- Suzuki coupling reaction catalyzed heterogeneously by Pd(salen)/ polyoxometalate compound: Another example for synergistic effect of organic/inorganic hybrid
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A hybrid compound consisting of palladium(salen) [salen = N,N′-bis(salicylidene)ethylenediamine] complex covalently linked to a lacunary Keggin-type polyoxometalate, K8[SiW11O 39](POM), was synthesized and characterized by FT-IR, elemental analysis, inductively coupled plasma and diffuse reflectance UV-visible spectroscopic methods. The hybrid, [Pd(salen)-POM], was investigated in the Suzuki cross-coupling in EtOH/H2O under mild reaction conditions. In comparison to the corresponding organic and inorganic moiety, the hybrid has shown greatly improved catalytic activity, and much higher yields toward coupling products were obtained with a low catalyst loading for various aryl halides, including unreactive and sterically hindered ones. The catalyst also exhibited prominent recyclable performance and no obvious loss of activity was observed after six consecutive runs.
- Tong, Jinhui,Wang, Haiyan,Cai, Xiaodong,Zhang, Qianping,Ma, Hengchang,Lei, Ziqiang
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- Magnetic nanoparticles-supported palladium catalyzed Suzuki-Miyaura cross coupling
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A new magnetic nanoparticles-supported palladium(II) nanomagnetic catalyst (Pd-AcAc-Am-Fe3O4?SiO2) was synthesized and characterized using attenuated total reflectance infrared spectroscopy (ATR-IR), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), energy-dispersive X-ray spectroscopy (EDS), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The nanomagnetic catalyst was used as an efficient catalyst for the Suzuki-Miyaura cross-coupling of various aryl bromides/chlorides/iodides with phenylboronic acid. The effect of varying solvents, base, temperature, reaction time and catalyst amount on the performance of the Suzuki-Miyaura cross-coupling is investigated. The notable advantages of heterogeneous nanomagnetic catalyst are excellent yields, mild reaction conditions, short reaction time, easy magnetic work-up and recyclability. Moreover, the new nanomagnetic catalyst could be easily recovered with an external magnet and reused at least six times without significant loss of its catalytic activity.
- Vibhute, Sandip P.,Mhaldar, Pradeep M.,Shejwal, Rajendra V.,Pore, Dattaprasad M.
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- Palladium nanoparticles immobilized on core-shell magnetic fibers as a highly efficient and recyclable heterogeneous catalyst for the reduction of 4-nitrophenol and Suzuki coupling reactions
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In this study, a novel core-shell magnetic fibrous nanocatalyst, Pd/Fe3O4@SiO2@KCC-1 with easily accessible active sites and a convenient recovery by applying an external magnetic field, was successfully developed. Fe3O4@SiO2@KCC-1 was functionalized with amino groups which act as robust anchors so that the palladium nanoparticles (Pd NPs) with an average diameter of about 4 nm were well-dispersed on the fibers of Fe3O4@SiO2@KCC-1 without obvious aggregation. The synthesized Pd/Fe3O4@SiO2@KCC-1 nanocatalyst exhibited excellent catalytic activity in the reduction of 4-nitrophenol by sodium borohydride, and the Suzuki cross coupling reactions of aryl chlorides with aryl boronic acids due to the easy accessibility of the active sites. Furthermore, the Pd/Fe3O4@SiO2@KCC-1 nanocatalyst was conveniently recovered by a magnet and could be reused for at least five cycles without significant loss in activity, thus confirming its good stability. Therefore, the abovementioned approach based on core-shell magnetic fibrous Fe3O4@SiO2@KCC-1 provided a useful platform for the fabrication of Pd NPs based catalysts with easy accessibility, superior activity and convenient recovery.
- Le, Xuanduong,Dong, Zhengping,Liu, Yansheng,Jin, Zhicheng,Huy, Thanh-Do,Le, Minhdong,Ma, Jiantai
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Read Online
- Palladium Palladium Nanoparticles Nanoparticles Supported Supported on β-cyclodextrin on β-Cyclodextrin Functionalised Functionalized Poly(amido Poly(amidoamine)s amine)s and their and Application Their Application in Suzuki-Miyaura in Suzuki-Miyaura Cross-Coupling Cross-Coupling Reactions Reactions
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Herein, the synthesis, characterization and catalytic application of an organic-inorganic, palladium (Pd)-containing hybrid material, poly(amidoamine)-cyclodextrin (Pd@PAAs-CD), is reported as an efficient catalyst for Suzuki-Miyaura coupling reactions. The structure of Pd@PAAs-CD was confirmed by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), inductively-coupled plasma atomic emission spectroscopy (ICP-AES), and 1H nuclear magnetic resonance (NMR) spectroscopy. Furthermore, an efficient protocol has been developed using Pd@PAAs-CD as the catalyst in a Suzuki-Miyaura cross-coupling reaction in an aqueous medium in high yields. By using cyclodextrin (CD) as the mediator grafted onto PAAs, the Pd nanoparticles (NPs) were dispersed and enhanced the catalytic reaction by promoting host-guest interactions with the CD. In addition, the reusability of the Pd@PAAs-CD hybrid material is demonstrated for use in multiple sequential cross-coupling reactions.
- Zhang, Wei,Yao, Zi-Jian,Deng, Wei
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p. 1667 - 1677
(2019/10/01)
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- De novo design approaches targeting an envelope protein pocket to identify small molecules against dengue virus
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Dengue fever is a mosquito-borne viral disease that has become a major public health concern worldwide. This disease presents with a wide range of clinical manifestations, from a mild cold-like illness to the more serious hemorrhagic dengue fever and dengue shock syndrome. Currently, neither an approved drug nor an effective vaccine for the treatment are available to fight the disease. The envelope protein (E) is a major component of the virion surface. This protein plays a key role during the viral entry process, constituting an attractive target for the development of antiviral drugs. The crystal structure of the E protein reveals the existence of a hydrophobic pocket occupied by the detergent n-octyl-β-d-glucoside (β-OG). This pocket lies at the hinge region between domains I and II and is important for the low pH-triggered conformational rearrangement required for the fusion of the virion with the host's cell. Aiming at the design of novel molecules which bind to E and act as virus entry inhibitors, we undertook a de novo design approach by “growing” molecules inside the hydrophobic site (β-OG). From more than 240000 small-molecules generated, the 2,4 pyrimidine scaffold was selected as the best candidate, from which one synthesized compound displayed micromolar activity. Molecular dynamics-based optimization was performed on this hit, and thirty derivatives were designed in silico, synthesized and evaluated on their capacity to inhibit dengue virus entry into the host cell. Four compounds were found to be potent antiviral compounds in the low-micromolar range. The assessment of drug-like physicochemical and in vitro pharmacokinetic properties revealed that compounds 3e and 3h presented acceptable solubility values and were stable in mouse plasma, simulated gastric fluid, simulated intestinal fluid, and phosphate buffered saline solution.
- Acosta Dávila, John Alejandro,Adler, Natalia S.,Aucar, Maria G.,Battini, Leandro,Bollini, Mariela,Cavasotto, Claudio N.,Cordo, Sandra M.,Fernández, Gabriela A.,Gamarnik, Andrea V.,García, Cybele C.,Gebhard, Leopoldo G.,Hernández de los Ríos, Alejandro,Leal, Emilse S.,Monge, María Eugenia,Morell, María L.,Videla, Mariela
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supporting information
(2019/08/30)
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- COMPOUND OR PHARMACEUTICALLY ACCEPTABLE SALT THEREOF, MYOGENESIS PROMOTER, MUSCULAR ATROPHY INHIBITOR, PHARMACEUTICAL COMPOSITION, AND TAZ ACTIVATOR
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PROBLEM TO BE SOLVED: To provide a myogenesis promoter, a muscular atrophy inhibitor, a pharmaceutical composition and a TAZ activator that are based on a compound useful for promotion of myogenesis or inhibition of muscular atrophy. SOLUTION: The invention provides a compound represented by the general formula (1) or general formula (2) in the figure, or a pharmaceutically acceptable salt thereof. SELECTED DRAWING: None COPYRIGHT: (C)2019,JPOandINPIT
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Paragraph 0089; 0092
(2019/08/12)
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- Diamines as interparticle linkers for silica-titania supported PdCu bimetallic nanoparticles in Chan-Lam and Suzuki cross-coupling reactions
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A series of highly efficient amine functionalized SiO2-TiO2 supported bimetallic PdCu catalysts with varied metal composition have been synthesized. Ethane-1,2-diamine, butane-1,4-diamine and hexane-1,6-diamine were employed as interparticle linkers for amine functionalization of a SiO2-TiO2 support material so as to study the effect of pendant chain length on stabilization and immobilization of bimetallic nanoparticles. The shortest carbon chain length on the support provided the best results, which may be due to the trapping of metal nanoparticles more efficiently by the basic nitrogen sites. The catalytic activities of these materials were evaluated for C-N and C-C coupling reactions. The most active catalyst, Pd1Cu1@12DA-STS, was characterized by various techniques including SEM, HR-TEM, ICP-AES, XRD, FTIR, EDX, CHN analysis and TGA studies. Moreover, the synthesized catalyst was found to be recyclable for up to five runs without significant loss of activity.
- Jamwal, Babita,Kaur, Manpreet,Sharma, Harsha,Khajuria, Chhavi,Paul, Satya,Clark
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p. 4919 - 4928
(2019/03/26)
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- Radical Arylation of Anilines and Pyrroles via Aryldiazotates
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The radical arylation of anilines and pyrroles can be achieved under transition-metal- and catalyst-free conditions by using aryldiazotates in strongly alkaline aqueous solutions. The aryldiazotates act as protected diazonium ions, which do not undergo azo coupling with electron-rich aromatic substrates, but can still serve as an aryl radical source at slightly elevated temperatures. Based on an improved preparation of aryldiazotates in aqueous solution, homolytic aromatic substitutions of anilines and pyrroles were conducted with good overall yields and high regioselectivity. Moreover, DFT calculations provided further mechanistic insights.
- Hofmann, Josefa,Gans, Eva,Clark, Timothy,Heinrich, Markus R.
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p. 9647 - 9656
(2017/07/22)
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- 3-Hydroxypyrimidine-2,4-diones as Selective Active Site Inhibitors of HIV Reverse Transcriptase-Associated RNase H: Design, Synthesis, and Biochemical Evaluations
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Human immunodeficiency virus (HIV) reverse transcriptase (RT) associated ribonuclease H (RNase H) remains an unvalidated antiviral target. A major challenge of specifically targeting HIV RNase H arises from the general lack of selectivity over RT polymerase (pol) and integrase (IN) strand transfer (ST) inhibitions. We report herein the synthesis and biochemical evaluations of three novel 3-hydroxypyrimidine-2,4-dione (HPD) subtypes carefully designed to achieve selective RNase H inhibition. Biochemical studies showed the two subtypes with an N-1 methyl group (9 and 10) inhibited RNase H in low micromolar range without siginificantly inhibiting RT polymerase, whereas the N-1 unsubstituted subtype 11 inhibited RNase H in submicromolar range and RT polymerase in low micromolar range. Subtype 11 also exhibited substantially reduced inhibition in the HIV-1 INST assay and no significant cytotoxicity in the cell viability assay, suggesting that it may be amenable to further structure-activity relationship (SAR) for identifying RNase H inhibitors with antiviral activity.
- Tang, Jing,Liu, Feng,Nagy, Eva,Miller, Lena,Kirby, Karen A.,Wilson, Daniel J.,Wu, Bulan,Sarafianos, Stefan G.,Parniak, Michael A.,Wang, Zhengqiang
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p. 2648 - 2659
(2016/04/10)
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- ELECTROCHROMIC COMPOUND, ELECTROCHROMIC COMPOSITION, AND ELECTROCHROMIC DISPLAY ELEMENT
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PROBLEM TO BE SOLVED: To provide an electrochromic compound having excellent yellow color development and excellent repeated durability. SOLUTION: The present invention provides an electrochromic compound represented by formula (I) (R1 to R20 independently represent H, a halogen atom, a univalent organic group, and a polymerizable functional group). SELECTED DRAWING: None COPYRIGHT: (C)2017,JPOandINPIT
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Paragraph 0136; 0139; 0140
(2017/02/02)
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- Strongly Directing Substituents in the Radical Arylation of Substituted Benzenes
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Although general interest in radical arylation reactions has grown rapidly in recent years, poor regioselectivities and the need to use a large excess of the radical-accepting arene have hindered their application to substituted benzenes. We now describe experimental and computational investigations into the substituent effects that lead to regioselective addition based on the recent discovery of anilines as outstanding substrates for radical arylations.
- Hofmann, Josefa,Clark, Timothy,Heinrich, Markus R.
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p. 9785 - 9791
(2016/10/31)
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- Structure-activity relationship study of E6 as a novel necroptosis inducer
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Necroptosis inducers represent a promising potential treatment for drug-resistant cancer. We herein describe the structure modification of E6, which was identified recently as a potent and selective necroptosis inducer. The studies described herein demonstrate for the first time that functionalized biphenyl derivatives possess necroptosis inducer activity. Furthermore, these studies have led to the identification of two promising compounds (5h and 5j) that can be used for further optimization studies as well as mechanism of action investigations.
- Mou, Jianfeng,Park, Ann,Cai, Yu,Yuan, Junying,Yuan, Chengye
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supporting information
p. 3057 - 3061
(2015/06/22)
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- Unified Protocol for Cobalt-Catalyzed Oxidative Assembly of Two Aryl Metal Reagents Using Oxygen as an Oxidant
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The first cobalt-catalyzed oxidative cross-coupling reaction of two aryl metal reagents is described. An equivalent amount of two aryl Grignard or lithium reagents, after mediation by an equivalent amount of simple ClTi(OEt)3, was facilely assembled under the catalysis of 1 mol % of CoCl2/10 mol % of DMPU using oxygen. The cross-couplings between various aryl metal reagents, especially between two structurally similar aryl Grignard reagents, proceeded smoothly and selectively and, thus, provided a highly general and efficient method for the construction of biaryl compounds.
- Liao, Lian-Yan,Liu, Kun-Ming,Duan, Xin-Fang
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p. 9856 - 9867
(2015/11/03)
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- Oxidative radical arylation of anilines with arylhydrazines and dioxygen from air
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Substituted 2-aminobiphenyls have been prepared from arylhydrazine hydrochlorides and anilines in biphasic radical arylation reactions with dioxygen from air as a most simple and readily available oxidant. Under optimized conditions, the free amino functionality of the aniline leads to high ortho:meta regioselectivities, now even for anilines bearing a donor substituent in the para position. Finally, the mild and metal-free new access to aminobiphenyls was shown to be applicable on a gram scale.
- Hofmann, Josefa,Jasch, Hannelore,Heinrich, Markus R.
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p. 2314 - 2320
(2014/04/03)
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- Process for the Synthesis of Aminobiphenylene
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The present invention relates to a process for the synthesis of 2-aminobiphenylene and derivatives thereof by reacting a benzene diazonium salt with an aniline compound under basic reaction conditions.
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Paragraph 0243; 0244; 0343; 0344; 0345; 0346; 0347-0349
(2014/02/15)
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- Regioselective radical arylation of anilines with arylhydrazines
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Substituted 2-aminobiphenyls have been prepared from arylhydrazines and anilines via radical arylation reactions under simple oxidative conditions. The strong directing effect of the free and unprotonated amino functionality leads to high regioselectivities, and anilines have been shown to be significantly better aryl radical acceptors than nitrobenzenes or phenyl ethers. The methodology is also applicable to phenols, which react best as phenolates under strongly basic conditions. Finally, radical arylation reactions of anilines and anilinium salts under various conditions have for the first time demonstrated that regioselectivity can also be controlled through the rearomatization step and that the addition of an aryl radical to a substituted benzene might even be reversible.
- Jasch, Hannelore,Scheumann, Julia,Heinrich, Markus R.
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p. 10699 - 10706
(2013/02/25)
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- Palladium nanoparticles immobilized on poly(vinyl chloride)-supported pyridinium as an efficient and recyclable catalyst for suzuki-miyaura cross-coupling reaction
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The palladium nanoparticles immobilized on the polymeric surface of poly(vinyl chloride)-supported pyridinium (PVC-Py-Pd0) were achieved by a simple procedure by applying the corresponding functionalized polymer and palladium chloride in ethanol solution. The as-prepared catalyst (PVC-Py-Pd 0) was found to be air and moisture stable and exhibits significant catalytic activity for Suzuki-Miyaura cross-coupling reaction of various aryl halides and phenylboronic acid under milder operating conditions. The procedure presented here showed several merits such as short reaction time, simple experimental and isolated procedure and excellent yields of products. Furthermore, the catalyst can be easily recovered and reused for at least six times with consistent activities. Copyright E-Journal of Chemistry 2004-2011.
- Zhou, Bo,Li, Yi-Qun
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experimental part
p. 1490 - 1497
(2012/05/05)
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- NOVEL HETEROCYCLIC AMIDE DERIVATIVES HAVING DIHYDROOROTATE DEHYDROGENASE INHIBITING ACTIVITY
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Novel heterocyclic amide derivatives having pharmacological effects, that is, compounds represented by the general formula (1) or salts thereof: (1) wherein X1-X2 is S-CH2 or the like; R1 is alkyl or the like; p is 0 to 7; R2 is hydrogen, alkyl, or the like; R3 is hydrogen, alkyl, or the like; Y1-Y2 is CH=CH or the like; R4 is halogeno, alkyl, or the like; q is 0 to 4; and R5 is halogeno, hydrogen, alkyl, or the like.
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Page/Page column 51; 52
(2010/10/20)
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- N- and C-attacks on aromatics of phenylnitrenium ion generated from N-phenylhydroxylamine in the presence of trifluoroacetic acid containing polyphosphoric acid or trifluoroacetic anhydride
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A phenylnitrenium ion formed from N-phenylhydroxylamine in the presence of trifluoroacetic acid (TFA) containing polyphosphoric acid (PPA) interacts with the counterion -O2CCF3 and the unshared electron-pair of H2O, showing Hammett's ρ values -5.2 and -4.0 for N- and C-attacks on aromatics PhX (X = H, Me, Et, Ph and Cl), respectively. The ratio N-/C-attack for this nitrenium ion is lower than for the nitrenium ion interacting with only the counterion; the latter nitrenium ion is generated by the use of trifluoroacetic anhydride (TFAA) instead of PPA or by reaction of phenyl azide with aromatics in TFA. The ratio for the former nitrenium ion is affected by the aromatic substituent X:X = Me > X = Et > X = Ph > X = H > X = OMe at 20 and 50°C. The order for X = Cl is between those of X = H and X = Ph at 20°C, but highest at 50°C. The ratio is increased by higher reaction temperature and by decreased concentration of TFA. The results are demonstrated from the mechanistic viewpoint for the nitrenium ions.
- Takeuchi, Hiroshi,Taniguchi, Tomohito,Ueda, Takahiro
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p. 295 - 300
(2007/10/03)
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- Carbocation-like reactivity patterns in X′-substituted-4-biphenylylnitrenium ions
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4-Azido-X′-substituted biphenyls (X′ = 4′-MeO, 4′-Me, 4′-F, 3′-Me, 4′-Cl, H, 3′-MeO, 3′-Cl, 4′-CF3) have been prepared and subjected to 248 nm flash photolysis irradiation in 20:80 acetonitrile:water. Transient X′-substituted 4-biphenylylnitrenium ions 10 (Ar-C6H4-N+H) are observed, with lifetimes ranging from 0.6 ms (4′-MeO) to 26 ns (4′-CF3). These cations are quenched by azide ion, with values of kaz ranging from 6 to 10×109 M-1 s-1, with the majority in the range (9-10)×109. This near constant kaz provides further evidence that arylnitrenium ions are quenched by azide ion at the diffusion limit. The solvent reactivities, plotted in a single-parameter Hammett plot against σ+(X), exhibit a poor correlation, with the points for the para π-electron donors deviating from the correlation line based on the other substituents in the direction of requiring a more negative substituent parameter. The data are more satisfactorily fit to the two-parameter Yukawa-Tsuno equation; the parameter r+ obtained in this fit is 2.8. Thus the resonance interaction of the para π-donor X′-substituents with the positive charge of the cation is underestimated by σ+, a situation that has previously been observed with benzylic-type carbenium ions. The conclusion is made that, in their reaction with water, 4-biphenylylnitrenium ions behave like benzyl cations bearing two additional stabilizing vinyl groups, i.e., as if they had the structure Ar-C+(C-to-C)2 double bond. The inherent reactivity and the pattern of the aryl substituent effects are in fact similar to those in the carbocation series Ar-C+(Ph)2.
- Ren,McClelland
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