- Argentivorous Molecules with Chromophores in Side Arms: Silver Ion-Induced Turn on and Turn off of Fluorescence
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The synthesis of argentivorous molecules (L1 and L2) having two chromophores (4-(anthracen-9-yl)benzyl or 4-(pyren-1-yl)benzyl groups) and two benzyl groups and the fluorescence properties of their silver complexes in a solution and the solid state are reported. A crystallographic approach for the Ag+ complexes with L1 and L2 revealed that the observed fluorescence changes stem from the excimer formation and extinction of fluorescent. Furthermore, binding stabilities of L1 and L2 toward Ag+ ions were estimated by the Ag+-induced UV-vis and PL spectral changes.
- Ju, Huiyeong,Taniguchi, Aya,Kikukawa, Kaoru,Horita, Hiroki,Ikeda, Mari,Kuwahara, Shunsuke,Habata, Yoichi
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supporting information
p. 9141 - 9147
(2021/06/28)
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- Hydroxyl radical-mediated oxidative cleavage of CC bonds and further esterification reaction by heterogeneous semiconductor photocatalysis
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A hydroxyl radical-mediated aerobic cleavage of alkenes and further sequence esterification reaction for the preparation of carbonyl compounds have been developed by using tubular carbon nitride (TCN) as a general heterogeneous photocatalyst under an oxygen atmosphere with visible light irradiation. This protocol has an excellent substrate scope and gives the desired aldehydes, ketones and esters in moderate to high yields. Importantly, this metal-free procedure employed photogenerated hydroxyl radicals in situ as green oxidation active species, avoiding the present additional initiators. The reaction could be carried out under solar light irradiation and was applicable to large-scale reactions. Furthermore, the recyclable TCN catalyst could be used several times without a significant loss of activities.
- Hong, Mei,Jia, Rui,Miao, Hongyan,Ni, Bangqing,Niu, Tengfei,Wang, Hui
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p. 6591 - 6597
(2021/09/10)
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- Method for synthesizing aromatic aldehyde through iron catalyzed oxidation allyl aromatic compound
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The invention discloses a method for synthesizing aromatic aldehyde through an iron catalyzed oxidation allyl aromatic compound. According to the specific method, under the promotion effect of hydrogen silane, with air or oxygen as the oxidant, the aromatic aldehyde compound is synthesized through the iron catalyzed oxidation allyl aromatic compound, the reaction temperature is 20-150 DEG C, and the time is 0.25-60 h. The method has the advantages that a catalyst source is wide, the price is low and the environment is protected; an oxidant source is wide, the price is low and no waste is generated; the reaction conditions are mild, selectivity is high and the yield is high; a substrate source is wide and stable; a substrate functional group is high in compatibility and a substrate is widein application range; complicated small molecules are compatible and can be well converted into aldehyde. The target product separation yield can reach up to 96% under the optimized reaction conditions.
- -
-
Paragraph 0039-0041; 0149
(2019/06/27)
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- Enantioselective Conjugate Addition of Aryl Halides and Triflates to Electron-Deficient Olefins via Nickel- And Rhodium-Catalyzed Sequential Relay Reactions
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Asymmetric conjugate addition of aryl halides or aryl triflates to electron-deficient olefins was realized by sequential Miyaura borylation and Hayashi-Miyaura conjugate addition in one pot. A nickel-catalyzed borylation of aryl halides or triflates and a rhodium-chiral diene complex catalyzed enantioselective conjugate addition was executed as a pair of relay reactions as a more efficient and greener protocol.
- Fan, Chenrui,Wu, Qixu,Zhu, Chengfeng,Wu, Xiang,Li, Yougui,Luo, Yunfei,He, Jian-Bo
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supporting information
p. 8888 - 8892
(2019/10/14)
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- A supramolecular photocatalyst composed of a polyoxometalate and a photosensitizing water-soluble porphyrin diacid for the oxidation of organic substrates in water
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A diprotonated form of a cationic water-soluble saddle-distorted porphyrin (H416+) forms stable supramolecular assemblies with multianionic polyoxometalates (POMs) by electrostatic interactions. An assembly of H416+ with a Ru-substituted POM can perform photocatalytic oxidation of organic substrates in water under visible-light irradiation through adduct formation of the H416+ moiety with an oxidant.
- Ishizuka, Tomoya,Ohkawa, Shumpei,Ochiai, Hidemi,Hashimoto, Muneaki,Ohkubo, Kei,Kotani, Hiroaki,Sadakane, Masahiro,Fukuzumi, Shunichi,Kojima, Takahiko
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supporting information
p. 1975 - 1980
(2018/05/23)
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- Synthesis of tetraarylborates via tetralithio intermediates and the effect of polar functional groups and cations on their crystal structures
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A novel general protocol for the preparation of functionalized (COOH, CHO, C(O)NHtBu, B(OH)2) tetraphenyl- and tetrakis(4′-biphenylyl)borates is reported. It involves four-fold halogen-lithium exchange in potassium tetrakis(iodophenyl)borates and tetrakis(4′-bromobiphenylyl)borate) using t-BuLi in THF at ?78 °C followed by treatment of the resulting tetralithio intermediates with electrophiles (CO2, DMF, t-BuNCO, B(OMe)3). X-ray crystal structures of ammonium tetrakis[4-(dihydroxyboryl)phenyl]borate, lithium tetrakis(3-carboxyphenyl)borate, and lithium tetrakis[4-(tert-butylcarbamoyl)phenyl]borate were determined showing a strong effect of the cation and polar functional group on supramolecular architecture.
- Tomaszewski, Patryk,Wiszniewski, Marcin,Serwatowski, Janusz,Wo?niak, Krzysztof,Durka, Krzysztof,Luliński, Sergiusz
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p. 16627 - 16637
(2018/12/05)
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- An efficient method for the hydrolysis of potassium organotrifluoroborates promoted by montmorillonite K10
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An efficient and non-expensive method for conversion of diverse potassium organotrifluoroborates to their corresponding boronic acids promoted by montmorillonite K10 using water as the reaction solvent is described. Further interconversion of potassium organotrifluoroborates to their corresponding boronic esters, via boronic acid intermediates was also successfully accomplished. The products were obtained in good yields, being the rate of hydrolysis influenced by the type of substituent present in the boronic acid.
- Silva, Renato L.,Santos, Cosme S.,Santos, Jonh A. M.,Oliveira, Roberta A.,Menezes, Paulo H.,Freitas, Juliano C. R.
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p. 1777 - 1785
(2018/09/04)
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- Bedford-type palladacycle-catalyzed miyaura borylation of aryl halides with tetrahydroxydiboron in water
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A mild aqueous protocol for palladium catalyzed Miyaura borylation of aryl iodides, aryl bromides and aryl chlorides with tetrahydroxydiboron (BBA) as a borylating agent is developed. The developed methodology requires low catalyst loading of Bedford-type palladacycle catalyst (0.05 mol %) and works best under mild reaction conditions at 40 °C in short time of 6 h in water. In addition, our studies show that for Miyaura borylation using BBA in aqueous condition, maintaining a neutral reaction pH is very important for reproducibility and higher yields of corresponding borylated products. Moreover, our protocol is applicable for a broad range of aryl halides, corresponding borylated products are obtained in excellent yields up to 93% with 29 examples demonstrating its broad utility and functional group tolerance.
- Zernickel, Anna,Du, Weiyuan,Ghorpade, Seema A.,Sawant, Dinesh N.,Makki, Arwa A.,Sekar, Nagaiyan,Eppinger, J?rg
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p. 1842 - 1851
(2018/02/23)
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- Development of a Concise Multikilogram Synthesis of LPA-1 Antagonist BMS-986020 via a Tandem Borylation-Suzuki Procedure
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The process development for the synthesis of BMS-986020 (1) via a palladium catalyzed tandem borylation/Suzuki reaction is described. Evaluation of conditions culminated in an efficient borylation procedure using tetrahydroxydiboron followed by a tandem Suzuki reaction employing the same commercially available palladium catalyst for both steps. This methodology addressed shortcomings of early synthetic routes and was ultimately used for the multikilogram scale synthesis of the active pharmaceutical ingredient 1. Further evaluation of the borylation reaction showed useful reactivity with a range of substituted aryl bromides and iodides as coupling partners. These findings represent a practical, efficient, mild, and scalable method for borylation.
- Smith, Michael J.,Lawler, Michael J.,Kopp, Nathaniel,McLeod, Douglas D.,Davulcu, Akin H.,Lin, Dong,Katipally, Kishta,Sfouggatakis, Chris
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p. 1859 - 1863
(2017/11/24)
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- A process for preparing aldehyde group benzene boric acid
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The invention discloses a method for preparing formyl phenylboronic acid, which comprises the following steps: heating halogenated phenylboronic acid in toluene or heptane under reflux for dewatering to form a tripolymer, mixing the tripolymer with dimethylformamide, dropwisely adding n-butyllithium at low temperature to react by a one-pot process, hydrolyzing with hydrochloric acid, and recrystallizing to obtain the formyl phenylboronic acid. The method is simple to operate, avoids the process of separating the intermediate after formyl protection in the conventional technique, has high universality, can obtain favorable yield for ortho-, meta- and para- formyl phenylboronic acids, and is beneficial to scale-up production.
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Paragraph 0018; 0021; 0022
(2017/07/04)
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- Palladium on Carbon-Catalyzed Chemoselective Oxygen Oxidation of Aromatic Acetals
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The development of an unprecedented chemoselective transformation has contributed to forming a novel synthetic process for target molecules. Chemoselective oxidation of aromatic acetals has been accomplished using a reusable palladium on carbon catalyst under atmospheric oxygen conditions to form ester derivatives with tolerance of aliphatic acetals and ketals.
- Yasukawa, Naoki,Asai, Shota,Kato, Maho,Monguchi, Yasunari,Sajiki, Hironao,Sawama, Yoshinari
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supporting information
p. 5604 - 5607
(2016/11/17)
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- Flow Chemistry on Multigram Scale: Continuous Synthesis of Boronic Acids within 1 s
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The benefits and limitations of a simple continuous flow setup for handling and performing of organolithium chemistry on the multigram scale is described. The developed metalation platform embodies a valuable complement to existing methodologies, as it combines the benefits of Flash Chemistry (chemical synthesis on a time scale of 1 s) with remarkable throughput (g/min) while mitigating the risk of blockages.
- Hafner, Andreas,Meisenbach, Mark,Sedelmeier, Joerg
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supporting information
p. 3630 - 3633
(2016/08/16)
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- Complete Monitoring of Coherent and Incoherent Spin Flip Domains in the Recombination of Charge-Separated States of Donor-Iridium Complex-Acceptor Triads
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The spin chemistry of photoinduced charge-separated (CS) states of three triads comprising one or two triarylamine donors, a cyclometalated iridium complex sensitizer and a naphthalene diimide (NDI) acceptor, was investigated by transient absorption spectroscopy in the ns-μs time regime. Strong magnetic-field effects (MFE) were observed for two triads with a phenylene bridge between iridium complex sensitizer and NDI acceptor. For these triads, the lifetimes of the CS states increased from 0.6 μs at zero field to 40 μs at about 2 T. Substituting the phenylene by a biphenyl bridge causes the lifetime of the CS state at zero field to increase by more than 2 orders of magnitude (τ = 79 μs) and the MFE to disappear almost completely. The kinetic MFE was analyzed in the framework of a generalized Hayashi-Nagakura scheme describing coherent (S, T0 虠 T±) as well as incoherent (S, T0 ? T±) processes by a single rate constant k±. The magnetic-field dependence of k± of the triads with phenylene bridge spans 2 orders of magnitude and exhibits a biphasic behavior characterized by a superposition of two Lorentzians. This biphasic MFE is observed for the first time and is clearly attributable to the coherent (B 10 mT) and incoherent (10 mT B 2 T) domains of spin motion induced by isotropic and anisotropic hyperfine coupling. The parameters of both domains are well understood in terms of the structural properties of the two triads, including the effect of electron hopping in the triad with two donor moieties. The kinetic model also accounts for the reduction of the MFE on reducing the rate constant of charge recombination in the triad with the biphenyl bridge. (Graph Presented).
- Klein, Johannes H.,Schmidt, David,Steiner, Ulrich E.,Lambert, Christoph
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supporting information
p. 11011 - 11021
(2015/09/15)
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- Oxygenation of Organoboronic Acids by a Nonheme Iron(II) Complex: Mimicking Boronic Acid Monooxygenase Activity
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Phenolic compounds are important intermediates in the bacterial biodegradation of aromatic compounds in the soil. An Arthrobacter sp. strain has been shown to exhibit boronic acid monooxygenase activity through the conversion of different substituted phenylboronic acids to the corresponding phenols using dioxygen. While a number of methods have been reported to cleave the C-B bonds of organoboronic acids, there is no report on biomimetic iron complex exhibiting this activity using dioxygen as the oxidant. In that direction, we have investigated the reactivity of a nucleophilic iron-oxygen oxidant, generated upon oxidative decarboxylation of an iron(II)-benzilate complex [(TpPh2)FeII(benzilate)] (TpPh2 = hydrotris(3,5-diphenyl-pyrazol-1-yl)borate), toward organoboronic acids. The oxidant converts different aryl/alkylboronic acids to the corresponding oxygenated products with the incorporation of one oxygen atom from dioxygen. This method represents an efficient protocol for the oxygenation of boronic acids with dioxygen as the terminal oxidant.
- Chatterjee, Sayanti,Paine, Tapan Kanti
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supporting information
p. 9727 - 9732
(2015/11/03)
-
- Superaromatic terpyridines based on corannulene responsive to metal ions
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Two superaromatic terpyridine ligands (1 and 2) incorporating a corannulene unit at the 4′-position are reported. The optical and metal sensing properties of both ligands were investigated by the naked eye, and UV-vis and fluorescence spectroscopy in this work. In 1, the corannulene motif is directly connected to the 4′-phenylterpyridine domain, while in 2, the corannulene motif and the 4′-phenylterpyridine domain are separated by an acetylene linker. Both 1 and 2 can work as chemosensors for metal ions and display different optical responses to various metal ions. It is shown that both ligands exhibit a colorimetric sensing ability for Fe2+ through an obvious color change from colorless to magenta, and this color change can be observed easily by the naked eye. The addition of Fe2+ also leads to significant changes in the absorption spectra of the ligands. A characteristic red shift in the emission spectra is observed in the presence of Zn 2+, which facilitates the discrimination of Zn2+ from other metal ions. In addition, density functional theory (DFT) and time-dependent-density functional theory (TD-DFT) calculations were performed and shown to be consistent with the observed experimental results. The Royal Society of Chemistry.
- Wu, Difeng,Shao, Tao,Men, Jian,Chen, Xiaochuan,Gao, Guowei
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supporting information
p. 1753 - 1761
(2014/01/06)
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- Cyclic thiourea/urea functionalized triphenylamine-based dyes for high-performance dye-sensitized solar cells
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Six cyclic thiourea/urea functionalized triphenylamine-based dyes (AZ1-AZ6) containing 2-cyanoacrylic acid as an acceptor and various linkers (phenyl, biphenyl, and bithiophene) were synthesized. They exhibited high photovoltaic performance owing to an improved short-circuit photocurrent density (J sc) and open-circuit voltage (Voc). Among them, AZ6 bearing a cyclic thiourea group and bithiophene linker showed the highest power conversion efficiency (PCE) up to 7.29%, which was comparable to that of N719 (PCE = 7.36%).
- Wu, Zhisheng,An, Zhongwei,Chen, Xinbing,Chen, Pei
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p. 1456 - 1459
(2013/07/05)
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- Nickel-catalyzed borylation of halides and pseudohalides with tetrahydroxydiboron [B2(OH)4]
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Arylboronic acids are gaining increased importance as reagents and target structures in a variety of useful applications. Recently, the palladium-catalyzed synthesis of arylboronic acids employing the atom-economical tetrahydroxydiboron (BBA) reagent has been reported. The high cost associated with palladium, combined with several limitations of both palladium- and copper-catalyzed processes, prompted us to develop an alternative method. Thus, the nickel-catalyzed borylation of aryl and heteroaryl halides and pseudohalides using tetrahydroxydiboron (BBA) has been formulated. The reaction proved to be widely functional group tolerant and applicable to a number of heterocyclic systems. To the best of our knowledge, the examples presented here represent the only effective Ni-catalyzed Miyaura borylations conducted at room temperature.
- Molander, Gary A.,Cavalcanti, Livia N.,Garcia-Garcia, Carolina
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p. 6427 - 6439
(2013/07/26)
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- Scope of the palladium-catalyzed aryl borylation utilizing bis-boronic acid
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The Suzuki-Miyaura reaction has become one of the more useful tools for synthetic organic chemists. Until recently, there did not exist a direct way to make the most important component in the coupling reaction, namely the boronic acid. Current methods to make boronic acids often employ harsh or wasteful reagents to prepare boronic acid derivatives and require additional steps to afford the desired boronic acid. The scope of the previously reported palladium-catalyzed, direct boronic acid synthesis is unveiled, which includes a wide array of synthetically useful aryl electrophiles. It makes use of the newly available second generation Buchwald XPhos preformed palladium catalyst and bis-boronic acid. For ease of isolation and to preserve the often sensitive C-B bond, all boronic acids were readily converted to their more stable trifluoroborate counterparts.
- Molander, Gary A.,Trice, Sarah L. J.,Kennedy, Steven M.,Dreher, Spencer D.,Tudge, Matthew T.
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supporting information; experimental part
p. 11667 - 11673
(2012/09/05)
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- Iron trichloride promoted hydrolysis of potassium organotrifluoroborates
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In the presence of iron trichloride, the hydrolysis of potassium organotrifluoroborates occurs smoothly at room temperature to afford the corresponding organoboronic acids in good to excellent yields. The hydrolysis is effective for aryltrifluoroborates as well as alkenyl- and alkyl- trifluoroborates.
- Blevins, David W.,Yao, Min-Liang,Yong, Li,Kabalka, George W.
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experimental part
p. 6534 - 6536
(2011/12/22)
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- Base free aryl coupling of diazonium compounds and boronic esters: Self-activation allowing an overall highly practical process
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Boronic esters have long been considered as poor partners in cross-coupling reactions with arene diazoniums. Here is reported an unprecedented application of self-activated boronic esters in a base-free cross-coupling reaction with diazonium salts under mild and user friendly conditions.
- Bonin, Helene,Delbrayelle, Dominique,Demonchaux, Patrice,Gras, Emmanuel
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supporting information; experimental part
p. 2677 - 2679
(2010/07/08)
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- Multistep phase-switch synthesis by using liquid-liquid partitioning of boronic acids: Productive tags with an expanded repertoire of compatible reactions
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(Figure Presented) Tagging along: A system for phase-switch synthesis has been developed. The boronic acid functionality is used as a phase tag that complexes to sorbitol and facilitates compound transfer from an organic solvent to water at high pH. The phase tag can then be used in a productive reaction step to generate targeted products, thereby eliminating purification by silica gel chromatography.
- Mothana, Sam,Grassot, Jean-Marie,Hall, Dennis G.
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supporting information; experimental part
p. 2883 - 2887
(2010/07/06)
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- Thermal and microwave hydrolysis of organotrifluoroborates mediated by alumina
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Hydrolysis of organotrifluoroborates to the corresponding organoboronic acids is readily achieved under either thermal or microwave conditions in the presence of alumina. The organoboronic acid products are obtained in good to excellent yields with essent
- Kabalka, George W.,Coltuclu, Vitali
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experimental part
p. 6271 - 6272
(2010/01/11)
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- Efficient hydrolysis of organotrifluoroborates via silica gel and water
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(Chemical Equation Presented) A general, mild, and efficient method for the hydrolysis of organotrifluoroborates to unveil boronic acids using silica gel and H2O was developed. This method proved to be tolerant of a broad range of aryl-, heteroaryl-, alkenyl-, and alkyltrifluoroborates as well as structurally diverse aminomethylated organotrifluoroborates.As anticipated, electron-rich substrates provided the corresponding boronic acids more readily than electron-poor substrates, owing to the resonance-stabilized difluoroborane intermediate. The method developed was expanded further for the conversion of organotrifluoroborates to the corresponding boronate esters. 2009 American Chemical Society.
- Molander, Gary A.,Cavalcanti, Livia N.,Canturk, Belgin,Pan, Po-Shen,Kennedy, Lauren E.
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supporting information; experimental part
p. 7364 - 7369
(2010/01/16)
-
- A new approach to combretastatin D2
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A concise and convergent route to combretastatin D2 is described together with some preliminary biological data. The Royal Society of Chemistry 2006.
- Cousin, David,Mann, John,Nieuwenhuyzen, Mark,Van Den Berg, Hendrik
-
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- NEW MATERIAL FOR TRANSPORTING ELECTRONS AND ORGANIC ELECTROLUMINESCENT DISPLAY USING THE SAME
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Novel materials for electron injection/transportation and emitting layers can greatly improve the stability of an organic electroluminescent display. Electroluminescent displays incorporating these materials produce blue light at low voltage levels. These novel organic materials include compounds in which 1 to 2 imidazole functional groups are introduced in the 2 or 2,6-site of 9,10 substituted anthracene. An organic electroluminescent display with an organic compound layer of these materials has high efficiency, thermal stability, operationally stability and maintains driving voltage before and after operation.
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Paragraph 0053
(2008/06/13)
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- Method for producing formylphenylboronic acids
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A process for preparing formylphenylboronic acids of the formula (I) by reaction of protected chlorobenzaldehydes of the formula (II) with lithium in an inert solvent to form compounds of the formula (III) and subsequent reaction with a boron compound of the formula BY3 to give compounds of the formula (I).
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- 3,3-disubstituted-oxindole derivatives useful as anticancer agents
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The present invention relates to compounds of formula 1 and to pharmaceutically acceptable salts, prodrugs, and solvates thereof, wherein n is 0 or 1 and R1, R2, R3, R4, and R5are as defined herein. The above compounds of formula 1 are useful in the treatment of hyperproliferative disorders, such as cancer, in mammals. The invention also relates to pharmaceutical compositions containing the compounds of formula 1, to methods of inhibiting abnormal cell growth, including cancer, in a mammal by administering the compounds of formula 1 to a mammal requiring such treatment, and to methods of preparing compounds of formula 1.
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- New material for transporting electrons and organic electroluminescent display using the same
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Novel materials for electron injection/transportation and emitting layers can greatly improve the stability of an organic electroluminescent display. Electroluminescent displays incorporating these materials produce blue light at low voltage levels. These novel organic materials include compounds in which 1 to 2 imidazole functional groups are introduced in the 2 or 2,6-site of 9,10 substituted anthracene. An organic electroluminescent display with an organic compound layer of these materials has high efficiency, thermal stability, operationally stability and maintains driving voltage before and after operation.
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- Process for the preparation of substituted phenylboronic acids
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Compounds of the formula (I) in which Q1and Q2are each OH or form a trimeric boric anhydride, Z is CHO, CH2Y, X or a protected aldehyde group, and X is CN, COOH, COCl, CONH2or C(OR)3, and Y is OH or NH2, and Z is in the o-, m- or p-position to the boronic acid radical, are prepared by a) reacting a compound of the formula (II) ?with Mg in the presence of an anthracene compound and, if desired, a transition-metal halide and, if desired, an Mg halide or in the presence of a transition-metal halide and, if desired, an Mg halide, to give the corresponding arylmagnesium chloride, b) reacting the latter with a borate of the formula B(OR′)3and hydrolyzing the product, with removal of the aldehyde protecting group, c) and, if desired, oxidizing or reducing the free aldehyde group.
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- Zinc borates: Functionalized hard nucleophiles for coupling reactions with secondary allylic acetates
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We have succeeded in developing zinc borates of the general structure 3 for coupling reaction with allylic acetates. The advantages of using compounds 3 are their compatibility with carbonyl groups such as aldehyde, ketone, and ester groups, and their high reactivity toward secondary allylic acetates. Zinc borates 3 were prepared from boronate esters 1 [R(T) = p-(CHO)C6H4, p-(Ac)C6H4, p-{Ac(CH2)2}C6H4, p-(Ac-OCH2)C6H4, p-{AcO(CH2)3}C6H4, p-{EtO2C(CH2}2}C6H4, (E)-CH=CH(CH2)4OAc] with MeZnCl; subsequent treatment with allylic acetates 4 [R = n-C5H11, c-C6H11, (CH2)2CH(-O(CH2}2O-)] in the presence of NiCl2(PPh3)2 (10 mol-%) in THF-DMI (1,3-dimethyl-2-imidazolidinone) (10 equiv.) at 40-50 °C overnight furnished the coupling products 5 in good yields. Among the products, 5bb, possessing one free and one protected aldehyde group, is a highlight of this type of reaction. The stereochemical aspects of the reaction were also examined. Thus, the alkenyl groups of (E)- and (Z)-alkenyl borates 3b and c were transformed with retention of the olefinic geometry into acetates 4a and b (R = n-C5H11, c-C6H11), while reaction of cyclic acetate 11 proceeded with inversion at the carbon center involved in the reaction. In addition, we found that the anions generated from (EtO)2P(= O)CH2CO2Et and (MeO)2P(=O)CH2Ac under Masamune's conditions attacked the aldehyde carbon in the boronate 1d to produce - after reduction of the double bond - the boronate esters 1i and 1j, respectively, in good yields.
- Kobayashi, Yuichi,Tokoro, Yuko,Watatani, Kengo
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p. 3825 - 3834
(2007/10/03)
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- A high-yield synthesis of 4-borono-DL-phenylalanine
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A high-yield synthesis of 4-borono-DL-phenylalanine has been achieved by a route which features a highly diastereoselective formation of the Z-isomer of a boron-containing dehydroamino acid derivative.
- Park, Ki Chul,Yoshino, Kazuo,Tomiyasu, Hiroshi
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p. 2041 - 2044
(2007/10/03)
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- The use of a modified Suzuki reaction for the synthesis of monoarylferrocenes
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A modification of the Suzuki cross-coupling reaction proved to be a clean and useful method for the preparation of monosubstituted arylferrocenes. Iodoferrocene was reacted with a series of substituted arylboronic acids in the presence of sodium carbonate and palladium acetate in aqueous ethanol at room temperature to produce a range of substituted monoarylferrocenes. A systematic investigation undertaken to determine optimal reaction conditions indicated that scrupulous deoxygenation of the solvent is critical. The use of stronger bases such as barium hydroxide and potassium carbonate is favourable and gives rise to better yields of monoarylferrocenes. The reactions also proceed efficiently in aqueous DMF, broadening the scope of the reaction allowing efficient reactions with boronic acids that show low solubility in organic solvents.
- Imrie, Christopher,Loubser, Christa,Engelbrecht, Pieter,McCleland, Cedric W.
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p. 2513 - 2523
(2007/10/03)
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- Process for the preparation of biphenyl derivatives
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Biphenyl derivatives and processes for the preparation of biphenyl derivatives are described. A compound of formula (I) is disclosed STR1 in which the substituent X is --CHO or --CH(OR1)OR2, where R1 and R2 independently of one another are (C1 -C6)-alkyl or R1 and R2 together are an alkylene group (--CH2)n --, where n is 2, 3 4 or 5 and R is --F, --Cl, --NO2, --(CH2)m --COOR3, --(CH2)m --CONHR3, --(CH2)m --CN, --SO2 NH--COOR3, --SO2 NH--CO--NHR3, --SO2 NH--SO2 --R3, --NHSO2 R3, STR2 --PO3 R3, --NH--SO2 --CF3, --SO2 NR4 where R3 is hydrogen, (C1 -C6)-alkyl, (C3 -C6)cycloalkyl, or (C1 -C6)-alkyl-(C3 -C6)cycloalkyl and R4 is a group =C--N(CH3)2, and m is 0, 1, 2, 3, or 4. The invention also relates to a process for the preparation of a compound of the formula (I) in which X is an optionally protected formyl group and R is a group which is itself inert to the reaction conditions of the synthesis, which comprises reacting a compound of the formula (II) STR3 with a substituted phenyl-halogen compound of the formula (III) STR4 wherein the substituent Hal is a halogen group.
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