- Development of Trifluoromethanesulfonic Acid-Immobilized Nitrogen-Doped Carbon-Incarcerated Niobia Nanoparticle Catalysts for Friedel-Crafts Acylation
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Heterogeneous trifluoromethanesulfonic acid-immobilized nitrogen-doped carbon-incarcerated niobia nanoparticle catalysts (NCI-Nb-TfOH) that show excellent catalytic performance with low niobium loading (1 mol %) in Friedel-Crafts acylation have been developed. These catalysts exhibit higher activity and higher tolerance to catalytic poisons compared with the previously reported TfOH-treated NCI-Ti catalysts, leading to a broader substrate scope. The catalysts were characterized via spectroscopic and microscopic studies.
- Yang, Xi,Yasukawa, Tomohiro,Yamashita, Yasuhiro,Kobayashi, Shū
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p. 15800 - 15806
(2021/10/25)
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- Aminophenone compounds as well as preparation method and application thereof
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The invention belongs to the technical field of medicinal chemistry, and particularly relates to aminophenone compounds as well as a preparation method and application thereof. The aminophenone compounds provided by the invention have a good inhibition effect on PDE4, also have good bioavailability, can be applied to preparation of drugs for treating PDE4-related diseases, and increase the optionsof drugs for treating PDE4-related diseases; and the effect of a part of the aminophenone compounds is equivalent to the effect of positive drugs, and the aminophenone compounds have good developmentpotential.
- -
-
Paragraph 0047; 0051-0053; 0229-0230; 0234-0236
(2021/02/06)
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- Combined Theoretical and Experimental Studies Unravel Multiple Pathways to Convergent Asymmetric Hydrogenation of Enamides
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We present a highly efficient convergent asymmetric hydrogenation of E/Z mixtures of enamides catalyzed by N,P-iridium complexes supported by mechanistic studies. It was found that reduction of the olefinic isomers (E and Z geometries) produces chiral amides with the same absolute configuration (enantioconvergent hydrogenation). This allowed the hydrogenation of a wide range of E/Z mixtures of trisubstituted enamides with excellent enantioselectivity (up to 99% ee). A detailed mechanistic study using deuterium labeling and kinetic experiments revealed two different pathways for the observed enantioconvergence. For α-aryl enamides, fast isomerization of the double bond takes place, and the overall process results in kinetic resolution of the two isomers. For α-alkyl enamides, no double bond isomerization is detected, and competition experiments suggested that substrate chelation is responsible for the enantioconvergent stereochemical outcome. DFT calculations were performed to predict the correct absolute configuration of the products and strengthen the proposed mechanism of the iridium-catalyzed isomerization pathway.
- Yang, Jianping,Massaro, Luca,Krajangsri, Suppachai,Singh, Thishana,Su, Hao,Silvi, Emanuele,Ponra, Sudipta,Eriksson, Lars,Ahlquist, M?rten S. G.,Andersson, Pher G.
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supporting information
p. 21594 - 21603
(2021/12/27)
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- Continuous Flow Acylation of (Hetero)aryllithiums with Polyfunctional N,N-Dimethylamides and Tetramethylurea in Toluene
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The continuous flow reaction of various aryl or heteroaryl bromides in toluene in the presence of THF (1.0 equiv) with sec-BuLi (1.1 equiv) provided at 25 °C within 40 sec the corresponding aryllithiums which were acylated with various functionalized N,N-
- Djukanovic, Dimitrije,Filipponi, Paolo,Heinz, Benjamin,Knochel, Paul,Mandrelli, Francesca,Martin, Benjamin,Mostarda, Serena
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supporting information
p. 13977 - 13981
(2021/09/13)
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- Well-Dispersed Trifluoromethanesulfonic Acid-Treated Metal Oxide Nanoparticles Immobilized on Nitrogen-Doped Carbon as Catalysts for Friedel–Crafts Acylation
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Although strong acid-treated metal oxides are useful heterogeneous superacid catalysts for various organic transformations, they usually have a limited density of acidic sites due to their low surface areas. Herein, heterogeneous trifluoromethanesulfonic acid immobilized nitrogen-doped carbon-incarcerated titanium nanoparticle (NP) catalysts have been developed that are composed of well-dispersed, small Ti NPs (ca 7 nm) that are otherwise difficult to achieve using acid-treated metal oxides. The catalysts showed high activity for Friedel–Crafts acylation with low titanium loading (2 mol%, 1 mg of metal for 1 mmol of substrate). A range of microscopic, spectroscopic and physicochemical studies revealed that the nitrogen-doped carbon immobilized the trifluoromethanesulfonic acid and that the addition of metals further changed the nature of the acidic species and enhanced catalytic activity.
- Yang, Xi,Yasukawa, Tomohiro,Maki, Tei,Yamashita, Yasuhiro,Kobayashi, Shū
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supporting information
p. 232 - 236
(2020/12/30)
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- Iron-Catalyzed C-C Single-Bond Cleavage of Alcohols
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An iron-catalyzed deconstruction/hydrogenation reaction of alcohols through C-C bond cleavage is developed through photocatalysis, to produce ketones or aldehydes as the products. Tertiary, secondary, and primary alcohols bearing a wide range of substituents are suitable substrates. Complex natural alcohols can also perform the transformation selectively. A investigation of the mechanism reveals a procedure that involves chlorine radical improved O-H homolysis, with the assistance of 2,4,6-collidine.
- Liu, Wei,Wu, Qiang,Wang, Miao,Huang, Yahao,Hu, Peng
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supporting information
p. 8413 - 8418
(2021/11/01)
-
- Allylic and Allenylic Dearomatization of Indoles Promoted by Graphene Oxide by Covalent Grafting Activation Mode
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The site-selective allylative and allenylative dearomatization of indoles with alcohols was performed under carbocatalytic regime in the presence of graphene oxide (GO, 10 wt percent loading) as the promoter. Metal-free conditions, absence of stoichiometric additive, environmentally friendly conditions (H2O/CH3CN, 55 °C, 6 h), broad substrate scope (33 examples, yield up to 92 percent) and excellent site- and stereoselectivity characterize the present methodology. Moreover, a covalent activation model exerted by GO functionalities was corroborated by spectroscopic, experimental and computational evidences. Recovering and regeneration of the GO catalyst through simple acidic treatment was also documented.
- Lombardi, Lorenzo,Bellini, Daniele,Bottoni, Andrea,Calvaresi, Matteo,Monari, Magda,Kovtun, Alessandro,Palermo, Vincenzo,Melucci, Manuela,Bandini, Marco
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supporting information
p. 10427 - 10432
(2020/07/24)
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- Quinolin-8-yl Formate: A New Option for Small-Scale Carbonylation Reactions in Microwave Reactors
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A convenient procedure for conducting small-scale carbonylations of aryl or benzyl halides in a microwave reactor by using quinolin-8-yl formate is described. The resulting 8-acyloxyquinolines were shown to be more reactive than phenyl esters in acyl-tran
- Maddocks, Christopher J.,Aathimanikandan, Sivakumar V.,Richardson, Jeffery,Ruble, J. Craig
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p. 1608 - 1612
(2020/09/09)
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- Rhodium-Catalyzed Deoxygenation and Borylation of Ketones: A Combined Experimental and Theoretical Investigation
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The rhodium-catalyzed deoxygenation and borylation of ketones with B2pin2 have been developed, leading to efficient formation of alkenes, vinylboronates, and vinyldiboronates. These reactions feature mild reaction conditions, a broad substrate scope, and excellent functional-group compatibility. Mechanistic studies support that the ketones initially undergo a Rh-catalyzed deoxygenation to give alkenes via boron enolate intermediates, and the subsequent Rh-catalyzed dehydrogenative borylation of alkenes leads to the formation of vinylboronates and diboration products, which is also supported by density functional theory calculations.
- Tao, Lei,Guo, Xueying,Li, Jie,Li, Ruoling,Lin, Zhenyang,Zhao, Wanxiang
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supporting information
p. 18118 - 18127
(2020/11/26)
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- Electrochemical [4+2] Annulation-Rearrangement-Aromatization of Styrenes: Synthesis of Naphthalene Derivatives
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We report the first electrochemical strategy to synthesize functionalized naphthalene derivatives through [4+2] annulation—rearrangement–aromatization from styrenes under mild conditions. The electrolysis does not require metals, oxidants and high valence substrates, indicating the atom and step-economy ideals. The dehydrodimer produced through [4+2] cycloaddition of 4-methoxy α-methyl styrene is isolated and proved to be the key intermediate for the following oxydehydrogenation to form carbon cation, which undergoes rearrangement–aromatization to afford the final products. This reaction represents a powerful access to construct multi-substituted naphthalene blocks in a single step.
- Ma, Yueyue,Lv, Jufeng,Liu, Chengyu,Yao, Xiantong,Yan, Guoming,Yu, Wei,Ye, Jinxing
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supporting information
p. 6756 - 6760
(2019/04/17)
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- I-Pr2NMgCl·LiCl Enables the Synthesis of Ketones by Direct Addition of Grignard Reagents to Carboxylate Anions
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The direct preparation of ketones from carboxylate anions is greatly limited by the required use of organolithium reagents or activated acyl sources that need to be independently prepared. Herein, a specific magnesium amide additive is used to activate and control the addition of more tolerant Grignard reagents to carboxylate anions. This strategy enables the modular synthesis of ketones from CO2 and the preparation of isotopically labeled pharmaceutical building blocks in a single operation.
- Colas, Kilian,Dos Santos, A. Catarina V. D.,Mendoza, Abraham
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supporting information
(2019/10/08)
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- Directed: Ortho-metalation-nucleophilic acyl substitution strategies in deep eutectic solvents: The organolithium base dictates the chemoselectivity
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Directed ortho metalation (DoM) or nucleophilic acyl substitution (SNAc) can be efficiently programmed on the same aromatic carboxylic acid amide, in a choline chloride-based eutectic mixture, by simply switching the nature of the organolithium reagent. Telescoped, one-pot ortho-lithiation/Suzuki-Miyaura cross-couplings have also been demonstrated for the first time in Deep Eutectic Solvents.
- Ghinato, Simone,Dilauro, Giuseppe,Perna, Filippo Maria,Capriati, Vito,Blangetti, Marco,Prandi, Cristina
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p. 7741 - 7744
(2019/07/12)
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- Table salt as a catalyst for the oxidation of aromatic alcohols and amines to acids and imines in aqueous medium: Effectively carrying out oxidation reactions in sea water
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A simple, efficient, sustainable and economical method for the oxidation of alcohols and amines has been developed based on chloride, a sea abundant anionic catalyst for the practical synthesis of a wide range of carboxylic acids, ketones and imines. Oxidation of aromatic alcohols was carried out using NaCl (20 mol%) as the catalyst, NaOH (50 mol%) and aq. TBHP (4 equiv.) as the oxidant in 55-92% isolated yields. Oxidation of aromatic amines to imines was achieved by using only 20 mol% of NaCl and aq. TBHP (4 equiv.) in 32-93% isolated yields. The chlorine species formed during the reaction as the active oxidation catalyst has been identified as ClO2- for alcohols and ClO-/ClO2- for amines by control experiments. This method is mostly free from chromatographic purification, which makes it suitable for large-scale synthesis. We have scaled up to 30 gram scale the synthesis of carboxylic acids and imines in good yields and have also carried out efficiently this new method using filtered sea water as the solvent and catalyst.
- Hazra, Susanta,Kushawaha, Ajay Kishor,Yadav, Deepak,Dolui, Pritam,Deb, Mayukh,Elias, Anil J.
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supporting information
p. 1929 - 1934
(2019/04/29)
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- Co (II)-C12 alkyl carbon chain multi-functional ionic liquid immobilized on nano-SiO2 nano-SiO2@CoCl3-C12IL as an efficient cooperative catalyst for C–H activation by direct acylation of aryl halides with aldehydes
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Nano-silica supported ionic liquids composed of alkyl carbon chain and transition metal chlorides anions have been prepared and successfully applied as a heterogeneous catalyst in the direct aldehyde C-H activation. Catalytic results indicated that nano-SiO2 supported ionic liquid consisting C12 alkyl carbon chain and CoCl3 anion nano-SiO2@CoCl3-C12IL showed excellent catalytic properties with good to excellent yields towards the desired aryl ketones. The excellent recyclability of the supported catalyst, mild reaction conditions, low catalyst loading, and operational simplicity are the important features of this methodology.
- Hu, Yu Lin,Wu, Ya Pan,Lu, Ming
-
-
- Pd-catalyzed Oxidative Cross-coupling of Alkyl Chromium(0) Fischer Carbene Complexes with Organoboronic Acids
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Alkyl chromium(0) carbene complexes have been explored as the cross-coupling partners in the palladium-catalyzed reaction with aryl or alkenyl boronic acids. This coupling reaction displays the versatile reactivities of alkyl chromium(0) carbenes under palladium catalysis. Mechanistically, this transformation is proposed to involve deprotonation of the alkyl chromium carbene substrate to generate a vinyl chromium anion intermediate that undergoes transmetalation to organopalladium species and reductive elimination.
- Wang, Kang,Yang, Jinghui,Yao, Xingqi,Wang, Jianbo
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supporting information
p. 3165 - 3168
(2018/10/15)
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- Palladium-catalyzed room temperature acylative cross-coupling of activated amides with trialkylboranes
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A highly efficient acylative cross-coupling of trialkylboranes with activated amides has been effected at room temperature to give the corresponding alkyl ketones in good to excellent yields by using 1,3-bis(2,6-diisopropyl)phenylimidazolylidene and 3-chloropyridine co-supported palladium chloride, the PEPPSI catalyst, in the presence of K2CO3 in methyl tert-butyl ether. The scope and limitations of the protocol were investigated, showing good tolerance of acyl, cyano, and ester functional groups in the amide counterpart while halo group competed via the classical Suzuki coupling. The trialkylboranes generated in situ by hydroboration of olefins with BH3 or 9-BBN performed similarly to those separately prepared, making this protocol more practical.
- Shi, Weijia,Zou, Gang
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- Suzuki-Miyaura coupling of simple ketones via activation of unstrained carbon-carbon bonds
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Here, we describe that simple ketones can be efficiently employed as electrophiles in Suzuki-Miyaura coupling reactions via catalytic activation of unstrained C-C bonds. A range of common ketones, such as cyclopentanones, acetophenones, acetone and 1-indanones, could be directly coupled with various arylboronates in high site-selectivity, which offers a distinct entry to more functionalized aromatic ketones. Preliminary mechanistic study suggests that the ketone α-C-C bond was cleaved via oxidative addition.
- Xia, Ying,Wang, Jianchun,Dong, Guangbin
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supporting information
p. 5347 - 5351
(2018/05/03)
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- A phosphine-free, heterogeneous palladium-catalyzed atom-efficient carbonylative cross-coupling of triorganoindiums with aryl halides leading to unsymmetrical ketones
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The first phosphine-free heterogeneous palladium-catalyzed carbonylative cross-coupling of aryl halides with triorganoindiums has been developed that proceeds smoothly under 1 or 2.5 atm of carbon monoxide in THF at 68 °C and provides a general and powerful tool for the synthesis of various valuable unsymmetrical ketones with high atom-economy, good yield, and recyclability of the catalyst. Our system not only avoids the use of phosphine ligands, but also solves the basic problem of palladium catalyst recovery and reuse.
- You, Shengyong,Xiao, Ruian,Liu, Haiyi,Cai, Mingzhong
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p. 13862 - 13870
(2017/11/27)
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- P -Selective (sp2)-C-H functionalization for an acylation/alkylation reaction using organic photoredox catalysis
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p-Selective (sp2)-C-H functionalization of electron rich arenes has been achieved for acylation and alkylation reactions, respectively, with acyl/alkylselenides by organic photoredox catalysis involving an interesting mechanistic pathway.
- Pandey, Ganesh,Tiwari, Sandip Kumar,Singh, Bhawana,Vanka, Kumar,Jain, Shailja
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p. 12337 - 12340
(2017/11/20)
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- A phosphine-free, atom-efficient cross-coupling reaction of triorganoindiums with acyl chlorides catalyzed by immobilization of palladium(0) in MCM-41
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The first phosphine-free heterogeneous palladium(0)-catalyzed cross-coupling of triorganoindiums with acyl chlorides has been developed that proceeds smoothly in THF at 68 °C and provides a general and powerful tool for the synthesis of various valuable aryl ketones and α,β-acetylenic ketones with high atom-economy and high yield. This phosphine-free heterogeneous palladium(0) catalyst can be easily prepared from commercially available reagents and recovered by a simple filtration of the reaction solution and used for at least 10 consecutive trials without any decreases in activity. Our system not only avoids the use of phosphine ligands, but also solves the basic problem of palladium catalyst recovery and reuse.
- Miao, Jiankang,Huang, Bin,Liu, Haiyi,Cai, Mingzhong
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p. 42570 - 42578
(2017/09/11)
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- Palladium-Catalyzed Denitrogenative Synthesis of Aryl Ketones from Arylhydrazines and Nitriles Using O2 as Sole Oxidant
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An efficient and simple palladium-catalyzed approach for the synthesis of aryl ketones from low-cost nitriles and arylhydrazines using molecular oxygen (O2) as sole oxidant via C-N bond cleavage is reported. Various aryl ketones were synthesized in moderate to good yields under mild conditions. A possible mechanism involving the PdII/Pd0 catalytic cycle process is depicted, and a cationic palladium intermediate was detected by ESI-MS.
- Wang, Xu,Huang, Yubing,Xu, Yanli,Tang, Xiaodong,Wu, Wanqing,Jiang, Huanfeng
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p. 2211 - 2218
(2017/02/26)
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- Catalytic Ring-Opening of Cyclic Alcohols Enabled by PCET Activation of Strong O-H Bonds
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We report a new photocatalytic protocol for the redox-neutral isomerization of cyclic alcohols to linear ketones via C-C bond scission. Mechanistic studies demonstrate that key alkoxy radical intermediates in this reaction are generated via the direct homolytic activation of alcohol O-H bonds in an unusual intramolecular PCET process, wherein the electron travels to a proximal radical cation in concert with proton transfer to a weak Br?nsted base. Effective bond strength considerations are shown to accurately forecast the feasibility of alkoxy radical generation with a given oxidant/base pair.
- Yayla, Hatice G.,Wang, Huaiju,Tarantino, Kyle T.,Orbe, Hudson S.,Knowles, Robert R.
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p. 10794 - 10797
(2016/09/09)
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- Supported Sulfonic Acids: Solid Catalysts for Batch and Continuous-Flow Synthetic Processes
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It's easy being green! In this work, supported sulfonic acids were used as effective catalysts for different classes of reactions. They have the advantage of being cheap, safe, and easy to recycle. Reaction conditions are mild, have good atom economy, and work-up steps are very easy, satisfying essential parameters of the "green chemistry" philosophy. Application of these catalysts to continuous-flow processes resulted in a considerable improvement in efficiency.
- Piscopo, Calogero G.
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p. 383 - 388
(2015/06/30)
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- Palladium complexes of heterobidentate ligands: Active catalysts for direct acylation of aryl halides with aldehydes via C(sp2)-H activation
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Abstract Heterobidentate P-S donor ligands [P-S = {2-(methylthio) phenyl}diphenylphosphine (a) and {2-((methylthio) methyl) phenyl}diphenylphosphine (b)], and their palladium complexes of the type [Pdη2-(P-S)Cl2] (1a, 1b) have been synthesised and characterised. Single crystal X-ray diffraction shows that in both the complexes, Pd occupies the centre of a slightly distorted square planar geometry. 1a forms a planner ring structure, whereas, the hexagonal ring of 1b bends from planarity to adjust any ring strain. Interesting differences between the complexes were observed in terms of the intermolecular forces. The catalytic activities of the synthesised complexes towards the direct acylation of aryl halides with aldehydes via C(sp2)-H activation were good to excellent. 1b shows better catalytic activity over 1a which may be attributed to the higher stability of the pentagonal ring of 1a. Aryl halides containing electron withdrawing group enhance the reaction, while electron donating substituent tend to retard the desired product formation. The difference in the bond lengths of Pd-P and Pd-S of the chelate complexes may impart hemilabile behaviour in the catalytic cycle by dissociating the weaker bond (Pd-S) to generate vacant coordination site at the metal centre and reassociate after the completion of the reaction.
- Saikia, Kokil,Dutta, Dipak Kumar
-
-
- One-pot Unsymmetrical Ketone Synthesis Employing a Pyrrole-Bearing Formal Carbonyl Dication Linchpin Reagent
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A one-pot procedure for the synthesis of unsymmetrical ketones utilizing a pyrrole-bearing carbonyl linchpin reagent (carbonyl linchpin N,O-dimethylhydroxylamine pyrrole; CLAmP) is reported. In contrast to other carbonyl dielectrophile equivalents, CLAmP enables the synthesis of ketones from a variety of organolithium and Grignard reagents. The electrophilic nature of CLAmP enables the addition of less reactive as well as thermally unstable nucleophiles. CLAmP was designed to form kinetically stable tetrahedral intermediates upon the addition of organometallic nucleophiles. Evidence for the existence of persistent tetrahedral intermediates was obtained through in situ IR studies.
- Heller, Stephen T.,Newton, James N.,Fu, Tingting,Sarpong, Richmond
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supporting information
p. 9839 - 9843
(2015/08/19)
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- Highly chemoselective and versatile method for direct conversion of carboxylic acids to ketones utilizing zinc Ate complexes
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Various carboxylic acids were directly transformed into the corresponding ketones by utilizing organozinc ate complexes, which provide high chemoselectivity without any overreaction to the undesired tertiary carbinol, owing to formation of a stable tetrahedral zincioketal intermediate. This method offers good overall atom/step/pot economy and operational simplicity. No need to overreact: Various carboxylic acids were directly transformed to the corresponding ketones by utilizing organozinc ate complexes, which provide high chemoselectivity without any overreaction to undesired tertiary carbinol, owing to formation of a stable tetrahedral zincioketal intermediate. This method offers good overall atom/step/pot economy and operational simplicity.
- Murata, Ryo,Hirano, Keiichi,Uchiyama, Masanobu
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supporting information
p. 1286 - 1290
(2015/06/08)
-
- Synthesis and reduction reactions of pyridones and 5-acyl-2-methoxypyridines
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The synthesis of a series of pyridones, from their 2-hydroxypyridine or 2-methoxypyridine precursors, is described, along with studies into their reductions to saturated heterocycles. A number of 5-acylpyridones were prepared and were evaluated as substrates for asymmetric transfer hydrogenation prior to conversion to saturated heterocycles. The enantioselective reduction of 5-acetyl-1-benzylpyrimidine-2,4(1H,3H)-dione is also described.
- Bisset, Alexander A.,Dishington, Allan,Jones, Teyrnon,Clarkson, Guy J.,Wills, Martin
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p. 7207 - 7220
(2017/09/12)
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- Continuous flow synthesis of ketones from carbon dioxide and organolithium or grignard reagents
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We describe an efficient continuous flow synthesis of ketones from CO 2 and organolithium or Grignard reagents that exhibits significant advantages over conventional batch conditions in suppressing undesired symmetric ketone and tertiary alcohol byproducts. We observed an unprecedented solvent-dependence of the organolithium reactivity, the key factor in governing selectivity during the flow process. A facile, telescoped three-step-one-flow process for the preparation of ketones in a modular fashion through the in-line generation of organometallic reagents is also established.
- Wu, Jie,Yang, Xiaoqing,He, Zhi,Mao, Xianwen,Hatton, T. Alan,Jamison, Timothy F.
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supporting information
p. 8416 - 8420
(2014/08/18)
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- Mild and direct conversion of esters to morpholine amides using diisobutyl(morpholino)aluminum: Application to efficient one-pot synthesis of ketones and aldehydes from esters
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Morpholine amide intermediates, which are easily prepared by aminolysis of various esters with diisobutyl(morpholino)aluminum, react with organolithium and reducing agents (DIBALH or LDBMA) without isolation of the aminolysis intermediates to give ketones in 83-95% yields and aldehydes quantitatively.
- Jeon, Ah Ram,Kim, Min Eai,Park, Jae Kyo,Shin, Won Kyu,An, Duk Keun
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p. 4420 - 4424
(2014/06/10)
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- An effective one-pot conversion of acid chlorides to aldehydes and ketones
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Aldehydes and ketones were synthesized from their respective acid chlorides via a one-pot protocol. Morpholine amide intermediates that were readily prepared by the aminolysis of various acid chlorides with diisobutyl(morpholino) aluminum smoothly reacted with the reducing agent LDBMA and the organolithium reagents under mild reaction conditions (0 C), giving almost excellent product yields of up to 95%.
- Park, Jae Kyo,Shin, Won Kyu,An, Duk Keun
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p. 3199 - 3203
(2013/06/27)
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- Catalytic Friedel-Crafts acylation: Magnetic nanopowder CuFe 2O4 as an efficient and magnetically separable catalyst
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Catalytic regioselective Friedel-Crafts acylation of an array of anisoles/arenes with various acid chlorides using 5-20 mol % of magnetic nanopowder CuFe2O4 is reported. Unlike the conventional Friedel-Crafts reactions, which are catalyzed by moisture sensitive homogeneous catalysts/promoters, the nanopowder CuFe2O4 catalyst is moisture insensitive and the product/ketone-catalyst isolation is easily achieved using the magnetic properties of CuFe2O4.
- Parella, Ramarao,Naveen,Kumar, Amit,Babu, Srinivasarao Arulananda
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p. 1738 - 1742
(2013/03/28)
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- Deaminative and decarboxylative catalytic alkylation of amino acids with ketones
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It cuts two ways: The cationic [Ru-H] complex catalyzes selective coupling of α- and β-amino acids with ketones to form α-alkylated ketone products. The reaction involves C-C and C-N bond cleavage which result in regio- and stereoselective alkylation using amino acids. A broad substrate scope and high functional-group tolerance is demonstrated. Copyright
- Kalutharage, Nishantha,Yi, Chae S.
-
supporting information
p. 13651 - 13655
(2014/01/06)
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- Nano-sulfated titania (TiO2/SO2-4) as a new solid acid catalyst for Friedel-Crafts acylation and Beckman rearrangement in solvent-free conditions
-
The present work describes a novel application of nano-sulfated titania (nano-ST) as a solid acid catalyst for Friedel-Crafts acylation and Beckmann rearrangement. A nano-ST catalyst has been synthesized and characterized using various techniques such as XRD, scanning electron morphology, transmission electron microscopy, FT-IR, measurement of the specific surface area by Brunauer-Emmett-Teller theory and thermal analysis. The influences of various reaction parameters such as reaction temperature, molar ratio of reactants, reaction time and solvent effects have been investigated. [image omitted].
- Hosseini-Sarvari, Mona,Safary, Ensieh
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experimental part
p. 463 - 473
(2012/06/16)
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- Synthesis and investigations on the oxidative degradation of C3/C5-Alkyl-1,2,4-triarylpyrroles as ligands for the estrogen receptor
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In this study, we synthesized 1,2,4-triarylpyrroles as ligands for the estrogen receptor (ER). Two pyrrole series were prepared with either C3-alkyl or C3/C5-dialkyl residues. Compounds from both series were susceptible to oxidative degradation-dialkylated compounds (t1/2=33-66h) to a higher extent than their monoalkylated congeners (t1/2=140-211h). Nevertheless, stability was sufficient for determination of in vitro ER binding affinity. The most active agonist in hormone-dependent, ERα-positive MCF-7/2a and U2-OS/α cells was 1,2,4-tris(4-hydroxyphenyl)-3-propyl-1H-pyrrole (6d) (MCF-7/2a: EC50=70nM; U2-OS/α: EC50=1.6nM). A corresponding inactivity in U2-OS/β cells demonstrated the high ERα selectivity. This trend was confirmed in a competition experiment using estradiol (E2) and purified hERα and hERβ proteins (relative binding affinity (RBA) calculated for 6d: RBA(ERα)=1.85%; RBA(ERβ) 0.01%). Generally, C3/C5-dialkyl substitution led to reduction of activity, possibly due to lower stability. Triarylpyrroles with C3-alkyl or C3/C5-dialkyl residues were synthesized as ligands for the estrogen receptor (ER). The compounds exhibited transcription activation selectively for ERα but only marginally displaced estradiol from its binding site. The compounds were susceptible to oxidative degradation-dialkylated compounds to a higher extent than their monoalkylated congeners. The reasons for instability were elucidated; thus, by changing the substitution pattern, it will be possible to generate stable triarylpyrroles.
- Schaefer, Anja,Wellner, Anja,Gust, Ronald
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scheme or table
p. 794 - 803
(2012/01/06)
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- Cyanocuprates convert carboxylic acids directly into ketones
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Carboxylic acids were converted directly in 56-99% yields into methyl, n-butyl, and isopropyl ketones using excess cyanocuprates R2CuLi 3 LiCN. A substrate with a stereocenter α to the carboxylic acid was converted into ketones with very little loss of enantiomeric purity. A variety of functional groups were tolerated including aryl bromides. This direct transformation of a carboxylic acid into ketone with minimal tertiary alcohol formation is proposed to involve a relatively stable copper ketal tetrahedral intermediate.
- Genna, Douglas T.,Posner, Gary H.
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supporting information; experimental part
p. 5358 - 5361
(2011/12/15)
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- Photochemically promoted transition metal-free cross-coupling of acylsilanes with organoboronic esters
-
Intermolecular carbon-carbon bond formation between acylsilanes and organoboronic esters was achieved by photoirradiation under almost neutral, transition metal-free conditions. In this reaction, siloxycarbenes generated by photoisomerization of acylsilanes reacted with boronic esters to give the formal B-C bond insertion intermediates, which underwent unique rearrangement to afford the cyclic α-alkoxyboronic esters. Acidic treatment of the resulting crude products under air furnished the cross-coupled ketones in good yields.
- Ito, Kazuta,Tamashima, Hiroto,Iwasawa, Nobuharu,Kusama, Hiroyuki
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p. 3716 - 3719
(2011/05/14)
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- A remarkable effect of ionic liquids in transition-metal-free aerobic oxidation of benzylic alcohols
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The transition-metal-free aerobic oxidation of benzylic alcohols is uniquely accelerated by a 1-butyl-3-methylimidazolium hexafluorophosphate (BMI-PF6)/PhCF3 biphasic system and Cs2CO 3 to afford the corresponding ketones in good yields. The reaction system is also applicable to an oxidative cross-esterification of primary benzyl alcohols with a higher aliphatic alcohol.
- Oda, Yoshiro,Hirano, Koji,Satoh, Tetsuya,Kuwabata, Susumu,Miura, Masahiro
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supporting information; experimental part
p. 5392 - 5394
(2011/10/19)
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- Direct acylation of aryl chlorides with aldehydes by palladium-pyrrolidine Co-catalysis
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A palladium catalyst system has been developed that allows for the direct acylation of aryl chlorides with aldehydes. The choice of ligand, as well as the presence of pyrrolidine and molecular sieves is shown to be critical to the catalysis, which appears to proceed via an enamine intermediate. The reaction was successful for a wide range of aryl chlorides and tolerant of functionality on the aldehyde component, giving easy access to alkyl aryl ketones in modest to good yields.
- Colbon, Paul,Ruan, Jiwu,Purdie, Mark,Xiao, Jianliang
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supporting information; experimental part
p. 3670 - 3673
(2010/10/20)
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- Biocatalytic promiscuity of lipase in chemoselective oxidation of aryl alcohols/acetates: a unique synergism of cal-b and [hmim]br for the metal-free h2o2 activation
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A unique synergistic combination of lipase and Ionic liquid [hmlm]Br Is reported for metal-free H2O2 activation, which is the first example of blocatalytlc promiscuity of CAL-B for chemoselectlve oxidation of aryl alcohols/acetates. The catalytic system exhibits excellent functional group compatibility under neutral conditions besides reusability up to ten cycles thereby making the process economically and environmentally viable.
- Sharma, Upendra K.,Sharma, Nandini,Kumar, Rakesh,Kumar, Rajesh,Sinha, Arun K.
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supporting information; experimental part
p. 4846 - 4848
(2010/01/16)
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- Et2Zn-mediated rearrangement of bromohydrins
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(Chemical Equation Presented) A simple and highly efficient method for the rearrangement of bromohydrins mediated by Et2Zn to synthesize carbonyl compounds was described. Various β-bromo alcohols were treated with 0.6 equiv of Et2Zn to form a zinc complex in CH 2Cl2 at room temperature for 2 h, followed by 1,2-migration to give the corresponding carbonyl compounds. This remarkable and clean rearrangement is general for acyclic and cyclic bromohydrins, and a variety of ring-expansive and -contractive carbonyl compounds were obtained in good to excellent yields according to the feature of the starting bromohydrins. The functional group tolerance of organozinc reagents in this reaction will be useful in organic synthesis. The scope and limitations of this rearrangement process were also investigated.
- Li, Lezhen,Cai, Peijie,Guo, Qingxiang,Xue, Song
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p. 3516 - 3522
(2008/09/20)
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- Direct acylation of aryl bromides with aldehydes by palladium catalysis
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A new protocol for the direct acylation of aryl bromides with aldehydes is established. It appears to involve palladium-amine cooperative catalysis, affording synthetically important alkyl aryl ketones in moderate to excellent yields in a straightforward manner, and broadening the scope of metal-catalyzed coupling reactions. Copyright
- Ruan, Jiwu,Saidi, Ourida,Iggo, Jonathan A.,Xiao, Jianliang
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supporting information; experimental part
p. 10510 - 10511
(2009/02/05)
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- Synthesis of novel nitro-substituted triaryl pyrazole derivatives as potential estrogen receptor ligands
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Novel tetrasubstituted pyrazole derivatives bearing a nitro substituent on their A-phenol ring were synthesized and their binding affinity towards the estrogen receptor (ER) subtypes ERα and ERβ was determined. Among compounds tested, the 2-nitrophenol derivative 5c was found to bind satisfactorily to both estrogen receptor subtypes (RBAα=5.17 and RBAβ=3.27). In general, the introduction of a nitro group into the A ring of these compounds was found to benefit their ERβ binding abilities.
- Naoum, Fotini,Kasiotis, Konstantinos M.,Magiatis, Prokopios,Haroutounian, Serkos A.
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p. 1259 - 1273
(2008/02/08)
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- One-step preparation of α-chlorostyrenes
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α-Chlorostyrenes were prepared via a one-step method involving Friedel-Crafts reaction of various aromatic substrates with acid chlorides in the presence of a heterogeneous Si-Fe catalyst.
- Borate, Hanumant B.,Gaikwad, Abaji G.,Maujan, Suleman R.,Sawargave, Sangmeshwer P.,Kalal, Kamalakar M.
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p. 4869 - 4872
(2008/02/05)
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- Direct and efficient one-pot preparation of ketones from aldehydes using N-tert-butylphenylsulfinimidoyl chloride
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(Chemical Equation Presented) A general, one-pot process has been established to prepare ketones from aldehydes using N-tert- butylphenylsulfinimidoyl chloride. By employing the developed protocol, a range of unsymmetrical ketones has been prepared in good yields from aldehydes in one simple synthetic operation.
- Crawford, James J.,Henderson, Kenneth W.,Kerr, William J.
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p. 5073 - 5076
(2007/10/03)
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- 1-(4-Methylphenyl)-2-pyrrolidin-1-yl-pentan-1-one (pyrovalerone) analogues: A promising class of monoamine uptake inhibitors
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Dopamine, serotonin, and norepinephrine are essential for neurotransmission in the mammalian system. These three neurotransmitters have been the focus of considerable research because the modulation of their production and their interaction at monoamine receptors has profound effects upon a multitude of pharmacological outcomes. Our interest has focused on neurotransmitter reuptake mechanisms in a search for medications for cocaine abuse. Herein we describe the synthesis and biological evaluation of an array of 2-aminopentanophenones. This array has yielded selective inhibitors of the dopamine and norepinephrine transporters with little effect upon serotonin trafficking. A subset of compounds had no significant affinity at 5HT1A, 5HT1B, 5HT1C, D1, D2, or D3 receptors. The lead compound, racemic 1-(4-methylphenyl)-2-pyrrolidin-1-yl-pentan-1-one 4a, was resolved into its enantiomers and the S isomer was found to be the most biologically active enantiomer. Among the most potent of these DAT/NET selective compounds are the 1-(3,4-dichlorophenyl)- (4u) and the 1-naphthyl- (4t) 2-pyrrolidin-1-yl-pentan-1-one analogues.
- Meltzer, Peter C.,Butler, David,Deschamps, Jeffrey R.,Madras, Bertha K.
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p. 1420 - 1432
(2007/10/03)
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- A new method for synthesis of α,α-disubstituted carbonyl compounds from carbonyl compounds with one-carbon homologation through β-oxido carbenoid rearrangement as the key reaction
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The addition reaction of carbonyl compounds with lithium α-sulfinyl carbanions of 1-chloroalkyl p-tolyl sulfoxides gave adducts, α-chloro β-hydroxy sulfoxides, in high to quantitative yields. The adducts were first treated with a base to give alkoxides, which were treated with i-PrMgCl or t-BuLi to give β-oxido carbenoids via a sulfoxide-metal exchange reaction. The β-oxido carbenoid rearrangement then took place to afford the enolates with one-carbon elongation. The enolate intermediates were found to be able to be trapped with electrophiles such as aldehydes, ethyl chloroformate, benzoyl chloride, haloalkanes to give α,α-disubstituted carbonyl compounds in moderate to good yields. This method provides a new and efficient way for synthesis of α,α-disubstituted carbonyl compounds from carbonyl compounds with one-carbon homologation in only two synthetic operations.
- Miyashita, Kohsuke,Satoh, Tsuyoshi
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p. 5067 - 5080
(2007/10/03)
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- Convenient Processes for the Synthesis of Aromatic Ketones from Aryl Bromides and Carboxylic Anhydrides Using a Cobalt Catalysis
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The cross-coupling of various para- and meta-substituted aromatic bromides, mostly bearing sensitive moieties, with several carboxylic acid anhydrides is reported. This reaction can be carried out in two steps, by forming an aromatic organozinc reagent via cobalt catalysis in the first step, or even more interestingly in a single step, also by using a cobalt-based catalyst. The aromatic ketones are obtained by these new, mild, and convenient methods in 30-79% yields versus starting aryl bromide. Results are also disclosed that suggest the role played by cobalt species in the coupling of organozinc reagents with electrophiles could be similar to those of more commonplace transition metal complexes.
- Kazmierski, Igor,Bastienne, Mylene,Gosmini, Corinne,Paris, Jean-Marc,Perichon, Jacques
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p. 936 - 942
(2007/10/03)
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- Pd-catalyzed carbonylative cross-coupling reactions by triorganoindiums: Highly efficient transfer of organic groups attached to indium under atmospheric pressure
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(Matrix presented) A highly atom-efficient synthetic method of unsymmetrical ketones was developed by using trialkyl- and triarylindiums, which could be employed as effective cross-coupling partners in Pd-catalyzed carbonylative cross-coupling reactions with a variety of organic electrophiles. The present method produced unsymmetrical ketones and 1,4-diacylbenzenes in good yields with highly efficient transfer of almost all the organic groups attached to the indium under atmospheric pressure of CO gas in THF at 66°C.
- Lee, Phil Ho,Lee, Sung Wook,Lee, Kooyeon
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p. 1103 - 1106
(2007/10/03)
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- Bis(sym-collidine)bromine(I) hexafluorophosphate as oxidant
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Primary and secondary alcohols in solution in methylene chloride are oxidised with bis(sym-collidine)bromine(I) hexafluorophosphate in good yields to the carbonyl compounds. For secondary and tertiary alcohols in which one of the substituents is a 4-methoxyphenyl group the oxidation takes place by cleavage of the phenyl-sp3 carbon bond and formation of bromoanisole and carbonyl compounds. (C) 2000 Elsevier Science Ltd.
- Rousseau,Robin
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p. 8881 - 8885
(2007/10/03)
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- Pyrazole ligands: Structure - Affinity/activity relationships and estrogen receptor-α-selective agonists
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We have found that certain tetrasubstituted pyrazoles are high-affinity ligands for the estrogen receptor (ER) (Fink et al. Chem. Biol. 1999, 6, 205-219) and that one pyrazole is considerably more potent as an agonist on the ERα than on the ERβ subtype (Sun et al. Endocrinology 1999, 140, 800-804). To investigate what substituent pattern provides optimal ER binding affinity and the greatest enhancement of potency as an ERα-selective agonist, we prepared a number of tetrasubstituted pyrazole analogues with defined variations at certain substituent positions. Analysis of their binding affinity pattern shows that a C(4)-propyl substituent is optimal and that a p-hydroxyl group on the N(1)-phenyl group also enhances affinity and selectivity for ERα. The best compound in this series, a propylpyrazole triol (PPT, compound 4g), binds to ERα with high affinity (ca. 50% that of estradiol), and it has a 410-fold binding affinity preference for ERα. It also activates gene transcription only through ERα. Thus, this compound represents the first ERα-specific agonist. We investigated the molecular basis for the exceptional ERα binding affinity and potency selectivity of pyrazole 4g by a further study of structure-affinity relationships in this series and by molecular modeling. These investigations suggest that the pyrazole triols prefer to bind to ERα with their C(3)-phenol in the estradiol A-ring binding pocket and that binding selectivity results from differences in the interaction of the pyrazole core and C(4)-propyl group with portions of the receptor where ERα has a smaller residue than ERβ. These ER subtype-specific interactions and the ER subtype-selective ligands that can be derived from them should prove useful in defining those biological activities in estrogen target cells that can be selectively activated through ERα.
- Stauffer,Coletta,Tedesco,Nishiguchi,Carlson,Sun,Katzenellenbogen,Katzenellenbogen
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p. 4934 - 4947
(2007/10/03)
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