- Method for catalytically synthesizing methyl p-tert-butylbenzoate based on deep eutectic solvent
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The invention discloses a method for preparing methyl p-tert-butylbenzoate based on a deep eutectic solvent catalyst (PTSA-DES), and the catalyst PTSA-DES is prepared by mixing choline chloride and p-toluenesulfonic acid; the methyl p-tert-butylbenzoate i
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Paragraph 0009; 0011-0015
(2021/04/21)
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- Activity of a New Chromium(III) Complex with a Pentadentate (N3O2) Schiff-Base Ligand in the Reaction of Carbon Dioxide with Propylene Oxide
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Abstract: The reaction of carbon dioxide with propylene oxide was carried out in the presence of a new pentadentate chromium complex, dichloro[2,6-diacetylpyridine bis(4-tert-butylbenzoylhydrazone)]chromium(III). The reaction kinetics was studied under different reaction conditions (temperature, pressure, and catalyst concentration). Optimal conditions for the synthesis of cyclic carbonate in the presence of the new chromium complex were found. The effective activation energy of the formation of cyclic carbonate was determined. The catalyst activity significantly depended on the substituent R in a 2,6-diacetylpyridine bis(4-R-benzoylhydrazone) ligand.
- Bazhenova, T. A.,Chukanova, O. M.,Kornev, A. B.,Manakin, Yu. V.,Sedov, I. V.,Sheverdenkina, O. G.,Yakushev, I. A.
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p. 428 - 435
(2021/06/14)
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- Kinetic study on the reaction of p-tert-butylbenzoic acid with methanol catalyzed by deep eutectic solvent based on choline chloride
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The synthesis of methyl p-tert-butylbenzoate using deep eutectic solvent (DES) as a green catalyst was studied in this work. Four DESs were prepared by combining choline chloride (ChCl) and p-toluenesulfonic acid monohydrate (PTSA) with different molar ratios (1:1–3). It was found that ChCl-1.5PTSA with a molar ratio of 1:1.5 was superior to other DESs both in physical properties and catalytic performance. Therefore, it was selected to carry out the kinetic experiments. The effects of stirring speed, temperature, molar ratio of methanol to p-tert-butylbenzoic acid, and catalyst loading on the conversion of p-tert-butylbenzoic acid were discussed. In addition, the reaction kinetics of p-tert-butylbenzoic acid and methanol with ChCl-1.5PTSA as catalyst was explored in the temperature range of 332.15–349.15 K, and the experimental data were well fitted by pseudo-homogeneous model. Moreover, the recyclability of ChCl-1.5PTSA was evaluated. The result shows that the catalyst could be easily separated from the reaction system without any extractant, and the performance of the catalyst remains stable in multiple times recycling. Therefore, ChCl-1.5PTSA is expected to be an efficient and environmentally friendly catalyst for the methyl esterification of p-tert-butylbenzoic acid with a bright future in industrial application.
- Guo, Yuan,Tang, Linmao,Xue, Weilan,Zeng, Zuoxiang
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p. 1241 - 1252
(2021/08/12)
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- Dual Nickel/Photoredox-Catalyzed Deaminative Cross-Coupling of Sterically Hindered Primary Amines
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We report a method to activate α-3° amines for deaminative arylation via condensation with an electron-rich aldehyde and merge this reactivity with nickel metallaphotoredox to generate benzylic quaternary centers, a common motif in pharmaceuticals and natural products. The reaction is accelerated by added ammonium salts. Evidence is provided in support of two roles for the additive: inhibition of nickel black formation and acceleration of the overall reaction rate. We demonstrate a robust scope of amine and haloarene coupling partners and show an expedited synthesis of ALK2 inhibitors.
- Dorsheimer, Julia R.,Ashley, Melissa A.,Rovis, Tomislav
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supporting information
p. 19294 - 19299
(2021/11/23)
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- Hydroxyl radical-mediated oxidative cleavage of CC bonds and further esterification reaction by heterogeneous semiconductor photocatalysis
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A hydroxyl radical-mediated aerobic cleavage of alkenes and further sequence esterification reaction for the preparation of carbonyl compounds have been developed by using tubular carbon nitride (TCN) as a general heterogeneous photocatalyst under an oxygen atmosphere with visible light irradiation. This protocol has an excellent substrate scope and gives the desired aldehydes, ketones and esters in moderate to high yields. Importantly, this metal-free procedure employed photogenerated hydroxyl radicals in situ as green oxidation active species, avoiding the present additional initiators. The reaction could be carried out under solar light irradiation and was applicable to large-scale reactions. Furthermore, the recyclable TCN catalyst could be used several times without a significant loss of activities.
- Hong, Mei,Jia, Rui,Miao, Hongyan,Ni, Bangqing,Niu, Tengfei,Wang, Hui
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p. 6591 - 6597
(2021/09/10)
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- Mild Copper-Catalyzed Addition of Arylboronic Esters to Di- tert -butyl Dicarbonate: An Easy Access to Methyl Arylcarboxylates
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An efficient copper-catalyzed addition of arylboronic esters to (Boc) 2O was developed. The reaction can be conducted under exceedingly mild conditions and is compatible with a variety of synthetically relevant functional groups. It therefore represents a useful alternative route for the synthesis of methyl arylcarboxylates. A preliminary mechanistic study indicated the involvement of an addition-elimination mechanism.
- Xu, Jin-Di,Su, Xiao-Bo,Wang, Cai,Yao, Li-Wei,Liu, Jing-Hui,Hu, Guo-Qin
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supporting information
p. 833 - 837
(2021/02/26)
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- Discovery of [1,2,4]triazole derivatives as new metallo-β-lactamase inhibitors
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The emergence and spread of metallo-β-lactamase (MBL)-mediated resistance to β-lactam antibacterials has already threatened the global public health. A clinically useful MBL inhibitor that can reverse β-lactam resistance has not been established yet. We here report a series of [1,2,4]triazole derivatives and analogs, which displayed inhibition to the clinically relevant subclass B1 (Verona integron-encoded MBL-2) VIM-2. 3-(4-Bromophenyl)-6,7-dihydro-5H-[1,2,4]triazolo [3,4-b][1,3]thiazine (5l) manifested the most potent inhibition with an IC50 (half-maximal inhibitory concentration) value of 38.36 μM. Investigations of 5l against other B1 MBLs and the serine β-lactamases (SBLs) revealed the selectivity to VIM-2. Molecular docking analyses suggested that 5l bound to the VIM-2 active site via the triazole involving zinc coordination and made hydrophobic interactions with the residues Phe61 and Tyr67 on the flexible L1 loop. This work provided new triazole-based MBL inhibitors and may aid efforts to develop new types of inhibitors combating MBL-mediated resistance.
- Yuan, Chen,Yan, Jie,Song, Chen,Yang, Fan,Li, Chao,Wang, Cheng,Su, Huiling,Chen, Wei,Wang, Lijiao,Wang, Zhouyu,Qian, Shan,Yang, Lingling
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- Palladium-Catalyzed Chlorocarbonylation of Aryl (Pseudo)Halides Through In Situ Generation of Carbon Monoxide
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An efficient palladium-catalyzed chlorocarbonylation of aryl (pseudo)halides that gives access to a wide range of carboxylic acid derivatives has been developed. The use of butyryl chloride as a combined CO and Cl source eludes the need for toxic, gaseous carbon monoxide, thus facilitating the synthesis of high-value products from readily available aryl (pseudo)halides. The combination of palladium(0), Xantphos, and an amine base is essential to promote this broadly applicable catalytic reaction. Overall, this reaction provides access to a great variety of carbonyl-containing products through in situ transformation of the generated aroyl chloride. Combined experimental and computational studies support a reaction mechanism involving in situ generation of CO.
- Bismuto, Alessandro,Boehm, Philip,Morandi, Bill,Roediger, Sven
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p. 17887 - 17896
(2020/08/19)
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- Copper-catalyzed oxidative methyl-esterification of 5-hydroxymethylfurfural using TBHP as an oxidizing and methylating reagent: A new approach for the synthesis of furan-2,5-dimethylcarboxylate
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Catalytic conversion of 5-hydroxymethylfurfural (HMF) into furan-2,5-dimethylcarboxylate (FDMC) is of great significance in the production of polyethylene furanoate (PEF), a renewable biomass-derived polymer that can replace the fossil dependent polyethylene terephthalate (PET). Herein, for the first time, we report the synthesis of FDMC from oxidative methyl-esterification of HMF using tert-butyl hydroperoxide (TBHP) as an oxidizing and methylating reagent catalyzed by mesoporous alumina nanospheres-embedded with CuO nanoparticles (CuO/m-Al2O3). The CuO/m-Al2O3 catalysts with different copper contents were prepared by evaporation-induced self-assembly of a structure-directing agent (Pluronic P-123). The decomposition of P-123 during calcination in air results into the formation of a mesoporous structure with highly dispersed CuO nanoparticles. The as-prepared 6-CuO/m-Al2O3 exhibits excellent catalytic activity towards oxidative methyl-esterification of HMF into FDMC with 92% yield and turnover frequency (TOF) of 0.56 h?1. Furthermore, oxidative methyl-esterification of a range of substrates through SP3 C[sbnd]H bond functionalization has also been demonstrated using the same catalyst.
- Gupta, Shyam Sunder R.,Kantam, Mannepalli Lakshmi,Vinu, Ajayan
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p. 259 - 269
(2020/06/27)
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- Generation of Alkyl Radical through Direct Excitation of Boracene-Based Alkylborate
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The generation of tertiary, secondary, and primary alkyl radicals has been achieved by the direct visible-light excitation of a boracene-based alkylborate. This system is based on the photophysical properties of the organoboron molecule. The protocol is applicable to decyanoalkylation, Giese addition, and nickel-catalyzed carbon-carbon bond formations such as alkyl-aryl cross-coupling or vicinal alkylarylation of alkenes, enabling the introduction of various C(sp3) fragments to organic molecules.
- Hashizume, Daisuke,Hosoya, Takamitsu,Nakamura, Kei,Ohmiya, Hirohisa,Sato, Yukiya,Sumida, Yuto
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supporting information
p. 9938 - 9943
(2020/06/27)
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- Methoxylation of Acyl Fluorides with Tris(2,4,6-trimethoxyphenyl)phosphine via C-OMe Bond Cleavage under Metal-Free Conditions
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Acyl fluorides are subjected to methoxylation with tris(2,4,6-trimethoxyphenyl)phosphine (TMPP) to afford the corresponding methyl esters in good to excellent yields. This transformation is featured by C(sp2)-OMe bond cleavage under metal-free conditions. Unprecedented utilization of TMPP as a methoxylating agent realized the installation of an OMe group into the desired products.
- Ishida, Takumi,Nishihara, Yasushi,Wang, Xiu,Wang, Zhenhua
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p. 7526 - 7533
(2020/06/27)
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- Palladium-catalyzed aryloxy- and alkoxycarbonylation of aromatic iodides in γ-valerolactone as bio-based solvent
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Fossil-based solvents and triethylamine as a toxic and volatile base were successfully replaced with γ-valerolactone as a non-volatile solvent and K2CO3 as inorganic base in the alkoxy- and aryloxycarbonylation of aryl iodides using phosphine-free Pd catalyst systems. By this, the traditional systems were not simply replaced but also significantly improved. In the study, the effects of different reaction parameters, i.e. the use of several other solvents, the temperature, the carbon monoxide pressure, the base and the catalyst concentrations, were evaluated in details on the efficiency of the carbonylations. To gather some information on the mechanism of these reactions, the effects of the electronic parameters (σ) of various aromatic substituents of the aryl iodides as well as the influence of para-substitution of phenol were investigated on the activity. For a comparison, the aryl-substituted aryl iodides were also reacted with methanol and aryl iodide was also alkoxycarbonylated using several different lower alcohols. From the observed correlations between the electronic parameters of the aromatic substituents and the rates, it appears that the rate determining step is the oxidative addition of Ar–I to Pd0, provided that sufficient amounts of nucleophiles are present for the ester formation. If this is not the case, the rate of nucleophile attack might determine the overall rate.
- Tukacs, József M.,Marton, Bálint,Albert, Eszter,Tóth, Imre,Mika, László T.
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- Pd-Colloids-Catalyzed/Ag2O-Oxidized General and Selective Esterification of Benzylic Alcohols
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Palladium colloids obtained from the degradation of Hermann–Beller palladacycle proved to be an efficient catalytic system in combination with silver oxide as a selective oxidant for the oxidative esterification of differently substituted benzyl alcohols in MeOH as solvent. Excellent reactivity exhibited by the catalytic system also allowed the alcoholic coupling partner to be changed from MeOH to a wide range of alcohols having diverse functionalities. The mildness of the developed protocol also made it possible to employ propargyl alcohol as the coupling partner without any observation of any interference of the terminal alkyne. Selective oxidative coupling of a primary alcoholic functional group over secondary in the case of glycols and glycerols was also made possible using the developed catalyst system. To test the relevancy of Pd/Ag combined catalysis mixed Pd/Ag colloids were synthesized, characterized by TEM, XRD and XPS and applied to oxidative-esterification successfully.
- Sable, Vaibhav,Shah, Jagrut,Sharma, Anuja,Kapdi, Anant R.
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supporting information
p. 2639 - 2647
(2019/07/08)
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- Discovery of 1,3,4-oxadiazol-2-one-containing benzamide derivatives targeting FtsZ as highly potent agents of killing a variety of MDR bacteria strains
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The spread of infections caused by multidrug-resistant (MDR) pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant S. aureus (VRSA), has created a need for new antibiotics with novel mechanisms of action. The bacterial division protein FtsZ has been identified as a novel drug target that can be exploited clinically. As part of an ongoing effort to develop FtsZ-targeting antibacterial agents, we describe herein the design, synthesis and bioactivity of six series of novel 1,3,4-oxadiazol-2-one-containing, 1,2,4-triazol-3-one-containing and pyrazolin-5-one-containing benzamide derivatives. Among them, compound A14 was found to be the most potent antibacterial agent, much better than clinical drugs such as ciprofloxacin, linezolid and erythromycin against all the tested gram-positive strains, particularly methicillin-resistant, penicillin-resistant and clinical isolated S. aureus. Subsequent studies on biological activities and docking analyses proved that A14 functioned as an effective compound targeting FtsZ. Preliminary SAR indicated a general direction for further optimization of these novel analogues. Taken together, this research provides a promising chemotype for developing newer FtsZ-targeting bactericidal agents.
- Bi, Fangchao,Song, Di,Qin, Yinhui,Liu, Xingbang,Teng, Yuetai,Zhang, Na,Zhang, Panpan,Zhang, Nan,Ma, Shutao
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p. 3179 - 3193
(2019/06/17)
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- Chelation-Based Homologation by Reaction of Organometallic Reagents with O -Alkyl S -Pyridin-2-yl Thiocarbonates: Synthesis of Esters from Grignard Reagents
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The one-carbon homologative esterification of Grignard reagents with O- alkyl S -pyridin-2-yl thiocarbonates has been explored. This one-step synthesis of esters from Grignard reagents is the first case to involve chelation-stabilized intermediates.
- Hashimoto, Yoshimitsu,Mano, Koudai,Morita, Nobuyoshi,Suzuki, Tomoyuki,Tamura, Osamu,Tanaka, Kosaku,Usami, Shun
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supporting information
p. 1561 - 1564
(2019/08/07)
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- TEMPO-Me: An Electrochemically Activated Methylating Agent
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Bench- and air-stable 1-methoxy-2,2,6,6-tetramethylpiperidine (TEMPO-Me) is relatively unreactive at ambient temperature in the absence of an electrochemical stimulus. In this report, we demonstrate that the one-electron electrochemical oxidation of TEMPO-Me produces a powerful electrophilic methylating agent in situ. Our computational and experimental studies are consistent with methylation proceeding via a SN2 mechanism, with a strength comparable to the trimethyloxonium cation. A protocol is developed for the electrochemical methylation of aromatic acids using TEMPO-Me.
- Norcott, Philip L.,Hammill, Chelsey L.,Noble, Benjamin B.,Robertson, Johnathon C.,Olding, Angus,Bissember, Alex C.,Coote, Michelle L.
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supporting information
p. 15450 - 15455
(2019/11/02)
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- Organocopper cross-coupling reaction for C-C bond formation on highly sterically hindered structures
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We describe a powerful, broadly applicable cross-coupling protocol that enables carbon-carbon bond formation at highly sterically hindered carbon centers (both sp2 and sp3) by employing organocopper reagents under palladium catalysis. Experimental studies and theoretical calculations indicated that the key to the unique reactivity of copper is the relatively low activation energy of the compact transmetalation transition state, due to Cu(i)-Pd(ii) interaction, which is associated with small values of deformation energy of the reactants. This reaction is applicable to a variety of bulky substrates, including compounds inert to previous cross-coupling chemistry and has high functional group tolerance.
- Oi, Miku,Takita, Ryo,Kanazawa, Junichiro,Muranaka, Atsuya,Wang, Chao,Uchiyama, Masanobu
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p. 6107 - 6112
(2019/06/27)
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- Palladium-Catalyzed Visible-Light-Driven Carboxylation of Aryl and Alkenyl Triflates by Using Photoredox Catalysts
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A visible-light-driven carboxylation of aryl and alkenyl triflates with CO2 is developed by using a combination of Pd and photoredox catalysts. This reaction proceeds under mild conditions and can be applied to a wide range of substrates including acyclic alkenyl triflates.
- Shimomaki, Katsuya,Nakajima, Tomoya,Caner, Joaquim,Toriumi, Naoyuki,Iwasawa, Nobuharu
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supporting information
p. 4486 - 4489
(2019/06/24)
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- Method for methylation reaction
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The invention relates to a method for a methylation reaction. The method is characterized in that a reaction substrate is reacted in an organic solvent in the presence of an alkali with methyl trifluoroacetate as a methylation reagent to obtain a corresponding methylated product. The method is a new methylation method, and has the advantages of cheapness, easiness in operation, mild reaction conditions, wide application range of the substrate, avoiding of dimethyl sulfate, iodomethane and other highly toxic methylation reagents, and obtaining of the methylated product with a high yield.
- -
-
Paragraph 0013
(2019/01/21)
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- Efficient and Recyclable RuCl3 ? 3H2O Catalyst Modified with Ionic Diphosphine for the Alkoxycarbonylation of Aryl Halides
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A series of ionic (mono-/di-)phosphines (L2, L4, and L6) with structural similarity and their corresponding neutral counterparts (L1, L3, and L5) were applied to modulate the catalytic performance of RuCl3 ? 3H2O. With the involvement of the ionic diphosphine (L4), in which the two phosphino-fragments were linked by butylene group, RuCl3 ? 3H2O with advantages of low cost, robustness, and good availability was found to be an efficient and recyclable catalyst for the alkoxycarbonylation of aryl halides. The L4-based RuCl3 ? 3H2O system corresponded to the best conversion of PhI (96 %) along with 99 % selectivity to the target product of methyl benzoate as well as the good generality to alkoxycarbonylation of different aryl halides (ArX, X=I and Br) with alcohols MeOH, EtOH, i-PrOH and n-BuOH. The electronic and steric effects of the applied phosphines, which were analyzed by the 31P NMR for 1J31P-77Se1J measurement and single-crystal X-ray diffraction, were carefully co-related to the performance RuCl3 ? 3H2O catalyst. In addition, the L4-based RuCl3 ? 3H2O system could be recycled successfully for at least eight runs in the ionic liquid [Bmim]PF6.
- Zhou, Qing,Liu, Lei,Guo, Wen-Di,Liang, Wen-Yu,Lu, Yong,Liu, Ye
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p. 166 - 172
(2019/02/01)
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- Superior performance of Co-N/m-C for direct oxidation of alcohols to esters under air
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A convenient, expeditious, and high-efficiency protocol for the transformation of alcohols into esters using a Co-modified N-doped mesoporous carbon material (Co-N/m-C) as the catalyst is proposed. The catalyst was prepared through direct pyrolysis of a macromolecular precursor. The catalyst prepared using a pyrolysis temperature of 900 °C (labeled Co-N/m-C-900) exhibited the best performance. The strong coordination between the ultra-dispersed cobalt species and the pyridine nitrogen as well as the large area of the mesoporous surface resulted in a high turnover frequency value (107.6 mol methyl benzoate mol?1 Co h?1) for the direct aerobic oxidation of benzyl alcohol to methyl benzoate. This value is much higher than those of state-of-the-art transition-metal-based nanocatalysts reported in the literature. Moreover, the catalyst exhibited general applicability to various structurally diverse alcohols, including benzylic, allylic, and heterocyclic alcohols, achieving the target esters in high yields. In addition, a preliminary evaluation revealed that Co-N/m-C-900 can be used six times without significant activity loss. In general, the process was rapid, simple, and cost-effective.
- Li, Ning,Shang, Sensen,Wang, Lianyue,Niu, Jingyang,Lv, Ying,Gao, Shuang
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p. 1249 - 1257
(2018/06/14)
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- Structural design, synthesis and substituent effect of hydrazone-N-acylhydrazones reveal potent immunomodulatory agents
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4-(Nitrophenyl)hydrazone derivatives of N-acylhydrazone were synthesized and screened for suppress lymphocyte proliferation and nitrite inhibition in macrophages. Compared to an unsubstituted N-acylhydrazone, active compounds were identified within initial series when hydroxyl, chloride and nitro substituents were employed. Structure-activity relationship was further developed by varying the position of these substituents as well as attaching structurally-related substituents. Changing substituent position revealed a more promising compound series of anti-inflammatory agents. In contrast, an N-methyl group appended to the 4-(nitrophenyl)hydrazone moiety reduced activity. Anti-inflammatory activity of compounds is achieved by modulating IL-1β secretion and prostaglandin E2 synthesis in macrophages and by inhibiting calcineurin phosphatase activity in lymphocytes. Compound SintMed65 was advanced into an acute model of peritonitis in mice, where it inhibited the neutrophil infiltration after being orally administered. In summary, we demonstrated in great details the structural requirements and the underlying mechanism for anti-inflammatory activity of a new family of hydrazone-N-acylhydrazone, which may represent a valuable medicinal chemistry direction for the anti-inflammatory drug development in general.
- Meira, Cássio S.,dos Santos Filho, José Maurício,Sousa, Caroline C.,Anjos, Pamela S.,Cerqueira, Jéssica V.,Dias Neto, Humberto A.,da Silveira, Rafael G.,Russo, Helena M.,Wolfender, Jean-Luc,Queiroz, Emerson F.,Moreira, Diogo R.M.,Soares, Milena B.P.
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p. 1971 - 1985
(2018/03/12)
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- Ni-Catalyzed Reductive Coupling of Electron-Rich Aryl Iodides with Tertiary Alkyl Halides
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This work illustrates the reductive coupling of electron-rich aryl halides with tertiary alkyl halides under Ni-catalyzed cross-electrophile coupling conditions, which offers an efficient protocol for the construction of all carbon quaternary stereogenic centers. The mild and easy-to-operate reaction tolerates a wide range of functional groups. The utility of this method is manifested by the preparation of cyclotryptamine derivatives, wherein successful incorporation of 7-indolyl moieties is of particular interest as numerous naturally occurring products are composed of these key scaffolds. DFT calculations have been carried out to investigate the proposed radical chain and double oxidative addition pathways, which provide useful mechanistic insights into the part of the reaction that takes place in solution.
- Wang, Xuan,Ma, Guobin,Peng, Yu,Pitsch, Chloe E.,Moll, Brenda J.,Ly, Thu D.,Wang, Xiaotai,Gong, Hegui
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supporting information
p. 14490 - 14497
(2018/11/02)
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- Visible-Light-Mediated Iminyl Radical Generation from Benzyl Oxime Ether: Synthesis of Pyrroline via Hydroimination Cyclization
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The treatment of an O-(4-methoxybenzyl) oxime ether bearing an olefin substituent and 1-chloroanthraquinone (1-Cl-AQN) catalyst in 2-butanone under visible-light irradiation affords pyrroline via an iminyl radical intramolecular hydroimination. Mechanistic studies indicate that iminyl radical generation mainly proceeds by hydrogen abstraction of the photocatalyst from the benzyl position of the oxime. Moreover, the hydrogen atom was identified in circulation from the benzylic position of the substrates between AQN and 2-butanone to quench the carbon radical without requiring any additional reagents.
- Usami, Kaoru,Yamaguchi, Eiji,Tada, Norihiro,Itoh, Akichika
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supporting information
p. 5714 - 5717
(2018/09/21)
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- Efficient and selective palladium-catalyzed direct oxidative esterification of benzylic alcohols under aerobic conditions
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A highly efficient palladium-catalyzed approach for the direct oxidative esterification of benzylic alcohols with methanol and long-chain aliphatic alcohols under mild conditions has been achieved. This practical catalyst system exhibits a broad substrate scope and good functional group tolerance. Catalytic amount of Bi(OTf)3 is used as co-catalyst to improve the activity and selectivity of the reactions. A variety of esters are obtained in yields of 43–96%.
- Hu, Yongke,Li, Bindong
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p. 7301 - 7307
(2017/11/29)
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- Selective Oxidative Esterification from Two Different Alcohols via Photoredox Catalysis
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Esters functionalities are important building blocks that are extensively used in the chemical industry and academic laboratories. Direct oxidative esterification from easy-available alcohols to esters would be a much more appealing approach, especially using O2as terminal oxidant. Inputting external energy by photocatalysis for dioxygen activation, a mild and simple method for ester synthesis from two different alcohols has been achieved in this work. This reaction is performed under neutral conditions using O2as the terminal oxidant. A variety of primary alcohols, especially long chain alcohols and secondary alcohols are tolerated in this system.
- Yi, Hong,Hu, Xia,Bian, Changliang,Lei, Aiwen
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- An electrochemical method for carboxylic ester synthesis from N-alkoxyamides
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An electrochemical method for the synthesis of carboxylic as well as hindered esters from N-alkoxyamides has been reported. The electrochemical reaction proceeds through constant current electrolysis (CCE) by taking advantage of the dual role of n-Bu4NI (TBAI) as the redox catalyst as well as the supporting electrolyte. Besides providing mild reaction conditions, the present protocol is free from external oxidants and conducting salts, thereby generating nitrogen as the nonhazardous side product. Additionally, the developed procedure is highly advantageous due to its short reaction time, wide substrate scope, and gram-scale synthesis.
- Subramanian, Kripa,Yedage, Subhash L.,Bhanage, Bhalchandra M.
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p. 10025 - 10032
(2018/05/31)
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- A arab League Fu Benzong synthetic method
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The invention discloses a synthetic method of avobenzone. The avobenzone is prepared by subjecting phenetole and methylbenzene, as starting materials, to alkylation, oxidation, esterification, acylation and condensation reaction. During oxidation, the oxidant potassium permanganate is added to a reaction system six times, thus thermal decomposition and deacidification of the potassium permanganate is avoided, and reaction yield is higher. During esterification, with methylsulphonic acid as catalyst, P-tert-butyl benzoic acid and methanol are subjected to reflux reaction for 8 hours according to a molar ratio: 1:7; the methanol is added in two stages for reaction, and the problem that water diversion fails in the reaction process is solved. During acylation, phosphotungstic acid is used as catalyst, reaction selectivity is improved, post-reaction treatment is simpler, and reaction yield is higher; the phosphotungstic acid is recyclable, thus cost is saved and industrial production is more benefited.
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Paragraph 0019; 0026; 0033
(2017/07/04)
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- Efficient flow fischer esterification of carboxylic acids with alcohols using sulfonic acid-functionalized silica as supported catalyst
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Flow Fischer esterification of carboxylic acids using hydroxy-substituted sulfonic acid-functionalized silica (HOSAS) packed into a stainless steel column reactor was investigated. HO-SAS well catalyzed flow esterification of long chain carboxylic acids with methanol within 3min of residence time at 110°C, and the methyl esters were quantitatively obtained. The flow esterification protocol was applied to the synthesis of a variety of esters (19 examples) and scalable synthesis was also successful.
- Furuta, Akihiro,Fukuyama, Takahide,Ryu, Ilhyong
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p. 607 - 612
(2017/06/19)
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- Methylation of mono- and dicarboxylic acids with dimethyl carbonate catalyzed with binder-free zeolite NaY
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Synthesis of methyl mono- and dicarboxylates was developed consisting in treating the corresponding acids with dimethyl carbonate in the presence of a heterogenic catalyst, crystalline aluminosilicate whose mechanically strong granules to 90–95% were built of crystal aggregates of zeolite Y with modulus of about 5.0 in the Na-form. Optimum catalyst and reagents ratio and the reaction conditions were found for the preparation in high yields of methyl esters of mono- and dicarboxylic acids.
- Khusnutdinov,Shchadneva,Mayakova, Yu. Yu.,Konovalova, Yu. S.,Khazipova,Kutepov
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p. 163 - 168
(2017/04/24)
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- Visible-light induced oxidative Csp3-H activation of methyl aromatics to methyl esters
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Direct functionalization of readily available hydrocarbons under mild conditions fulfills the requirements of green and sustainable chemistry. In this work, a mild and green catalytic oxidative Csp3-H activation of methyl aromatics using O2via photocatalysis has been achieved. A lot of methyl aromatics can be tolerated, providing a green route for aromatic methyl carboxylates. In addition, this protocol can be performed on a gram scale.
- Zhang, Lingling,Yi, Hong,Wang, Jue,Lei, Aiwen
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supporting information
p. 5122 - 5126
(2016/10/05)
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- Based on 4,4 the structure of the- [...][...] 9, the 9-bit [...] a main body material and its application (by machine translation)
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Based on 4,4 the structure of the- [...][...] 9, the 9-bit [...] a main body material and its application, the present invention discloses a kind HOMO line condition and at the same time has a high level and the main material with excellent performance, its to 4, the 4-bit connected [...][...] as the molecule skeleton structure, in its 9,9 the connecting substituent [...] -position, which can be connected with transmission performance of the cavity diphenylammonium unit Dn, but also can be connected with electronic transmission performance unit An: phosphorusoxychloride unit, sulfur and oxygen unit, in addition to the two special spiral ring-like structure can be formed. The main body material of the present invention synthetic method is simple and easy to operate, which is suitable to be widely used. Main body material by the present invention of the organic electroluminescent light-emitting device is phosphorescent blue light, has high efficiency, high brightness, low efficiency low starting voltage attenuation and electroluminescent performance, can be widely applied to the organic electroluminescent field. (by machine translation)
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Paragraph 0059; 0060
(2016/10/10)
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- An efficient nonconventional glycerol-based solid acid catalyzed synthesis and biological evaluation of phosphonate conjugates of 1,2,4-triazole thiones
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A series of diethyl (3-((5-aryl-1H-1,2,4-triazol-3-yl)thio)propyl)phos-phonates (7a-t) has been synthesized in excellent yields by coupling diethyl (3-bromopropyl)phosphonate and 5-aryl-1H- 1,2,4-triazol-3-thiones employing an efficient, green and nonconventional heterogeneous SO3Hcarbon catalyst derived from glycerol. In addition, a facile and green approach for the esterification of carboxylic acids by utilizing glycerol-based solid acid catalyst has been reported. Structures of the synthesized compounds were characterized by IR, NMR and HRMS studies. These triazole derivatives were screened for their in vitro cytotoxicity using the standard MTT (3-(4,5-dimethylthiazol-2- yl)-2,5-diphenyltetra-zolium bromide) assay against a panel of five different human cancer cell lines (HeLa: Cervix, A549: Lung, A375: Skin, MDA-MB-231: Breast and T98G: Brain). The antimicrobial activities of the synthesized compounds were investigated against four bacterial strains: Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and three fungal strains: Aspergillus Niger, Aspergillus terreus, Aspergillus fumigatus. Preliminary results indicate that the compound 7f displayed maximum anticancer activity and the compounds 7d, 7e, 7f, 7m and 7q exhibited moderate antibacterial activity. The compounds 7g, 7h, 7o and 7p showed good antifungal activity with high inhibition zone diameter compared to the standard drug.
- Murty, Madugula S.R.,Katiki, Mohana R.,Rao, Busam R.,Narayanan, Sai S.,Anto, Ruby J.,Buddana, Sudhreer K.,Prakasham, Reddy S.,Devi, Bethala L.A.P.,Prasad, Rachapudi B.N.
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p. 968 - 981
(2016/10/31)
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- Silyl Radical Activation of Alkyl Halides in Metallaphotoredox Catalysis: A Unique Pathway for Cross-Electrophile Coupling
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A strategy for cross-electrophile coupling has been developed via the merger of photoredox and transition metal catalysis. In this report, we demonstrate the use of commercially available tris(trimethylsilyl)silane with metallaphotoredox catalysis to efficiently couple alkyl bromides with aryl or heteroaryl bromides in excellent yields. We hypothesize that a photocatalytically generated silyl radical species can perform halogen-atom abstraction to activate alkyl halides as nucleophilic cross-coupling partners. This protocol allows the use of mild yet robust conditions to construct Csp3-Csp2 bonds generically via a unique cross-coupling pathway.
- Zhang, Patricia,Le, Chi Chip,MacMillan, David W. C.
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supporting information
p. 8084 - 8087
(2016/07/16)
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- Efficient Baeyer-Villiger electro-oxidation of ketones with molecular oxygen using an activated carbon fiber electrode in ionic liquid [bmim][OTf]
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A new and efficient method for the synthesis of lactones and esters involving the application of an molecular oxygen-based electro-catalytic oxidation system and ionic liquid [bmim][OTf] as electrolyte has been developed. The reaction between various ketones with molecular oxygen proceeds in a three-electrode cell under constant current conditions in [bmim][OTf] at room temperature to give the corresponding esters and lactones in good to excellent isolated yield. Additionally, the possible mechanism of Baeyer-Villiger oxidation of ketones in the electro-catalytic system is proposed.
- Hu, Yu Lin,Xie, Yi Bi,Li, De Jiang
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p. 297 - 306
(2016/08/05)
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- Nickel-Catalyzed Reductive Coupling of Aryl Bromides with Tertiary Alkyl Halides
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A mild Ni-catalyzed reductive arylation of tertiary alkyl halides with aryl bromides has been developed that delivers products bearing all-carbon quaternary centers in moderate to excellent yields with excellent functional group tolerance. Electron-deficient arenes are generally more effective in inhibiting alkyl isomerization. The reactions proceed successfully with pyridine or 4-(dimethylamino)pyridine, while imidazolium salts slightly enhance the coupling efficiency.
- Wang, Xuan,Wang, Shulin,Xue, Weichao,Gong, Hegui
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supporting information
p. 11562 - 11565
(2015/09/28)
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- Aerobic Copper-Catalyzed O-Methylation with Methylboronic Acid
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The oxidative coupling of alkylboronic acids with oxygen nucleophiles offers a strategy for replacing toxic, electrophilic alkylating reagents. Although the Chan-Lam reaction has been widely applied in the arylation of heteroatom nucleophiles, O-alkylation with boronic acids is rare. We report a Cu-catalyzed nondecarboxylative methylation of carboxylic acids with methylboronic acid that proceeds in air with no additional oxidant. An isotope-labeling study supports an oxidative cross-coupling mechanism, in analogy to that proposed for Chan-Lam arylation.
- Jacobson, Clare E.,Martinez-Mu?oz, Noelia,Gorin, David J.
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p. 7305 - 7310
(2015/07/28)
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- Efficient and convenient oxidation of aldehydes and ketones to carboxylic acids and esters with H2O2 catalyzed by Co4HP2Mo15V3O62 in ionic liquid [TEBSA][BF4]
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A simple, efficient, and eco-friendly procedure for the oxidation of aldehydes and ketones to carboxylic acids and esters with H2O2 catalyzed by Co4HP2Mo15V3O62 in ionic liquid [TEBSA][BF4] has been developed. This atom-economical protocol affords the target products in good to high yields. The products can be separated by a simple extraction with organic solvent, and the catalytic system can be recycled and reused without loss of catalytic activity. Additionally, the possible mechanism of oxidation in the catalytic system is proposed. This journal is
- Hu, Yu-Lin,Li, De-Jiang,Li, Dong-Sheng
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p. 24936 - 24943
(2015/03/30)
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- Magnetically Recyclable Nano-Fe 2O 3-Catalyzed Chemoselective Synthesis and Antioxidant Activity of Diethyl (3-((5-Aryl-1 H-1,2,4-triazol-3-yl)thio)propyl) phosphonates
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An efficient, green, and chemoselective S-alkylation of 5-aryl-1H-1,2,4-triazole-3-thiones with diethyl (3-bromopropyl)phosphonate in water, catalyzed by nano-Fe2O3 under ligand-and base-free conditions, is reported. Clean reaction, less expensive catalyst, excellent yields, and easy workup are the advantages of the present method. The catalyst can be easily collected by a magnet and recycled without significant loss in catalytic activity. The newly synthesized compounds were screened for their antioxidant property by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging assay. The majority of the compounds exhibited good antioxidant activity.
- Murty,Katiki, Mohana Rao,Rao, B. Ramalingeswara,Nanubolu, Jagadeesh Babu,Buddana, Sudheer Kumar,Prakasham
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p. 2724 - 2737
(2014/08/18)
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- Synthesis and antifungal activity of substituted salicylaldehyde hydrazones, hydrazides and sulfohydrazides
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Efficient synthetic procedures for the preparation of acid hydrazines and hydrazides were developed by converting the corresponding carboxylic acid into the methyl ester catalyzed by Amberlyst-15, followed by a reaction with hydrazine monohydrate. Sulfohydrazides were prepared from the corresponding sulfonyl chlorides and hydrazine monohydrate. Both of these group of compounds were condensed with substituted salicylaldehydes using gradient concentration methods that generated a large library of hydrazone, hydrazide and sulfohydrazide analogs. Antifungal activity of the prepared analogs showed that salicylaldehyde hydrazones and hydrazides are potent inhibitors of fungal growth with little to no mammalian cell toxicity, making these analogs promising new targets for future therapeutic development.
- Backes, Gregory L.,Neumann, Donna M.,Jursic, Branko S.
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p. 4629 - 4636
(2014/11/08)
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- Asymmetric hydroxylative phenol dearomatization promoted by chiral binaphthylic and biphenylic iodanes
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The long-standing quest for chiral hypervalent organoiodine compounds (i.e., iodanes) as metal-free reagents for asymmetric synthesis continues. Although remarkable progress has recently been made in organoiodine-catalyzed reactions using a terminal oxidant in stoichiometric amounts, there is still a significant need for "flaskable" chiral iodane reagents. Herein, we describe the synthesis of new iodobinaphthyls and iodobiphenyls, their successful and selective DMDO-mediated oxidation into either λ3- or λ5-iodanes, and the evaluation of their capacity to promote asymmetric hydroxylative phenol dearomatization (HPD) reactions. Most notably, a C2-symmetrical biphenylic λ5-iodane promoted the HPD-induced conversion of the monoterpene thymol into the corresponding ortho-quinol-based [4+2] cyclodimer (i.e., bis(thymol)) with enantiomeric excesses of up to 94 %.
- Bosset, Cyril,Coffinier, Romain,Peixoto, Philippe A.,El Assal, Mourad,Pouysegu, Laurent,Quideau, Stephane,Miqueu, Karinne,Sotiropoulos, Jean-Marc
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supporting information
p. 9860 - 9864,5
(2014/10/15)
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- Photooxidative cleavage of aromatic alkenes into aldehydes using catalytic iodine and molecular oxygen under visible light irradiation
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We report a method for the photooxidative cleavage of aromatic alkenes to give aldehydes using molecular oxygen as the terminal oxidant, visible light, a catalytic amount of iodine and trifluoroacetic acid.
- Fujiya, Akitoshi,Kariya, Atsumasa,Nobuta, Tomoya,Tada, Norihiro,Miura, Tsuyoshi,Itoh, Akichika
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p. 884 - 888
(2014/04/03)
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- Synthesis and evaluation of some substituted heterocyclic fluconazole analogues as antifungal agents
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A new series of fluconazole analogues of 1-(1H-1,2,4-triazol-1-yl)-2-(2,4- difluoro-phenyl)-3-4-(substituted-heterocyclic ring-1H-1,2,3- triazol-1-yl)-2-propanols (1-10) were designed, synthesized and evaluated as antifungal agents. Preliminary antifungal tests showed that most of the title compounds exhibited moderate activity with broad spectrum against eight human pathogenic fungi in vitro, compounds 1 and 6 had the best antifungal activity against Candida albicans with the value of MIC80 = 0.5 μg/mL respectively.
- Wang, Shudong,Zhang, Lei,Jin, Yongsheng,Tang, Jin Hao,Su, Hua,Yu, Shichong,Ren, Haixiang
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p. 2362 - 2364
(2014/06/09)
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- Selective oxidation of alcohols to esters using heterogeneous Co 3O4-N@C catalysts under mild conditions
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Novel cobalt-based heterogeneous catalysts have been developed for the direct oxidative esterification of alcohols using molecular oxygen as benign oxidant. Pyrolysis of nitrogen-ligated cobalt(II) acetate supported on commercial carbon transforms typical homogeneous complexes to highly active and selective heterogeneous Co3O4-N@C materials. By applying these catalysts in the presence of oxygen, the cross and self-esterification of alcohols to esters proceeds in good to excellent yields.
- Jagadeesh, Rajenahally V.,Junge, Henrik,Pohl, Marga-Martina,Radnik, Joerg,Brueckner, Angelika,Beller, Matthias
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supporting information
p. 10776 - 10782
(2013/08/23)
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- Copper-catalyzed methyl esterification reactions via C-C bond cleavage
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The highly effective synthesis of methyl esters from benzylic alcohols, aldehydes, or acids via copper-catalyzed C-C cleavage from tert-butyl hydroperoxide is reported in this paper for the first time. Our protocol is easily accessible and practical, making it a possible supplement for the traditional way.
- Zhu, Yan,Yan, Hong,Lu, Linhua,Liu, Defu,Rong, Guangwei,Mao, Jincheng
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p. 9898 - 9905
(2013/10/22)
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- Copper-catalyzed N-methylation of amides and O-methylation of carboxylic acids by using peroxides as the methylating reagents
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The copper-catalyzed N-methylation of amides and O-methylation of carboxylic acids by using peroxides as the methylating reagent are described. Various amides and carboxylic acids were methylated affording N-substituted amides and esters. Tentative mechanistic studies suggest that this reaction is likely to involve a radical process.
- Xia, Qinqin,Liu, Xiaolong,Zhang, Yuejiao,Chen, Chao,Chen, Wanzhi
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supporting information
p. 3326 - 3329
(2013/07/26)
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- Aerobic oxidative esterification of benzyl alcohols with catalytic tetrabromomethane under visible light irradiation
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We report a useful method for the facile synthesis of aromatic esters from benzyl alcohols with molecular oxygen and catalytic tetrabromomethane in alcohol under visible light irradiation with a fluorescent lamp. This is the first metal-free reaction using molecular oxygen as the terminal oxidant.
- Nobuta, Tomoya,Fujiya, Akitoshi,Hirashima, Shin-Ichi,Tada, Norihiro,Miura, Tsuyoshi,Itoh, Akichika
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p. 5306 - 5308
(2012/11/07)
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- Direct aerobic photo-oxidative syntheses of aromatic methyl esters from methyl aromatics using anthraquinone-2,3-dicarboxylic acid as organophotocatalyst
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This paper reports a useful method for facile direct syntheses of aromatic methyl esters from methyl aromatics by aerobic photo-oxidation using anthraquinone-2,3-dicarboxylic acid as an organophotocatalyst.
- Tada, Norihiro,Ikebata, Yuki,Nobuta, Tomoya,Hirashima, Shin-Ichi,Miura, Tsuyoshi,Itoh, Akichika
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experimental part
p. 616 - 619
(2012/07/13)
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- Synthesis of new S-alkylated-3-mercapto-1,2,4-triazole derivatives bearing cyclic amine moiety as potent anticancer agents
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A series of 3-[3-[4-(Substituted)-1-cyclicamine]propyl]thio-5- substituted[1,2,4]triazoles (8a-j) were synthesized with good yields starting from corresponding carboxylic acids. The cytotoxicity studies of these derivatives were studied against five different human cancer cell lines. Three compounds had shown good anticancer activity. The triazole derivatives, 8i and 8j were most potent particularly against U937 and HL-60 cells. The cytotoxic potency of the compounds varied between the cell lines suggesting that a structural property of these compounds as possible determinants of their biological activity.
- Murty,Ram, Kesur R.,Rao, Rayudu Venkateswara,Yadav,Rao, Janapala Venkateswara,Pamanji,Velatooru
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experimental part
p. 276 - 281
(2012/06/18)
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- Synthesis, biological evaluation and molecular docking studies of novel 2-(1,3,4-oxadiazol-2-ylthio)-1-phenylethanone derivatives
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In present study, a series of new 2-(1,3,4-oxadiazol-2-ylthio)-1- phenylethanone derivatives (6a-6x) as potential focal adhesion kinase (FAK) inhibitors were synthesized. The bioassay assays demonstrated that compound 6i showed the most potent activity, which inhibited the growth of MCF-7 and A431 cell lines with IC50 values of 140 ± 10 nM and 10 ± 1 nM, respectively. Compound 6i also exhibited significant FAK inhibitory activity (IC50 = 20 ± 1 nM). Docking simulation was performed to position compound 6i into the active site of FAK to determine the probable binding model.
- Zhang, Li-Rong,Liu, Zhi-Jun,Zhang, Hui,Sun, Jian,Luo, Yin,Zhao, Ting-Ting,Gong, Hai-Bin,Zhu, Hai-Liang
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scheme or table
p. 3615 - 3621
(2012/07/27)
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