- Electrochemical Trifluoromethoxylation of (Hetero)aromatics with a Trifluoromethyl Source and Oxygen
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Trifluoromethoxylated aromatics (ArOCF3) are valuable structural motifs in the area of drug discovery due to the enhancement of their desired physicochemical properties upon the introduction of the trifluoromethoxy group (CF3O). Although significant progress has been made recently in the introduction of CF3O group into aromatics, current methods either require the use of expensive trifluoromethoxylation reagents or require harsh reaction conditions. We present a conceptually new and operationally simple protocol for the direct C?H trifluoromethoxylation of (hetero)aromatics by the combination of the readily available trifluoromethylating reagent and oxygen under electrochemical reaction conditions. This reaction proceeds through the initial generation of CF3 radical followed by conversion to CF3O radical, addition to (hetero)aromatics and rearomatization. The utility of this electrochemical trifluoromethoxylation is illustrated by the direct incorporation of CF3O group into a variety of (hetero)aromatics as well as bio-relevant molecules.
- Ouyang, Yao,Qing, Feng-Ling,Xu, Xiu-Hua
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supporting information
(2021/12/06)
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- Development and Molecular Understanding of a Pd-Catalyzed Cyanation of Aryl Boronic Acids Enabled by High-Throughput Experimentation and Data Analysis
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A synthetic method for the palladium-catalyzed cyanation of aryl boronic acids using bench stable and non-toxic N-cyanosuccinimide has been developed. High-throughput experimentation facilitated the screen of 90 different ligands and the resultant statistical data analysis identified that ligand σ-donation, π-acidity and sterics are key drivers that govern yield. Categorization into three ligand groups – monophosphines, bisphosphines and miscellaneous – was performed before the analysis. For the monophosphines, the yield of the reaction increases for strong σ-donating, weak π-accepting ligands, with flexible pendant substituents. For the bisphosphines, the yield predominantly correlates with ligand lability. The applicability of the designed reaction to a wider substrate scope was investigated, showing good functional group tolerance in particular with boronic acids bearing electron-withdrawing substituents. This work outlines the development of a novel reaction, coupled with a fast and efficient workflow to gain understanding of the optimal ligand properties for the design of improved palladium cross-coupling catalysts.
- De Jesus Silva, Jordan,Bartalucci, Niccolò,Jelier, Benson,Grosslight, Samantha,Gensch, Tobias,Schünemann, Claas,Müller, Bernd,Kamer, Paul C. J.,Copéret, Christophe,Sigman, Matthew S.,Togni, Antonio
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- Radical C?H Trifluoromethoxylation of (Hetero)arenes with Bis(trifluoromethyl)peroxide
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Trifluoromethoxylated (hetero)arenes are of great interest for several disciplines, especially in agro- and medicinal chemistry. Radical C?H trifluoromethoxylation of (hetero)arenes represents an attractive approach to prepare such compounds, but the high cost and low atom economy of existing .OCF3 radical sources make them unsuitable for the large-scale synthesis of trifluoromethoxylated building blocks. Herein, we introduce bis(trifluoromethyl)peroxide (BTMP, CF3OOCF3) as a practical and efficient trifluoromethoxylating reagent that is easily accessible from inexpensive bulk chemicals. Using either visible light photoredox or TEMPO catalysis, trifluoromethoxylated arenes could be prepared in good yields under mild conditions directly from unactivated aromatics. Moreover, TEMPO catalysis allowed for the one-step synthesis of valuable pyridine derivatives, which have been previously prepared via multi-step approaches.
- Dix, Stefan,Golz, Paul,Schmid, Jonas R.,Riedel, Sebastian,Hopkinson, Matthew N.
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supporting information
p. 11554 - 11558
(2021/07/09)
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- Copper-promoted cyanation of aryl iodides with N,N-dimethyl aminomalononitrile
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A copper-promoted cyanation of aryl iodides has been successfully developed by using N,N-dimethyl aminomalononitrile as the cyanide source with moderate toxicity and better stability. This reaction features broad substrate scope, excellent reaction yields, readily available catalyst, and simple reaction conditions.
- Liu, Si-Zhan,Li, Jing,Xue, Cao-Gen,Xu, Xue-Tao,Lei, Lin-Sheng,Huo, Chen-Yu,Wang, Zhen,Wang, Shao-Hua
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supporting information
(2021/02/01)
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- Visible-Light-Promoted Metal-Free Synthesis of (Hetero)Aromatic Nitriles from C(sp3)?H Bonds**
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The metal-free activation of C(sp3)?H bonds to value-added products is of paramount importance in organic synthesis. We report the use of the commercially available organic dye 2,4,6-triphenylpyrylium tetrafluoroborate (TPP) for the conversion of methylarenes to the corresponding aryl nitriles via a photocatalytic process. Applying this methodology, a variety of cyanobenzenes have been synthesized in good to excellent yield under metal- and cyanide-free conditions. We demonstrate the scope of the method with over 50 examples including late-stage functionalization of drug molecules (celecoxib) and complex structures such as l-menthol, amino acids, and cholesterol derivatives. Furthermore, the presented synthetic protocol is applicable for gram-scale reactions. In addition to methylarenes, selected examples for the cyanation of aldehydes, alcohols and oximes are demonstrated as well. Detailed mechanistic investigations have been carried out using time-resolved luminescence quenching studies, control experiments, and NMR spectroscopy as well as kinetic studies, all supporting the proposed catalytic cycle.
- Murugesan, Kathiravan,Donabauer, Karsten,K?nig, Burkhard
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supporting information
p. 2439 - 2445
(2020/12/07)
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- One pot synthesis of aryl nitriles from aromatic aldehydes in a water environment
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In this study, we found a green method to obtain aryl nitriles from aromatic aldehyde in water. This simple process was modified from a conventional method. Compared with those approaches, we used water as the solvent instead of harmful chemical reagents. In this one-pot conversion, we got twenty-five aryl nitriles conveniently with pollution to the environment being minimized. Furthermore, we confirmed the reaction mechanism by capturing the intermediates, aldoximes.
- Chen, Qingqing,Han, Hongwei,Lin, Hongyan,Ma, Xiaopeng,Qi, Jinliang,Wang, Xiaoming,Yang, Yonghua,Zhou, Ziling
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p. 24232 - 24237
(2021/07/29)
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- Atomically Dispersed Ru on Manganese Oxide Catalyst Boosts Oxidative Cyanation
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There is a strong incentive for environmentally benign and sustainable production of organic nitriles to avoid the use of toxic cyanides. Here we report that manganese oxide nanorod-supported single-site Ru catalysts are active, selective, and stable for oxidative cyanation of various alcohols to give the corresponding nitriles with molecular oxygen and ammonia as the reactants. The very low amount of Ru (0.1 wt %) with atomic dispersion boosts the catalytic performance of manganese oxides. Experimental and theoretical results show how the Ru sites enhance the ammonia resistance of the catalyst, bolstering its performance in alcohol dehydrogenation and oxygen activation, the key steps in the oxidative cyanation. This investigation demonstrates the high efficiency of a single-site Ru catalyst for nitrile production.
- Gates, Bruce C.,Guan, Erjia,Meng, Xiangju,Wang, Chengtao,Wang, Hai,Wang, Liang,Wang, Sai,Xiao, Feng-Shou,Xu, Dongyang,Xu, Hua,Yang, Bo,Zhang, Jian
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p. 6299 - 6308
(2020/07/21)
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- Photocatalytic trifluoromethoxylation of arenes and heteroarenes in continuous-flow
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The first example of photocatalytic trifluoromethoxylation of arenes and heteroarenes under continuous-flow conditions is described. Application of continuous-flow microreactor technology allowed to reduce the residence time up to 16 times in comparison t
- Cendón, Borja,Gulías, Moisés,Ho, Michelle,No?l, Timothy,Nyuchev, Alexander V.,Sambiagio, Carlo,Struijs, Job J. C.,Wan, Ting,Wang, Ying
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supporting information
p. 1305 - 1312
(2020/07/10)
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- Sequential Xanthalation and O-Trifluoromethylation of Phenols: A Procedure for the Synthesis of Aryl Trifluoromethyl Ethers
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Molecules containing trifluoromethoxyaryl groups are of interest in pharmaceutical, agrochemical, and materials science research, due to their unique physical and electronic properties. Many of the known methods to synthesize aryl trifluoromethyl ethers require harsh reagents and highly controlled reaction conditions and rarely occur when heteroaromatic units are present. The two-step O-trifluoromethylation of phenols via aryl xanthates is one such method that suffers from these drawbacks. Herein, we report a method for the synthesis of aryl trifluoromethyl ethers from phenols by the facile conversion of the phenol to the corresponding aryl and heteroaryl xanthates with newly synthesized imidazolium methylthiocarbonothioyl salts and conversion of these xanthates to the trifluoromethyl ethers under mild reaction conditions.
- Yoritate, Makoto,Londregan, Allyn T.,Lian, Yajing,Hartwig, John F.
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p. 15767 - 15776
(2019/12/04)
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- Ni-Catalyzed Reductive Cyanation of Aryl Halides and Phenol Derivatives via Transnitrilation
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Herein, we report a Ni-catalyzed reductive coupling for the synthesis of benzonitriles from aryl (pseudo)halides and an electrophilic cyanating reagent, 2-methyl-2-phenyl malononitrile (MPMN). MPMN is a bench-stable, carbon-bound electrophilic CN reagent that does not release cyanide under the reaction conditions. A variety of medicinally relevant benzonitriles can be made in good yields. Addition of NaBr to the reaction mixture allows for the use of more challenging aryl electrophiles such as aryl chlorides, tosylates, and triflates. Mechanistic investigations suggest that NaBr plays a role in facilitating oxidative addition with these substrates.
- Mills, L. Reginald,Graham, Joshua M.,Patel, Purvish,Rousseaux, Sophie A. L.
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supporting information
p. 19257 - 19262
(2019/12/02)
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- Silver-Mediated Trifluoromethoxylation of (Hetero)aryldiazonium Tetrafluoroborates
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Here we report a silver-mediated trifluoromethoxylation of (hetero)aryldiazonium tetrafluoroborates by converting an aromatic amino group into an OCF3 group. This method, which can be considered to be a trifluoromethoxylation variation of the classic Sandmeyer-type reaction, uses readily available aryl and heteroaromatic amines as starting materials and AgOCF3 as trifluoromethoxylating reagents. The broad substrate scope and simple, mild reaction condition made this transformation a valuable method in constructing aryl-OCF3 bonds.
- Yang, Yu-Ming,Yao, Jian-Fei,Yan, Wei,Luo, Zhuangzhu,Tang, Zhen-Yu
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supporting information
p. 8003 - 8007
(2019/10/11)
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- Visible-Light Photoredox-Catalyzed and Copper-Promoted Trifluoromethoxylation of Arenediazonium Tetrafluoroborates
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We report the development of photoredox-catalyzed and copper-promoted trifluoromethoxylation of arenediazonium tetrafluoroborates, with trifluoromethyl arylsulfonate (TFMS) as the trifluoromethoxylation reagent. This new method takes advantage of visible-light photoredox catalysis to generate the aryl radical under mild conditions, combined with copper-promoted selective trifluoromethoxylation. The reaction is scalable, tolerates a wide range of functional groups, and proceeds regioselectively under mild reaction conditions. Furthermore, mechanistic studies suggested that a Cs[Cu(OCF3)2] intermediate might be generated during the reaction.
- Yang, Shaoqiang,Chen, Miao,Tang, Pingping
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supporting information
p. 7840 - 7844
(2019/05/15)
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- Method for trifluoro methoxylation of arylamine
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The invention provides a method for synthesizing an aryltrifluoromethoxy compound from an arylamine compound. The method comprises the steps of: performing a diazotization reaction on arylamine, and performing a one-pot reaction between the obtained aryl diazonium salt and trifluoromethoxy silver in an acetonitrile solvent so as to obtain the corresponding aryltrifluoromethoxy product. The obtained product has a high yield, and the process is simple.
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Paragraph 0080; 0081
(2018/10/11)
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- Radical Trifluoromethoxylation of Arenes Triggered by a Visible-Light-Mediated N?O Bond Redox Fragmentation
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A simple trifluoromethoxylation method enables non-directed functionalization of C?H bonds on a range of substrates, providing access to aryl trifluoromethyl ethers. This light-driven process is distinctly different from conventional procedures and occurs through an OCF3 radical mechanism mediated by a photoredox catalyst, which triggers an N?O bond fragmentation. The pyridinium-based trifluoromethoxylation reagent is bench-stable and provides access to synthetic diversity in lead compounds in an operationally simple manner.
- Jelier, Benson J.,Tripet, Pascal F.,Pietrasiak, Ewa,Franzoni, Ivan,Jeschke, Gunnar,Togni, Antonio
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supporting information
p. 13784 - 13789
(2018/09/14)
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- Practical CuCl/DABCO/4-HO-TEMPO-catalyzed oxidative synthesis of nitriles from alcohols with air as oxidant
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A mild and efficient methodology for the direct oxidative synthesis of nitriles from easily available alcohols and aqueous ammonia by employing CuCl/DABCO/4-HO-TEMPO as the catalysts is described. This protocol uses the air as a green oxidant and aqueous ammonia as the nitrogen source at room temperature. A variety of aryl, heterocyclic and allylic alcohols are smoothly converted into the corresponding nitriles in good to excellent yields.
- Hu, Yongke,Chen, Lei,Li, Bindong
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supporting information
p. 464 - 466
(2017/11/13)
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- Photoinduced Copper(I)-Catalyzed Cyanation of Aromatic Halides at Room Temperature
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The first photoinduced copper(I)-catalyzed cyanation of aromatic halides at room temperature has been developed. The sp2 cyanation reaction exhibits outstanding tolerance to functional groups including primary amines and carboxylic acids, and chemoselectivity to SN2-reactive alkyl chlorides. Mechanistic investigations indicate that the reaction occurs via a single-electron transfer (SET) between the aryl halide and an excited copper(I) cyanide catalytic intermediate. (Figure presented.).
- Kim, Kicheol,Hong, Soon Hyeok
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supporting information
p. 2345 - 2351
(2017/07/22)
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- Ligand controlled switchable selectivity in ruthenium catalyzed aerobic oxidation of primary amines
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A ligand controlled catalytic system for the aerobic oxidation of 1° amines to nitriles and imines has been developed where the varying π-acidic feature of BIAN versus phen in the frameworks of ruthenium catalysts facilitates switchable selectivity.
- Ray, Ritwika,Chandra, Shubhadeep,Yadav, Vishal,Mondal, Prasenjit,Maiti, Debabrata,Lahiri, Goutam Kumar
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supporting information
p. 4006 - 4009
(2017/04/11)
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- Fluorodecarboxylation for the Synthesis of Trifluoromethyl Aryl Ethers
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The synthesis of mono-, di-, and trifluoromethyl aryl ethers by fluorodecarboxylation of the corresponding carboxylic acids is reported. AgF2induces decarboxylation of aryloxydifluoroacetic acids, and AgF, either generated in situ or added separately, serves as a source of fluorine to generate the fluorodecarboxylation products. The addition of 2,6-difluoropyridine increased the reactivity of AgF2, thereby increasing the range of functional groups and electronic properties of the aryl groups that are tolerated. The reaction conditions used for the formation of trifluoromethyl aryl ethers also served to form difluoromethyl and monofluoromethyl aryl ethers.
- Zhang, Qing-Wei,Brusoe, Andrew T.,Mascitti, Vincent,Hesp, Kevin D.,Blakemore, David C.,Kohrt, Jeffrey T.,Hartwig, John F.
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supporting information
p. 9758 - 9762
(2016/08/10)
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- Cu-Catalyzed Cyanation of Arylboronic Acids with Acetonitrile: A Dual Role of TEMPO
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The cyanation of arylboronic acids by using acetonitrile as the "CN" source has been achieved under a Cu(cat.)/TEMPO system (TEMPO=2,2,6,6-tetramethylpiperidine N-oxide). The broad substrate scope includes a variety of electron-rich and electron-poor arylboronic acids, which react well to give the cyanated products in high to excellent yields. Mechanistic studies reveal that TEMPO-CH2CN, generated in situ, is an active cyanating reagent, and shows high reactivity for the formation of the CN- moiety. Moreover, TEMPO acts as a cheap oxidant to enable the reaction to be catalytic in copper. The cyanation of arylboronic acids by using acetonitrile as the "CN" source has been achieved under a Cu(cat.)/TEMPO system. Electron-rich and electron-poor arylboronic acids react well to give the cyanated products in high to excellent yields. Mechanistic studies reveal that TEMPO-CH2CN, generated in situ, is an active cyanating reagent. Moreover, TEMPO, a cheap oxidant, enables the reaction to be catalytic in copper (see scheme; TEMPO=2,2,6,6-tetramethylpiperidine N-oxide).
- Zhu, Yamin,Li, Linyi,Shen, Zengming
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supporting information
p. 13246 - 13252
(2015/09/15)
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- Fluorine in drug design: A case study with fluoroanisoles
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Anisole and fluoroanisoles display distinct conformational preferences, as evident from a survey of their crystal structures. In addition to altering the free ligand conformation, various degrees of fluorination have a strong impact on physicochemical and pharmacokinetic properties. Analysis of anisole and fluoroanisole matched molecular pairs in the Pfizer corporate database reveals interesting trends: 1) PhOCF3 increases log D by ~1 log unit over PhOCH3 compounds; 2) PhOCF3 shows lower passive permeability despite its higher lipophilicity; and 3) PhOCF3 does not appreciably improve metabolic stability over PhOCH3. Emerging from the investigation, difluoroanisole (PhOCF2H) strikes a better balance of properties with noticeable advantages of log D and transcellular permeability over PhOCF3. Synthetic assessment illustrates that the routes to access difluoroanisoles are often more straightforward than those for trifluoroanisoles. Whereas replacing PhOCH3 with PhOCF3 is a common tactic to optimize ADME properties, our analysis suggests PhOCF2H may be a more attractive alternative, and greater exploitation of this motif is recommended.
- Xing, Li,Blakemore, David C.,Narayanan, Arjun,Unwalla, Ray,Lovering, Frank,Denny, R. Aldrin,Zhou, Huanyu,Bunnage, Mark E.
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p. 715 - 726
(2015/04/14)
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- Synthesis of aryl dihydrothiazol acyl shikonin ester derivatives as anticancer agents through microtubule stabilization
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The high incidence of cancer and the side effects of traditional anticancer drugs motivate the search for new and more effective anticancer drugs. In this study, we synthesized 17 kinds of aryl dihydrothiazol acyl shikonin ester derivatives and evaluated their anticancer activity through MTT assay. Among them, C13 showed better antiproliferation activity with IC50 = 3.14 ± 0.21 μM against HeLa cells than shikonin (IC50 = 5.75 ± 0.47 μM). We then performed PI staining assay, cell cycle distribution, and cell apoptosis analysis for C13 and found that it can cause cell arrest in G2/M phase, which leads to cell apoptosis. This derivative can also reduce the adhesive ability of HeLa cells. Docking simulation and confocal microscopy assay results further indicated that C13 could bind well to the tubulin at paclitaxel binding site, leading to tubulin polymerization and mitotic disruption.
- Lin, Hong-Yan,Li, Zi-Kang,Bai, Li-Fei,Baloch, Shahla Karim,Wang, Fang,Qiu, Han-Yue,Wang, Xue,Qi, Jin-Liang,Yang, Raong-Wu,Wang, Xiao-Ming,Yang, Yong-Hua
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- Iron nitrate/TEMPO: A superior homogeneous catalyst for oxidation of primary alcohols to nitriles in air
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A highly practical, one-step, facile synthesis of aromatic, heteroaromatic, allylic and aliphatic nitriles from primary alcohols catalyzed by ferric nitrate [Fe(NO3)3·9H2O] in the presence of TEMPO, aqueous ammonia and air at room temperature is described.
- Dighe, Shashikant U.,Chowdhury, Deepan,Batra, Sanjay
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p. 3892 - 3896
(2015/01/09)
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- Per-6-amino-β-cyclodextrin/CuI catalysed cyanation of aryl halides with K4[Fe(CN)6]
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Efficient cyanation of aryl halides is achieved using less toxic K 4[Fe(CN)6] as the reagent and amino-β-cyclodextrins as supramolecular ligands for CuI. Four different amino cyclodextrins viz. per-6-amino-β-CD, per-6-methylamino-β-CD, per-6-butyl-amino-β-CD and mono-6-amino-β-CD are prepared and studied. Aryl and heteroaryl nitriles are obtained in good to excellent yield for even bromo derivatives of flavone and 2-aminopyrans. This system uses catalytic amounts (10 mol%) of both copper iodide and per-6-amino-β-cyclodextrin. Easy separation, the absence of nitrogen atmosphere and excellent yield are the other significant outcomes of this protocol. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
- Azath, Ismail Abulkalam,Suresh, Palaniswamy,Pitchumani, Kasi
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supporting information
p. 2334 - 2339
(2013/01/15)
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- Cyclic aromatic analogues of the hendrickson reagent; NMR studies and electrophilic properties
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Two novel cyclic aromatic analogues of the Hendrickson POP reagent, 1,1,3,3-tetraphenyl-1,3-dihydro-2,1,3-benzoxadiphosphole-1,3-diium bis(trifluoromethanesulfinate) and bis(trifluoromethanesulfonate), have been readily prepared by the treatment of 1,2-bis(diphenylphosphino)benzene or 1,2-bis(diphenylphosphoryl)benzene, respectively, with trifluoromethanesulfonic anhydride in dichloromethane. 31P and 19F NMR studies indicated that while the latter complex is formed as the sole product, the former species was shown to be the predominant component in equilibrium with 1-(diphenylphosphino)-2-[diphenyl(trifluoromethylsulfonyloxy)phosphonio]benzene trifluoromethanesulfinate and 1,2-bis[diphenyl(trifluoromethylsulfonyloxy) phosphonio]benzene bis(trifluoromethanesulfinate). The dehydrating POP systems were exploited in the conversion of aldoximes into nitriles. The dehydration occurred rapidly at room temperature and produced high yields with a variety of alkyl- and arylaldoximes, tolerating a wide range of substrates and functional groups. Georg Thieme Verlag Stuttgart New York.
- Moussa, Ziad
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experimental part
p. 460 - 468
(2012/03/11)
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- Phosphonium salt-catalysed synthesis of nitriles from in situ activated oximes
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A metal-free catalytic method for the conversion of aromatic and aliphatic aldoximes to nitriles at room temperature using oxalyl chloride (1.2 equiv) in combination with 5 mol % of triphenylphosphine oxide is reported. Of the many potential pathways leading from oxime to nitrile a manifold involving chlorophosphonium salt-catalysed decomposition of oxime chlorooxalates formed in situ is shown to be operative.
- Denton, Ross M.,An, Jie,Lindovska, Petra,Lewis, William
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supporting information; experimental part
p. 2899 - 2905
(2012/05/05)
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- A general rhodium-catalyzed cyanation of aryl and alkenyl boronic acids
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Give me a cyanide: N-cyano-N-phenyl-p-methylbenzenesulfonamide as a cyanation reagent allows the synthesis of aryl(alkenyl) nitriles in good yield under mild conditions (see scheme; cod=cycloocta-1,5-diene). Combination of the procedure with the direct borylation of arenes and hydroboration of alkynes leads to the straightforward synthesis of various nitriles.
- Anbarasan, Pazhamalai,Neumann, Helfried,Beller, Matthias
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supporting information; experimental part
p. 519 - 522
(2011/03/16)
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- NMR Studies and electrophilic properties of triphenylphosphine-trifluoromethanesulfonic anhydride; a remarkable dehydrating reagent system for the conversion of aldoximes into nitriles
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NMR Studies on the reaction of triphenylphosphine with various amounts of triflic anhydride at 0 °C is described. The reagent structure resulting from mixing 1.3 equiv of Ph3P with Tf2O (1.0 mmol) has been established as an equilibrium mixture consisting mainly of triphenyl(trifluoromethylsulfonyloxy)phosphonium trifluoromethanesulfinate and the corresponding bis(triphenyl)oxodiphosphonium trifluoromethanesulfinate dimer. The electrophilic properties of the system have been exploited in the development of a mild method for converting aldoximes into nitriles. The dehydration occurs at 0 °C under very mild conditions by initial activation of the oxime oxygen, followed by treatment with a base and subsequent elimination of triphenylphosphine oxide. The substrate scope and functional group tolerance of this useful method are explored.
- Moussa, Ziad,Ahmed, Saleh A.,ElDouhaibi, Ahmad S.,Al-Raqa, Shaya Y.
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experimental part
p. 1826 - 1831
(2010/09/07)
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- Shape-dependent catalytic activity of copper oxide-supported Pd(0) nanoparticles for Suzuki and cyanation reactions
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Palladium nanoparticles supported on different shapes of nanocrystalline CuO are prepared by the treatment of Cu(NO3)2 and Pd(OAc)2 in polyethylene glycol (PEG-6000). The shapes of the CuO/Pd composite are dependent on the amount of PEG used. Suzuki coupling was catalyzed efficiently by the oval-shaped material, whereas the rod shape facilitates the cyanation reaction. The CuO/Pd catalyst is recovered and reused for subsequent Suzuki reactions; however, cyanation poisons the catalyst for further use. Both these reactions are very clean and high yielding.
- Chattopadhyay, Kalicharan,Dey, Raju,Ranu, Brindaban C.
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supporting information; experimental part
p. 3164 - 3167
(2009/08/09)
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- IN VIVO IMAGING COMPOUNDS
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The invention relates to a compound of formula (I) having use for in vivo imaging of the NR2B subtype of the NMDA receptor. [image]
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- SULFONYL-SUBSTITUTED BICYCLIC COMPOUNDS AS MODULATORS OF PPAR
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The present invention relates to compounds and methods useful as inhibitors of PPAR, particularly PPARδ, and for the treatment or prevention of PPAR-mediated diseases, including metabolic diseases.
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Page/Page column 16
(2008/06/13)
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- CF3 oxonium salts, O-(trifluoromethyl)dibenzofuranium salts: In situ synthesis, properties, and application as a real CF3+ species reagent
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(Chemical Equation Presented) We report in situ synthesis of the first CF3 oxonium salts, thermally unstable O-(trifluoromethyl)- dibenzofuranium salts, which furthermore have different counteranions (BF 4-, PF6-, SbF6 -, and Sb2F11-) and ring substituents (tert-butyl, F, and OCH3), by photochemical decomposition of the corresponding 2-(trifluoromethoxy)biphenylyl-2′- diazonium salts at -90 to -100°C. The yields markedly increased in the order of BF4- 6- 6- 2F11-. The CF3 oxonium salts were fully assigned by means of 1H and 19F NMR spectroscopy at low temperature. The CF3 salts decomposed to form CF4 and dibenzofurans. The half-life times at -60°C of the 2-tert-butyl salts having different counteranions were 29 min for BF4- salt 2d, 36 min for PF6- salt 2c, 270 min for SbF6- salt 2a, and 415 min for Sb2F11- salt 2b. Those at -60°C of the Sb2F11- salts having different 2-substituents were 13 min for F salt 3b, 63 min for H (unsubstituted) salt 1b, and 415 min for tert-butyl salt 2b. Thus, the stability of the CF3 oxonium salts increased in the order of BF4- 6 - 6- 2F 11- and F 3+ species source to the direct O- and N-trifluoromethylations of alcohols, phenols, amines, anilines, and pyridines under very mild conditions. The thermal decomposition method with a mixture of diazonium salt 17a and aryl- or alkylsulfonic acids, pyridine, or pyridines having an electron-withdrawing group also afforded CF3O or CF 3N products. The trifluoromethylation mechanism is discussed and an SN2 mechanism containing the transient formation of free CF 3+ is proposed. Thus, the present study has demonstrated that the exceedingly reactive CF3+ species can be generated much easier than the CH3+ species, contrary to the common sense that CF3+ is extremely difficult to generate in solution.
- Umemoto, Teruo,Adachi, Kenji,Ishihara, Sumi
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p. 6905 - 6917
(2008/02/11)
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- FUROISOQUINOLINE DERIVATIVES, PROCESS FOR PRODUCING THE SAME AND USE THEREOF
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A compound having a partial structure represented by Formula: or a salt thereof has an excellent phosphodiesterase (PDE) IV-inhibiting effect, and is useful as a prophylactic or therapeutic agent against inflammatory diseases, for example, bronchial asthma, chronic obstructive pulmonary disease (COPD), rheumatoid arthritis, autoimmune disease, diabetes and the like.
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- 2-, 3-, and 4-(Trifluoromethoxy)phenyllithiums: Versatile intermediates offering access to a variety of new organofluorine compounds
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Consecutive treatment of (trifluoromethoxy)benzene with sec-butyllithium and electrophilic reagents affords previously inaccessible ortho-substituted derivatives in generally excellent yields. 2-(Trifluoromethoxy)phenyllithium acts as the key intermediate. The 3- and 4-isomers can readily be generated from the corresponding 3- and 4-bromo precursors by halogen-metal interconversion with butyllithium or tertbutyllithium. Upon trapping of the 2-, 3- and 4-(trifluoromethoxy)phenyllithiums with 11 different electrophiles the expected products were formed in generally high yields. Only the attempted nucleophilic addition of 2-(trifluoromethoxy)phenyllithium to oxirane did not succeed. This failure is tentatively attributed to a lowering of the nucleophilicity by fluorine-lithium interactions. Conformationally restricted analogs - i.e., 2,2-difluoro-1,3-benzodioxol-4-phenyllithium and its 5-fluoro- and 5-bromo-substituted congeners - did indeed react smoothly with oxirane, affording the adducts in ordinary yields.
- Castagnetti, Eva,Schlosser, Manfred
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p. 691 - 695
(2007/10/03)
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- Method for producing aromatic nitriles
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PCT No. PCT/EP98/00696 Sec. 371 Date Aug. 17, 1999 Sec. 102(e) Date Aug. 17, 1999 PCT Filed Feb. 9, 1998 PCT Pub. No. WO98/37058 PCT Pub. Date Aug. 27, 1998A process for preparing aromatic nitriles from corresponding chloroaromatics by reaction with cyanides.
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- Chlorination of 4-methoxybenzoyl chloride
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An improved process for chlorinating 4-methoxybenzoyl chloride on the methyl group with molecular chlorine is done neat at elevated temperature in the absence of light of radical-forming intensity.
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- Preparation of aryl trifluoromethyl ethers
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A one-step process for the synthesis of aryl trifluoromethyl ethers by reacting phenol or certain substituted phenols with a perhalomethane and hydrogen fluoride is provided. The compounds produced by the process of this invention are useful intermediates in the production of dyestuffs and pharmaceuticals.
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