (QY) for the prepared NFCNDs was found to be 12.6%. The surface morphology, functional groups, and crystallinity of NFCNDs were evaluated by HR-TEM, FT-IR, XRD and Raman spectroscopic methods, respectively. The Raman results revealed the moderate graphite structure of NFCNDs, and the calculated ID/IG value was 0.49. The spherical appearance of the synthesized NFCNDs was confirmed by HR-TEM, and the calculated size of the NFCNDs was 4 nm. The XRD and SAED pattern results gives an evidence for the amorphous nature of the prepared NFCNDs. The thermal stability of NFCNDs was studied by TGA analysis. The resulting NFCNDs acted as a green nanocatalyst and thus efficiently improved the reducing capability of sodium borohydride (NaBH4) in the catalytic reduction of methylene blue (MB) and methyl orange (MO) dyes. Furthermore, the bright cyan emission characteristics of synthesized NFCNDs were utilized as a labeling agent in anti-counterfeiting applications.
- Abirami, Natarajan,Arul, Velusamy,Arulmozhi, Rajaram,Kavitha, Ganesan,Vinoth Kumar, Jothi
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p. 27745 - 27756
(2021/08/25)
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- Tuneable Copper Catalysed Transfer Hydrogenation of Nitrobenzenes to Aniline or Azo Derivatives
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A highly versatile and flexible copper nanoparticle (Cu(0) NPs) catalytic system has been developed for the controlled and selective transfer hydrogenation of nitroarene. Interestingly, the final catalytic product is strongly dependent on the nature of the hydrogen donor source. The yield of nitrobenzene reduction to aniline increased from 20% to an almost quantitative yield over a range of alcohols, diols and aminoalcohols. In glycerol at 130 °C aniline was isolated in 93% yield. In ethanolamine, the reaction was conveniently performed at a lower temperature (55 °C) and gave selectively substituted azobenzene (92% yield). Experimental studies provide support for a reaction pathway in which the Cu(0) NPs catalysed transfer hydrogenation of nitrobenzene to aniline proceeds via the condensation route. The high chemoselectivity of both protocols has been proved in experiments on a panel of variously substituted nitroarenes. Enabling technologies, microwaves and ultrasound, used both separately and in combination, have successfully increased the reaction rate and reaction yield. (Figure presented.).
- Moran, Maria Jesus,Martina, Katia,Baricco, Francesca,Tagliapietra, Silvia,Manzoli, Maela,Cravotto, Giancarlo
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supporting information
p. 2689 - 2700
(2020/05/18)
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- A Common, Facile and Eco-Friendly Method for the Reduction of Nitroarenes, Selective Reduction of Poly-Nitroarenes and Deoxygenation of N-Oxide Containing Heteroarenes Using Elemental Sulfur
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A transition metal-free, environment-friendly and practical protocol was developed either for the reduction of nitroarenes or for the deoxygenation of N-oxide containing heteroarenes. The reaction proceeded with the use of a non-toxic and cheap feedstock as elemental sulfur in aqueous methanol under relatively mild conditions. Green chemistry credentials were widely favorable compared to traditional and industrial protocols with good E-factors and a low production of waste. The strategy allowed the efficient reduction of a large variety of substituted-nitroarenes including various o-nitroanilines as well as selective reduction of various poly-nitroarenes in excellent yields with a broad substrate scope. The protocol was successfully extended to the deoxygenation of some N-oxide containing heteroarenes, like benzofuroxans, phenazine N,N'-dioxides, pyridine N-oxides, 2H-indazole N1-oxides, quinoxaline N1,N4-dioxides and benzo[d]imidazole N1,N3-dioxides. A gram-scale example for the synthesis of luminol, in green conditions, was reported. A solid mechanism of reaction was proposed from experimental evidences.
- Cerecetto, Hugo,Romero, Angel H.
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supporting information
(2020/03/23)
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- WEE1 inhibitors as well as preparation and application thereof
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The invention relates to WEE1 inhibitors as well as preparation and application thereof. The present invention relates to compounds of formula (I), or pharmaceutically acceptable salts, solvates, polymorphs or isomers thereof, and their use in the preparation of medicaments for the treatment of diseases associated with WEE1 activity.
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Paragraph 0726; 0733-0736
(2020/10/14)
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- Preparation method of cationic blue dye
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The invention belongs to the technical field of dyes, and particularly relates to a preparation method of a cationic blue dye. According to the invention, a compound II is used as a diazonium component and a compound I is used as a coupling component for synthesizing the cationic blue dye for the first time; and the method has the advantages of simple process, environmental friendliness, high product purity, high yield and the like. The results of multiple production experiments with scales not below pilot tests show that mother liquor (such as mother liquor in steps 2, 3 and 4) in the reaction process can be cyclically used 6-8 times without treatment, so the amount of high-salt, high-COD and high-chroma wastewater is greatly reduced, a working environment is effectively improved while product yield is further increased and reaction reagent cost is saved, and the product still keeps high purity; and thus, product quality is guaranteed, production cost is reduced, and obvious economicbenefits, social benefits and environmental benefits are produced.
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Paragraph 0140; 0143
(2020/02/14)
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- NOVEL IMPROVED METHOD FOR SYNTHESIZING DIAMINOPHENOTHIAZINE COMPOUNDS
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The present invention relates to chemical synthesis and purification. Specifically, the present invention relates to a novel and improved method of synthesizing high purity diaminophenothiazine compounds of Formula I, specifically Methylene Blue and its pharmaceutically acceptable salt or hydrates thereof. The present invention relates to an improved method of synthesizing Methylene Blue compound of higher purities than those achievable by using known methods of synthesis as per the requirements of the international pharmacopoeias like USP and EP.
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Paragraph 00211
(2020/12/30)
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- Indicator Dyes and Catalytic Nanoparticles for Irreversible Visual Hydrogen Sensing
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Using ultraviolet-visible (UV-vis) absorption spectroscopy, we have tested the reactivity of various indicator molecules combined with catalytic bimetallic gold-palladium nanoparticles (Au-Pd NPs) in solution for an irreversible and visual response to H2. Our aim was to identify the most suitable indicator/Au-Pd NP system for the future development of a thin, wearable, and visual H2 sensor for noninvasive monitoring of in vivo Mg-implant biodegradation in research and clinical settings with fast response time. The indicators studied were bromothymol blue, methyl red, and resazurin, and the reactions of each system with H2 in the presence of Au-Pd NPs caused visual and irreversible color changes that were concluded to proceed via redox processes. The resazurin/Au-Pd NP system was deemed best-suited for our research objectives because (1) this system had the fastest color change response to H2 at levels relevant to in vivo Mg-implant biodegradation compared to the other indicator/Au-Pd NP systems tested, (2) the observed redox chemistry with H2 followed well-understood reaction pathways reported in the literature, and (3) the redox products were nontoxic and appropriate for medical applications. Studying the effects of the concentrations of H2, Au-Pd NPs, and resazurin on the color change response time within the resazurin/Au-Pd NP system revealed that the H2-sensing elements can be optimized to achieve a faster or slower color change with H2 by varying the relative amounts of resazurin and Au-Pd NPs in solution. The results from this study are significant for future optical H2 sensor design.
- Smith, Michael E.,Stastny, Angela L.,Lynch, John A.,Yu, Zhao,Zhang, Peng,Heineman, William R.
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p. 10651 - 10658
(2020/09/18)
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- Method for N-methylation reaction of nitro-compound
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The invention discloses a method for direct N-methylation reaction by taking a nitro-compound as a raw material. The method adopts a Cu-based catalyst and polyformaldehyde and can realize the direct N-methylation reaction of the nitro-compound under mild conditions.
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Paragraph 0050-0054
(2019/01/23)
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- COMPOSITION FOR PREVENTING OR TREATING HAIR LOSS INCLUDING BENZENE DIAMINE DERIVATIVE
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Provided are a compound represented by the following Formula I, or a solvate, stereoisomer, or pharmaceutically acceptable salt thereof, and a composition for preventing or treating hair loss, the compound including the compound as an active ingredient:
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Paragraph 0057; 0066-0067
(2019/04/14)
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- Chemoselective reduction of nitroarenes with hydrazine over a highly active alumina-supported cobalt nanocatalyst
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A green and efficient procedure is reported for the chemoselective reduction of nitroarenes catalyzed by a highly active alumina-supported cobalt nanocatalyst in the presence of hydrazine hydrate. The nanocatalyst can be applied under mild reflux conditions for the synthesis of arlyamines in high yields. Moreover, the catalyst can be easily recovered by simple filtration and reused several times without obvious loss in its catalytic activity.
- Albadi, Jalal,Samimi, Heshmat Allah,Jalali, Mehdi
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p. 740 - 744
(2019/10/14)
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- Design, synthesis and biological evaluation of novel 7-amino-[1,2,4]triazolo[4,3-f]pteridinone, and 7-aminotetrazolo[1,5-f]pteridinone derivative as potent antitumor agents
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To develop novel therapeutic agents with anticancer activities, two series of novel 7-amino-[1,2,4]triazolo[4,3-f]pteridinone, and 7-aminotetrazolo[1,5-f]pteridinone derivatives were designed and synthesized. All compounds were tested for anti-proliferative activities against five cancer cell lines. The structure-activity relationships (SARs) studies were conducted through the variation in two regions, the moiety of A ring and the terminal aniline B on pteridinone core. 1-Methyl-1,2,4-triazole derivative L7 with 2,6-dimethylpiperazine showed the most potent antiproliferative activity against A549, PC-3, HCT116, MCF-7 and MDA-MB-231 cell lines with IC50 values of 0.16 μM, 0.30 μM, 0.51 μM, 0.30 μM, and 0.70 μM, respectively. Combined with the results of the molecular docking and enzymatic studies, the PLK1 was very likely to be one of the drug targets of compound L7. Furthermore, to clarify the anticancer mechanism of compound L7, further explorations in the bioactivity were conducted. The results showed that compound L7 obviously inhibited proliferation of A549 cell lines, induced a great decrease in mitochondrial membrane potential leading to apoptosis of cancer cells, suppressed the migration of tumor cells, and arrested G1 phase of A549 cells.
- Hou, Yunlei,Zhu, Liangyu,Li, Zhiwei,Shen, Qi,Xu, Qiaoling,Li, Wei,Liu, Yajing,Gong, Ping
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p. 690 - 709
(2019/01/04)
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- Design, synthesis and biological evaluation of novel 2,4-diaminopyrimidine derivatives as potent antitumor agents
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For developing novel therapeutic agents with anticancer activities, two series of novel 2,4-diaminopyrimidine derivatives possessing triazolopiperazine or 1,4,8-triazaspiro[4.5]decan-3-one scaffolds were designed and synthesized. Preliminary investigations showed that some compounds exhibited moderate to excellent potency against four tested cancer cell lines as compared with palbociclib and momelotinib. In particular, the most promising compounds 9k and 13f showed the most potent antitumor activities with IC50 values of 2.14/1.98 μM, 3.59/2.78 μM, 5.52/4.27 μM, and 3.69/4.01 μM against A549, HCT-116, PC-3 and MCF-7 cell lines, respectively. Structure-activity relationship (SAR) studies were conducted based on the variation of the moiety of the aromatic ring and the terminal aniline on the pyrimidine core. Furthermore, the mechanism of their anticancer activity was clarified by further exploring the bioactivity. The results showed that compound 9k obviously inhibited the proliferation of A549 cell lines, induced a great decrease in the mitochondrial membrane potential leading to apoptosis of cancer cells, suppressed the migration of tumor cells and prolonged the A549 cell cycle distribution, representing blockage at the G2-M phase and accumulation at the S phase.
- Hu, Gang,Wang, Chu,Xin, Xin,Li, Shuaikang,Li, Zefei,Zhao, Yanfang,Gong, Ping
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p. 10190 - 10202
(2019/07/03)
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- A Broader-scope Analysis of the Catalytic Reduction of Nitrophenols and Azo Dyes with Noble Metal Nanoparticles
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In addition to the broad environmental implications associated with the removal of nitroaromatics from industrial effluent, the catalytic reduction of 4-nitrophenol (4NP) has emerged as a benchmark model for quantifying catalytic activity of metal nanoparticles. Here we present a series of noble metal nanoparticles immobilized on amorphous carbon (Au@C, Ag@C, Pt@C and Pd@C). All materials show competitive catalytic activity over 4NP, amino-substituted nitrophenols (ANPs) and azo dyes. Overall, Pd@C exhibits superior activity that increases further when exposed to recycling protocol. Moreover, testing all materials synthesized over a broader substrate scope with added functionalities reveals inconsistencies in the prognosticating ability of the ubiquitous 4NP model reaction. By incorporating variably substituted ANPs into the substrate scope and averaging performance, the resulting rank of catalyst activity more accurately reflects activity trends when applied to other reducible functionalities, such as -N=N- groups in azo dyes.
- Shultz, Lorianne R.,Hu, Lin,Preradovic, Konstantin,Beazley, Melanie J.,Feng, Xiaofeng,Jurca, Titel
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p. 2590 - 2595
(2019/05/15)
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- Synthesis of high surface area transition metal sponges and their catalytic properties
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We have reported sucrose-mediated facile route for the preparation of high surface area cobalt (Co), nickel (Ni), and copper (Cu) sponges. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed the sponge-like and nanoparticle-like morphologies of the metal sponges. The catalytic activity of the metal sponges was studied via the reduction of organic pollutants, including 4-nitrophenol (4-NP), methyl orange (MO) and methylene blue (MB) in water. It was found that the Cu sponge exhibited the fastest rate for the reduction of 4-NP, MO, and MB, followed by the Co and Ni sponges, respectively. The metal sponges exhibited excellent catalytic stability for the reduction of 4-NP for multiple cycles. In addition, due to their magnetic properties, the Co and Ni sponges could be easily recovered and reused by applying an external magnetic field.
- Islam, Md. Tariqul,Rosales, Jose,Saenz-Arana, Ricardo,Arrieta, Roy,Kim, Hoejin,Sultana, Kazi Afroza,Lin, Yirong,Villagran, Dino,Noveron, Juan C.
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p. 10045 - 10055
(2019/07/03)
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- Borohydride-free catalytic reduction of organic pollutants by platinum nanoparticles supported on cellulose fibers
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This study presents hydrogen gas-assisted reduction of organic pollutants viz. 4-nitrophenol (4-NP) and methyl orange (MO) by platinum nanoparticles (PtNPs) immobilized on cellulose fibers (CF). Because sodium borohydride (NaBH4) causes secondary pollution in water by its decomposition products, hydrogen (H2) gas was used as a clean, highly active, and alternative reducing agent. As the catalyst, PtNPs of about 2 nm in diameter were synthesized and supported on CF by employing a facile method. The nanocomposites (PtNPs@CF) demonstrated excellent catalytic activity and cyclic stability in the reduction of 4-NP and MO using H2 gas as the clean, environmentally friendly, highly reactive, and an alternative reducing agent to NaBH4. The catalytic reduction followed the pseudo-first-order reaction kinetic with apparent rate constants of 3.6 × 10?1 min?1 and 5.3?10?1 min?1 for 4-NP and MO, respectively. The results of this study further indicate that the H2 gas (reducing agent) and PtNPs@CF nanocomposite (catalyst) can potentially be used for the reduction of a wide variety of other organic and inorganic compounds in water.
- Islam, Md Tariqul,Sultana, Kazi Afroza,Noveron, Juan C.
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- Catalytic applications of β-cyclodextrin/palladium nanoparticle thin film obtained from oil/water interface in the reduction of toxic nitrophenol compounds and the degradation of azo dyes
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A supramolecular catalyst of Pd/β-cyclodextrin thin film is synthesized via a facile and one-pot procedure at an oil-water interface. Macrocyclic oligosaccharides of cyclodextrins with glucose units have a wide range of applications due to their hydrophobic and chiral interior. Due to the ability of this supramolecular catalyst to form inclusion complexes with small organic molecules, the as-synthesized catalyst was applied for the reduction of toxic nitroaromatic compounds (p, o, m-nitrophenol and 4-Cl-2-nitrophenol) and the degradation of harmful azo dyes (methyl orange and bismarck brown) with considerable results. This investigation illustrates the change of the catalyst properties in the presence of molecular receptors attached to the catalyst surface.
- Zare Asadabadi, Azam,Hoseini, S. Jafar,Bahrami, Mehrangiz,Nabavizadeh, S. Masoud
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p. 6513 - 6522
(2019/05/10)
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- AMINATION AND HYDROXYLATION OF ARYLMETAL COMPOUNDS
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In one aspect, the present disclosure provides methods of preparing a primary or secondary amine and hydroxylated aromatic compounds. In some embodiments, the aromatic compound may be unsubstituted, substituted, or contain one or more heteroatoms within the rings of the aromatic compound. The methods described herein may be carried out without the need for transition metal catalysts or harsh reaction conditions.
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Paragraph 0098; 0134; 0135; 0189
(2018/03/25)
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- STABILIZATION OF ACTIVE METAL CATALYSTS AT METAL-ORGANIC FRAMEWORK NODES FOR HIGHLY EFFICIENT ORGANIC TRANSFORMATIONS
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Metal-organic framework (MOFs) compositions based on post?synthetic metalation of secondary building unit (SBU) terminal or bridging OH or OH2 groups with metal precursors or other post-synthetic manipulations are described. The MOFs provide a versatile family of recyclable and reusable single-site solid catalysts for catalyzing a variety of asymmetric organic transformations, including the regioselective boryiation and siiylation of benzyiic C—H bonds, the hydrogenation of aikenes, imines, carbonyls, nitroarenes, and heterocycles, hydroboration, hydrophosphination, and cyclization reactions. The solid catalysts can also be integrated into a flow reactor or a supercritical fluid reactor.
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Paragraph 0354-0356; 0359
(2019/01/07)
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- Application of Silicon-Initiated Water Splitting for the Reduction of Organic Substrates
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The use of water as a donor for hydrogen suitable for the reduction of several important classes of organic compounds is described. It is found that the reductive water splitting can be promoted by several metalloids among which silicon shows the best efficiency. The developed methodologies were applied for the reduction of nitro compounds, N-oxides, sulfoxides, alkenes, alkynes, hydrodehalogenation as well as for the gram-scale synthesis of several substrates of industrial importance.
- Gevorgyan, Ashot,Mkrtchyan, Satenik,Grigoryan, Tatevik,Iaroshenko, Viktor O.
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p. 375 - 382
(2018/06/04)
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- Green synthesis of gold, silver, platinum, and palladium nanoparticles reduced and stabilized by sodium rhodizonate and their catalytic reduction of 4-nitrophenol and methyl orange
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Sodium rhodizonate was used as a bifunctional reducing as well as stabilizing agent for the single step synthesis of gold (Au), silver (Ag), platinum (Pt), and palladium (Pd) nanoparticles (NPs) in water. Transmission electron microscopy analysis revealed that Pt, Au, Ag, and PdNPs have average core diameters of about 2, 8, 26, and 39 nm, respectively. The ability of these nanoparticles towards the catalytic reduction of 4-nitrophenol (4-NP) with sodium borohydride (NaBH4) and the dual-catalytic oxidation of formic acid followed by the reduction of methyl orange (MO) was studied. The apparent rate constants (kapp) of the catalytic reduction of 4-NP in the presence of Ag, Au, Pt, and PdNPs were calculated to be 2.1482, 1.1167, 1.088 × 10-1, and 1.65 × 10-2 min-1, respectively. However, for the dual-catalytic oxidation of formic acid followed by the reduction of MO, the kapp values were calculated to be 4.145, 1.25 × 10-2, 6.7 × 10-3, and 9.0 × 10-5 for the Pt, Pd, Au, and AgNPs, respectively.
- Islam, Md. Tariqul,Saenz-Arana, Ricardo,Wang, Huiyao,Bernal, Ricardo,Noveron, Juan C.
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p. 6472 - 6478
(2018/04/23)
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- Cu(BDC) as a catalyst for rapid reduction of methyl orange: room temperature synthesis using recycled terephthalic acid
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Terephthalic acid was recycled from waste PET bottles with a basic hydrolysis technique and characterized with UV and FTIR spectroscopy. Copper-based metal–organic framework Cu(BDC) was synthesized at room temperature without any additive; two different temperatures were chosen to activate the obtained material. Characterization studies were performed using XRD, N2 physisorption, STEM and EDX. The obtained material was tested as a catalyst for the reduction of methyl orange with NaBH4 in aqueous solutions. Thermal activation at 160?°C proved to be mandatory for catalytic activity; although higher temperature activation did not cause significant enhancement. Rapid dye removal was monitored by continuous photometry at λmax. The results were quite satisfactory (about 85% removal in 5?min); even higher than the published results for precious metal (i.e., Au, Pt and Ag) nanoparticles. In an increased reaction scale, UV–visible spectra and mass spectrum were recorded to help elucidating the possible reaction mechanism. In addition, recycling experiment were performed in 100-ml scale without any kind of re-activation (washing or drying) to show the ability of Cu(BDC) as a stable catalyst for reductive dye removal (and probably similar reactions as well).
- Rahmani, Alireza,Rahmani, Hossein,Zonouzi, Afsaneh
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p. 449 - 455
(2018/02/09)
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- A preparation method of methylene blue
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The invention discloses a preparation method of methylene blue, and belongs to the technical field of intermediate synthesis in fine chemical engineering. The preparation method comprises the following steps: in a condensed hydrochloric acid solution, carrying out nitrosation reactions between sodium nitrite and N,N-dimethylaniline so as to obtain an intermediate namely p-nitroso-N,N-dimethylaniline; subjecting p-nitroso-N,N-dimethylaniline to hydrogenation reduction to prepare p-amino-N,N-dimethylaniline; oxidizing p-amino-N,N-dimethylaniline, then adding sodium thiosulfate to carry out addition reactions to prepare 2-amino-5-dimethylaminophenyl thiosulfonic acid, adding N,N-dimethylaniline into 2-amino-5-dimethylaminophenyl thiosulfonic acid to carry out oxidative condensation reactions to generate bis(4-dimethylaminophenyl) thiosulfonic acid; and making bis(4-dimethylaminophenyl) thiosulfonic acid carry out ring-closing reactions to obtain methylene blue. The provided preparation method has the advantages of high product purity, simple technology flow, low manufacture cost, suitability for industrial production, easily-available raw materials, and little pollution to the environment.
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Paragraph 0015; 0022; 0047; 0059; 0060; 0070; 0071; 0081
(2018/04/02)
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- Simple Nickel Salts for the Amination of (Hetero)aryl Bromides and Iodides with Lithium Bis(trimethylsilyl)amide
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Recent developments in the chemistry of C-N bond formation and the synthesis of anilines have allowed for the use of first-row transition metals to catalyze these transformations. Much of the progress in this area has been driven by comprehensive screening for privileged/tailored ligands, which can be costly and not readily available in a research laboratory setting. In this communication we report a protocol in which simple nickel salts catalyze the C-N cross-coupling reaction between (hetero)aryl bromides and iodides with lithium bis(trimethylsilyl)amide without the need for any additive ligand. This method is amenable to low nickel catalyst loadings (1%) as well as gram-scale reactions. Because of the good functional group tolerance and compatibility with heterocyclic moieties, this method is useful for academic laboratory settings where access to tailored ligands and noble-metal catalysts could be challenging.
- Martinez, Gabriel Espinosa,Nugent, Joseph W.,Fout, Alison R.
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supporting information
p. 2941 - 2944
(2018/09/21)
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- Catalytic Reductions and Tandem Reactions of Nitro Compounds Using in Situ Prepared Nickel Boride Catalyst in Nanocellulose Solution
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A mild and efficient method for the in situ reduction of a wide range of nitroarenes and aliphatic nitrocompounds to amines in excellent yields using nickel chloride/sodium borohydride in a solution of TEMPO-oxidized nanocellulose in water (0.01 wt %) is described. The nanocellulose has a stabilizing effect on the catalyst, which increases the turnover number and enables low loading of nickel catalyst (0.1-0.25 mol % NiCl2). In addition, two tandem protocols were developed in which the in situ formed amines were either Boc-protected to carbamates or further reacted with an epoxide to yield β-amino alcohols in excellent yields.
- Prathap, Kaniraj Jeya,Wu, Qiong,Olsson, Richard T.,Dinér, Peter
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supporting information
p. 4746 - 4749
(2017/09/23)
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- Discovery of Potent, Selective Stem Cell Factor Receptor/Platelet Derived Growth Factor Receptor Alpha (c-KIT/PDGFRα) Dual Inhibitor for the Treatment of Imatinib-Resistant Gastrointestinal Stromal Tumors (GISTs)
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Stem cell factor receptor (c-KIT) and platelet derived growth factor receptor alpha (PDGFRα) kinases play an important role in gastrointestinal stromal tumors (GISTs). Here, we have discovered an c-KIT/PDGFRα dual inhibitor, compound 31, with single-digit nanomolar potency against c-KIT and PDGFRα. Compared to Imatinib (1), 31 showed better antiproliferative efficacy against various TEL-c-KIT/PDGFRα-BaF3 isogenic cells, including three 1-resistant BaF3 cell lines, as well as against GIST-T1 and GIST-882 cell lines. Furthermore, compound 31 showed a good KinomeScan selectivity (468 kinases) (S score (1) = 0.01 at 1 μM concentration), good metabolic stability in liver microsomes, and no hERG inhibitory activity. It was worth noting that 31 inhibited GIST-T1 tumor growth (TGI = 81.5%) and even the BaF3-TEL-cKIT-T670I tumor progression (TGI = 41.9%, 1-resistant GISTs) at a dosage of 100 mg/kg/day without exhibiting apparent toxicity.
- Lu, Yanli,Mao, Fei,Li, Xiaokang,Zheng, Xinyu,Wang, Manjiong,Xu, Qing,Zhu, Jin,Li, Jian
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supporting information
p. 5099 - 5119
(2017/06/28)
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- Single-Site Cobalt Catalysts at New Zr12(μ3-O)8(μ3-OH)8(μ2-OH)6 Metal-Organic Framework Nodes for Highly Active Hydrogenation of Nitroarenes, Nitriles, and Isocyanides
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We report here the synthesis of a robust and porous metal-organic framework (MOF), Zr12-TPDC, constructed from triphenyldicarboxylic acid (H2TPDC) and an unprecedented Zr12 secondary building unit (SBU): Zr12(μ3-O)8(μ3-OH)8(μ2-OH)6. The Zr12-SBU can be viewed as an inorganic node dimerized from two commonly observed Zr6 clusters via six μ2-OH groups. The metalation of Zr12-TPDC SBUs with CoCl2 followed by treatment with NaBEt3H afforded a highly active and reusable solid Zr12-TPDC-Co catalyst for the hydrogenation of nitroarenes, nitriles, and isocyanides to corresponding amines with excellent activity and selectivity. This work highlights the opportunity in designing novel MOF-supported single-site solid catalysts by tuning the electronic and steric properties of the SBUs.
- Ji, Pengfei,Manna, Kuntal,Lin, Zekai,Feng, Xuanyu,Urban, Ania,Song, Yang,Lin, Wenbin
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p. 7004 - 7011
(2017/05/31)
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- Traceless Directing-Group Strategy in the Ru-Catalyzed, Formal [3 + 3] Annulation of Anilines with Allyl Alcohols: A One-Pot, Domino Approach for the Synthesis of Quinolines
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A unique, ruthenium-catalyzed, [3 + 3] annulation of anilines with allyl alcohols in the synthesis of substituted quinolines is reported. The method employs a traceless directing group strategy in the proximal C-H bond activation and represents a one-pot Domino synthesis of quinolines from anilines.
- Kumar, Gangam Srikanth,Kumar, Pravin,Kapur, Manmohan
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supporting information
p. 2494 - 2497
(2017/05/24)
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- A New Route for Synthesis of 2-Substituted-3-amino-5-phenyl-7-N,N-dimethylamino Phenazinium Chloride Salts
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2-Methyl-3-amino-5-phenyl-7-N, N-dimethylamino phenazinium chloride salts were synthesized in better yields via the cyclization of 4-amino-N,N-dimethylaniline with toluidine derivatives and aminobenzene under the oxidation of sodium bicarbonate.
- Liu, Yuan,Jin, Ling,Liu, Jun-Feng
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p. 1931 - 1936
(2017/05/29)
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- Preparation and catalytic properties of magnetic rectorite-chitosan-Au composites
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A novel composite was assembled by introducing magnetic Fe3O4nanoparticles, chitosan and Au nanoparticles (AuNPs) on rectorite (REC) surfaces. The obtained REC-Fe3O4-CTS-Au composite was characterized and used as the catalyst to remove 4-nitrophenol (4-NP) and methyl orange (MO) from water in the presence of NaBH4. The large surface of REC and the abundant hydroxyl group of chitosan on REC surface could restrain the agglomeration of AuNPs. REC-Fe3O4-CTS-Au exhibited the superiority in catalytic efficiency. At the catalyst dosage of 150?mg/L, it took only 15?min for 0.2?mM 4-NP solution to reach complete reduction, and 30?min for 1.0?mM 4-NP solution. This catalyst had the higher catalytic activity for 4-NP than MO reduction. Moreover, the catalyst could be conveniently separated and recycled from the reaction mixtures using an external magnetic field, and reused for 4-NP (or MO) reduction in fourteen cycles with retaining the original 99% (or 95%) conversion efficiency. This work indicates that REC-Fe3O4-CTS-Au can be a promising catalyst for the highly efficient degradation of organic dyes.
- Zhang, Rufei,Zheng, Pengwu,Ma, Xiaofei
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p. 381 - 389
(2016/09/02)
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- Rapid heteroatom transfer to arylmetals utilizing multifunctional reagent scaffolds
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Arylmetals are highly valuable carbon nucleophiles that are readily and inexpensively prepared from aryl halides or arenes and widely used on both laboratory and industrial scales to react directly with a wide range of electrophiles. Although C-C bond formation has been a staple of organic synthesis, the direct transfer of primary amino (-NH2) and hydroxyl (-OH) groups to arylmetals in a scalable and environmentally friendly fashion remains a formidable synthetic challenge because of the absence of suitable heteroatom-transfer reagents. Here, we demonstrate the use of bench-stable N-H and N-alkyl oxaziridines derived from readily available terpenoid scaffolds as efficient multifunctional reagents for the direct primary amination and hydroxylation of structurally diverse aryl- and heteroarylmetals. This practical and scalable method provides one-step synthetic access to primary anilines and phenols at low temperature and avoids the use of transition-metal catalysts, ligands and additives, nitrogen-protecting groups, excess reagents and harsh workup conditions.
- Gao, Hongyin,Zhou, Zhe,Kwon, Doo-Hyun,Coombs, James,Jones, Steven,Behnke, Nicole Erin,Ess, Daniel H.,Kürti, László
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p. 681 - 688
(2017/06/30)
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- Photocatalytic methanol assisted production of hydrogen with simultaneous degradation of methyl orange
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Platinized TiO2 prepared by photodeposition was evaluated for activity in the simultaneous conversion of methyl orange (MO), and methanol assisted formation of hydrogen. Low concentrations of MO were found ineffective for generation of hydrogen in measurable quantities upon illumination of Pt/TiO2 in water. On the other hand, methanol induced hydrogen formation was significant. Surprisingly, when methyl orange was added to the methanol/water solution, hydrogen formation was significantly suppressed. The origin of this detrimental effect of methyl orange lies in the strong and preferred adsorption of the dye on the Pt sites of the catalyst, resulting in hydrogenation of the azo bond and suppression of the catalyzed formation of hydrogen. The hydrogenation of the azo bond is corroborated by dis-colorization of the solution and the observation of a mass fragment in LC-MS analysis corresponding to a hydrogenated product of MO (m/z = 172). Similar to hydrogen formation, dye dis-colorization is stimulated by the presence of methanol, without the formation of new chemical compounds, confirming the role of methanol as a hole scavenger in the photocatalytic processes. Finally the presence of oxygen (in lean conditions) delays dye hydrogenation and hydrogen formation, which we discuss is due to oxygen adsorption and formation of superoxide anions over the Pt sites (leading to oxidation of methanol), which is preferred over N=N bond hydrogenation, and proton reduction.
- Rom?o, Joana,Salata, Rafal,Park, Sun-Young,Mul, Guido
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p. 206 - 212
(2016/05/10)
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- Unprecedented iron-catalyzed selective hydrogenation of activated amides to amines and alcohols
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The first example of hydrogenation of amides homogeneously catalyzed by an earth-abundant metal complex is reported. The reaction is catalyzed by iron PNP pincer complexes. A wide range of secondary and tertiary N-substituted 2,2,2-trifluoroacetamides were hydrogenated to form amines and trifluoroethanol.
- Garg, Jai Anand,Chakraborty, Subrata,Ben-David, Yehoshoa,Milstein, David
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supporting information
p. 5285 - 5288
(2016/05/02)
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- Zwitterionic buffer-induced visible light excitation of TiO2 for efficient pollutant photodegradation
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Excitation of TiO2 for visible light absorption by surface complexation with antenna organic molecules is an effective strategy to improve its solar utilization efficiency for photocatalytic application, but the existing antenna molecules are mostly toxic and environmentally-aggressive, severely limiting their practical application. In this study, we tested the potential of zwitterionic buffers (Good's buffers) as an environmentally-benign alternative. The addition of Good's buffers significantly enhanced methyl orange (MO) photodegradation by TiO2 under visible light, but the enhancement degree varied with the different buffer types, buffer concentration and solution pH. The presence of 4-(2-hydroxyerhyl) piperazine-1-erhanesulfonic acid (HEPES) as a typical Good's buffer led to over 90% MO removal within 180 min, whereas only slight MO removal was observed in the TiO2 alone system during the same period. Such an induced visible light photocatalytic activity was attributed to a complexation between the conjugate acid structured buffer molecule and TiO2, which favors a ligand-to-metal charge transfer (LMCT). The LMCT activity was strongly dependent on the molecule structure, especially the states of hydroxyl and amino groups of Good's buffers. The pH buffering ability of the buffers also contributed to the efficient MO photodegradation. This study suggests a great potential of Good's buffers as both green antenna molecules and pH buffer for strengthening TiO2-based photocatalytic remediation processes.
- Xiao, Xiang,Zhu, Wen-Wen,Lei, Yu-Bin,Liu, Qiu-Yue,Li, Qian,Li, Wen-Wei
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p. 35449 - 35454
(2016/05/19)
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- Scale-up synthesis of zero-valent iron nanoparticles and their applications for synergistic degradation of pollutants with sodium borohydride
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The scale-up synthesis of nZVI (zero-valent iron nanoparticles) was optimized by response surface modeling (RSM). The synthesized nZVI was employed for synergistic degradation of metronidazole (MNZ) or methyl orange (MO) in the presence of sodium borohydr
- Ravikumar,Dubey, Swati,pulimi, Mrudula,Chandrasekaran, Natarajan,Mukherjee, Amitava
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p. 589 - 598
(2016/10/24)
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- Simple and convenient copper-catalyzed amination of aryl halides to primary arylamines using NH4OH
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In this study, we investigated the direct synthesis of primary arylamines from aryl iodides and bromides by Cu-catalyzed amination using ammonium hydroxide (27% NH3in H2O) as nucleophile. In this article, two protocols are described: (1) a variety of aryl halides were treated with CuI (10?mol?%) and DMEDA (15?mol?%) in NH4OH/DMSO, or (2) with only CuI (10?mol?%) in NH4OH/PEG300. In each case, the desired primary arylamines were obtained in excellent yields. Although DMEDA and PEG have previously been employed as a ligand or solvent, respectively, the substrates were limited or additional ligands were required for successful conversion. Notably, our new protocols do not require additional inorganic bases, whereas previous methods have used a base. As such, these new protocols are one of the most simple, convenient, and efficient methods that have been reported, to date.
- Jung, Hee Seon,Yun, Taeil,Cho, Yungyeong,Jeon, Heung Bae
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p. 5988 - 5993
(2016/09/16)
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- A terminally protected dipeptide: from crystal structure and self-assembly, through co-assembly with carbon-based materials, to a ternary catalyst for reduction chemistry in water
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A terminally protected, hydrophobic dipeptide Boc-l-Cys(Me)-l-Leu-OMe (1) was synthesized and its 3D-structure was determined by single crystal X-ray diffraction analysis. This peptide is able to hierarchically self-assemble in a variety of superstructures, including hollow rods, ranging from the nano- to the macroscale, and organogels. In addition, 1 is able to drive fullerene (C60) or multiwalled carbon nanotubes (MWCNTs) in an organogel by co-assembling with them. A hybrid 1-C60-MWCNT organogel was prepared and converted (through a high vacuum-drying process) into a robust, high-volume, water insoluble, solid material where C60 is well dispersed over the entire superstructure. This ternary material was successfully tested as a catalyst for: (i) the reduction reaction of water-soluble azo compounds mediated by NaBH4 and UV-light with an overall performance remarkably better than that provided by C60 alone, and (ii) the NaBH4-mediated reduction of benzoic acid to benzyl alcohol. Our results suggest that the self-assembly properties of 1 might be related to the occurrence in its single crystal structure of a sixfold screw axis, a feature shared by most of the linear peptides known so far to give rise to nanotubes.
- Mazzier, Daniela,Carraro, Francesco,Crisma, Marco,Rancan, Marzio,Toniolo, Claudio,Moretto, Alessandro
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p. 238 - 245
(2015/12/30)
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- Indium(III)-Catalyzed Reduction of Nitrobenzenes to Anilines: Scope and Limitations
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We have demonstrated that a combination of indium(III) iodide and 1,1,3,3-tetramethyldisiloxane (TMDS) effectively catalyzes the chemoselective reduction of nitrobenzenes with a variety of functional groups (halogens, alkyl, alkoxy, hydroxy, ester, amino, amide, cyanide, thiol, and an alkene moiety), producing the corresponding aniline derivatives.
- Sakai, Norio,Asama, Shun,Konakahara, Takeo,Ogiwara, Yohei
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p. 3179 - 3185
(2015/10/19)
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