- Spatially orthogonal chemical functionalization of a hierarchical pore network for catalytic cascade reactions
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The chemical functionality within porous architectures dictates their performance as heterogeneous catalysts; however, synthetic routes to control the spatial distribution of individual functions within porous solids are limited. Here we report the fabrication of spatially orthogonal bifunctional porous catalysts, through the stepwise template removal and chemical functionalization of an interconnected silica framework. Selective removal of polystyrene nanosphere templates from a lyotropic liquid crystal-templated silica sol-gel matrix, followed by extraction of the liquid crystal template, affords a hierarchical macroporous-mesoporous architecture. Decoupling of the individual template extractions allows independent functionalization of macropore and mesopore networks on the basis of chemical and/or size specificity. Spatial compartmentalization of, and directed molecular transport between, chemical functionalities affords control over the reaction sequence in catalytic cascades; herein illustrated by the Pd/Pt-catalysed oxidation of cinnamyl alcohol to cinnamic acid. We anticipate that our methodology will prompt further design of multifunctional materials comprising spatially compartmentalized functions.
- Parlett, Christopher M.A.,Isaacs, Mark A.,Beaumont, Simon K.,Bingham, Laura M.,Hondow, Nicole S.,Wilson, Karen,Lee, Adam F.
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- Synthesis and Structures of Ti-Pd Heterobimetallic Complexes
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Heterobimetallic complexes containing titanium and palladium were prepared from O,N,O-N,N multidentate ligands. The ligands each contained an O,N,O-tridentate part based on a 2,6-lutidine scaffold and an N,N-bidentate di(pyridin-2-yl) part. The O,N,O-moiety selectively coordinated to a titanium atom on treatment with titanium(tetraisopropoxide), although one of the di(pyridin-2-yl) groups in the N,N-moiety coordinated to the titanium atom. The N,N-bidentate di(pyridin-2-yl) moiety coordinated to the palladium atom on treatment with bis(benzonitrile)palladium(II) chloride to afford a heterobimetallic complex. The dynamic behavior of the complexes in solution was studied by NMR spectroscopy. Heterobimetallic complexes containing titanium and palladium were prepared from O,N,O-N,N multidentate ligands and structurally characterized.
- Suzuki, Noriyuki,Haraga, Kenji,Shimamura, Tatsuki,Masuyama, Yoshiro
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- Synthesis and characterization of two new molten acid salts: Safe and greener alternatives to sulfuric acid for the hydrolytic conversion of 1,1,1,3-tetrachloro-3-phenylpropane to cinnamic acid
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Available online Two new acid salts were synthesized, and their chemical structures were characterized by various spectra data analyses. Although 1H NMR did not show acid proton of [HSO4]?, the FTIR spectra of molten acid salts act as key support to approve of their chemical structures. The structure elucidation of the molten acid salts demonstrated the existence of 4,4?-trimethylene-N,N?-dipiperidinium dication with sulfate and hydrogen sulfate anion(s). Thus, sulfuric acid can act as a diprotic or monoprotic Br?nsted acid when it is treated by a secondary amine regarding the initial mole ratio of sulfuric acid and amine. Also, the catalytic activity of these molten acid salts was investigated for the hydrolytic conversion of (1,3,3,3-tetrachloropropyl)benzene to cinnamic acid. The desired product was obtained in 88 ± 2.0% yield under optimal conditions. The molten acid salts were high recyclable and their chemical structure and catalytic efficiency showed no significant change even after the 5th run. Furthermore, TMDP-SA (1:1) showed a much weaker corrosive property compared with TMDP-SA (1:2) and SA (98%), and the surface of stainless steel was intact even after 24 h. This fact and the acidity of two molten acid salts also confirm the proposed chemical structures.
- Gorjian, Hayedeh,Johan, Mohd Rafie,Khaligh, Nader Ghaffari,Zaharani, Lia
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- Synthesis, characterization and catalytic oxidation property of copper(I) complexes containing monodentate acylthiourea ligands and triphenylphosphine
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The reactions between [CuCl2(PPh3)2] and 3,3-diphenyl-1-(2,4-dichlorobenzoyl)thiourea (HL1), 3,3-diisobutyl-1-(2,4-dichlorobenzoyl)thiourea (HL2) or 3,3-diethyl-1-(2,4-dichlorobenzoyl)thiourea (HL3) in benzene gave new four-coordinated tetrahedral copper(I) complexes of the type [CuCl(HL)(PPh3)2] (1–3) [HL = 3,3-dialkyl/aryl-1-(2,4-dichlorobenzoyl)thiourea derivatives]. These complexes were then characterized by analytical and spectroscopic (IR, UV/Vis,1H,13C and31P NMR) techniques. The molecular structure of a representative complex, [CuCl(HL1)(PPh3)2] (1), was determined by the single crystal X-ray diffraction method which reveals a distorted tetrahedral geometry around the Cu(I) ion. The complexes 1–3 (0.007 mmol) were found to be active catalysts for the oxidation of primary and secondary alcohols 5.0 mmol to their corresponding acids and ketones, respectively, in the presence of hydrogen peroxide (6.0 mmol) in 1-butyl-3-methylimidazolium hexafluorophosphate {[bmim][PF6]} (0.1 mL) without any additive and base, at 70 °C.
- Gunasekaran,Bhuvanesh,Karvembu
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- Robust Fe3O4/SiO2-Pt/Au/Pd magnetic nanocatalysts with multifunctional hyperbranched polyglycerol amplifiers
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Here we report a facile approach to prepare multicarboxylic hyperbranched polyglycerol (HPG)-grafted SiO2-coated iron oxide (Fe 3O4/SiO2) magnetic hybrid support. This support combined the both features of Fe3O4 and HPG, facile magnetic separation, and favorable molecular structure with numerous functional groups. With the use of the grafted-HPGs as templates, various noble metal nanocatalysts such as Pt, Au, and Pd were directly grown on the surfaces of magnetic support with ultrasmall and nearly monodisperse sizes (e.g., the average sizes of Pt, Au, and Pd are 4.8 ± 0.5, 6.0 ± 0.6, and 4.0 ± 0.4 nm, respectively) and high coverage densities. Because of the amplification effect of HPG, high loading capacities of the nanocatalysts, around 0.296, 0.243, and 0.268 mmol/g for Pt, Au, and Pd, respectively, were achieved. Representative catalytic reactions including reduction of 4-nitrophenol, alcohol oxidation, and Heck reaction demonstrated the high catalytic activity of the noble metal nanocatalysts. Because of the stabilization of HPG templates, the nanocatalysts can be readily recycled by a magnet and reused for the next reactions with high efficiencies. The robust multifunctional magnetic hybrids will find important applications in catalysis and other fields such as drug delivery and bioseparations.
- Zhou, Li,Gao, Chao,Xu, Weijian
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- Amine grafting on coordinatively unsaturated metal centers of MOFs: Consequences for catalysis and metal encapsulation
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(Figure Presented) The coordinatively unsaturated sites in MIL-101, Cr 3(F,OH)(H2O)2O[(O2C)-C 6H4(CO2)]3·nH2O (n≈25), having zeotypic giant pores can be selectively functionalized in a way differing from that of mesoporous silica. Metal-organic frameworks, grafted with ethylenediamine or diethylenetriamine on the unsaturated CrIII sites of MIL-101, exhibit remarkably high activities in the Knoevenagel condensation relative to that of the mesophase.
- Hwang, Young Kyu,Hong, Do-Young,Chang, Jong-San,Jhung, Sung Hwa,Seo, You-Kyong,Kim, Jinheung,Vimont, Alexandre,Daturi, Marco,Serre, Christian,Ferey, Gerard
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- Post-synthesis functionalization of MIL-101 using diethylenetriamine: A study on adsorption and catalysis
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An effective metal organic framework (MOF) catalyst (DETA-MIL-101) was prepared by grafting an electron-rich triamine functional group to the open metal sites in MIL-101. The samples were characterized via XRD, FT-IR, and N2 adsorption-desorption measurements, and their N content was measured using EA. The CO2 and H2O adsorption-desorption properties were measured and compared with those of non-functionalized MIL-101. Their catalytic performances in the Knoevenagel condensation between benzaldehyde and malononitrile were examined, and the catalyst stabilities were confirmed using recycling and hot filtering experiments. Finally, the Pd 2+ ions (0.5, 1.0, and 3.0 wt%) were immobilized onto the amine species that were grafted to the MIL-101 using PdCl2 and were tested for Heck reactions of the acrylic acid and iodobenzene in N,N-dimethylacetamide as a solvent with triethylamine additives as a function of time. The catalyst stability was re-established via recycling and hot filtering experiments.
- Kim, Se-Na,Yang, Seung-Tae,Kim, Jun,Park, Ji-Eun,Ahn, Wha-Seung
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- Platinum catalysed aerobic selective oxidation of cinnamaldehyde to cinnamic acid
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Aerobic selective oxidation of allylic aldehydes offers an atom and energy efficient route to unsaturated carboxylic acids, however suitable heterogeneous catalysts offering high selectivity and productivity have to date proved elusive. Herein, we demonstrate the direct aerobic oxidation of cinnamaldehyde to cinnamic acid employing silica supported Pt nanoparticles under base-free, batch and continuous flow operation. Surface and bulk characterisation of four families of related Pt/silica catalysts by XRD, XPS, HRTEM, CO chemisorption and N2 porosimetry evidence surface PtO2 as the common active site for cinnamaldehyde oxidation, with a common turnover frequency of 49,000 ± 600 h-1; competing cinnamaldehyde hydrogenolysis is favoured over metallic Pt. High area mesoporous (SBA-15 or KIT-6) and macroporous-mesoporous SBA-15 silicas confer significant rate and cinnamic acid yield enhancements versus low area fumed silica, due to superior platinum dispersion. High oxygen partial pressures and continuous flow operation stabilise PtO2 active sites against in-situ reduction and concomitant deactivation, further enhancing cinnamic acid productivity.
- Durndell, Lee J.,Cucuzzella, Costanza,Parlett, Christopher M.A.,Isaacs, Mark A.,Wilson, Karen,Lee, Adam F.
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- Cascade Aerobic Selective Oxidation over Contiguous Dual-Catalyst Beds in Continuous Flow
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Cascade reactions represent an atom-economical and energy-efficient technology by which to reduce the number of manipulations required for chemical manufacturing. Biocatalytic cascades are ubiquitous in nature; however, controlling the sequence of interactions between reactant, intermediate(s), and active sites remains a challenge for chemocatalysis. Here, we demonstrate an approach to achieve efficient cascades using chemical catalysts through flow chemistry. Close-coupling of Pd/SBA-15 and Pt/SBA-15 heterogeneous catalysts in a dual bed configuration under continuous flow operation affords a high single pass yield of 84% (a 20-fold enhancement over batch operation) and high stability for >14000 turnovers in the cascade oxidation of cinnamyl alcohol to cinnamic acid, despite both catalysts being individually inactive for this reaction. Judicious ordering of Pd (first bed) and Pt (second bed) catalysts is critical to promote cascade oxidation with respect to undesired hydrogenation and hydrogenolysis, the latter favored over the reverse-bed sequence or a single mixed PdPt reactor bed. The intrinsic catalytic performance of each bed is preserved in the optimal dual-bed configuration, enabling quantitative prediction of final product yields for reactants/intermediates whose individual oxidation behavior is established. Continuous processing using contiguous reactor beds enables plug-and-play design of cascades employing "simple" catalysts.
- Durndell, Lee J.,Isaacs, Mark A.,Li, Chao'En,Parlett, Christopher M. A.,Wilson, Karen,Lee, Adam F.
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- Coordinative Role of Alkali Cations in Organic Reactions.V. The Perkin Reaction
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The Perkin condensation of benzaldehyde (PhCHO) and acetic anhydride (Ac2O) in the presence of an alkali acetate (M+OAc-) involves extensive participation of M+ and take place best with K+OAc-.Employing an excess of meticulousy dehydrated K+OAc-, a record high yield of cinnamic acid (ca.75percent) can be obtained in a 60 min reaction.The product of the reaction before hydrolysis is not PhCH=CHCOOCOCH3 as usually believed but potassium cinnamate plus K+(OAc,HOAc)-.Conductometric solution stability studies on M+-ligand (M+=Na+ and K+; Ligand=PhCHO, o-NO2C6H4CHO,o-HOC6H4CHO) systems in 2-propanol show that stabilty sequences for PhCHO and o-NO2C6H4CHO are NaOAc+OAc- in 2-propanol.
- Poonia, Narinder S.,Sen, Swagata,Porwal, Prafulla K.,Jayakumar, A.
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- The influence of cyclomaltooligosaccharides (cyclodextrins) on the enzymatic decomposition of L-phenylalanine catalyzed by phenylalanine ammonia-lyase
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Cyclomaltohexaose (α-cyclodextrin) and cyclomaltoheptaose (β-cyclodextrin) as well as their four methyl ether derivatives, that is, hexakis(2,3-di-O-methyl)cyclomaltohexaose, hexakis(2,3,6-tri-Omethyl) cyclomaltohexaose, heptakis(2,3-di-O-methyl)cyclomaltoheptaose, and heptakis(2,3,6-tri-Omethyl) cyclomaltoheptaose were investigated as the additives in the course of enzymatic decomposition of L-phenylalanine catalyzed by phenylalanine ammonia-lyase. Only a few of those additives behaved like classical inhibitors of the enzymatic reaction under investigation because the values of the Michaelis constants that were obtained, as well as the maximum velocity values depended mostly atypically on the concentrations of those additives. In most cases cyclodextrins caused mixed inhibition, both competitive and noncompetitive, but they also acted as activators for selected concentrations. This atypical behaviour of cyclodextrins is caused by three different and independent effects. The inhibitory effect of cyclodextrins is connected with the decrease of substrate concentration and unfavourable influence on the flexibility of the enzyme molecules. On the other hand, the activating effect is connected with the decrease of product concentration (the product is an inhibitor of the enzymatic reaction under investigation). All these effects are caused by the ability of the cyclodextrins to form inclusion complexes.
- Gubica, Tomasz,Pelka, Agnieszka,Palka, Katarzyna,Temeriusz, Andrzej,Kanska, Marianna
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- Cleavage of Carboxylic Esters by Aluminum and Iodine
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A one-pot procedure for deprotecting carboxylic esters under nonhydrolytic conditions is described. Typical alkyl carboxylates are readily deblocked to the carboxylic acids by the action of aluminum powder and iodine in anhydrous acetonitrile. Cleavage of lactones affords the corresponding ω-iodoalkylcarboxylic acids. Aryl acetylates undergo deacetylation with the participation of the neighboring group. This method enables the selective cleavage of alkyl carboxylic esters in the presence of aryl esters.
- Sang, Dayong,Yue, Huaxin,Fu, Yang,Tian, Juan
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p. 4254 - 4261
(2021/03/09)
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- An efficient heterogeneous Cu(I) complex for the catalytic oxidation of alcohols and sulfides: synthesis, characterization, and investigation of the catalyst activity
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A heterogeneous Cu(I) complex was synthesized by reaction of C5H4NC(O)NHP(O)[NHC(CH3)3]2 (L) with CuCl and used as a catalyst for green oxidation of aromatic alcohols and sulfides. According to the characterization results obtained from 31P NMR, UV-Vis, FT-IR, mass, XRD, elemental analysis, and molar conductivity techniques, the chemical formula of the complex (1) was suggested as [CuClL2]. Parameters on the catalytic activity (reaction temperature, the substrate to oxidant molar ratio, catalyst amount, and solvent type) were optimized, using H2O2 as a green oxidant, and excellent conversion amounts (100%) were achieved under optimal conditions. Moreover, the generality and recyclability of the catalyst were tested and confirmed. A comparison between the oxidation results of the alcohol and sulfide in the presence of 1 with other catalysts indicated that in most cases 1 showed better efficiency, in a more reasonable reaction time and conditions.
- Oroujzadeh, Nasrin,Baradaran, Zahra,Sedrpoushan, Alireza
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p. 2344 - 2364
(2021/08/06)
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- Ligand-controlled divergent dehydrogenative reactions of carboxylic acids via C–H activation
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Dehydrogenative transformations of alkyl chains to alkenes through methylene carbon-hydrogen (C–H) activation remain a substantial challenge. We report two classes of pyridine-pyridone ligands that enable divergent dehydrogenation reactions through palladium-catalyzed b-methylene C–H activation of carboxylic acids, leading to the direct syntheses of a,b-unsaturated carboxylic acids or g-alkylidene butenolides. The directed nature of this pair of reactions allows chemoselective dehydrogenation of carboxylic acids in the presence of other enolizable functionalities such as ketones, providing chemoselectivity that is not possible by means of existing carbonyl desaturation protocols. Product inhibition is overcome through ligand-promoted preferential activation of C(sp3)–H bonds rather than C(sp2)–H bonds or a sequence of dehydrogenation and vinyl C–H alkynylation. The dehydrogenation reaction is compatible with molecular oxygen as the terminal oxidant.
- Wang, Zhen,Hu, Liang,Chekshin, Nikita,Zhuang, Zhe,Qian, Shaoqun,Qiao, Jennifer X.,Yu, Jin-Quan
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p. 1281 - 1285
(2021/12/10)
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- Synthesis, in vitro cytotoxicity, and molecular docking study of novel 3,4-dihydroisoquinolin-1(2H)-one based piperlongumine analogues
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With the aim of expanding the scope of SAR on piperlongumine (PL), a naturally occurring anticancer molecule, we have designed a novel hybrid molecule bearing 3,4-dihydroisoquinolin-1(2H)-one and trans-cinnamic acids. The structure, based on hybridization strategy, is used for hybridization of naturally occurring scaffolds. We have synthesized 14 hybrid molecules by coupling 3,4-dihydroisoquinolin-1(2H)-one core with cinnamic acids using the mix anhydride approach. The newly synthesized inhibitors were evaluated for cell viability against breast cancer MCF-7 and cervical cancer HeLa cell lines. Furthermore, the active compounds were screened for their potential in breast cancer MDA-MB-231, cervical cancer C33A cell lines, prostate cancer DU-145, PC-3, and normal VERO cells. From the series, compound 10g was seen to inhibit MCF-7 cell growth significantly with GI50 50 = 20 μM) and C33A (GI50 = 3.2 μM). While the inhibitor 10i inhibits MCF-7 breast cancer cell growth GI50 = 3.42 μM along with inhibition of cell growth in MDA-MB-231 (GI50 = 30 μM), HeLa (GI50 = 7.67 μM), C33A (GI50 = 13 μM), DU-145 (GI50 = 6.45 μM), PC-3 (GI50 = 8.68 μM), and VERO (GI50 = 2.93 μM), respectively. Furthermore, molecular docking study demonstrated these compounds could bind tightly to the colchicine domain of tubulin through a network of favorable steric and electrostatic interactions and thus act as a tubulin polymerization inhibitor.
- Kulkarni, Mahesh R.,Lad, Nitin P.,Khedkar, Vijay M.,Gaikwad, Nitin D.
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p. 1359 - 1370
(2021/04/09)
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- Efficiency of lithium cations in hydrolysis reactions of esters in aqueous tetrahydrofuran
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Lithium cations were observed to accelerate the hydrolysis of esters with hydroxides (KOH, NaOH, LiOH) in a water/tetrahydrofuran (THF) two-phase system. Yields in the hydrolysis of substituted benzoates and aliphatic esters using the various hydroxides were compared, and the effects of the addition of lithium salt were examined. Moreover, it was presumed that a certain amount of LiOH was dissolved in THF by the coordination of THF with lithium cation and hydrolyzed esters even in the THF layer, as in the reaction by a phase-transfer catalyst.
- Hayashi, Kazuhiko,Ichimaru, Yoshimi,Sugiura, Kirara,Maeda, Azusa,Harada, Yumi,Kojima, Yuki,Nakayama, Kanae,Imai, Masanori
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p. 581 - 594
(2021/06/06)
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- Discovery of 6-Oxo-4-phenyl-hexanoic acid derivatives as RORγt inverse agonists showing favorable ADME profile
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The retinoic acid receptor-related orphan nuclear receptor gamma t (RORγt), which is a promising therapeutic target for immune diseases, is a major transcription factor of genes related to psoriasis pathogenesis, such as interleukin (IL)-17A, IL-22, and IL-23R. Inspired by the co-crystal structure of RORγt, a 6-oxo-4-phenyl-hexanoic acid derivative 6a was designed, synthesized, and identified as a ligand of RORγt. The structure–activity relationship (SAR) studies in 6a, which focus on the improvement of its membrane permeability profile by introducing chlorine atoms, led to finding 12a, which has a potent RORγt inhibitory activity and a favorable pharmacokinetic profile.
- Nakajima, Ryota,Oono, Hiroyuki,Kumazawa, Keiko,Ida, Tomohide,Hirata, Jun,White, Ryan D.,Min, Xiaoshan,Guzman-Perez, Angel,Wang, Zhulun,Symons, Antony,Singh, Sanjay K.,Mothe, Srinivasa Reddy,Belyakov, Sergei,Chakrabarti, Anjan,Shuto, Satoshi
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supporting information
(2021/02/09)
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- Phenanthroline functionalized polyacrylonitrile fiber with Pd(0) nanoparticles as a highly active catalyst for the Heck reaction
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A series of polyacrylonitrile fibers (PANF) functionalized with nitrogen-containing ligands were prepared and then used to synthesize fiber-supported Pd(0) nanoparticle catalysts. The phenanthroline-functionalized PANF with immobilized Pd(0) nanoparticles (PANPhenF-Pd(0)) had the best catalytic activity for the Heck reaction under solvent-free conditions. The PANPhenF-Pd(0) efficiently stabilized the nanoparticles and they were well-dispersed with Pd(0) particle sizes of about 3 nm. The PANPhenF-Pd(0) structure was further characterized by a variety of instrumental methods. A probable mechanism based on the fiber's microenvironment is proposed for the Heck reaction catalyzed by PANPhenF-Pd(0). The PANPhenF-Pd(0) catalyst is easily recovered from the reaction system and can be used up to six times with only a slight decrease in catalytic activity and with low Pd leaching. The PANPhenF-Pd(0) catalyst also has excellent catalytic activity for gram-scale use.
- Xiao, Jian,Zhang, Haonan,Ejike, Anyaegbu Chima,Wang, Lu,Tao, Minli,Zhang, Wenqin
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- MOF-Zn-NHC as an efficient N-heterocyclic carbene catalyst for aerobic oxidation of aldehydes to their corresponding carboxylic acids: Via a cooperative geminal anomeric based oxidation
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As an efficient heterogenous N-heterocyclic carbene (NHC) catalyst, MOF-Zn-NHC was used in the aerobic oxidation of aryl aldehydes to their corresponding carbocyclic acids via an anomeric based oxidation. Features such as mild reaction conditions and no need for a co-catalyst or oxidative reagent can be considered as the major advantages of the presented method in this study. This journal is
- Babaee, Saeed,Zarei, Mahmoud,Zolfigol, Mohammad Ali
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p. 36230 - 36236
(2021/12/02)
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- Siloxy Esters as Traceless Activators of Carboxylic Acids: Boron-Catalyzed Chemoselective Asymmetric Aldol Reaction**
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The catalytic asymmetric aldol reaction is among the most useful reactions in organic synthesis. Despite the existence of many prominent reports, however, the late-stage, chemoselective, catalytic, asymmetric aldol reaction of multifunctional substrates is still difficult to achieve. Herein, we identified that in situ pre-conversion of carboxylic acids to siloxy esters facilitated the boron-catalyzed direct aldol reaction, leading to the development of carboxylic acid-selective, catalytic, asymmetric aldol reaction applicable to multifunctional substrates. Combining experimental and computational studies rationalized the reaction mechanism and led to the proposal of Si/B enediolates as the active species. The silyl ester formation facilitated both enolization and catalyst turnover by acidifying the α-proton of substrates and attenuating poisonous Lewis bases to the boron catalyst.
- Fujita, Taiki,Kanai, Motomu,Mitsunuma, Harunobu,Sameera, W. M. C.,Yamane, Mina
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p. 24598 - 24604
(2021/10/14)
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- Discovery of Novel Benzothiazepinones as Irreversible Covalent Glycogen Synthase Kinase 3β Inhibitors for the Treatment of Acute Promyelocytic Leukemia
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Recently, irreversible inhibitors have attracted great interest in antitumors due to their advantages of forming covalent bonds to target proteins. Herein, some benzothiazepinone compounds (BTZs) have been designed and synthesized as novel covalent GSK-3β inhibitors with high selectivity for the kinase panel. The irreversible covalent binding mode was identified by kinetics and mass spectrometry, and the main labeled residue was confirmed to be the unique Cys14 that exists only in GSK-3β. The candidate 4-3 (IC50 = 6.6 μM) showed good proliferation inhibition and apoptosis-inducing ability to leukemia cell lines, low cytotoxicity on normal cell lines, and no hERG inhibition, which hinted the potential efficacy and safety. Furthermore, 4-3 exhibited decent pharmacokinetic properties in vivo and remarkably inhibited tumor growth in the acute promyelocytic leukemia (APL) mouse model. All the results suggest that these newly irreversible BTZ compounds might be useful in the treatment of cancer such as APL.
- Zhang, Peng,Min, Zhihui,Gao, Yang,Bian, Jiang,Lin, Xin,He, Jie,Ye, Deyong,Li, Yilin,Peng, Chao,Cheng, Yunfeng,Chu, Yong
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p. 7341 - 7358
(2021/06/28)
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- Design, synthesis, and evaluation of different scaffold derivatives against NS2B-NS3 protease of dengue virus
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The number of deaths or critical health issues is a threat in the infection caused by Dengue virus, which complicates the situation, as only symptomatic treatment is the current solution. In this regard we have targeted the dengue protease NS2B-NS3 that is responsible for the replication. The series was designed with the help of molecular modeling approach using docking protocols. The series comprised of different scaffolds viz. cinnamic acid analogs (CA1–CA11), chalcone (C1–C10) and their molecular hybrids (Lik1–Lik10), analogs of benzimidazole (BZ1-BZ5), mercaptobenzimidazole (BS1-BS4), and phenylsulfanylmethylbenzimidazole (PS1-PS4). Virtual screening of various natural phytoconstituents was employed to determine the interactions of designed analogs with the residues of catalytic triad in the active site of NS2B-NS3. We have further synthesized the selected leads. The synthesized analogs were evaluated for the cytotoxicity and NS2B-NS3 protease inhibition activity and compared with known anti-dengue natural phytoconstituent quercetin as the standard. CA2, BZ1, and BS2 were found to be more potent and efficacious than the standard quercetin as evident from the protease inhibition assay.
- Ganji, Lata R.,Gandhi, Lekha,Musturi, Venkataramana,Kanyalkar, Meena A.
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p. 285 - 301
(2020/11/19)
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- Chlorination Reaction of Aromatic Compounds and Unsaturated Carbon-Carbon Bonds with Chlorine on Demand
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Chlorination with chlorine is straightforward, highly reactive, and versatile, but it has significant limitations. In this Letter, we introduce a protocol that could combine the efficiency of electrochemical transformation and the high reactivity of chlorine. By utilizing Cl3CCN as the chloride source, donating up to all three chloride atom, the reaction could generate and consume the chlorine in situ on demand to achieve the chlorination of aromatic compounds and electrodeficient alkenes.
- Liu, Feng,Wu, Na,Cheng, Xu
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supporting information
p. 3015 - 3020
(2021/05/05)
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- Synthesis method of isochroman compound
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The invention discloses a synthesis method of an isochroman compound, which comprises the following steps of adding dichloromethane and phosphorus tribromide into 3, 4, 5-trimethoxy benzyl alcohol, and reacting to obtain 1-bromomethyl-3, 4, 5-trimethoxy benzene, adding tetrahydrofuran, cinnamyl alcohol, sodium hydride and 1-bromomethyl-3, 4, 5-trimethoxybenzene into a reactor, and reacting to obtain 1-[(cinnamyl oxy)methyl]-3, 4, 5-trimethoxybenzene, adding cyanuric acid into a reactor containing a potassium hydroxide aqueous solution to react, dropwise adding a silver nitrate aqueous solution, and reacting to obtain silver isocyanurate, adding silver isocyanurate, phenyl selenium bromide and anhydrous dichloromethane into a reactor, and reacting to obtain N, N, N-triphenyl seleno isocyanurate, reacting N, N, N-triphenyl seleno isocyanurate, dichloromethane, boron trifluoride diethyl etherate and a 1-[(cinnamyl oxy)methyl]-3, 4, 5-trimethoxybenzene compound to obtain a target product. The method is simple in reaction operation, mild in reaction condition, relatively high in yield and environment-friendly.
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Paragraph 0046-0048
(2021/05/15)
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- In quest of small-molecules as potent non-competitive inhibitors against influenza
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A series of scaffolds namely aurones, 3-indolinones, 4-quinolones and cinnamic acid-piperazine hybrids, was designed, synthesized and investigated in vitro against influenza A/H1N1pdm09 virus. Designed molecules adopted different binding mode i.e., in 430-cavity of neuraminidase, unlike sialic acid and oseltamivir in molecular docking studies. All molecules reduced the viral titer and exhibited non-cytotoxicity along with cryo-protective property towards MDCK cells. Molecules (Z)-2-(3′-Chloro-benzylidene)-1,2-dihydro-indol-3-one (2f), (Z)-2-(4′-Chloro-benzylidene)-1,2-dihydro-indol-3-one (2g) and 2-(2′-Methoxy-phenyl)-1H-quinolin-4-one (3a) were the most interesting molecules identified in this research, endowed with robust potencies showing low-nanomolar EC50 values of 4.0 nM, 6.7 nM and 4.9 nM, respectively, compared to reference competitive and non-competitive inhibitors: oseltamivir (EC50 = 12.7 nM) and quercetin (EC50 = 0.56 μM), respectively. Besides, 2f, 2g and 3a exhibited good neuraminidase inhibitory activity in sub-micromolar range (IC50 = 0.52 μM, 3.5 μM, 1.3 μM respectively). Moreover, these molecules were determined as non-competitive inhibitors similar to reference non-competitive inhibitor quercetin unlike reference competitive inhibitor oseltamivir in kinetics studies.
- Malbari, Khushboo,Saha, Priyanka,Chawla-Sarkar, Mamta,Dutta, Shanta,Rai, Swita,Joshi, Mamata,Kanyalkar, Meena
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- Dual Nickel/Ruthenium Strategy for Photoinduced Decarboxylative Cross-Coupling of α,β-Unsaturated Carboxylic Acids with Cycloketone Oxime Esters
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Herein, a dual nickel/ruthenium strategy is developed for photoinduced decarboxylative cross-coupling between α,β-unsaturated carboxylic acids and cycloketone oxime esters. The reaction mechanism is distinct from previous photoinduced decarboxylation of α,β-unsaturated carboxylic acids. This reaction might proceed through a nickelacyclopropane intermediate. The C(sp2)-C(sp3) bond constructed by the aforementioned reaction provides an efficient approach to obtaining various cyanoalkyl alkenes, which are synthetically valuable organic skeletons in organic and medicinal chemistry, under mild reaction conditions. The protocol tolerates many critical functional groups and provides a route for the modification of complex organic molecules.
- Gao, Ang,Jiang, Run-Chuang,Liu, Chuang-Chuang,Liu, Qi-Le,Lu, Xiao-Yu,Xia, Ze-Jie
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supporting information
p. 8829 - 8842
(2021/06/30)
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- Photo-Promoted Decarboxylative Alkylation of α, β-Unsaturated Carboxylic Acids with ICH2CN for the Synthesis of β, γ-Unsaturated Nitriles
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An efficient, catalyst/photocatalyst-free, and cost-effective methodology for the decarboxylative alkylation of α,β-unsaturated carboxylic acids to synthesize β,γ-unsaturated nitriles has been developed. The reaction proceeded in an environmentally benign atmosphere of blue light-emitting diode irradiation with K2CO3 and water at room temperature. The methodology worked for a wide range of substrates (22 examples) with up to 83% yield. The protocol is also compatible for gram-scale synthesis.
- Pan, Chunxiang,Yang, Chunhui,Li, Kangkui,Zhang, Keyang,Zhu, Yuanbin,Wu, Shiyuan,Zhou, Yongyun,Fan, Baomin
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supporting information
p. 7188 - 7193
(2021/10/01)
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- Meta-substituted piperlongumine derivatives attenuate inflammation in both RAW264.7 macrophages and a mouse model of colitis
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Piperlongumine (PL) has been showed to have multiple pharmacological activities. In this study, we reported the synthesis of three series of PL derivatives, and evaluation of their anti-inflammatory effects in both lipopolysaccharide (LPS)-induced Raw264.7 macrophages and a dextran sulfate sodium (DSS)-induced mouse model of colitis. Our results presented that two meta-substituent containing derivatives 1–3 and 1–6, in which γ-butyrolactam replaced α,β-unsaturated δ-valerolactam ring of PL, displayed low cytotoxicity and effective anti-inflammatory activity. Molecular docking also showed that the meta-substituted derivative, compared with the corresponding ortho- or para-substituted derivative, had significant interactions with the amino acid residues of CD14, which was the core receptors recognizing LPS. In vitro and in vivo studies, 1–3 and 1–6 could inhibit the expression of pro-inflammatory cytokines, and the excessive production of reactive nitrogen species and reactive oxygen species. Oral administration of 100 mg/kg/day of 1–3 or 1–6 alleviated the severity of clinical symptoms of colitis in mice, and significantly reduced the colonic tissue damage to protect the colonic tissue from the DSS-induced colitis. These results suggested that meta-substituted derivatives 1–3 and 1–6 were potential anti-inflammatory agents, which may lead to future pharmaceutical development.
- Gong, Zhaotang,Liu, Guoyun,Mu, Wenwen,Wang, Ziqing,Yang, Jie
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- Design, Synthesis, and in Vitro and in Vivo Biological Evaluation of Limonin Derivatives for Anti-Inflammation Therapy
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In this study, limonin derivatives were used to design new anti-inflammatory compounds with high pharmacological activity and low toxicity. A total of 23 new limonin derivatives were discovered, synthesized, and screened for their anti-inflammatory activity against lipopolysaccharide (LPS)-treated RAW 264.7 cells. Of them, compound f4 was found to be the most active, with a higher efficiency compared with limonin and celecoxib. Subsequently, we studied the mechanism underlying the activity of f4 and found that it inhibited proinflammatory cytokines by blocking the NF-κB/MAPK signaling pathway in LPS-treated RAW 264.7 cells as well as mice. In conclusion, f4 may be a promising anti-inflammatory lead compound.
- Bian, Ming,Gong, Guohua,Lei, Pang,Du, Huanhuan,Bai, Chunmei,Wei, Chengxi,Quan, Zheshan,Ma, Qianqian
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p. 13487 - 13499
(2021/11/17)
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- Catalytic alcohol oxidation using cationic Schiff base manganeseIII complexes with flexible diamino bridge
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Four Schiff base manganese(III) complexes with derivatives of [(R,R)-N,N’-bis(salicy1idene)-1,2-cyclohexanediaminato)] including substituents on salicylaldehyde such as 3-methoxy, 3,5-di-tert-butyl and 3,5-chloro were synthesized and characterized using a combination of IR, UV–Vis, and HR ESI-MS techniques. The catalytic activity of these complexes was tested in the oxidation of 1-phenylethanol to acetophenone, revealing very good performances for all of the four manganese complexes. The catalytic reactions were carried out in the presence of tert-butyl hydroperoxide (TBHP) as oxidant and imidazole as co-catalyst. Complex Mn-4, bearing electron withdrawing [(R,R)-N,N’-bis(3,5-di-chloro-salicylidene)-1,2-cyclohexanediaminato)] ligand was found to be the most stable of the tested Mn(III) complexes and was selected for the oxidation of several primary and secondary alcohols.
- Kakavand, Meysam,Mastrorilli, Piero,Mesto, Ernesto,Neshat, Abdollah,Osanlou, Farzane,Schingaro, Emanuela,Todisco, Stefano
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- Chemoselective reduction of ?,¢-unsaturated carbonyl and carboxylic compounds by hydrogen iodide
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The selective reduction of ?,¢-unsaturated carbonyl compounds was achieved to produce saturated carbonyl compounds with aqueous HI solution. The introduction of an aryl group at an ? or ¢ position efficiently facilitated the reduction with good yield. The reaction was applicable to compounds bearing carboxylic acids and halogen atoms. Through the investigation of the reaction mechanism, it was found that Michael-type addition of iodide occurred to produce ¢-iodo compounds followed by the reduction of C-I bond via anionic and radical paths.
- Matsumoto, Shoji,Marumoto, Hayato,Akazome, Motohiro,Otani, Yasuhiko,Kaiho, Tatsuo
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p. 590 - 599
(2021/03/29)
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- Platinum supported on nanosilica and fibrous nanosilica for hydrogenation reactions
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Platinum nanoparticles supported on nanosilica (NP) and fibrous nanosilica (dendritic fibrous nano-spheres, DFNS) were prepared by direct grafting of the Pt precursor onto the silanol groups or via a polyethylenimine (PEI) linker. From the SEM and TEM images the average diameter of the nanosilica and fibrous nanosilica (DFNS), was determined to be 21.4 and 503 nm, respectively. While surface areas as measured by ASAP is 463.4 m2 g?1 for DFNS and 142.5 m2 g?1 for the nanosilica. For the four Pt containing catalysts (Pt/NP, Pt/DFNS, Pt/PEI/NP and Pt/PEI/DFNS), a Pt loading between 1.35 × 1017 and 8.46 × 1017 Pt atoms per gram support were determined. The PEI-containing catalyst gave higher Pt-loading than the direct anchoring of the Pt onto the silanol groups of the support. The catalysts were further characterised ATR FTIR and XPS. After oxidation of the pre-catalysts 85% of the Pt was in the oxide form. While after reduction, ca. 82% the Pt supported on DFNS was in the metallic form. Reduction of the Pt supported on NP, resulted in 100% of the Pt in the Pt0 oxidation state. These catalysts were tested for the hydrogenation of C[dbnd]C and/or C[dbnd]O bonds in cyclohexene, benzaldehyde and cinnamaldehyde. The % conversion and product distribution will be discussed in term of diameter, surface area and Pt-loading.
- Erasmus, E.,Xantini, Z.
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- Hydrolysis of amides to carboxylic acids catalyzed by Nb2O5
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Hydrolysis of amides to carboxylic acids is an industrially important reaction but is challenging due to the difficulty of cleaving the resonance stabilized amidic C-N bond. Twenty-three heterogeneous and homogenous catalysts were examined in the hydrolysis of acetamide. Results showed that Nb2O5was the most effective heterogeneous catalyst with the greatest yield of acetic acid. A series of Nb2O5catalysts calcined at various temperatures were characterized and tested in the hydrolysis of acetamide to determine the effects of crystal phase and surface properties of Nb2O5on catalytic performance. The high catalytic performance observed was attributed mainly to the facile activation of the carbonyl bond by Lewis acid sites that function even in the presence of basic inhibitors (NH3and H2O). The catalytic studies showed the synthetic advantages of the present method, such as simple operation, catalyst recyclability, additive free, solvent free, and wide substrate scope (>40 examples; up to 95% isolated yield).
- Siddiki,Rashed, Md. Nurnobi,Touchy, Abeda Sultana,Jamil, Md. A. R.,Jing, Yuan,Toyao, Takashi,Maeno, Zen,Shimizu, Ken-Ichi
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p. 1949 - 1960
(2021/03/26)
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- Access to α,β-unsaturated carboxylic acids through water-soluble palladium catalyzed hydroxycarbonylation of alkynes using water as the solvent
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A sulfoxantphos modified palladium-catalyzed synthesis of α,β-unsaturated carboxylic acids from alkynes with CO and H2O was described. The atom-economic hydroxycarbonylation of various symmetrical and unsymmetrical alkynes can be achieved with chemo-, stereo-, and regioselectivity, affording the corresponding carboxylic acids in good to excellent yields. Using water as the reaction solvent, the water-soluble palladium catalyst was easily separated from the product and could be reused for 5 cycles.
- Gao, Mingjie,Jia, Xiaofei,Lv, Jinhe,Ren, Xinyi,Song, Jiaxin,Xie, Congxia,Zhang, Jinrong,Zhang, Kai,Zhao, Jinyu,Zhou, Ziqin,Zong, Lingbo
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p. 4708 - 4713
(2021/07/26)
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- Monosubstituted 3,3-Difluorocyclopropenes as Bench-Stable Reagents: Scope and Limitations
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A general approach to gem-difluorocyclopropenes synthesis based on the reaction of alkynes with Ruppert-Prakash reagent is reported. The proposed method is evaluated for the synthesis of a wide difluorocyclopropenes scope based on their bench lifespan and hydrolytic stability. The tolerance of the method for common functional groups was shown. Previously unavailable difluorocyclopropenes substituted with aliphatic were prepared using the proposed procedure. The retain of stability was proven by the multigram scale synthesis and further storage in the temperature interval ?78 to ?4 °C over a year. This makes them attractive building blocks and intermediates for organic synthesis. The reasons for dropping stability were defined. The relations between the structure of the substituents and the stability of the difluorocyclopropene ring were determined and discussed.
- Nosik, Pavel S.,Pashko, Mykola O.,Poturai, Andrii S.,Kvasha, Denys A.,Pashenko, Alexander E.,Rozhenko, Alexander B.,Suikov, Sergiy,Volochnyuk, Dmitriy M.,Ryabukhin, Sergey V.,Yagupolskii, Yurii L.
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p. 6604 - 6615
(2021/12/08)
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- An Ir3L2complex with anion binding pockets: photocatalyticE-Zisomerizationviamolecular recognition
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A molecular host with photosensitizing centers provides photo-responsive host-guest properties based on its molecular recognition ability. Here, we construct a self-assembled photoactive Ir(iii) cage-shaped complex that contains anion binding pockets on its rim. The anion recognition ability of the complex enables efficient catalysis of the visible-light-inducedE-Zisomerization of an anionic styrene derivative.
- Fujita, Makoto,Koyamada, Kenta,Sunohara, Haruka,Takezawa, Hiroki
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supporting information
p. 9300 - 9302
(2021/09/20)
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- Stereodivergent silver-catalyzed synthesis of pyroglutamic acid esters
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We report here a silver-catalyzed method for the enantio- and diastereodivergent synthesis of chiral pyroglutamic acid esters with multiple stereocenters. This process proceeds through asymmetric conjugate addition of glycine imine esters to a broad range of β-substituted α,β-unsaturated perfluorophenyl esters followed by lactamization. By leveraging catalyst control and stereospecificity of the 1,4-addition process, all four product stereoisomers containing two adjacent stereocenters are accessible with high stereoselectivity.
- Kim, Byungjun,Lee, Sarah Yunmi,Song, Yuna
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supporting information
p. 11052 - 11055
(2021/10/30)
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- One-pot chemoenzymatic reactions in water enabled by micellar encapsulation
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The use of micellar conditions to enable one-pot reactions involving both transition metal and enzymatic catalysts is reported. Representative enzymatic transformations under micellar conditions are unaffected by the presence of non-ionic surfactants, including designer surfactants such as TPGS-750-M. Furthermore, the presence of enzymes has a negligible effect on transition metal catalysis under micellar conditions in water. Finally, three one-pot chemoenzymatic reactions in water are reported in which the micelle-forming surfactant TPGS-750-M is a crucial factor for reaction efficiency.
- Adams, Nicholas P.,Bushi, Jurgen,Hastings, Courtney J.,Kolb, Samuel J.
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supporting information
p. 6187 - 6193
(2020/10/18)
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- Uncommon overoxidative catalytic activity in a new halo-tolerant alcohol dehydrogenase
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Alcohol dehydrogenases (ADH) are versatile and useful enzymes employed as biocatalysts, especially for the selective oxidation of primary and secondary alcohols, and for the reduction of carbonyl moieties. A new alcohol dehydrogenase (HeADH-II) has been identified from the genome of the halo-adapted bacterium Halomonas elongata, which proved stable in the presence of polar organic solvents and salt exposure. Unusual for this class of enzymes, HeADH-II lacks enantiopreference and is capable of oxidizing both alcohols and aldehydes, enabling a direct overoxidation of primary alcohols to carboxylic acids. HeADH-II was coupled with a NADH-oxidase from Lactobacillus pentosus (LpNOX) to increase the process yields and allowing recycling of the cofactor. The enzymatic oxidation of primary alcohols was also paired with in situ condensation of the intermediate aldehydes with hydroxylamine to prepare the corresponding aldoximes, with particular attention to perillartine (a powerful sweetener), whose enzymatic synthesis starting from natural sources, leads to an equally natural product.
- Contente, Martina L.,Fiore, Noemi,Cannazza, Pietro,Roura Padrosa, David,Molinari, Francesco,Gourlay, Louise,Paradisi, Francesca
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supporting information
p. 5679 - 5685
(2020/09/17)
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- Copper (II) immobilized on magnetically separable L-arginine-β-cyclodextrin ligand system as a robust and green catalyst for direct oxidation of primary alcohols and benzyl halides to acids in neat conditions
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Copper (II) immobilized on L-arginine-β-cyclodextrin-functionalized magnetite nanoparticles (nano-Fe3O4@L-arginine-CD-Cu(II)) were successfully synthesized and fully characterized using FT-IR, XRD, SEM, EDX, ICP, TGA and VSM techniques. The catalytic activity of these magnetically retrievable nanoparticles was evaluated in the direct oxidation of primary alcohols and benzyl halides to acids in neat conditions that was observed to proceed well and products were obtained in good yields. In addition to showing good catalytic activity, the magnetic catalyst is easy to synthesize and can be recycled at least five times with little loss in activity.
- Nejad, Masoumeh Jadidi,Salamatmanesh, Arefe,Heydari, Akbar
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- Catalytic oxidation of alcohols and alkyl benzenes to carbonyls using Fe3O4?SiO2?(TEMPO)-: Co -(Chlorophyll-CoIII) as a bi-functional, self-co-oxidant nanocatalyst
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Chlorophyll b was extracted from heliotropium europaeum plant, demetalated, allylated and grafted to acrylated TEMPO through a copolymerization protocol. Then, the chlorophyll monomers were coordinated to Co ions, immobilized on magnetic nanoparticles and the resulting hybrid was used as a powerful catalyst for a variety of oxidation reactions. By using the present method, oxidation of benzylic alcohols and alkyl benzenes to carbonyls was accomplished in water under aerobic conditions. Moreover, direct oxidation of alcohols to carboxylic acids was performed by adding NaOCl to the mixture. All entries were oxidized to the corresponding desired product with high to excellent yields and up to 97% selectivity. The catalyst was thoroughly characterized by CV, TGA, VSM, XRD, XPS, DLS, FE-SEM, TEM, UV-Vis, EDX, and BET analyses. The activity of the catalyst was investigated by applying various components of the catalyst to the oxidation model separately. The reasonable mechanisms are suggested based on the cooperation between the TEMPO groups and cobalt(iii) (or Co(iv)) sites on the catalyst. The catalyst could be recovered and reused for at least 7 consecutive recycles without any considerable reactivity loss. This journal is
- Hamah-Ameen, Baram Ahmed,Kazemnejadi, Milad,Mahmoudi, Boshra,Rostami, Amin
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p. 6600 - 6613
(2020/11/16)
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- Synthesis of a Cellulosic Pd(salen)-Type Catalytic Complex as a Green and Recyclable Catalyst for Cross-Coupling Reactions
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Abstract: A green recyclable cellulose-supported Pd(salen)-type catalyst was synthesized through sequential three steps: chlorination with thionyl chloride, modification by ethylenediamine, and the formation of Schiff base with salicylaldehyde to immobilize palladium chloride through multiple binding sites. This novel heterogeneous cellulosic Pd(salen)-type catalytic complex was fully characterized by FT-IR, SEM, TEM, XPS, ICP-AES and TG. The traditional cross-coupling chemistry, such as Suzuki, Heck, Sonogashira, Buchwald–Hartwig amination and etherification, was then investigated in the presence of the above cellulose-palladium nanoparticle. Studies have shown that the synthesized catalyst shows high activity and efficiency for all types of transformations, providing the corresponding carbon–carbon or carbon–heteroatom coupling products in a general and mild manner. Furthermore, the catalyst demonstrates high to excellent yields and is easily recycled by simple filtration for up to twelve cycles without any significant loss of catalytic activity. Graphic Abstract: [Figure not available: see fulltext.]
- Sun, Peng,Yang, Jiaojiao,Chen, Chunxia,Xie, Kaijun,Peng, Jinsong
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p. 2900 - 2910
(2020/03/31)
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- Palladium Immobilized on 2,2′-Dipyridyl-Based Hypercrosslinked Polymers as a Heterogeneous Catalyst for Suzuki–Miyaura Reaction and Heck Reaction
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Abstract: 2,2′-Bipyridine was successfully integrated into the skeleton of hypercrosslinked polymers networks (HCPs-bipy) via Friedel–Crafts reaction and Scholl coupling reaction, and PdCl2 was locked in this network polymers by coordination with pyridine motif. The preparation of HCPs-bipy has the advantages of low cost, mild conditions, easy separation and high yield. FT-IR, TGA, N2 sorption, ICP, XPS, SEM, EDX and TEM was employed to characterize the structure and composition of the heterogeneous catalysts. The result indicates that HCPs-bipy-Pd possess high specific surface areas, large microporous volume, thermal stability, and highly dispersion of palladium species. HCPs-bipy-Pd can be applied in Suzuki–Miyaura reactions and Heck reactions as robust heterogeneous catalyst to afford high yield. The reusability test demonstrates that HCPs-bipy-Pd could be recovered and reused for at least five times without losing catalytic activity. Graphic Abstract: [Figure not available: see fulltext.].
- Liu, Cijie,Xu, Wei,Xiang, Dexuan,Luo, Qionglin,Zeng, Shunqin,Zheng, Lijuan,Tan, Yujie,Ouyang, Yuejun,Lin, Hongwei
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p. 2558 - 2565
(2020/03/23)
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- Novel and efficient polymer supported copper catalyst for heck reaction
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A novel polymer supported copper complex (m-PAN-Cu) is prepared by immobilizing Cuprous Iodide (CuI) on amidoxime modified Polyacrylonitrile (mPAN) and characterised by FTIR, XRD, EDX, ICP-MS and XPS analyses. This complex was further explored as a general and efficient heterogeneous catalyst for Heck coupling reaction of a series of aryl halides with olefins and afforded the corresponding coupling products in moderate to good yields. This catalyst offers easy preparation, good stability, excellent catalytic activity and reusability. This is the first study involving an amidoxime modified PAN supported copper catalyst towards greener and efficient Heck reaction.
- Anas, Saithalavi,Anjali, Suresh,Sruthi, Pambingal Rajan,Varghese, Nicy
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- Pd nanoparticles supported on reduced graphene oxide as an effective and reusable heterogeneous catalyst for the Mizoroki–Heck coupling reaction
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A general method for the synthesis of palladium nanoparticles loaded on reduced graphene oxide functionalized with diethylenetriamine (PdNPs/rGO-NH2) using a sonochemical procedure is described. The heterogeneous nanocomposite was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray, thermogravimetric analysis, high-angle annular dark field scanning transmission electron microscopy, X-ray photoelectron spectroscopy, UV–visible absorption, and inductively coupled plasma optical emission spectrometry. The PdNPs/rGO-NH2 was very effective for the Mizoroki–Heck coupling reaction of several aryl iodide compounds with different alkenes in the presence of triethylamine. The reaction provides the coupling products in good to excellent yields (59–100%). Additionally, the PdNPs/rGO-NH2 catalyst can be reutilized for six successive runs without any apparent diminution of its catalytic reactivity.
- Mirza-Aghayan, Maryam,Mohammadi, Marzieh,Addad, Ahmed,Boukherroub, Rabah
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- Catalytic C-H Bond Oxidation Using Dioxygen by Analogues of Heme Superoxide
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Heme active sites are capable of oxidizing organic substrates by four electrons using molecular oxygen (heme dioxygenases), where a dioxygen (O2) adduct of heme (FeIII-O2-) acts as the primary oxidant, in contrast to monooxygenases, where high-valent species are involved. This chemistry, although lucrative, is difficult to access using homogeneous synthetic systems. Over the past few years using a combination of self-assembly and in situ resonance Raman spectroscopy, the distribution of different reactive intermediates formed during the electrochemical reduction of oxygen has been elucidated. An FeIII-O2- species, which is the reactive species of dioxygenase, is an intermediate in heterogeneous electrochemical O2 reduction by iron porphyrins and its population, under electrochemical conditions, may be controlled by controlling the applied potential. Iron porphyrins having different axial ligands are constructed on a self-assembled monolayer of thiols on an electrode, and these constructs can activate O2 and efficiently catalyze the dioxygenation of 3-methylindole and oxidation of a series of organic compounds having C-H bond energies between 80 and 90 kcal mol-1 at potentials where FeIII-O2- species are formed on the electrode. Isotope effects suggest that hydrogen-atom transfer from the substrate is likely to be the rate-determining step. Axial thiolate ligands are found to be more efficient than axial imidazoles or phenolates with turnover numbers above 60000 and turnover frequencies over 60 s-1. These results highlight a new reaction engineering approach to harness O2 as a green oxidant for efficient chemical oxidation.
- Dey, Abhishek,Mukherjee, Manjistha
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p. 7415 - 7425
(2020/06/17)
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- A heterogeneous bio-inspired peroxide shunt for catalytic oxidation of organic molecules
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Heme enzymes are capable of catalytically oxidising organic substrates using peroxide via the formation of a high-valent intermediate. Iron porphyrins with three different axial ligands are created on self-assembled monolayer-modified gold electrodes, which can oxidize C-H bonds and epoxidize alkenes efficiently. The kinetic isotope effects suggest that the hydrogen atom transfer reaction by a highly reactive oxidant is likely to be the rate-determining step. Effect of different axial ligands and different secondary structures of the iron porphyrin confirms that the thiolate axial ligand with a hydrophobic distal pocket is the most efficient for this oxidation chemistry.
- Mukherjee, Manjistha,Dey, Abhishek
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supporting information
p. 11593 - 11596
(2020/10/19)
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- Method for preparing aromatic carboxylic acid compound
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The invention discloses a method for preparing an aromatic carboxylic acid compound. The method comprises the following steps: 1) heating carbon dioxide and hydrosilane in the presence of a copper catalyst in a reaction medium A; and 2) adding a reaction medium B, aryl halide, a palladium catalyst and a base to the reaction mixture in the step 1), sealing the reaction system, and performing a heating reaction. The method has the advantages that raw materials are simple and easy to obtain, the raw materials are cheap and stable, the catalyst is common, easy to obtain and stable, the reaction conditionsaremild, the aftertreatment is simple, the yield is high, and the like.
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Paragraph 0085-0086; 0165-0167; 0177
(2020/02/14)
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- Design, synthesis and biological evaluation of novel 1H-1,2,4-triazole, benzothiazole and indazole-based derivatives as potent FGFR1 inhibitors viafragment-based virtual screening
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Fibroblast growth-factor receptor (FGFR) is a potential target for cancer therapy. We designed three novel series of FGFR1 inhibitors bearing indazole, benzothiazole, and 1H-1,2,4-triazole scaffold via fragment-based virtual screening. All the newly synthesised compounds were evaluated in vitro for their inhibitory activities against FGFR1. Compound 9d bearing an indazole scaffold was first identified as a hit compound, with excellent kinase inhibitory activity (IC50 = 15.0 nM) and modest anti-proliferative activity (IC50 = 785.8 nM). Through two rounds of optimisation, the indazole derivative 9 u stood out as the most potent FGFR1 inhibitors with the best enzyme inhibitory activity (IC50 = 3.3 nM) and cellular activity (IC50 = 468.2 nM). Moreover, 9 u also exhibited good kinase selectivity. In addition, molecular docking study was performed to investigate the binding mode between target compounds and FGFR1.
- Liu, Jian,Wen, Yu,Gao, Lina,Gao, Liang,He, Fengjun,Zhou, Jingxian,Wang, Junwei,Dai, Rupeng,Chen, Xiaojing,Kang, Di,Hu, Lihong
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- Knoevenagel-Doebner condensation promoted by chitosan as a reusable solid base catalyst
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The development of green and sustainable processes using naturally occurring biopolymers is becoming one of the suitable remedies to replace the conventional catalytic systems that generate large amount of byproducts with high risk factors. In this context, although Knoevenagel-Doebner condensation reaction has been reported with many organocatalysts including proline, no attempts were made to develop heterogeneous catalysts with environmental concerns. Considering these factors in mind, the title reaction is studied with chitosan as a heterogeneous solid base catalyst for the synthesis of α,β-unsaturated carboxylic acids through the condensation followed by decarboxylation reactions. Chitosan offers many advantages including high stability as evidenced by leaching, reusability tests, wide substrate scope and providing higher yields of the desired products with high purity. Powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscope (SEM) and elemental analysis revealed that there are no major changes in the structural integrity and morphology of chitosan before and after catalysis under the optimized reaction conditions.
- Anbu, Nagaraj,Hariharan, Surendran,Dhakshinamoorthy, Amarajothi
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- Introducing of potent cytotoxic novel 2-(aroylamino)cinnamamide derivatives against colon cancer mediated by dual apoptotic signal activation and oxidative stress
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Curcumin and trans-cinnamaldehyde are acrolein-based Michael acceptor compounds that are commonly found in domestic condiments, and known to cause cancer cell death via redox mechanisms. Based on the structural features of these compounds we designed and synthesized several 2-cinnamamido-N-substituted-cinnamamide (bis-cinnamamide) compounds. One of the derivatives, (Z)-2-[(E)-cinnamamido]-3-phenyl-N-propylacrylamide 8 showed a moderate antiproliferative potency (HCT-116 cell line inhibition of 32.0 μM), no inhibition of normal cell lines C-166, and proven cellular activities leading to apoptosis. SAR studies led to more than 10-fold increase in activity. Our most promising compound, [(Z)-3-(1H-indol-3-yl)-N-propyl-2-[(E)-3-(thien-2-yl)propenamido)propenamide] 45 killed colon cancer cells at IC50 = 0.89 μM (Caco-2), 2.85 μM (HCT-116) and 1.65 μM (HT-29), while exhibiting much weaker potency on C-166 and BHK normal cell lines (IC50 = 71 μM and 77.6 μM, respectively). Cellular studies towards identifying the compounds mechanism of cytotoxic activities revealed that apoptotic induction occurs in part as a result of oxidative stress. Importantly, the compounds showed inhibition of cancer stem cells that are critical for maintaining the potential for self-renewal and stemness. The results presented here show discovery of covalently acting Michael addition compounds that potently kill cancer cells by a defined mechanism, with prominent selectivity profile over non-cancerous cell lines.
- Abdel-Bakky, Mohamed S.,Abdelghany, Tamer M.,Ahmed, Hany E. A.,Ahmed, Mostafa H.,Boothello, Rio,El-Araby, Moustafa E.,Elhaggar, Radwan S.,Malebari, Azizah M.,Omar, Abdelsattar M.,Patel, Bhaumik B,Safo, Martin K.
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- New coumarin/sulfocoumarin linked phenylacrylamides as selective transmembrane carbonic anhydrase inhibitors: Synthesis and in-vitro biological evaluation
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Two novel series of phenylacrylamide linked coumarins and sulfocoumarins (6a-p, 8a-i, and 14a-g) were synthesized and evaluated against four physiologically relevant human carbonic anhydrases (hCAs, EC 4.2.1.1), isoforms hCA I, hCA II, hCA IX and hCA XII for their inhibitory action. All new compounds when screened for carbonic anhydrase inhibitory activity have shown selective inhibition towards the tumor associated isoforms hCA IX and XII over CA I and II, with inhibition constants in the submicromolar to low nanomolar range. Compound 6b and 14g exhibited significant inhibition with low nanomolar potency against hCA IX, whereas 6k was effective against hCA XII. Compounds 6b, 14g and 6k may be considered as lead molecules for future development of cancer therapeutics based on a novel mechanism of action.
- Angeli, Andrea,Arifuddin, Mohammed,Singh, Priti,Supuran, Claudiu T.,Swain, Baijayantimala
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- Radical-Cation Vinylcyclopropane Rearrangements by TiO2Photocatalysis
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Radical cation vinylcyclopropane rearrangements by TiO2 photocatalysis in lithium perchlorate/nitromethane solution are described. The reactions are triggered by oxidative single electron transfer, which is followed by immediate ring-opening of the cyclopropanes to generate distonic radical cations as unique reactive intermediates. This approach can also be applied to vinylcyclobutane, leading to the construction of six-membered rings. A stepwise mechanism via distonic radical cations is proposed based on preliminary mechanistic studies, which is supported by density functional theory calculations.
- Maeta, Naoya,Kamiya, Hidehiro,Okada, Yohei
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supporting information
p. 6551 - 6566
(2020/07/14)
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- Diazaphosphinyl radical-catalyzed deoxygenation of α-carboxy ketones: A new protocol for chemo-selective C-O bond scission: Via mechanism regulation
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C-O bond cleavage is often a key process in defunctionalization of organic compounds as well as in degradation of natural polymers. However, it seldom occurs regioselectively for different types of C-O bonds under metal-free mild conditions. Here we report a facile chemo-selective cleavage of the α-C-O bonds in α-carboxy ketones by commercially available pinacolborane under the catalysis of diazaphosphinane based on a mechanism switch strategy. This new reaction features high efficiency, low cost and good group-tolerance, and is also amenable to catalytic deprotection of desyl-protected carboxylic acids and amino acids. Mechanistic studies indicated an electron-transfer-initiated radical process, underlining two crucial steps: (1) the initiator azodiisobutyronitrile switches originally hydridic reduction to kinetically more accessible electron reduction; and (2) the catalytic phosphorus species upconverts weakly reducing pinacolborane into strongly reducing diazaphosphinane. This journal is
- Cheng, Jin-Pei,Yang, Jin-Dong,Zhang, Jingjing
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p. 8476 - 8481
(2020/09/07)
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- Exploration of New Biomass-Derived Solvents: Application to Carboxylation Reactions
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A range of hitherto unexplored biomass-derived chemicals have been evaluated as new sustainable solvents for a large variety of CO2-based carboxylation reactions. Known biomass-derived solvents (biosolvents) are also included in the study and the results are compared with commonly used solvents for the reactions. Biosolvents can be efficiently applied in a variety of carboxylation reactions, such as Cu-catalyzed carboxylation of organoboranes and organoboronates, metal-catalyzed hydrocarboxylation, borocarboxylation, and other related reactions. For many of these reactions, the use of biosolvents provides comparable or better yields than the commonly used solvents. The best biosolvents identified are the so far unexplored candidates isosorbide dimethyl ether, acetaldehyde diethyl acetal, rose oxide, and eucalyptol, alongside the known biosolvent 2-methyltetrahydrofuran. This strategy was used for the synthesis of the commercial drugs Fenoprofen and Flurbiprofen.
- Gevorgyan, Ashot,Hopmann, Kathrin H.,Bayer, Annette
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p. 2080 - 2088
(2020/02/20)
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- Ni-Catalyzed Carboxylation of C(sp2)-S Bonds with CO2: Evidence for the Multifaceted Role of Zn
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Nickel-catalyzed reductive carboxylation reactions of aryl electrophiles typically require the use of metallic reducing agents. At present, the prevailing perception is that these serve as both a source of electrons and as a source of Lewis acids that may aid CO2 insertion into the Ni-C bond. Herein, we provide evidence for the in situ formation of organometallic species from the metallic reductant, a step that has either been ruled out or has been unexplored in catalytic carboxylation reactions with metal powder reductants. Specifically, we demonstrate that Zn(0) acts as a reductant and that Zn(II) generates arylzinc species that might play a role in the C(sp2)-S carboxylation of arylsulfonium salts. Overall, the reductive Ni-catalyzed C(sp2)-S carboxylation reaction proceeds under mild conditions in a non-amide solvent, displays a wide substrate scope, and can be applied to the formal para C-H carboxylation of arenes.
- Yanagi, Tomoyuki,Somerville, Rosie J.,Nogi, Keisuke,Martin, Ruben,Yorimitsu, Hideki
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p. 2117 - 2123
(2020/02/28)
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- Characteristics and hazards of the cinnamaldehyde oxidation process
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Pressure and temperature behavior of the cinnamaldehyde oxidation process was determined using a custom-designed mini closed pressure vessel test (MCPVT), which is a new method to investigate the stability and hazard assesment of the cinnamaldehyde oxidation reaction. The oxidation products were analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that cinnamaldehyde was stable under nitrogen atmosphere but very unstable under oxygen atmosphere. The initial oxidation products were analyzed by iodimetry and the cinnamaldehyde peroxide value could reach 139.44 mmol kg?1when the oxidation temperature was 308 K. The oxidation kinetics of cinnamaldehyde were studied by using the pressureversustime (P-t) curves obtained from the MCPVT process. The reaction is a second-order reaction, the kinetic equation is ln k= ?2233.66 × (1/T) + 11.19, and the activation energyEais 18.57 kJ mol?1at 308-338 K. The explosion of the cinnamaldehyde oxidation reaction was observed by MCPVT, in which the onset temperature was 373 K. The main products of cinnamaldehyde oxidation are acetaldehyde, benzaldehyde, phenylacetaldehyde, acetophenone, 2-hydroxyphenyl acetone, cinnamaldehyde epoxide, benzoic acid, and cinnamic acid. Oxidation is a three-step process: (1) cinnamaldehyde reacts with oxygen to form peroxides; (2) complex oxidation reactions are caused by the thermal decomposition of peroxides; (3) rapid oxidation and thermal decomposition lead to explosion hazard.
- Dai, Su-Yi,Lai, Fang,Li, Wei-Guang,Li, Yuan-Lin,Liang, Min,Liu, Xiong-Min,Ma, Li,Yu, Chang
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p. 19124 - 19133
(2020/06/08)
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- Metal-free Photocatalytic Aerobic Oxidative Cleavage of C?C Bonds in 1,2-Diols
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The preparation of carbonyl compounds by the aerobic oxidative cleavage of C?C bonds in 1,2-diols under mild reaction conditions is a very significant reaction and is widely employed in various scenarios. Avoiding the use of harmful stoichiometric oxidants and adopting a greener chemical process remain a challenge for this reaction to date. In this manuscript, a heterogeneous metal-free photocatalytic strategy without any additive was developed for aerobic oxidative cleavage of C?C bonds in 1,2-diols at ambient conditions with visible light. The reaction mechanism was further studied through a series of control experiments and density functional theory (DFT) calculations. In addition, the catalytic system showed a broad substrates scope, including aliphatic (linear or cyclic) 1,2-diols, benzylic, alkenyl 1,2-diols, and α-hydroxy acids (such as lactic acid). Thus, this strategy could serve as a method for the transformation of 1,2-diols to corresponding carbonyl compounds by the aerobic oxidative cleavage of C?C bonds.
- Zhu, Rui,Zhou, Gongyu,Teng, Jia-nan,Li, Xinglong,Fu, Yao
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p. 5248 - 5255
(2020/08/21)
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- Palladium-Catalyzed Highly Regioselective Hydrocarboxylation of Alkynes with Carbon Dioxide
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A Pd-catalyzed highly regioselective hydrocarboxylation of alkynes with carbon dioxide has been established. By the combination of Pd(PPh3)4 and 2,2′-bis(diphenylphosphino)-1,1′-binaphthalene (binap), a variety of functionalized alkynes, including aryl alkynes, aliphatic alkynes, propargylamines, and propargyl ethers, could be leveraged to provide a wide array of α-acrylic acids in high yields with high regioselectivity under mild reaction conditions. Experimental and DFT mechanistic studies revealed that this reaction proceeded via the cyclopalladation process of alkynes and carbon dioxide in the presence of binap to generate a five-membered palladalactone intermediate and enabled the formation of Markovnikov adducts. Moreover, this strategy provided an effective method for the late-stage functionalization of alkyne-containing complicated molecules, including natural products and pharmaceuticals.
- Chen, Pengquan,Cheng, Ruixiang,Jiang, Huanfeng,Lei, Ming,Lou, Hongming,Qi, Chaorong,Shi, Fuxing,Wang, Lu,Wu, Wanqing,Xiong, Wenfang,Zhu, Baiyao
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p. 7968 - 7978
(2020/08/21)
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- Hydrodebromination of Aromatic Bromides Catalyzed by Unsupported Nanoporous Gold: Heterolytic Cleavage of Hydrogen Molecule
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Unsupported nanoporous gold (AuNPore) is a highly efficient, practically applicable, and recyclable catalyst for hydrodebromination of aromatic bromides. The AuNPore-catalyzed hydrodebromination of aromatic bromides proceeded smoothly at relatively low hydrogen pressure and temperature to achieve good to excellent yields of the corresponding non-bromine variants. The selective hydrodebromination reaction occurred exclusively in the coexistence of chlorine atom. For the first time, a mechanistic study revealed that the H?H bond splits in a heterolysis manner on the surface of AuNPore to generate Au?H hydride species.
- Bao, Ming,Feng, Xiujuan,Yamamoto, Yoshinori,Zhang, Sheng,Zhao, Yuhui
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p. 4951 - 4957
(2020/09/09)
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