- Design and Photophysical Studies of Acridine-Based RuIIComplexes for Applications as DNA Photoprobes
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A series of new extended planar aromatic ligands based on an acridine core (dpac = dipyrido[3,2-a:2′,3′-c]acridine; dpacF2= 7,8-difluorodipyrido[3,2-a:2′,3′-c]acridine; dpacF4= 6,7,8,9-tetrafluorodipyrido[3,2-a:2′,3′-c]acridine) and their respective RuIIcomplexes were synthesized and extensively studied. The photophysical and theoretical studies revealed that Ru-DPAC and Ru-DPACF2allow emission from a3MLCTphen/dpacexcited state at 597 and 604 nm, respectively, whereas the lowest excited state for Ru-DPACF4shifts from a bright3MLCTphen/dpacstate towards a poorly luminescent3MLCTdpacstate (λem= 609 nm) owing to the formation of hydrogen bonds with water molecules in the excited state. These complexes exhibit up to sevenfold luminescence enhancement in the presence of complementary and mismatched DNA, demonstrating a strong binding to polynucleotides. The results emphasize the interest in RuIIcomplexes bearing acridine derivatives as DNA interacting agents as a complement to the well-known phenazine-based derivatives.
- Deraedt, Quentin,Marcélis, Lionel,Auvray, Thomas,Hanan, Garry S.,Loiseau, Frédérique,Elias, Benjamin
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- Magnetic ethyl-based organosilica supported Schiff-base/indium: A very efficient and highly durable nanocatalyst
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In the present study a novel core-shell structured magnetic bifunctional organosilica was prepared through modification of Fe3O4 nanoparticles with a mixture of bis(triethoxysilyl) ethane (BTEE) and 3-aminopropyltrimethoxysilane (APTES) followed by treatment with 2-hydroxybenzaldehyde. This nanomaterial was applied as efficient support for immobilization of indium chloride. The prepared nanomaterial was denoted as Fe3O4@BOS@SB/In and characterized using Fourier transform infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TGA), energy-dispersive X-ray (EDX) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) and powder X-ray diffraction (PXRD). The Fe3O4@BOS@SB/In was successfully applied as a powerful catalyst for green reduction of nitrobenzenes in water at room temperature. This catalyst was recovered and reused several times without significant decrease in efficiency and stability.
- Mirbagheri, Reza,Elhamifar, Dawood
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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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- Chemoselective reduction of nitroarenes, N-acetylation of arylamines, and one-pot reductive acetylation of nitroarenes using carbon-supported palladium catalytic system in water
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Developing and/or modifying fundamental chemical reactions using chemical industry-favorite heterogeneous recoverable catalytic systems in the water solvent is very important. In this paper, we developed convenient, green, and efficient approaches for the chemoselective reduction of nitroarenes, N-acetylation of arylamines, and one-pot reductive acetylation of nitroarenes in the presence of the recoverable heterogeneous carbon-supported palladium (Pd/C) catalytic system in water. The utilize of the simple, effective, and recoverable catalyst and also using of water as an entirely green solvent along with relatively short reaction times and good-to-excellent yields of the desired products are some of the noticeable features of the presented synthetic protocols. Graphic abstract: [Figure not available: see fulltext.].
- Zeynizadeh, Behzad,Mohammad Aminzadeh, Farkhondeh,Mousavi, Hossein
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p. 3289 - 3312
(2021/05/11)
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- Electrochemical access to benzimidazolone and quinazolinone derivatives: Via in situ generation of isocyanates
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Isocyanates are the key intermediates for several organic transformations towards the synthesis of diverse pharmaceutical targets. Herein, we report the development of an oxidant-free protocol for electrochemical in situ generation of isocyanates. This strategy highlights expedient access to benzimidazolones and quinazolinones and eliminates the need for exogenous oxidants. Furthermore, detailed mechanistic studies provide strong support towards our hypothesis of in situ isocyanate generation. This journal is
- Saha, Debarshi,Taily, Irshad Maajid,Naik, Sumitra,Banerjee, Prabal
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p. 631 - 634
(2021/01/29)
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- Transition metal-free approach to azafluoranthene scaffolds by aldol condensation/[1+2+3] annulation tandem reaction of isocyanoacetates with 8-(alkynyl)-1-naphthaldehydes
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A transition metal-free aldol condensation/[1+2+3] annulation reaction of isocyanoacetates with 8-(alkynyl)-1-naphthaldehydes has been developed for the general synthesis of azafluoranthenes. This domino reaction enables successive formation of three new bonds and two rings from readily accessible starting materials in a single operation. Furthermore, this methodology can also be utilized to construct chromeno[4,3-c]pyridines and benzo[c][2,6]naphthyridines in moderate yields.
- Dong, Penghui,Majeed, Kashif,Wang, Lingna,Guo, Zijian,Zhou, Fengtao,Zhang, Qiuyu
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supporting information
p. 4855 - 4858
(2021/05/25)
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- Me3SI-promoted chemoselective deacetylation: a general and mild protocol
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A Me3SI-mediated simple and efficient protocol for the chemoselective deprotection of acetyl groups has been developedviaemploying KMnO4as an additive. This chemoselective deacetylation is amenable to a wide range of substrates, tolerating diverse and sensitive functional groups in carbohydrates, amino acids, natural products, heterocycles, and general scaffolds. The protocol is attractive because it uses an environmentally benign reagent system to perform quantitative and clean transformations under ambient conditions.
- Gurawa, Aakanksha,Kashyap, Sudhir,Kumar, Manoj
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p. 19310 - 19315
(2021/06/03)
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- Construction of a benzo[b]azepine skeleton through decarboxylative ylide [6+1] annulations with modified vinyl benzoxazinanones
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A Lewis acid-promoted [6+1] annulation between sulfur ylides and modified vinyl benzoxazinanones was described. In this reaction, the newly designed vinyl benzoxazinanones could serve as a novel six-atom synthon, and the key to success is the installation of an electron-withdrawing group on the alkene moiety of the benzoxazinanones. A broad range of substrates are compatible with this mild reaction system, thereby providing a facile and practical approach for constructing a benzo[b]azepine skeleton.
- Li, Qing-Zhu,Jia, Zhi-Qiang,Chen, Lin,Zhang, Xiang,Leng, Hai-Jun,Zeng, Rong,Liu, Yan-Qing,Zou, Wen-Lin,Li, Jun-Long
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supporting information
p. 814 - 818
(2021/02/16)
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- Access to 5,6-Spirocycles Bearing Three Contiguous Stereocenters via Pd-Catalyzed Stereoselective [4 + 2] Cycloaddition of Azadienes
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We present herein a highly diastereo- and enantioselective Pd-catalyzed [4 + 2] cycloaddition of benzofuran-derived azadienes with vinyl benzoxazinanones, which represents a rare highly stereoselective cycloaddition of this class of fused azadienes as a two-atom synthon. The use of a phosphoramidite ligand bearing a chiral secondary amine with a simple biphenyl backbone proved to be the key to construct the novel spirocyclic tetrahydroquinoline scaffold containing three contiguous stereocenters as a single diastereomer in high enantioselectivity.
- Fairuz Binte Sheikh Ismail, Siti Nur,Yang, Binmiao,Zhao, Yu
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supporting information
p. 2884 - 2889
(2021/05/05)
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- Metal-Free C-C/C-N/C-C Bond Formation Cascade for the Synthesis of (Trifluoromethyl)sulfonylated Cyclopenta[ b]indolines
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A bis(triflyl)ethylation [triflyl = (trifluoromethyl)sulfonyl] inserted into a sequential cyclization cascade resulted in the direct formation of gem-bis(triflyl)ated cyclopenta[b]indolines from anilide-derived allenols and alkenols. This catalyst- and irradiation-free sequence facilitated the efficient preparation of functionalized tricyclic indoline cores bearing two contiguous stereocenters. The formed cyclopenta[b]indolines can be easily transformed into a wide variety of triflylated indolines, including the tetracycle ring system found in polyveoline.
- Lázaro-Milla, Carlos,Yanai, Hikaru,Almendros, Pedro
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supporting information
p. 2921 - 2926
(2021/05/05)
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- A Convenient Formal [4+2] Heterocylization Route to Bis(triflyl)tetrahydroquinolines
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We report the sustainable and efficient synthesis of a new type of quinoline derivatives bearing one or two SO2CF3 groups. The protocol is metal-, catalyst- and irradiation-free, involves the use of readily available and stable precursors, and avoids the formation of side products. Also, the mild conditions of the process allow the tolerance of a wide range of functional groups.
- Lázaro-Milla, Carlos,Almendros, Pedro
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supporting information
p. 13534 - 13538
(2021/08/13)
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- Preparation and Application of α-Imino Ketones through One-Pot Tandem Reactions Based on Heyns Rearrangement
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α-Imino ketone is a useful building block for the preparation of α-amino ketones and α-amino alcohols. However, its preparation has been seldomly seen. Herein, a metal-free and operationally simple strategy has been developed to generate α-imino ketones with high regioselectivity. Meanwhile, the method allowed for the preparation of various N,O-ketals with high regioselectivities and diastereoselectivities through cascade reactions in one pot.
- Li, Ling,Zhang, Shiqi,Deng, Xiongfei,Li, Guangxun,Tang, Zhuo,Zhao, Gang
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supporting information
p. 6819 - 6824
(2021/09/08)
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- A [4+3] Cycloaddition Reaction of Aza-ortho-quinone Methides with C,N-Cyclic Azomethine Imines for Synthesis of 1,2,4-Triazepines
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The base-induced formal [4+3] cycloaddition reaction of C,N-cyclic azomethine imines with aza-ortho-quinone methides, generated in situ, is reported. This protocol provided an efficient method for the synthesis of biologically important 1,2,4-triazepine derivatives, with a wide substrate scope and excellent functional-group tolerance, and it gives moderate to excellent yields under mild conditions. Several of the derivatives exhibited in vitro antitumor activities against the A2780 cell line in a screening of the cancer cell lines HCT-116, H2228, and A2780 by an MTT assay.
- Wang, Xinyue,Li, Zefei,Feng, Chang,Zhen, Qi,Guo, Mingzhang,Yao, Yaning,Zou, Xinyu,Wang, Pengfei,Hou, Yunlei,Gong, Ping
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supporting information
p. 2090 - 2096
(2021/09/06)
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- Copper nanoparticles (CuNPs) catalyzed chemoselective reduction of nitroarenes in aqueous medium
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Abstract: A procedure for practical synthesis of CuNPs from CuSO4·5H2O is established, under appropriate reaction conditions, using rice (Oryza sativa) as an economic source of reducing as well as a stabilizing agent. Optical and microscopic techniques are employed for the characterization of the synthesized CuNPs and the sizes of the particles were found to be in the range of 8 ± 2 nm. The nanoparticles are used as a catalyst for chemoselective reduction of aromatic nitro compounds to corresponding amines under ambient conditions and water as a reaction medium. Graphic abstract: CuNPs are synthesized using hydrolysed rice and used as catalyst for chemoselective reduction of nitroarenes to their corresponding amines in water. [Figure not available: see fulltext.]
- Chand, Dillip Kumar,Rai, Randhir
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- Adhesive functionalized ascorbic acid on CoFe2O4: A core-shell nanomagnetic heterostructure for the synthesis of aldoximes and amines
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This paper reports on the simple synthesis of novel green magnetic nanoparticles (MNPs) with effective catalytic properties and reusability. These heterogeneous nanocatalysts were prepared by the anchoring of Co and V on the surface of CoFe2O4 nanoparticles coated with ascorbic acid (AA) as a green linker. The prepared nanocatalysts have been identified by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray atomic mapping, thermogravimetric analysis, X-ray powder diffraction, vibrating sample magnetometer analysis, coupled plasma optical emission spectrometry and Fourier transform infrared spectroscopy. The impact of CoFe2O4@AA-M (Co, V) was carefully examined for NH2OH·HCl oximation of aldehyde derivatives first and then for the reduction of diverse nitro compounds with sodium borohydride (NaBH4) to the corresponding amines under green conditions. The catalytic efficiency of magnetic CoFe2O4@AA-M (Co, V) nanocatalysts was investigated in production of different aldoximes and amines with high turnover numbers (TON) and turnover frequencies (TOF) through oximation and reduction reactions respectively. Furthermore, the developed environment-friendly method offers a number of advantages such as high turnover frequency, mild reaction conditions, high activity, simple procedure, low cost and easy isolation of the products from the reaction mixture by an external magnetic field and the catalyst can be reused for several consecutive runs without any remarkable decrease in catalytic efficiency.
- Sorkhabi, Serve,Ghadermazi, Mohammad,Mozafari, Roya
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p. 41336 - 41352
(2020/11/30)
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- Applicability of aluminum amalgam to the reduction of arylnitro groups
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An array of arylnitro compounds with various functionality were treated with freshly-prepared aluminum amalgam in THF/water solution and resulted in the corresponding arylamines. The Al(Hg)-mediated reductions are relatively rapid with consumption of the amalgam and disappearance of starting material occurring over 20–30 min. The workup of the reductions involves only removal of the insoluble by-products by filtration followed by concentration. Only in some cases is chromatography required to secure the pure product. The desired arylamines are furnished in quantities of 25–100 mg, which in some cases, could be taken on to the next reaction without further purification. Reductions of 4-nitrobenzyl derivatives of carbohydrates or nucleosides were selective in affording the corresponding 4-aminobenzyl products. To show applicability in click chemistry, selected aminobenzyl products are directly azidated to yield products that were then used in click reactions to afford the corresponding 1,2,3-triazoles.
- Luzzio, Frederick A.,Monsen, Paige J.
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- Palladium-Catalyzed Selective Reduction of Carbonyl Compounds
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Two new examples of structurally characterized β-diketiminate analogues i.e., conjugated bis-guanidinate (CBG) supported palladium(II) complexes, [LPdX]2; [L= {(ArHN)(ArN)–C=N–C=(NAr)(NHAr)}; Ar = 2,6-Et2-C6H3], X = Cl (1), Br (2) have been reported. The synthesis of complexes 1–2 was achieved by two methods. Method A involves deprotonation of LH by nBuLi followed by the treatment of LLi (insitu formed) with PdCl2 in THF, which afforded compound 1 in good yield (75 %). In Method B, the reaction between free LH and PdX2 (X = Cl or Br) in THF allowed the formation of complexes 1 (Yield 73 %) and 2 (Yield 52 %), respectively. Moreover, these complexes were characterized thoroughly by several spectroscopic techniques (1H, 13C NMR, UV/Vis, FT-IR, and HRMS), including single-crystal X-ray structural and elemental analyses. In addition, we tested the catalytic activity of these complexes 1–2 for the hydroboration of carbonyl compounds with pinacolborane (HBpin). We observed that compound 1 exhibits superior catalytic activity when compared to 2. Compound 1 efficiently catalyzes various aldehydes and ketones under solvent-free conditions. Furthermore, both inter- and intramolecular chemoselectivity hydroboration of aldehydes over other functionalities have been established.
- Sarkar, Nabin,Mahato, Mamata,Nembenna, Sharanappa
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p. 2295 - 2301
(2020/05/18)
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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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- Ynamide Smiles Rearrangement Triggered by Visible-Light-Mediated Regioselective Ketyl-Ynamide Coupling: Rapid Access to Functionalized Indoles and Isoquinolines
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In the past decades, significant advances have been made on radical Smiles rearrangement. However, the eventually formed radical intermediates in these reactions are limited to the amidyl radical, except for the few examples initiated by a N-centered radical. Here, a novel and practical radical Smiles rearrangement triggered by photoredox-catalyzed regioselective ketyl-ynamide coupling is reported, which represents the first radical Smiles rearrangement of ynamides. This method enables facile access to a variety of valuable 2-benzhydrylindoles with broad substrate scope in generally good yields under mild reaction conditions. In addition, this chemistry can also be extended to the divergent synthesis of versatile 3-benzhydrylisoquinolines through a similar ketyl-ynamide coupling and radical Smiles rearrangement, followed by dehydrogenative oxidation. Moreover, such an ynamide Smiles rearrangement initiated by intermolecular photoredox catalysis via addition of external radical sources is also achieved. By control experiments, the reaction was shown to proceed via key ketyl radical and α-imino carbon radical intermediates.
- Chen, Yang-Bo,Sun, Zhou,Wang, Ze-Shu,Ye, Long-Wu,Zhang, Hao-Wen,Zhu, Chunyin
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supporting information
p. 3636 - 3644
(2020/03/06)
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- Pd-Catalyzed Decarboxylative Olefination: Stereoselective Synthesis of Polysubstituted Butadienes and Macrocyclic P-glycoprotein Inhibitors
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The efficient and stereoselective synthesis of polysubstituted butadienes, especially the multifunctional butadienes, represents a great challenge in organic synthesis. Herein, we wish to report a distinctive Pd(0) carbene-initiated decarboxylative olefination approach that enables the direct coupling of diazo esters with vinylethylene carbonates (VECs), vinyl oxazolidinones, or vinyl benzoxazinones to afford alcohol-, amine-, or aniline-containing 1,3-dienes in moderate to high yields and with excellent stereoselectivity. This protocol features operational simplicity, mild reaction conditions, a broad substrate scope, and gram-scalability. Notably, a structurally unique allylic Pd(II) intermediate was isolated and characterized. DFT calculation and control experiments demonstrated that a rare Pd(0) carbene intermediate could be involved in this reaction. Moreover, the polysubstituted butadienes as novel building blocks were unprecedentedly assembled into macrocycles, which efficiently inhibited the P-glycoprotein and dramatically reversed multidrug resistance in cancer cells by 190-fold.
- Chen, Xiangyang,Hao, Jiping,Houk, K. N.,Li, Yingzi,Lou, Liguang,Quan, Haitian,Song, Bichao,Wang, Lu,Xia, Yuanzhi,Xie, Peipei,Xu, Zhongliang,Yang, Weibo
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supporting information
p. 9982 - 9992
(2020/06/27)
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- Visible-light-induced radical isocyanide insertion protocol for the synthesis of difluoromethylated spiro[indole-3,3′-quinoline] derivatives
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Herein, we report the first protocol for visible-light-induced radical isocyanide insertion reactions between 3-(2-isocyanobenzyl)-indoles and bromodifluoroacetates or bromodifluoroacetamides. The protocol, which has good functional group tolerance and a broad substrate scope, constitutes an efficient and general route to difluoromethylated spiro[indole-3,3′-quinoline] derivatives. This journal is
- Zhang, Jingjing,Xu, Wentao,Qu, Yi,Liu, Yuxiu,Li, Yongqiang,Song, Hongjian,Wang, Qingmin
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supporting information
p. 15212 - 15215
(2020/12/21)
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- One-pot synthesis of 2-hydroxymethylindoles: via photoredox-catalyzed ketyl-ynamide coupling/1,3-allylic alcohol transposition
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An efficient visible-light-mediated ketyl-ynamide coupling by employing ynamides bearing alkyl sulfonyl substituents to deliver eneindolin-3-ols has been developed. Subsequent 1,3-transposition of allylic alcohols in one pot is capable of synthesizing 2-hydroxymethylindoles in generally moderate to good yields. The synthetic utility of this protocol has also been demonstrated by the facile and practical synthesis of two bioactive molecules. The use of readily available substrates, a simple procedure and benign reaction conditions render this method a viable alternative for the synthesis of 2-hydroxymethylindoles. This journal is
- Chen, Yang-Bo,Wang, Kun,Wang, Ze-Shu,Xu, Zhou,Ye, Long-Wu
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supporting information
p. 4483 - 4488
(2020/08/10)
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- The immobilized Cu nanoparticles on magnetic montmorillonite (MMT?Fe3O4?Cu): As an efficient and reusable nanocatalyst for reduction and reductive-acetylation of nitroarenes with NaBH4
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In this study, the immobilization of copper nanoparticles on superparamagnetic montmorillonite, MMT?Fe3O4?Cu, was studied. Magnetically nanoparticles (MNPs) of iron oxide (Fe3O4) were primarily prepared by a chemical co-precipitation method. Next, the prepared Fe3O4 MNPs were intercalated within the interlamellar spaces and external surface of sodium-exchanged montmorillonite. Finally, Cu NPs were immobilized on magnetic montmorillonite by a simply mixing of an aqueous solution of CuCl2·2H2O with MMT?Fe3O4 followed by the reduction with NaBH4. Characterization of MMT?Fe3O4 clay system represented that through the immobilization of Fe3O4 MNPs, disordered-layers structure of MMT was easily reorganized to an ordered-layers arrangement. The synthesized composite systems were characterized using FT-IR, SEM, EDX, XRD, VSM, BET and ICP-OES analyses. SEM analysis exhibited that dispersion of Cu NPs, with the size distribution of 15–25 nm, on the surface of magnetic clay was taken place perfectly. BET surface analysis indicated that after the immobilization of Fe3O4 and Cu species, the surface area and total pore volume of MMT?Fe3O4?Cu system was decreased. Next, the Cu-clay nanocomposite system showed a perfect catalytic activity towards reduction of nitroarenes to anilines as well as reductive-acetylation of nitroarenes to acetanilides using NaBH4 and Ac2O in water as a green and economic solvent. The copper magnetic clay catalyst can be easily separated from the reaction mixture by an external magnetic field and reused for six consecutive cycles without the significant loss of its catalytic activity.
- Zeynizadeh, Behzad,Rahmani, Soleiman,Tizhoush, Hengameh
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- Enhanced catalytic activity of natural hematite-supported ppm levels of Pd in nitroarenes reduction
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In this work, Pd NPs supported on amine-modified natural hematite have been prepared and characterized. Using this simple catalyst, nitroaromatic compounds as a major cause of industrial pollution were reduced to corresponding amines with ppm levels of Pd in the presence of designer surfactant TPGS-750-M and NaBH4 at room temperature in aqueous media. Synergistic effect between hematite and Pd is responsible for the observed enhanced catalytic activity. This catalyst was recycled for at least four times with a small decrease in the activity.
- Gholinejad, Mohammad,Shojafar, Mohammad,Sansano, José M.
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p. 2033 - 2043
(2020/04/07)
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- Half-sandwich ruthenium complexes with Schiff base ligands bearing a hydroxyl group: Preparation, characterization and catalytic activities
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Three half-sandwich ruthenium(II) complexes with hydroxyl group functionalized Schiff-base ligands [Ru(p-cymene)LCl] (2a-2c) have been synthesized and characterized. All ruthenium complexes were fully characterized by 1H and 13C NMR spectra, mass spectrometry and infrared spectrometry. The molecular structure of ruthenium complex 2c was confirmed by single-crystal X-ray diffraction methods. Furthermore, these half-sandwich ruthenium complexes were found to exhibit high catalytic activity for nitro compounds reduction using NaBH4 reducing agent in the presence of cetyltrimethylammonium bromide (CTAB) in water at room temperature.
- Jia, Wei-Guo,Wang, Zhi-Bao,Zhi, Xue-Ting
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- Co/Cu bimetallic ZIF as New heterogeneous catalyst for reduction of nitroarenes and dyes
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Nowadays one of the great challenges is to design new bimetallic catalysts with enhanced catalytic activity, selectivity and recycling properties. In this work, the preparation of new Co/Cu bimetallic Zeolitic Imidazolate Framework (Co-Cu/ZIF) as an efficient catalyst for the reduction of nitro compounds and organic dyes is described. Co-Cu/ZIF was characterized with different techniques such as SEM, TEM, XRD, XPS, TGA, FT-IR and UV–vis absorption indicating formation of entirely uniform cubic particles. Using this catalyst, structurally different aromatic nitro compounds were reduced efficiently to corresponding amines in excellent yields. Kinetic studies revealed that the reduction rates of nitrophenol isomers follow 3-NP > 4-NP > 2-NP order. The catalytic activity of Co-Cu/ZIF was further investigated in the reduction of organic dyes such as methyl orange (MO) and rhodamine B (RhB). This catalyst was recycled for at least ten runs in the reduction of 4-nitrophenol without a noticeable decrease in activity and reused catalyst was characterized.
- Gholinejad, Mohammad,Naghshbandi, Zhwan,Sansano, José M.
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- Green and convenient protocols for the efficient reduction of nitriles and nitro compounds to corresponding amines with NaBH4 in water catalyzed by magnetically retrievable CuFe2O4 nanoparticles
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Abstract: In this study, firstly, CuFe2O4 nanoparticles were prepared by a simple operation. The structure of the mentioned nanoparticles was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma-optical emission spectrometry, vibrating sample magnetometer and also Brunauer–Emmett–Teller and Barrett–Joyner–Halenda analyses. The prepared magnetically copper ferrite nanocomposite was successfully applied as a simple, cost-effective, practicable, and recoverable catalyst on the green, highly efficient, fast, base-free, and ligand-free reduction of nitriles and also on the affordable and eco-friendly reduction of nitro compounds with the broad substrate scope to the corresponding amines with NaBH4 in water at reflux in high to excellent yields. Graphical abstract: [Figure not available: see fulltext.].
- Zeynizadeh, Behzad,Mohammad Aminzadeh, Farkhondeh,Mousavi, Hossein
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- Ultra-low-loading palladium nanoparticles stabilized on nanocrystalline Polyaniline (Pd@PANI): A efficient, green, and recyclable catalyst for the reduction of nitroarenes
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Ultra-low-loading Pd@PANI nanocomposites (0.048 w.t% Pd) were synthesized via a method that combined interfacial polymerization and in situ composite with camphor sulfonic acid ((+)-CSA) as a dopant. Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectra, and X-ray photoelectron spectroscopy (XPS) were performed to characterize the structures. It can be used as an efficient catalyst for the reduction of nitroarenes in aqueous solution by using a smaller amount of NaBH4 (2.5 equiv.) at room temperature with high activity (TON?=?3.4?×?103), good stability (cycled eight times), as well as wide applicability (27 substrates). The catalyst also showed a marvelous activity in the gram-level reaction (yield?=?92%). UV–Visible spectrophotometry was used to investigate the reaction kinetics for the reduction of 4-nitrophenol to 4-aminophenol, and the results reconfirmed the excellent performance of the catalyst. The unique properties and superior performance of the prepared ultra-low-loading Pd@PANI nanocomposites lead it be an attractive alternative catalyst for conventional organic catalytic applications.
- Wang, Gang,Yuan, Shuo,Wu, Zhiqiang,Liu, Wanyi,Zhan, Haijuan,Liang, Yanping,Chen, Xiaoyan,Ma, Baojun,Bi, Shuxian
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- Effect of linker and metal on photoreduction and cascade reactions of nitroaromatics by M-UiO-66 metal organic frameworks
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The use of metal organic frameworks (MOFs) as photocatalysts is a promising and growing area of research. Given the diverse architectures, linkers, and metals, it is important to understand their effects on catalysis. Herein we compare six MOFs of the UiO-66 family towards photocatalytic reduction of nitro-aromatics to anilines. These MOFs differ in metal identity (Hf, Zr) and linker, and hence this systematic study provides insights to developing next generation MOFs. We found that Hf-based MOFs are superior to the more commonly studied Zr-analogues. Moreover, the linker identity also impact the photocatalysis, with pyridine-based linkers out-performing aniline based linkers and those that lack an embedded basic site. The MOFs studied have unique selectivities for the photoreduction and also allow for the one-pot synthesis of imines from aromatic aldehydes and nitro-aromatics.
- Elkin,Saouma
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supporting information
(2019/08/30)
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- Leucine ureido derivatives as aminopeptidase N inhibitors using click chemistry. Part II
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Aminopeptidase N (APN) has been proved to be deeply associated with cancer angiogenesis, metastasis and invasion. Therefore, APN gains increasing attention as a promising anti-tumor target. In the current study, we report the design, synthesis, biological evaluation and structure-activity relationship of one new series of leucine ureido derivatives containing the 1,2,3-triazole moiety. Among them, compound 31f was identified as the best APN inhibitor with IC50 value being two orders of magnitude lower than that of the positive control bestatin. Compound 31f possessed selective cytotoxicity to several tumor cell lines over the normal cell line human umbilical vein endothelial cells (HUVECs). Notably, when combined with 5-fluorouracil (5-Fu), 31f exhibited synergistic anti-proliferation effect against several tumor cell lines. At the same concentration, 31f exhibited much better anti-angiogenesis activities than bestatin in the HUVECs capillary tube formation assay and the rat thoracic aorta rings test. In the in vitro anti-invasion assay, 31f also exhibited superior potency over bestatin. Moreover, considerable in vivo antitumor potencies of 31f alone or in combination with 5-Fu were observed without significant toxic signs in a mouse heptoma H22 tumor transplant model.
- Cao, Jiangying,Zang, Jie,Kong, Xiujie,Zhao, Chunlong,Chen, Ting,Ran, Yingying,Dong, Hang,Xu, Wenfang,Zhang, Yingjie
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p. 978 - 990
(2019/02/09)
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- Palladium-Catalyzed Regioselective Syn-Chloropalladation-Olefin Insertion-Oxidative Chlorination Cascade: Synthesis of Dichlorinated Tetrahydroquinolines
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A palladium catalyzed cascade process involving syn-chloropalladation, intramolecular olefin insertion, and oxidative C-Cl bond formation reactions was demonstrated for the synthesis of dichlorinated tetrahydroquinolines in high yields (up to 93%). The N-propargyl arylamines having a tethered α,β-unsaturated carbonyl moiety underwent a regioselective syn-chloropalladation followed by a Heck-type reaction to deliver the tetrahydroquinoline scaffold. The rare insertion of the second chlorine atom was rationalized comprising a PdII/IV catalytic cycle and oxidative cleavage of the C-PdII bond.
- Vinoth, Perumal,Karuppasamy, Muthu,Vachan,Muthukrishnan, Isravel,Maheswari, C. Uma,Nagarajan, Subbiah,Pace, Vittorio,Roller, Alexander,Bhuvanesh, Nattamai,Sridharan, Vellaisamy
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- Palladium Nanoparticles on a Creatine-Modified Bentonite Support: An Efficient and Sustainable Catalyst for Nitroarene Reduction
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Creatine as the nitrogen-rich, green and cheap compound is used for modification of natural bentonite and the resulting material is employed for the stabilization of Palladium nanoparticles having an average diameter of 3 nm. This new material bento-crt@Pd is characterized using different techniques such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), solid state UV-vis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and energy-dispersive X-ray spectroscopy (EDX). This green catalyst promotes efficient reduction of aromatic nitro compounds in aqueous media. By using this catalyst nitroarenes having electron donating as well as electron withdrawing groups were reduced efficiently to their corresponding amines at room temperature. The catalyst can be recycled seven times and the reused catalyst was characterized by TEM and XPS.
- Gholinejad, Mohammad,Rasouli, Zahra,Najera, Carmen,Sansano, José M.
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p. 1122 - 1129
(2019/09/06)
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- Direct Access to 9-Chloro-1 H-benzo[ b]furo[3,4- e]azepin-1-ones via Palladium(II)-Catalyzed Intramolecular syn-Oxypalladation/Olefin Insertion/sp2-C-H Bond Activation Cascade
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An efficient Pd(II)-catalyzed cascade approach was established for the synthesis of 9-chloro-1H-benzo[b]furo[3,4-e]azepin-1-ones starting from N-propargyl arylamines having a pendant α,β-unsaturated ester scaffold. The mechanism of this sequential process involved intramolecular syn-oxypalladation followed by olefin insertion and ortho sp2-C-Cl bond formation reactions. This high atom- and step-economical cascade sequence generated two heterocycle rings and three new bonds in a single synthetic operation.
- Karuppasamy, Muthu,Vachan,Vinoth, Perumal,Muthukrishnan, Isravel,Nagarajan, Subbiah,Ielo, Laura,Pace, Vittorio,Banik, Subrata,Maheswari, C. Uma,Sridharan, Vellaisamy
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p. 5784 - 5788
(2019/08/26)
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- Synergistic Effects of ppm Levels of Palladium on Natural Clinochlore for Reduction of Nitroarenes
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Augmenting the modified naturally occurring clay clinochlore with ppm amounts of palladium leads to a new and very effective reagent for the reduction of numerous aromatic nitro species. When palladium nanoparticles are supported on pyridyltriazole-modified clinochlore, iron within clinochlore acts synergistically with palladium to catalyze the reduction of a wide variety of nitroarenes at room temperature in aqueous media. Based on E-factor calculations, the catalyst system is found to be in line with green chemistry standards and can be recycled up to five times.
- Gholinejad, Mohammad,Oftadeh, Erfan,Shojafar, Mohammad,Sansano, José M.,Lipshutz, Bruce H.
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p. 4240 - 4248
(2019/09/06)
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- The reductive deaminative conversion of nitriles to alcohols using: Para -formaldehyde in aqueous solution
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We report herein, for the first time, the application of para-formaldehyde (pFA) to the reductive deamination of both aliphatic and aromatic nitriles in aqueous solution under transfer hydrogenation conditions. A broad range of primary alcohols have been synthesized selectively with very good to excellent yields under the optimized conditions. The study disclosed that the air-stable, inexpensive and commercially available catalyst [Ru(p-cymene)Cl2]2 acts as the catalyst precursor in this reaction, converting to other more active catalytic species in the presence of pFA, resulting in its degradation to CO2 and H2. Nitriles are also showed to play a dual role in this transformation, both as a substrate and as a ligand, where the dimeric catalyst structures convert to monomeric ones upon the coordination of nitrile molecules.
- Tavakoli, Ghazal,Prechtl, Martin H. G.
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p. 6092 - 6101
(2019/11/11)
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- Benzoazepine-Fused Isoindolines via Intramolecular (3 + 2)-Cycloadditions of Azomethine Ylides with Dinitroarenes
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Aminobenzaldehydes bearing a pendant 3,5-dinitrophenyl group react thermally with N-substituted α-amino acids to form unprecedented benzoazepine-fused isoindolines. The reaction proceeds via a dearomatization/rearomatization sequence involving an intramolecular (3 + 2)-cycloaddition between the in situ formed azomethine ylide and the dinitroarene. Various glycine derivatives are tolerated as well as branched substrates based on cyclic, α-mono-, and α,α-disubstituted amino acids, giving single diastereomers in many cases. The method is scalable and gives products with a nitro group ready for further manipulation.
- Wales, Steven M.,Rivinoja, Daniel J.,Gardiner, Michael G.,Bird, Melissa J.,Meyer, Adam G.,Ryan, John H.,Hyland, Christopher J. T.
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supporting information
p. 4703 - 4708
(2019/06/27)
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- Asymmetric [4+2] cycloaddition of azlactones with dipolar copper–allenylidene intermediates for chiral 3,4-dhydroquinolin-2-one derivatives
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In this paper, a pybox-copper catalyzed enantioselective decarboxylative [4+2] cycloaddition reaction of ethynyl benzoxazinanones with azlactones has been developed, which provides optically active 3,4-dihydroquinolin-2-ones in high yields with good enantioselectivities and diastereoselectivities. In this transformation, the chiral dipolar copper–allenylidene intermediates are kinetically generated via decarboxylative ethynyl benzoxazinanones, followed by the attack of the enolate azlactones to form enantiomerically enriched 3,4-dihydroquinolin-2-one structures.
- Sun, Bing-Bing,Hu, Qing-Xian,Hu, Jia-Ming,Yu, Jie-Qiang,Jia, Jun,Wang, Xing-Wang
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supporting information
p. 1967 - 1970
(2019/06/27)
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- A new bifunctional heterogeneous nanocatalyst for one-pot reduction-Schiff base condensation and reduction-carbonylation of nitroarenes
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In this work, synthesis of Pd-NHC-γ-Fe2O3-n-butyl-SO3H and its activity as a bifunctional heterogeneous nanocatalyst containing Pd-NHC and acidic functional groups, are described. This newly synthesized nanomagnetic catalyst is fully characterized by different methods such as FT-IR, XPS, TEM, VSM, ICP and TG analysis. At first, the catalytic activity of Pd-NHC-γ-Fe2O3-n-butyl-SO3H is evaluated for the reduction of nitroarenes in aqueous media using NaBH4 as a clean source of hydrogen generation at ambient temperature. Using the promising results obtained from the nitroarene reduction, this catalytic system is used for two one-pot protocols including reduction-Schiff base condensation and reduction-carbonylation of various nitroarenes. In these reactions the in situ formed amines are further reacted with aldehydes to yield imines or carbonylated to amides. The desired products are obtained in good to high yields in the presence of Pd-NHC-γ-Fe2O3-n-butyl-SO3H as a bifunctional catalyst. The catalyst is reused with the aid of a magnetic bar for up to six consecutive cycles without any drastic loss of its catalytic activity.
- Sobhani, Sara,Chahkamali, Farhad Omarzehi,Sansano, José Miguel
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p. 1362 - 1372
(2019/01/24)
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- Starch functionalized creatine for stabilization of gold nanoparticles: Efficient heterogeneous catalyst for the reduction of nitroarenes
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Selective reduction of nitroaromatic pollutants into amines with recoverable and reusable heterogeneous catalysts is highly desirable. Herein, we prepared and characterized an efficient novel catalyst comprising 4 nm size Au nanoparticles supported on creatine modified starch. Using this catalyst, efficient reduction of nitroarenes into amines at room temperature in aqueous media was achieved. The presence of creatine in the structure of the catalyst plays important role in amount of Au loading, efficiency of the catalyst, recycling times, and leaching of Au compared to starch supported Au without creatine.
- Gholinejad, Mohammad,Dasvarz, Neda,Shojafar, Mohammad,Sansano, José M.
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- Sequential Phosphine-Catalyzed [4 + 2] Annulation of β′-Acetoxy Allenoates: Enantioselective Synthesis of 3-Ethynyl-Substituted Tetrahydroquinolines
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The first enantioselective sequential phosphine-catalyzed (SPC as abbreviation) mode for the formation of tetrahydroquinolines with an ethynyl-substituted all-carbon quaternary stereogenic center is reported. In this SPC process, a novel [4 + 2] annulation process was devised employing α-substituted allenoates as C2 synthons (α-β′, 1,2-dipole) for the first time. 3-Ethynyl-substituted tetrahydroquinolines were readily prepared in good yields and high enantioselectivities.
- Zhang, Qinglong,Jin, Hongxing,Feng, Jiaxu,Zhu, Yannan,Jia, Penghao,Wu, Chengzhou,Huang, You
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supporting information
p. 1407 - 1411
(2019/03/07)
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- Hydrogenation of nitroaromatics to anilines catalyzed by air-stable arene ruthenium (II)–NNN pincer complexes
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A series of air-stable, phosphine-free arene ruthenium (II)–NNN pincer complexes (RuL, RuL1, RuL2 and RuL3) have been synthesized and characterized by spectroscopic and single-crystal X-ray analysis. Further, arene ruthenium (II)–NNN pincer complexes have been used as catalyst for hydrogenation of nitroaromatics into aniline in the presence of NaBH4 at room temperature. The catalytic process suggested highly chemo-selective nitroreduction with wide functional group tolerance.
- Pitchaimani, Jayaraman,Gunasekaran, Nanjappan,Anthony, Savarimuthu Philip,Moon, Dohyun,Madhu, Vedichi
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- Synthesis, Characterization, and Catalytic Activities of Palladium Complexes with Phenylene-Bridged Bis(thione) Ligands
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The neutral phenylene-bridged bis(thione) compounds, 1,3-bis(3′-ethylimidazolyl-2′-thione)benzene (Betb), 1,3-bis(3′-butylimidazolyl-2′-thione)benzene (Bbtb), and 1,3-bis(3′-allylimidazolyl-2′-thione)benzene (Batb), have been synthesized and characterized. Reactions of palladium precursor PdCl2(CH3CN)2 with phenylene-bridged bis(thione) ligands in 1:2 ratio resulted in the formation of the complexes: PdCl2(L)2 (L = Betb, 3a; L = Bbtb, 3b; L = Batb, 3c, respectively). In contrast, treatment of the ligands with PdCl2(CH3CN)2 in 1:1 ratio gave cyclometalation palladium complexes Pd2+Cl(L-) (L = Betb-H, 4a; L = Bbtb-H, 4b; L = Batb-H, 4c) through the metal-induced C-H activation. Complexes 4a-c can also be obtained by the reaction of bis(thione) ligands and PdCl2 in 1:1 ratio. The reaction of 3a-c with additional PdCl2(CH3CN)2 also afforded complexes 4a-c. All ligands and palladium complexes were fully characterized by one-/two-dimensional NMR spectra, mass spectrometry, and infrared spectrometry. And the molecular structures of 3a-c, 4a, and 4c have been determined by the single-crystal X-ray diffraction method. Furthermore, the detailed spectroscopic properties and catalytic activities of the complexes for the reduction of nitro compounds were discussed in terms of the modification of the coordination ligands to the center metal.
- Jia, Wei-Guo,Gao, Li-Li,Wang, Zhi-Bao,Sun, Li-Ying,Han, Ying-Feng
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p. 1946 - 1954
(2019/05/08)
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- Novel leucine ureido derivatives as aminopeptidase N inhibitors using click chemistry
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The over-expression of aminopeptidase N on diverse malignant cells is associated with the tumor angiogenesis and metastasis. In this report, one new series of leucine ureido derivatives containing the triazole moiety was designed, synthesized and evaluated as APN inhibitors. Among them, compound 13v showed the best APN inhibition with an IC50 value of 0.089 ± 0.007 μM, which was two orders of magnitude lower than that of bestatin (IC50 = 9.4 ± 0.5 μM). Compound 13v also showed dose-dependent anti-angiogenesis activities. Even at the lower concentration (10 μM), compound 13v presented similar anti-angiogenesis activity compared with bestatin at 100 μM in both the human umbilical vein endothelial cells (HUVECs) capillary tube formation assay and the rat thoracic aorta rings test. Moreover, compared with bestatin, 13v exhibited comparable, if not better in vivo anti-metastasis activity in a mouse H22 pulmonary metastasis model.
- Cao, Jiangying,Ma, Chunhua,Zang, Jie,Gao, Shuai,Gao, Qianwen,Kong, Xiujie,Yan, Yugang,Liang, Xuewu,Ding, Qin'ge,Zhao, Chunlong,Wang, Binghe,Xu, Wenfang,Zhang, Yingjie
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p. 3145 - 3157
(2018/06/01)
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- Visible-Light-Driven Chemoselective Hydrogenation of Nitroarenes to Anilines in Water through Graphitic Carbon Nitride Metal-Free Photocatalysis
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Green and efficient procedures are essential for the chemoselective hydrogenation of functionalized nitroarenes to form industrially important anilines. Herein, it is shown that visible-light-driven, chemoselective hydrogenation of functionalized nitroarenes with groups sensitive to forming anilines can be achieved in good to excellent yields (82–100 %) in water under relatively mild conditions and catalyzed by low-cost and recyclable graphitic carbon nitride. The process is also applicable to gram-scale reaction, with a yield of aniline of 86 %. A study of the mechanism reveals that visible-light-induced electrons are responsible for the hydrogenation reactions, and thermal energy can also promote the photocatalytic activity. A study of the kinetics shows that this reaction possibly occurs through one-step hydrogenation or stepwise condensation routes. A wide range of applications can be expected for this green, efficient, and highly selective photocatalysis system in reduction reactions for the synthesis of fine chemicals.
- Xiao, Gang,Li, Peifeng,Zhao, Yilin,Xu, Shengnan,Su, Haijia
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supporting information
p. 1950 - 1955
(2018/07/31)
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- Controlled Transformations of Aryl Halides in a Flow System: Selective Synthesis of Aryl Azides and Aniline Derivatives
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Copper-mediated nitrogenation of aryl halides with sodium azide can result in either aryl azides or aniline derivatives. The selectivity of the transformation is highly dependent on reaction time and temperature, which led to contradictory literature results with respect to product selectivity and the conditions applied. The advantages of a strictly controlled flow reactor environment were exploited in order to facilitate selective haloarene transformations. Reaction conditions were carefully investigated to understand their role on product selectivity. Aryl azides and aryl amines were successfully prepared from the same starting materials using the same auxiliaries by means of precise control over residence time and reaction temperature, thereby ensuring time-, cost- and atom-efficient syntheses. (Figure presented.).
- Georgiádes, ádám,?tv?s, Sándor B.,Fül?p, Ferenc
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p. 1841 - 1849
(2018/04/09)
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- Highly Diastereoselective Synthesis of Trifluoromethyl Indolines by Interceptive Benzylic Decarboxylative Cycloaddition of Nonvinyl, Trifluoromethyl Benzoxazinanones with Sulfur Ylides under Palladium Catalysis
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A highly diastereoselective synthesis of trifluoromethyl-substituted indolines under palladium catalysis is disclosed. The reaction proceeds by interceptive decarboxylative benzylic cycloaddition (IDBC) of nonvinyl, trifluoromethyl benzoxazinanones with sulfur ylides. The palladium-π-benzyl zwitterionic intermediates are suggested for this transformation, and this would be the first example of an IDBC reaction.
- Punna, Nagender,Das, Pulakesh,Gouverneur, Véronique,Shibata, Norio
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supporting information
p. 1526 - 1529
(2018/03/23)
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- A [4 + 3] Annulation Reaction of aza- o-Quinone Methides with Arylcarbohydrazonoyl Chlorides for Synthesis of 2,3-Dihydro-1 H-benzo[ e][1,2,4]triazepines
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An unprecedented [4 + 3] annulation reaction of aza-ortho-quinone methides with arylcarbohydrazonoyl chlorides has been achieved under mild conditions. The annulation underwent a sequential conjugate addition/intramolecular annulation/rearrangement, providing a useful method for the synthesis of biologically interesting 2,3-dihydro-1H-benzo[e][1,2,4]triazepine.
- Guo, Zhenyan,Jia, Hao,Liu, Honglei,Wang, Qijun,Huang, Jiaxing,Guo, Hongchao
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supporting information
p. 2939 - 2943
(2018/05/28)
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- Enantioselective Construction of Tetrahydroquinazoline Motifs via Palladium-Catalyzed [4 + 2] Cycloaddition of Vinyl Benzoxazinones with Sulfamate-Derived Cyclic Imines
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A palladium-catalyzed enantioselective [4 + 2] cycloaddition reaction of vinyl benzoxazinones with sulfamate-derived cyclic imines is described, affording the tetrahydroquinazolines bearing several functional rings in high yields (up to 99% yield) with good to excellent diastereoselectivities and excellent enantioselectivities (up to 96% ee). This reaction represents the first Pd-catalyzed asymmetric decarboxylative cycloaddition of vinyl benzoxazinones with imines.
- Wang, Chang,Li, Yan,Wu, Yang,Wang, Qijun,Shi, Wangyu,Yuan, Chunhao,Zhou, Leijie,Xiao, Yumei,Guo, Hongchao
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supporting information
p. 2880 - 2883
(2018/05/29)
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- Phosphine-Catalyzed Reaction between 2-Aminobenzaldehydes and Dialkyl Acetylenedicarboxylates: Synthesis of 1,2-Dihydroquinoline Derivatives and Toward the Development of an Olefination Reaction
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A series of 1,2-dihydroquinolines were synthesized in good to excellent yields by reacting 2-aminobenzaldehyde derivatives and dialkyl acetylenedicarboxylates with catalytic amounts of phosphine. This reaction was rendered catalytic by the selective in situ phosphine oxide reduction with the use of phenylsilane. Furthermore, with the same starting materials and with an additional role of the reducing agent, a new olefination reaction was discovered. Hydrogen/deuterium (H/D) exchange experiments revealed the possible mechanism of this reaction.
- Han, Xu,Saleh, Nidal,Retailleau, Pascal,Voituriez, Arnaud
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supporting information
p. 4584 - 4588
(2018/08/09)
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- Pd-Catalyzed Three-Component Domino Reaction of Vinyl Benzoxazinanones for Regioselective and Stereoselective Synthesis of Allylic Sulfone-Containing Amino Acid Derivatives
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A Pd-catalyzed, highly regioselective and stereoselective three-component domino allylic substitution/N-H carbene insertion reaction under mild conditions is described. This reaction demonstrates a wide substrate scope and satisfactory functional group tolerance, providing a broad range of allylic sulfone-containing amino acid derivatives. Moreover, DBU mediates highly diastereoselective cross-dehydrogenative coupling annulation of allylic sulfones without using peroxides or any metal oxidants. This developed protocol affords 7-membered ring heterocyclic compounds incorporating both sulfone-containing amino acid esters and one quaternary carbon center. Mechanistic studies indicate that an unusual umpolung of glycine occurred in this annulation.
- Hao, Jiping,Xu, Yi,Xu, Zhongliang,Zhang, Zhiqiang,Yang, Weibo
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supporting information
p. 7888 - 7892
(2019/01/04)
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- Simple and Practical Synthesis of Various New Nickel Boride-Based Nanocomposites and their Applications for the Green and Expeditious Reduction of Nitroarenes to Arylamines under Wet-Solvent-Free Mechanochemical Grinding
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In this paper, we report a simple synthesis of four new nickel boride-based nanocomposites, namely Ni2B@ZrCl4, Ni2B@Cu2O, Ni2B@CuCl2 and Ni2B@FeCl3, from commercially available and cheap starting materials. All of the new Ni2B-based nanocomposites were well characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Further, the catalytic applications of these new nanocomposites were successfully evaluated in the wet-solvent-free reduction of aromatic nitro compounds to arylamines with sodium borohydride (NaBH4) at room temperature by a mechanochemical grinding technique. All the introduced catalytic systems provide excellent yields of arylamines in very short reaction times for a wide range of substrates. Also, recoverability and reusability of the new nanocomposites were investigated.
- Mousavi, Hossein,Zeynizadeh, Behzad,Younesi, Reza,Esmati, Mozhgan
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p. 595 - 609
(2018/09/10)
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