- Antitumor-active cobalt-alkyne complexes derived from acetylsalicylic acid: Studies on the mode of drug action
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Cobalt-alkyne complexes are drugs with remarkable cytotoxicity. From the complexes tested up to now we selected the aspirin derivative [2-acetoxy-(2-propynyl)benzoate]hexacarbonyl-dicobalt (Co-ASS) as the lead compound. To get more insight into the mode o
- Ott, Ingo,Schmidt, Kathrin,Kircher, Brigitte,Schumacher, Petra,Wiglenda, Thomas,Gust, Ronald
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- Synthesis of chloroesters by the reaction of ethers with acyl chlorides catalyzed by ZnO
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An efficient method for the synthesis of chloroesters by the reaction of ethers with acyl chlorides catalyzed by nano-ZnO under solvent-free condition at room temperature was described. The method is compatible with a range of ethers including tricyclic ethers, tetracyclic ethers, pentacyclic ethers and hexacyclic ethers and have afforded the products with moderate to good yields. The ZnO could be reused up to three times and the product yield after three cycles is 87%.
- Tang, Yuqi,Feng, Chengliang,Yang, Wanfeng,Ji, Min,Wang, Wei,Chen, Junqing
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- Pd/Cu-Catalyzed Vinylation of Terminal Alkynes with (2-Bromoethyl)diphenylsulfonium Triflate
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The potential of (2-bromoethyl)diphenylsulfonium triflate to be a powerful vinylation reagent was determined by the Sonogashira cross-coupling reactions with terminal alkynes. The vinylation proceeded smoothly at 25 °C under Pd/Cu catalysis to afford a variety of 1- and 2-unsubstituted 1,3-enynes in moderate to excellent yields. This protocol represents the first application of (2-haloethyl)diphenylsulfonium triflate as a CH═CH2 transfer source in organic synthesis.
- Ming, Xiao-Xia,Wu, Shuai,Tian, Ze-Yu,Song, Jia-Wei,Zhang, Cheng-Pan
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supporting information
p. 6795 - 6800
(2021/09/08)
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- New ursolic acid derivatives bearing 1,2,3-triazole moieties: design, synthesis and anti-inflammatory activity in vitro and in vivo
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Abstract: In order to discover novel anti-inflammatory agents, three series of compounds obtained by appending 1,2,3-triazole moieties on ursolic acid were designed and synthesized. All compounds have been screened for their anti-inflammatory activity by using an ear edema model. The potent anti-inflammatory compound was subjected to in vitro cyclooxygenase COX-1/COX-2 inhibition assays. In general, the derivatives were found to be potent anti-inflammatory activity. Especially, the compound 11b exhibited the strongest activity of all of the compounds prepared, with 82.81% inhibition after intraperitoneal administration, which was better than celecoxib as a positive control. Molecular docking results unclose the rationale for the interaction of the compound 11b with COX-2 enzyme. Further studies revealed that compound 11b exhibited effective COX-2 inhibitory activity, with half-maximal inhibitor concentration (IC50) value of 1.16?μM and selectivity index (SI = 64.66) value close to that of celecoxib (IC50 = 0.93?μM, SI = 65.47). Taken together, these results could suggest a promising chemotype for development of new COX-2-targeting anti-inflammatory agent. Graphic abstract: [Figure not available: see fulltext.]
- Bai, Xue-Qian,Cao, Li-Ting,Li, Chun-Shi,Sun, Si-Mei,Zhang, Tian-Yi,Zhao, Dong-Hai
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- Enantioselective Addition of Alkynyl Esters and Ethers to Aldehydes Catalyzed by a Cyclopropyl Amino Alcohol Based Zinc Catalyst
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A novel and highly enantioselective synthesis of hydroxyalkynyl esters and ethers through the asymmetric addition of alkynyl esters or ethers to aldehydes promoted by a cyclopropyl amino alcohol based zinc catalyst has been developed. The method afforded a library of new enantioenriched hydroxyalkynol esters and ethers (up to 93percent yield; 95percent ee), and it was compatible with a broad range of functional groups. Moreover, it could be used in the synthesis of carbon-chain-elongated enantioenriched hydroxyalkynol esters and (2 R,5 R)-musclide-A1, a cardiotonic potentiating principle from musk.
- Bian, Qinghua,Li, Fengqi,Li, Shuoning,Ma, Sijie,Walsh, Patrick J.,Wang, Lifeng,Wang, Min,Zhong, Jiangchun,Zhou, Yun
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supporting information
p. 60 - 64
(2019/12/30)
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- Synthesis of Cyclopenta[b]indoles via a Formal [3+2] Cyclization of N-Sulfonyl-1,2,3-triazoles and Indoles
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Annulation of benzoxy-tethered N-sulfonyl-1,2,3-triazoles and indoles has been developed in this paper, providing an efficient and convenient access to valuable cyclopenta[b]indoles in moderate to good yields. α,β-Unsaturated imine, which generated in situ from denitrogenation and 1,2-OBz migration of triazole, provided three carbons for the formal [3+2] cyclization reaction for the first time. (Figure presented.).
- Duan, Shengguo,Zhang, Wan,Hu, Yuntong,Xu, Ze-Feng,Li, Chuan-Ying
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supporting information
p. 3570 - 3575
(2020/08/05)
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- Fischer Carbene Pentannulation with Alkynes Having Adjacent Carbonate or Acyloxy Groups: Synthesis of 3-Substituted 1-Indanones
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Various aryl Fischer carbenes reacted with alkynes having adjacent acyloxy or carbonate groups to regioselectively deliver 3-substituted 1-indanones. The acyloxy or carbonate group probably coordinates with the Cr metal to give a tetra-coordinated chromium complex forming a six-membered ring that retards CO insertion for ketene formation, which is required for benzannulation. Alternatively, the ortho position aryl ring attack results in pentannulation, providing regioselectively 3-substituted 1-indanones. The method is extended to the synthesis of the core structure of 3-epi-mutisianthol.
- Bhattacharyya, Shubhankar,Chavan, Vijay P.,Fernandes, Rodney A.,Gholap, Sachin P.,Saiyed, Akeel S.
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supporting information
p. 3438 - 3443
(2020/04/20)
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- Regioselective synthesis, antibacterial, and antioxidant activities of ester-linked 1,4-disubstituted 1,2,3-triazoles
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Abstract: Synthesis of ester-linked 1,4-disubstituted 1,2,3-triazoles was carried out in water through cycloaddition between benzoic acid prop-2-yn-1-yl esters and aromatic azides using cellulose-supported cuprous iodide nanoparticles. Structures of all t
- Kaushik,Sangwan, Jyoti
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p. 807 - 819
(2020/05/18)
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- Novel ferrocene-based 1,2,3-triazolyl compounds: Synthesis, anti-migration properties and catalytic effects on oxidizers during combustion
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To tackle high-migratory and high-volatility problem of marketed neutral ferrocene-based burning rate catalysts, twenty-one ferrocene-based 1,2,3-triazolyl compounds (Fc-TAZs) were synthesized by click reaction and characterized completely by NMR, FT-IR,
- Cheng, Wenqian,Shi, Xiaoling,Zhang, Yu,Jian, Yajun,Zhang, Guofang
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- The bioisosteric modification of pyrazinamide derivatives led to potent antitubercular agents: Synthesis via click approach and molecular docking of pyrazine-1,2,3-triazoles
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Tuberculosis remains as a major public health risk which causes the highest mortality rate globally and an improved regimen is required to treat the drug-resistant strains. Pyrazinamide is a first-line antitubercular drug used in combination therapy with other anti-TB drugs. Herein, we describe the modification of pyrazinamide structure using bioisosterism and rational approaches by incorporating the 1,2,3-triazole moiety. Three sets of pyrazine-1,2,3-triazoles (3a-o, 5a-o and 9a-l) are designed, synthesized and evaluated for their in vitro inhibitory potency against mycobacterium tuberculosis H37Rv. The pyrazine-1,2,3-triazoles synthesized through the bioisosteric modification displayed improved activity as compared to rationally modified pyrazine-1,2,3-triazoles. Among 42 title compounds, seven derivatives demonstrated significant anti-tubercular activity with the MIC of 1.56 μg/mL, which are two-fold more potent than the parent compound pyrazinamide. Further, the synthesized pyrazinamide analogs demonstrated moderate inhibition activity against several bacterial strains and possessed an acceptable in vitro cytotoxicity profile as well. Additionally, the activity profile of pyrazine-1,2,3-triazoles was validated by performing the molecular docking studies against the Inh A enzyme. Furthermore, in silico ADME prediction revealed good oral bioavailability for the potent molecules.
- Reddyrajula, Rajkumar,Dalimba, Udayakumar
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supporting information
(2019/12/24)
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- Regioselective Gold-Catalyzed Hydration of CF3- and SF5-alkynes
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The regioselective gold-catalyzed hydration of CF3- and SF5-alkynes is described. The corresponding trifluoromethylated and pentasulfanylated ketones are obtained in up to 91% yield as single regioisomers showcasing the use of CF3 and SF5 as highly efficient directing groups in this reaction. Notably, this transformation represents the first use of CF3- and SF5-alkynes in gold catalysis.
- Cloutier, Mélissa,Roudias, Majdouline,Paquin, Jean-Fran?ois
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supporting information
p. 3866 - 3870
(2019/05/24)
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- Relative Rates of Metal-Free Azide-Alkyne Cycloadditions: Tunability over 3 Orders of Magnitude
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The thermal (3 + 2) dipolar azide-alkyne cycloaddition, proceeding without copper or strained alkynes, is an underutilized ligation with potential applications in materials, bioorganic, and synthetic chemistry. Herein, we investigate the effects of alkyne substitution on the rate of this reaction, both experimentally and computationally. Electron-withdrawing groups accelerate the reaction, providing a range of relative rates from 1.0 to 2100 between the slowest and fastest alkynes studied. Unexpectedly, aryl groups conjugated to the alkyne significantly retard the reaction rate. In contrast, a sulfonyl, ester-substituted alkyne is reactive enough that it couples with an azide at room temperature in a few hours. This reactivity scale should provide a guide to those who wish to use this ligation under mild conditions.
- Skelly, Patrick W.,Sae-Jew, Jirapon,Kitos Vasconcelos, Ana Paula,Tasnim, Jerin,Li, Longbo,Raskatov, Jevgenij A.,Braslau, Rebecca
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- Relative Rates of Metal-Free Azide-Alkyne Cycloadditions: Tunability over 3 Orders of Magnitude
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The thermal (3 + 2) dipolar azide-alkyne cycloaddition, proceeding without copper or strained alkynes, is an underutilized ligation with potential applications in materials, bioorganic, and synthetic chemistry. Herein, we investigate the effects of alkyne substitution on the rate of this reaction, both experimentally and computationally. Electron-withdrawing groups accelerate the reaction, providing a range of relative rates from 1.0 to 2100 between the slowest and fastest alkynes studied. Unexpectedly, aryl groups conjugated to the alkyne significantly retard the reaction rate. In contrast, a sulfonyl, ester-substituted alkyne is reactive enough that it couples with an azide at room temperature in a few hours. This reactivity scale should provide a guide to those who wish to use this ligation under mild conditions.
- Skelly, Patrick W.,Sae-Jew, Jirapon,Kitos Vasconcelos, Ana Paula,Tasnim, Jerin,Li, Longbo,Raskatov, Jevgenij A.,Braslau, Rebecca
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p. 13615 - 13623
(2019/11/14)
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- Design, synthesis and biological evaluation of novel inhibitors against cyanobacterial pyruvate dehydrogenase multienzyme complex E1
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Cyanobacterial pyruvate dehydrogenase multienzyme complex E1 (PDHc E1)is a potential target enzyme for finding inhibitors to control harmful cyanobacterial blooms. In this study, a series of novel triazole thiamin diphosphate (ThDP)analogs were designed a
- Feng, Jiangtao,He, Haifeng,Zhou, Yuan,Guo, Xiaoliang,Liu, Honglin,Cai, Meng,Wang, Fang,Feng, Lingling,He, Hongwu
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p. 2413 - 2420
(2019/01/30)
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- Rhodium-catalysed synthesis of fused pyrimidine derivatives employing N-sulfonyl-1,2,3-triazoles as a 1-aza-[4C] synthon
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A new synthetic application of N-sulfonyl-1,2,3-triazoles acting as a 1-aza-[4C] synthon via the 1,2-shift reaction of an α-imine rhodium carbene was developed for the synthesis of fused pyrimidine derivatives. The high reactivity of the strained three-me
- Xu, Ze-Feng,An, Yuehui,Chen, Yidian,Duan, Shengguo
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supporting information
p. 1849 - 1853
(2019/06/20)
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- Containing ferrocene group of benzoic acid esters of combustion catalyst and its preparation method (by machine translation)
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The invention discloses a containing ferrocene group of benzoic acid esters of combustion catalyst and its preparation method, the catalyst for combustion of the structural formula In the formula R1 - R4 Independently represents a h
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Paragraph 0018; 0019
(2019/04/06)
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- Novel triazole-tetrahydroisoquinoline hybrids as human aromatase inhibitors
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Novel thirteen triazole-tetrahydroisoquinoline derivatives (2a-m) were synthesized and evaluated for their aromatase inhibitory activities. Seven triazoles showed significant aromatase inhibitory activity (IC50 = 0.07–1.9 μM). Interestingly, th
- Chamduang, Chanamon,Pingaew, Ratchanok,Prachayasittikul, Veda,Prachayasittikul, Supaluk,Ruchirawat, Somsak,Prachayasittikul, Virapong
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- Neighboring Carbonyl Group Assisted Oxyacetoxylation of Propargylic Carboxylates with Retention of Chirality under Metal Free Condition
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A metal-free oxyacetoxylation method of primary, secondary and tertiary propargylic carboxylates with retention of chirality was presented. The reaction proceeds through the intramolecular nucleophilic attack of the neighboring carbonyl group on an alkynyliodonium intermediate. The process is general with broad substrate scope and is amenable for application to a variety of propargyl carboxylates including those obtained from natural products. Insight into the mechanistic pathway by isotopic labelling (using H2O18 and D2O) and controlled experiments confirmed. (Figure presented.).
- Pradhan, Tapas R.,Mohapatra, Debendra K.
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supporting information
p. 3605 - 3611
(2019/07/04)
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- An Atom-Economic and Stereospecific Access to Trisubstituted Olefins through Enyne Cross Metathesis Followed by 1,4-Hydrogenation
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The combination of intermolecular enyne cross metathesis and subsequent 1,4-hydrogenation opens a stereocontrolled and atom-economic access to trisubstituted olefins. By investigating different combinations of functionalized alkyne and alkene substrates, we found that the outcome (yield, E / Z ratio) of the Grubbs II-catalyzed enyne cross-metathesis step depends on the substrate's structure, the amount of the alkene (used in excess), and the (optional) presence of ethylene. In any case, the 1,4-hydrogenation, catalyzed by 1,2-dimethoxybenzene-Cr(CO) 3, proceeds stereospecifically to yield exclusively the E -products from both the E- and Z- 1,3-diene intermediates obtained by metathesis. A rather broad scope and functional group compatibility of the method is demonstrated by means of 15 examples.
- Ratsch, Friederike,Schmalz, Hans-Günther
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supporting information
p. 785 - 792
(2018/01/27)
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- Divergent Elementoboration: 1,3-Haloboration versus 1,1-Carboboration of Propargyl Esters
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This work showcases the 1,3-haloboration reaction of alkynes in which boron and chlorine add to propargyl systems in a proposed sequential oxazoliumborate formation with subsequent ring-opening and chloride migration. In addition, the functionalization of
- Wilkins, Lewis C.,Soltani, Yashar,Lawson, James R.,Slater, Ben,Melen, Rebecca L.
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supporting information
p. 7364 - 7368
(2018/05/03)
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- An expedient ‘click’ approach for the synthetic evaluation of ester-triazole-tethered organosilica conjugates
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The present work articulates the synthesis of a new series of organo-functionalized triethoxysilanes derived from versatile carboxylic acids and 3-azidopropyltriethoxysilane in excellent yields. A proficient and convenient route implicating the Cu(I)-catalysed 1,3-cycloaddition of organic azide with terminal alkynes, labelled as click silylation, has been developed for the generation of ester-triazole-linked alkoxysilanyl scaffolds (4a–f). All the synthesized compounds have been thoroughly characterized using elemental analysis and Fourier transform infrared, 1H NMR and 13C NMR spectroscopic techniques. Importantly, the fabricated alkoxysilanes are potentially amenable for an in situ sol–gel condensation reaction with silica nanospheres leading to the incorporation of organic functionality via covalent grafting onto the nanostructured particle system. As a proof of concept, a one-pot preparation of organic–inorganic hybrid nanoparticles is presented using bis-silane 4?f. The efficiency and selectivity of the prepared nanocomposite towards metal ions is highlighted using adsorption experiments, and the immobilized nanoparticles present a high sensing efficiency towards Cu2+ and Pb2+ ions while demonstrating better response than that of the bulk material.
- Singh, Gurjaspreet,Rani, Sunita
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- Synthesis and Antimicrobial Evaluation of (1-(2-(Benzyloxy)-2-oxoethyl)-1H-1,2,3-triazol-4-yl)methyl Benzoate Analogues
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A convenient one pot synthesis of 20 (1-(2-(benzyloxy)-2-oxoethyl)-1H-1,2,3-triazol-4-yl)methyl benzoate analogues (5a–5t) with ester functionality was carried out via Cu(I) catalyzed click reaction between prop-2-yn-1-yl benzoates and benzyl 2-azidoacetates. The structure of synthesized triazoles were explicated by various spectral techniques like FT-IR, 1H NMR, 13C NMR, and high-resolution mass spectrometry and evaluated for in vitro antimicrobial potential against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Enterobacter aerogenes, Candida albicans, and Aspergillus niger. Most of synthesized triazole derivatives exhibited average to excellent activity against tested microbial strains.
- Kaushik,Pahwa, Ashima,Kumar, Devinder,Kumar, Ashwani,Singh, Dharmendra,Kumar, Krishan,Luxmi, Raj
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p. 1720 - 1728
(2018/07/25)
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- Metal-Free Decarboxylative Trichlorination of Alkynyl Carboxylic Acids: Synthesis of Trichloromethyl Ketones
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2,2,2-Trichloroacetophenone derivatives were synthesized via decarboxylative trichlorination from arylpropiolic acids and trichloroisocyanuric acid (TCCA). The reaction was performed in the presence of water at room temperature, and the desired products were obtained in good yields. The reaction showed good functional group tolerance towards halide, cyano, nitro, ketone, ester and aldehyde groups. In addition, the 2,2,2-trichloroacetophenone derivatives were readily transformed into esters, amides, and hydrazides. Based on experiments with H218O (water-18O), we proposed a cationic reaction pathway as the mechanism and suggested two different pathways for producing aryl- and alkyl-substituted propiolic acids. (Figure presented.).
- Jayaraman, Aravindan,Cho, Eunjeong,Irudayanathan, Francis Mariaraj,Kim, Jimin,Lee, Sunwoo
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p. 130 - 141
(2017/12/26)
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- Tris(2,4,6-trifluorophenyl)borane: An Efficient Hydroboration Catalyst
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The metal-free catalyst tris(2,4,6-trifluorophenyl)borane has demonstrated its extensive applications in the 1,2-hydroboration of numerous unsaturated reagents, namely alkynes, aldehydes and imines, consisting of a wide array of electron-withdrawing and donating functionalities. A range of over 50 borylated products are reported, with many reactions proceeding with low catalyst loading under ambient conditions. These pinacol boronate esters, in the case of aldehydes and imines, can be readily hydrolyzed to leave the respective alcohol and amine, whereas alkynyl substrates result in vinyl boranes. This is of great synthetic use to the organic chemist.
- Lawson, James R.,Wilkins, Lewis C.,Melen, Rebecca L.
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supporting information
p. 10997 - 11000
(2017/08/22)
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- Click synthesis of some mono/bis 1,2,3-triazoles with ester linkage and their microbicidal activity
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Synthesis of some new 1,4-disubstituted 1,2,3-triazoles with ester functionality is reported employing Cu(I) catalyzed Huisgen [3+2] cycloaddition reaction of prop-2-yn-1-yl benzoates with 1,4-phenylenebis(methylene) bis(2-azidoacetate) and benzyl 2-azidoacetates. The synthesized compounds were well characterized through FTIR, 1H NMR, 13C NMR and HRMS. Further, the synthesized triazole derivatives were accessed for in vitro antimicrobial activity against one Gram-positive bacterial strain Staphylococcus aureus, three Gram-negative bacterial strains Escherichia coli, Klebsiella pneumoniae, Enterobacter aerogenes and two fungi Candida albicans and Aspergillus niger. Few of the synthesized disubstituted 1,2,3-triazoles displayed moderate to good inhibitory activity against tested microbial strains.
- Kaushik,Pahwa, Ashima
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p. 2171 - 2176
(2017/10/06)
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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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- Transition-Metal-Free Poly(thiazolium) Iodide/1,8-Diazabicyclo[5.4.0]undec-7-ene/Phenazine-Catalyzed Esterification of Aldehydes with Alcohols
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Poly(3,4-dimethyl-5-vinylthiazolium) iodide was used as a polymer precatalyst in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and phenazine for the oxidative esterification of aldehydes with alcohols. Selective functionalization of OH groups was achieved in the presence of NH2 groups. The poly(thiazolium) iodide/DBU/phenazine system exhibited excellent catalytic activity and could be reused five times without loss of activity.
- Chun, Supill,Chung, Young Keun
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supporting information
p. 3787 - 3790
(2017/07/26)
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- Graphene Oxide: An Efficient Acid Catalyst for the Construction of Esters from Acids and Alcohols
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Graphene oxide was found to be an efficient and reusable acid catalyst for the esterification reaction. A wide range of aliphatic and aromatic acids and alcohols were compatible with the standard conditions and afforded the corresponding products in good yields. The heterogeneous catalyst can be easily recovered and recycled in dichloro-ethane solvent with good catalytic activity.
- Chen, Zhengwang,Wen, Yuelu,Fu, Yejuan,Chen, Hai,Ye, Min,Luo, Guotian
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supporting information
p. 981 - 985
(2017/05/05)
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- Zirconocene-catalyzed direct (trans)esterification of acyl acids (esters) and alcohols in a strict 1:1 ratio under solvent-free conditions
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A highly efficient way for the direct (trans)esterification of acyl acids (esters) and alcohols in a strict 1:1 ratio using a zirconocene complex (1, 1 mol%), a strong Lewis acid of good water tolerance, as a catalyst under solvent-free conditions has been developed. A wide range of acid and alcohol (esters) substrates undergo (trans)esterification to produce carboxylic ester motifs in moderate to good or excellent yields with good functional tolerance, such as that towards C-Br as well as CC and CC bonds. And complex 1 can be recycled six times without showing a significant decline in catalytic efficiency. It was demonstrated that cyclandelate, which is used to treat high blood pressure as well as heart and blood-vessel diseases, can be directly synthesized on a gram scale with 81% yield (6.70 g) using complex 1.
- Tang, Zhi,Jiang, Qiutao,Peng, Lifen,Xu, Xinhua,Li, Jie,Qiu, Renhua,Au, Chak-Tong
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supporting information
p. 5396 - 5402
(2017/11/22)
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- The Propargyl Rearrangement to Functionalised Allyl-Boron and Borocation Compounds
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A diverse range of Lewis acidic alkyl, vinyl and aryl boranes and borenium compounds that are capable of new carbon–carbon bond formation through selective migratory group transfer have been synthesised. Utilising a series of heteroleptic boranes [PhB(Cs
- Wilkins, Lewis C.,Lawson, James R.,Wieneke, Philipp,Rominger, Frank,Hashmi, A. Stephen K.,Hansmann, Max M.,Melen, Rebecca L.
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supporting information
p. 14618 - 14624
(2016/10/03)
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- Alkene-directed N-attack chemoselectivity in the gold-catalyzed [2+2+1]-annulations of 1,6-enynes with N-hydroxyanilines
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Kinetically unstable nitrones are generated from gold-catalyzed reactions of 1,6-enynes with N-hydroxyanilines, and subsequently trapped by tethered alkenes to furnish [2+2+1]-annulations. Our experimental data reveal that such nitrones arise from atypical N-attack chemoselectivity that is triggered by tethered alkenes to facilitate the key protodeauration reaction. Kinetically unstable nitrones are generated from gold-catalyzed reactions of 1,6-enynes with N-hydroxyanilines, and subsequently trapped by tethered alkenes to furnish [2+2+1]-annulations. These findings open the door to new ways to access ketone nitrones with good stereoselectivity.
- Huple, Deepak B.,Mokar, Bhanudas D.,Liu, Rai-Shung
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supporting information
p. 14924 - 14928
(2016/02/05)
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- Synthesis, characterization, and antimicrobial potential of some 1,4-disubstituted 1,2,3-bistriazoles
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A convenient synthesis of some new 1,4-disubstituted 1,2,3-bistriazoles (3a-3f, 4a-4f, 6a-6b, 7a-7b) is reported via copper(I)-catalyzed Huisgen 1,3-dipolar cycloaddition of various terminal alkynes with 1,4-bis(azidomethyl)benzene and 1,6-diazidohexane.
- Kaushik,Kumar, Krishan,Singh, Dharmendra,Singh,Jindal, Deepak Kumar,Luxmi, Raj
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supporting information
p. 1977 - 1985
(2015/08/18)
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- Metal-Free Direct Oxidation of Aldehydes to Esters Using TCCA
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Aromatic and aliphatic aldehydes are simply converted into esters by an efficient oxidative esterification carried out under mild conditions. The aldehydes are converted in situ into their corresponding acyl chlorides, which are then reacted with primary and secondary aliphatic, benzylic, allylic, and propargylic alcohols and phenols. A variety of esters are obtained in high yields.
- Gaspa, Silvia,Porcheddu, Andrea,De Luca, Lidia
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supporting information
p. 3666 - 3669
(2015/08/18)
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- Synthesis of novel 1,4-disubstituted 1,2,3-triazolo-bosentan derivatives - evaluation of antimicrobial and anticancer activities and molecular docking
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Novel 1,4-disubstituted 1,2,3-triazolo bosentan derivatives 1a-n from bosentan 2 were synthesized in good yields by sequential chlorination, azidation followed by Cu(i) catalyzed 1,3-dipolar cycloaddition. All obtained compounds 1a-n were evaluated for their antimicrobial and in vitro anticancer activities and by in silico docking studies. Among all tested compounds 1e,f and 1h-j show better antimicrobial activities against the tested bacteria and fungi. When subjected to anticancer testing, compounds 1g-j and 1n show significant activities against both A549 and SKOV-3 cell lines with IC50 values at 7.81 μg mL-1 and among them compound 1i exhibited very potent activity. In addition, no toxicity was calculated up to 2 mg mL-1 in Vero cells. In silico studies were conducted to investigate the possible bonding modes of 1a-n with target receptors namely DNA topoisomerase IV (4 EMV) and anaplastic lymphoma kinase (2XP2). Among them, compounds 1e and 1h show maximum binding energies with 4EMV and 2XP2 receptors, respectively which also exhibited good antimicrobial and potent anticancer activities.
- Easwaramoorthi,Rajendran, A. Jeya,Rao, K. Chennakesava,Arun,Balachandran,Perumal,Emi, Nobuhiko,Mahalingam,Duraipandiyan,Al-Dhabi
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p. 105266 - 105278
(2015/12/30)
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- Safe Removal of the Allyl Protecting Groups of Allyl Esters using a Recyclable, Low-Leaching and Ligand-Free Palladium Nanoparticle Catalyst
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A safe, facile and low-leaching (up to 0.04ppm) method has been developed for the removal of allyl, prenyl and benzyl protecting groups from the corresponding esters, using a sulfur-modified gold-supported palladium (SAPd) nanoparticle catalyst, which is known to be non-flammable. The catalyst itself was found to be recyclable and the reaction appeared to proceed on the surface of the SAPd.
- Takagi, Koji,Fukuda, Hayato,Shuto, Satoshi,Otaka, Akira,Arisawa, Mitsuhiro
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p. 2119 - 2124
(2015/06/23)
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- Direct macrolactonization of seco acids via hafnium(IV) catalysis
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Efficient direct macrolactonization of seco acids can be catalyzed by Hf(OTf)4 in high yields, forming water as the sole byproduct. The Hf(OTf)4 catalyst possesses unique reactivity characteristics relative to other Lewis acids, as it promotes macrolactonization over hydrolysis even in the presence of excess water. In addition to forming a variety of macrolactones and benzolactones (55-90%), intermolecular direct esterifications of carboxylic acids and alcohols were also possible and demonstrated compatibility with common carbamate, silyl ether, alkoxymethyl ether, and acetal protecting groups. All of the macrolactonization and esterification processes developed are operationally simple, "one-pot" reactions that exploit a commercially available catalyst without the need for slow addition or azeotropic techniques.
- De Léséleuc, Mylene,Collins, Shawn K.
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p. 1462 - 1467
(2015/03/14)
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- 7-Chloroquinolinotriazoles: Synthesis by the azide-alkyne cycloaddition click chemistry, antimalarial activity, cytotoxicity and SAR studies
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Twenty-seven 7-chloroquinolinotriazole derivatives with different substituents in the triazole moiety were synthesized via copper-catalyzed cycloaddition (CuAAC) click chemistry between 4-azido-7-chloroquinoline and several alkynes. All the synthetic compounds were evaluated for their in vitro activity against Plasmodium falciparum (W2) and cytotoxicity to Hep G2A16 cells. All the products disclosed low cytotoxicity (CC50 > 100 μM) and five of them have shown moderate antimalarial activity (IC50 from 9.6 to 40.9 μM). As chloroquine analogs it was expected that these compounds might inhibit the heme polymerization and SAR studies were performed aiming to explain their antimalarial profile. New structural variations can be designed on the basis of the results obtained.
- Pereira, Guilherme R.,Brand?o, Geraldo Célio,Arantes, Lucas M.,De Oliveira Jr., Háliton A.,De Paula, Renata Cristina,Do Nascimento, Maria Fernanda A.,Dos Santos, Fábio M.,Da Rocha, Ramon K.,Lopes, Júlio César D.,De Oliveira, Alaíde Braga
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p. 295 - 309
(2014/02/14)
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- TRICYCLIC HETEROCYCLES AS BET PROTEIN INHIBITORS
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The present invention relates to tricyclic heterocycles which are inhibitors of BET proteins such as BRD2, BRD3, BRD4, and BRD-t and are useful in the treatment of diseases such as cancer.
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Page/Page column 161
(2014/09/29)
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- Mn-catalyzed aromatic C-H alkenylation with terminal alkynes
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The first manganese-catalyzed aromatic C-H alkenylation with terminal alkynes is described. The procedure features an operationally simple catalyst system containing commercially available MnBr(CO)5 and dicyclohexylamine (Cy2NH). The reaction occurs readily in a highly chemo-, regio-, and stereoselective manner delivering anti-Markovnikov E-configured olefins in high yields. Experimental study and DFT calculations reveal that (1) the reaction is initiated by a C-H activation step via the cooperation of manganese and base; (2) manganacycle and alkynylmanganese species are the key reaction intermediates; and (3) the ligand-to-ligand H-transfer and alkynyl-assisted C-H activation are the key steps rendering the reaction catalytic in manganese.
- Zhou, Bingwei,Chen, Hui,Wang, Congyang
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supporting information
p. 1264 - 1267
(2013/03/14)
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- Combining oxidative N-heterocyclic carbene catalysis with click chemistry: A facile one-pot approach to 1,2,3-triazole derivatives
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A combination of the oxidative N-heterocyclic carbene catalysis and click chemistry has been explored for the direct, one-pot synthesis of 1,2,3-triazole derivatives from aromatic aldehydes. This procedure was found to be very efficient and a variety of 1
- Ramanjaneyulu,Reddy, Virsinha,Arde, Panjab,Mahesh, Sriram,Anand, R. Vijaya
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p. 1489 - 1496
(2013/07/26)
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- Esterification of free fatty acids (Biodiesel) using nano sulfated-titania as catalyst in solvent-free conditions
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Nano sulfated titania was tested as catalyst for esterification of free fatty acids, specially methanolic and ethanolic esterification of stearic acid (biodiesels). Factorial design evidenced a positive effect of reaction temperature, amount of catalyst, and solvents on ester conversion. This nano-sized sulfated titania has been prepared by a sol-gel hydrothermal process. This prepared sulfated titania showed high catalytic activity in direct esterification of fatty acids as well as benzoic acids with various alcohols and phenols under solvent-free conditions. This method is of great value because of its environmentally benign character, easy handling, high yields, convenient operation, and green. FT-IR studies are shown that the catalyst can be reused for acylation without loss of catalytic activity.
- Hosseini-Sarvari, Mona,Sodagar, Esmat
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p. 229 - 238
(2013/05/09)
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- BROMODOMAIN INHIBITORS AND USES THEREOF
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The present invention relates to compounds useful as inhibitors of bromodomain-containing proteins. The invention also provides pharmaceutically acceptable compositions comprising compounds of the present invention and methods of using said compositions in the treatment of various disorders.
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Page/Page column 73-74
(2012/06/16)
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- A regio- and diastereoselective platinum-catalyzed tandem [2+1]/[3+2] cycloaddition sequence
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Platinum complexes bearing phosphinous acids have efficiently promoted a tandem intermolecular sequence of [2+1]/[3+2] cycloaddition reactions. This process gave access to novel tricyclic systems and the cascade reactions were regio- and diastereoselective (see scheme; Cy=cyclohexyl). The [3+2] cycloaddition reaction was investigated further and two different alkyne partners were used. Copyright
- Achard, Thierry,Lepronier, Aymeric,Gimbert, Yves,Clavier, Herve,Giordano, Laurent,Tenaglia, Alphonse,Buono, Gerard
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supporting information; experimental part
p. 3552 - 3556
(2011/06/09)
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- TBAF-promoted elimination of vicinal dibromides having an adjacent O-functional group: Syntheses of 2-bromoalk-1-enes and alkynes
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Syntheses of 2-bromoalk-1-enes and alkynes were achieved in good yields by dehydrobromination of vicinal dibromides with tetrabutylammonium fluoride. Neighboring O-functional-group participation is important in determining elimination reactivity. Georg Thieme Verlag Stuttgart New York.
- Kutsumura, Noriki,Kubokawa, Keisuke,Saito, Takao
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experimental part
p. 2377 - 2382
(2011/09/16)
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- Synthesis and characterization of 2-Alkyl -5-{4-[(3-nitrophenyl- 5isoxazolyl)methoxy]phenyl}-2H-tetrazoles
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Heteroaryl substituted analogs of antirhnoviral (A), was prepared by a convergent approach. 3-Nitrophenyl-5bromooromethylisoxazoles 5a-b were synthesized by [3+2] cycloaddition of 3-(benzoyloxy)-propyne 2 to in situ generated arylnitrile oxides followed by deprotection of cycloadducts 3a-b and bromination of the resulting alcohols 4a-b. Coupling of 3nitrophenyl-5- bromooromethylisoxazoles (5a-b) with 4-[5-(2-alkyl-2H-tetrazolyl)]phenols (6a-d) in N-methylpyrrolidinone under mild conditions afforded a new series of 2-alkyl-5-{4-[1-(3-nitrophenyl-5-isoxazolyl)methyloxy]phenyl}-2H-tetrazoles (7a-h) in high yields. The structures of the synthesized compounds were confirmed by their 1H NMR, Mass spectral, and Elemental Analysis data.
- Mirzaei,Edjlali
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experimental part
p. 685 - 694
(2010/10/20)
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- Synthesis of para-substituted 1,4,5,6,7,7-hexachlorobicyclo-[2.2.1]hepta-2, 5-dien-2-ylmethyl benzoates
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[4 + 2]-Cycloaddition of hexachlorocyclopentadiene to para-substituted prop-2-yn-1-yl benzoates gave the corresponding 1,4,5,6,7,7-hexachlorobicyclo[2. 2.1]hepta-2,5-dien-2-ylmethyl benzoates. The structure of the adducts was confirmed by independent synthesis, esterification of para-substituted benzoic acids with 1,4,5,6,7,7-hexachlorobicyclo[2.2.1]hepta-2,5-dien-2-ylmethanol.
- Mamedbeili,Kyazimova,Gasanov,Efendieva,Rzabekova
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experimental part
p. 322 - 325
(2010/09/07)
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- Synthesis of 1,4,5,6-tetrachloro-7,7-dimethoxybicyclo[2.2.1]hepta-2,5- dienylmethyl esters of p-substituted benzoic acids
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The possibility of preparing 1,4,5,6-tetrachloro-7,7-dimethoxybicyclo[2.2. 1]hepta-2,5-dienyl-methyl esters of p-substituted benzoic acids by [4+2]cycloaddition of tetrachlorodimethoxycyclo-pentadine to propargyl esters of the corresponding acids was exam
- Mamedbeili,Kyazimova,Zeinalov,Gasanov,Nagiev
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experimental part
p. 691 - 694
(2010/08/21)
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- Protic acid immobilized on solid support as an extremely efficient recyclable catalyst system for a direct and atom economical esterification of carboxylic acids with alcohols
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(Chemical Equation Presented) A convenient and clean procedure of esterification is reported by direct condensation of equimolar amounts of carboxylic acids with alcohols catalyzed by an easy to prepare catalyst system of perchloric acid immobilized on silica gel (HClO4-SiO2). The direct condensation of aryl, heteroaryl, styryl, aryl alkyl, alkyl, cycloalkyl, and long-chain aliphatic carboxylic acids with primary/secondary alkyl/cycloalkyl, allyl, propargyl, and long-chain aliphatic alcohols has been achieved to afford the corresponding esters in excellent yields. Chiral alcohol and N-t-Boc protected chiral amino acid also resulted in ester formation with the representative carboxylic acid or alcohol without competitive N-t-Boc deprotection and detrimental effect on the optical purity of the product demonstrating the mildness and chemoselectivity of the procedure. The esters of long-chain (>C10) acids and alcohols are obtained in high yields. The catalyst is recovered and recycled without significant loss of activity. The industrial application of the esterification process is demonstrated by the synthesis of prodrugs of ibuprofen and a few commercial flavoring agents. Other protic acids such as H2SO4, HBr, TfOH, HBF4, and TFA that were adsorbed on silica gel were less effective compared to HClO4-SiO2 following the order HClO4-SiO 2 ? H2SO4-SiO2 > HBr-SiO 2 > TfOH-SiO2 ? HBF4-SiO2 ≈ TFA-SiO2. When HClO4 was immobilized on other solid supports the catalytic efficiency followed the order HClO4-SiO 2 > HClO4-K10 > HClO4-Al 2O3 (neutral) > HClO4-Al2O 3 (acidic) > HClO4-Al2O3 (basic).
- Chakraborti, Asit K.,Singh, Bavneet,Chankeshwara, Sunay V.,Patel, Alpesh R.
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supporting information; experimental part
p. 5967 - 5974
(2009/12/24)
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- The regiospecific synthesis of some new 3,5-disubstituted isoxazoles
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The compounds with isoxazolemoiety havemany pharmacological, biological and industrial applications, specifically their antiviral activity. In this research work, seven new compounds of 3,5-disubstituted isoxazoles were synthesized. Propargyl alcohol (1)
- Edjlali, Ladan
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experimental part
p. 1322 - 1325
(2009/12/03)
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- Stereospecific approach to α,β-disubstituted nitroalkenes via coupling of α-bromonitroalkenes with boronic acids and terminal acetylenes
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(Z)-α-Bromo-β-substituted nitroethylenes undergo facile Suzuki coupling with aryl, heteroaryl, and vinylboronic acids in the presence of Pd(PPh3)4 as catalyst to afford (E)-α,β-disubstituted nitroethylenes in high yield (up to 95%) and complete specificity. Similar coupling of α-bromonitroethylenes with terminal acetylenes (Sonogashira coupling) provides a novel route to (E)-nitroenynes. These Pd-catalyzed coupling methods offer a convenient and stereospecific entry into a diverse array of synthetically and biologically useful α,β-disubstituted nitroethylenes.
- Ganesh, Madhu,Namboothiri, Irishi N.N.
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p. 11973 - 11983
(2008/03/13)
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