- Asymmetric 1,4-Addition of Arylboronic Acids to β,γ-Unsaturated α-Ketoesters using Heterogeneous Chiral Metal Nanoparticle Systems
-
Asymmetric 1,4-addition reactions with β,γ-unsaturated α-ketoesters are valuable because the resulting chiral ketoester compounds can be converted into various useful species that are often used as chiral building blocks in drug and natural product synthesis. However, β,γ-unsaturated α-ketoesters have two reactive points in terms of nucleophilic additions, which will lead to the 1,4-adduct, the 1,2-adduct and to the combined 1,4- and 1,2-adduct. Therefore, controlling this chemoselectivity is an important factor for the development of these transformations. Here, we developed an asymmetric 1,4-addition of aryl boronic acids to β,γ-unsaturated α-ketoesters by using heterogeneous chiral rhodium nanoparticle systems with a chiral diene ligand bearing a secondary amide moiety. The newly developed polydimethylsilane-immobilized rhodium nanoparticle catalysts showed high activity, high chemoselectivity, and excellent enantioselectivity, and this is the first heterogeneous catalytic system for this asymmetric reaction. Metal nanoparticle catalysts were recovered and reused without loss of activity or leaching of metal. (Figure presented.).
- Miyamura, Hiroyuki,Yasukawa, Tomohiro,Zhu, Zhiyuan,Kobayashi, Shū
-
supporting information
p. 353 - 359
(2019/12/15)
-
- Aryl boronic acid preparation method
-
The invention belongs to the technical field of fine chemical engineering, and relates to an aryl boronic acid preparation method. In the prior art, aryl boronic acid as a novel safe and environmentally-friendly arylation reagent is widely used in scientific research and production of various fine chemicals containing aryl structures in the fields of medicines, pesticides, advanced materials and the like; and the aryl boronic acid compound preparation method reported in the disclosed literature has problems of harsh reaction conditions and high cost. A purpose of the invention is to provide amethod, wherein an aryl boron compound is formed by carrying out a reaction on a Grignard reagent and trialkyl borate under mild conditions, the composition of the aryl boron compound is converted from the main component diaryl borate into the main component aryl borate, and the aryl borate is hydrolyzed to obtain aryl boric acid, so that the preparation cost of the acyl aryl boric acid compound can be remarkably reduced, and the method has good practical application prospect.
- -
-
Paragraph 0033-0040
(2020/01/25)
-
- Chemoselective Rhodium-Catalyzed Borylation of Bromoiodoarenes under Mild Conditions
-
A chemoselective rhodium-catalyzed borylation has been developed for the preparation of aryl boronate esters. The reaction proceeds under mild conditions with excellent selectivity for C-I bonds in bromoiodoarenes and exhibits broad functional group tolerance. This procedure can act as a complementary approach toward bifunctional arenes along with other metal-catalyzed borylations. Additionally, the reaction's utility in the preparation of monomers for metal-catalyzed cross-coupling polymerization is demonstrated.
- Varni, Anthony J.,Bautista, Michael V.,Noonan, Kevin J.T.
-
p. 6770 - 6777
(2020/07/21)
-
- Axially chiral tridentate isoquinoline derived ligands for diethylzinc addition to aldehydes
-
The synthesis and resolution of new tridentate isoquinoline-derived ligands has been developed. The key steps in the synthetic sequence include successive, chemo-selective Suzuki-Miyaura cross-couplings of 1,3-dichloroisoquinoline with suitable arylboronic acids. The new ligands prepared in this manner were resolved either via molecular complexation with N-benzylcinchonidinium chloride as with 1-[3-(2-hydroxyphenyl)isoquinolin-1-yl]naphthalen-2-ol or via chromatographic separation of its epimeric camphorsulfonates as for 1,3-bis-(2-hydroxynaphthalen-1-yl)isoquinoline. 4-tert-Butyl-2-chloro-6-[1-(2-hydroxymethylnaphthalen-1-yl)isoquinolin-3-yl]phenol was resolved by chiral semi-preparative HPLC. The application of these ligands in the diethylzinc addition to aldehydes was investigated. In certain cases, the desired secondary alcohols were obtained in high yield with excellent enantiomeric excess (ee > 99%) at low catalyst loading (1 mol%).
- Sweetman, Brian A.,Guiry, Patrick J.
-
p. 5567 - 5581
(2018/08/09)
-
- Copper-Catalyzed Monoorganylation of Trialkyl Borates with Functionalized Organozinc Pivalates
-
Organozinc pivalates, a recently developed air- and moisture-stable organozinc species, were found for the first time as excellent organometallic species in the monoorganylation of trialkyl borates whereby boronic acids were prepared in high yields. The significant advantage of organozinc pivalates over another previously employed organometallic reagents, e. g., organolithium reagents, Grignard reagents and organozinc halides, is that the generation of multiorganylation byproducts such as borinic acids and trialkylboranes were completely suppressed. Additionally, the in situ generated boronates could be directly arranged into Suzuki-Miyaura type cross-coupling reactions to produce biaryls in high yields.
- Fu, Ying,Gou, Bei-Lei,Shi, Chun-Zhao,Du, Zhengyin,Shen, Tong
-
p. 4253 - 4257
(2018/09/18)
-
- Bedford-type palladacycle-catalyzed miyaura borylation of aryl halides with tetrahydroxydiboron in water
-
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
-
p. 1842 - 1851
(2018/02/23)
-
- An efficient method for the hydrolysis of potassium organotrifluoroborates promoted by montmorillonite K10
-
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.
-
p. 1777 - 1785
(2018/09/04)
-
- Synthesis and evaluation of sulfonamide derivatives as potent Human Uric Acid Transporter 1 (hURAT1) inhibitors
-
This letter presents synthesis and structure-activity relationship study of sulfonamide derivatives as inhibitors of Human Uric Acid Transporter 1 (hURAT1). Among all tested sulfonamide derivatives, compounds 9b, 16i and 19b exhibited excellent inhibition activity with IC50 value of 10, 2, and 83?nM, respectively. In addition, compounds 9b and 19b demonstrated moderate PK profile in rats.
- Yang, Xintuo,Pang, Xuehai,Fan, Lei,Li, Xinghai,Chen, Yuanwei
-
supporting information
p. 1919 - 1922
(2017/04/10)
-
- Evidence for Oxidative Decay of a Ru-Bound Ligand during Catalyzed Water Oxidation
-
In the evaluation of systems designed for catalytic water oxidation, ceric ammonium nitrate (CAN) is often used as a sacrificial electron acceptor. One of the sources of failure for such systems is oxidative decay of the catalyst in the presence of the st
- Kagalwala, Husain N.,Tong, Lianpeng,Zong, Ruifa,Kohler, Lars,Ahlquist, M?rten S. G.,Fan, Ting,Gagnon, Kevin J.,Thummel, Randolph P.
-
p. 2607 - 2615
(2017/06/01)
-
- Borinic Acids via Direct Arylation of Amine-Borane Complexes: An Air- and Water-Stable Boron Source
-
A synthesis of borinic acids and borinates was optimized using amine-borane complexes as a water and air insensitive borylating agent. The reaction operates under convenient conditions using a non-cryogenic temperature and with no flash chromatography, and it gives no boron impurities. The reaction proceeds through a tandem dehydrogenation-double addition mechanism.
- Richard, Jimmy,Birepinte, Mélodie,Charbonnier, Jean Baptiste,Liautard, Virginie,Pinet, Sandra,Pucheault, Mathieu
-
p. 736 - 744
(2017/02/15)
-
- Compound containing anthracene and pyrene and preparing method and application thereof
-
The invention provides a compound containing anthracene and pyrene and a preparing method and application thereof. The compound has a structure shown in formula I, wherein R1 and R3 are independently selected from substituted or unsubstituted C1-C60 alkyl groups, substituted or unsubstituted C6-C60 aryl groups, substituted or unsubstituted C10-C60 condensed ring groups or substituted or unsubstituted C5-C60 heterocyclic groups; R2 is selected from hydrogen, substituted or unsubstituted C6-C60 aryl groups, substituted or unsubstituted C5-C60 heterocyclic groups, substituted or unsubstituted C10-C60 condensed ring groups or substituted or unsubstituted C5-C60 arylamine groups; n is 0 or 1. When current density is 20 mA/cm2, the current efficiency of the compound with the structure shown in formula I is as high as 8.9 cd/A, and service life is as long as 8500 h which is much longer than that of existing electroluminescent materials.
- -
-
Paragraph 0147-0152
(2017/02/24)
-
- FUSED RING COMPOUND CONTAINING FURAN OR SALT THEREOF AND PHARMACEUTICAL COMPOSITION COMPRISING SAME
-
The present invention provides a fused ring compound containing furan or a pharmaceutically acceptable salt thereof, a method for preparing same, a pharmaceutical composition comprising same, and a use thereof. The fused ring compound containing furan or a phannaceutically acceptable salt thereof inhibits the activity of phosphatidylinositol 3-kinase (PI3K) and can therefore be used in a pharmaceutical composition for treating and preventing respiratory diseases, inflammatory diseases, proliferative diseases, cardiovascular diseases, or central nervous system diseases which occur due to the over-activation of PI3K.
- -
-
Paragraph 0855; 0863-0864
(2015/06/03)
-
- An easy route to (hetero)arylboronic acids
-
An unprecedented spontaneous reactivity between diazonium salts and diboronic acid has been unveiled, leading to a versatile arylboronic acid synthesis directly from (hetero)arylamines. This fast reaction (35 min overall) tolerates a wide range of functional groups and is carried out under very mild conditions. The radical nature of the reaction mechanism has been investigated.
- Erb, William,Hellal, Akila,Albini, Mathieu,Rouden, Jacques,Blanchet, Jerome
-
supporting information
p. 6608 - 6612
(2014/06/09)
-
- Synthesis of macrocyclic ketones exploiting palladium-catalyzed activation of carboxylic acids as an enabling step
-
The novel synthesis of macrocyclic arylketones via palladium-catalyzed cross-coupling of arylboronic acids and carboxylic acids, activated by the treatment with di(N-succinimidyl) carbonate, is disclosed. This allows the high yielding synthesis of various
- Kapdi, Anant R.,Fairlamb, Ian J. S.
-
supporting information
p. 961 - 964
(2013/06/27)
-
- Nickel-catalyzed borylation of halides and pseudohalides with tetrahydroxydiboron [B2(OH)4]
-
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
-
p. 6427 - 6439
(2013/07/26)
-
- New 5-aryl-1H-imidazoles display in vitro antitumor activity against apoptosis-resistant cancer models, including melanomas, through mitochondrial targeting
-
We designed and synthesized 48 aryl-1H-imidazole derivatives and investigated their in vitro growth inhibitory activity in cancer cell lines known to present various levels of resistance to proapoptotic stimuli. The IC50 in vitro growth inhibitory concentration of these compounds ranged from >100 μM to single digit μM. Among the most active compounds, 2i displayed similar in vitro growth inhibition in cancer cells independent of the cells' levels of resistance to proapoptotic stimuli and was found to be cytostatic in melanoma cell lines. Compound 2i was then tested by the National Cancer Institute Human Tumor Cell Line Anti-Cancer Drug Screen, and the NCI COMPARE algorithm did not reveal any correlation between its growth inhibition profiles with the NCI database compound profiles. The use of transcriptomically characterized melanoma models then enabled us to highlight mitochondrial targeting by 2i. This hypothesis was further confirmed by reactive oxygen production measurement and oxygen consumption analysis.
- Mathieu, Véronique,Van Den Berge, Emilie,Ceusters, Justine,Konopka, Tomasz,Cops, Antonin,Bruyère, Céline,Pirker, Christine,Berger, Walter,Trieu-Van, Tran,Serteyn, Didier,Kiss, Robert,Robiette, Rapha?l
-
p. 6626 - 6637
(2013/10/01)
-
- ELECTROLUMINESCENT MATERIALS COMPRISING FLUORENE DERIVATIVES
-
OLED compounds of the general structure: B—S-A-S—B in which rod-like nuclei A includes a condensed aromatic ring structure in turn having fluorene ring structures condensed with at least one additional fluorene ring structures wherein the fluorene ring systems provided by the condensed aromatic structure are substituted at the 9-position, and in which the 9-positions of the fluorenes are not susceptible to oxidation.
- -
-
Page/Page column 29
(2013/03/26)
-
- Magnesium and calcium complexes containing biphenyl-based tridentate iminophenolate ligands for ring-opening polymerization of rac -lactide
-
A series of racemic 2-[(2′-methoxybiphenyl-2-ylimino)methyl]-4-R 2-6-R1-phenols (L1H-L8H) were reacted with {Mg[N(SiMe3)2]2}2 and Ca[N(SiMe3)2]2·2THF (THF = tetrahydrofuran), respectively, to provide nine heteroleptic magnesium complexes L1-8MgN(SiMe3)2 [R1 = iPr, R2 = H (1a); R1 = tBu, R 2 = Me (2a and 2a·THF); R1 = R2 = tBu (3a); R1 = R2 = CMe2Ph (4a); R1 = CPh3, R2 = tBu (5a); R 1 = 1-piperidinylmethyl, R2 = tBu (6a); R 1 = Cl, R2 = tBu (7a); R1 = Br, R2 = tBu (8a)], two homoleptic calcium complexes (L 2,5)2Ca (2b and 5b), and one heteroleptic calcium complex [(L4)CaN(SiMe3)2·THF] (4b), which have been fully characterized. In the solid state, magnesium complexes 2a and 6a are isostructural, and each possesses a monomeric structure, while magnesium complexes 7a and 8a are dimeric, where the two metal centers are bridged by two phenolate oxygen atoms of the ligands. The coordination geometry around the magnesium center in these complexes can be best described as a distorted tetrahedral geometry. Although bearing the same iminophenoloate ligand, the molecular structures of complexes 2a and 2a·THF are different from each other. In complex 2a·THF, the coordination of one molecule of THF to the magnesium atom leads to dissociation of the methoxy group of the ligand from the metal center. The homoleptic calcium complex 2b has a six-coordinate metal core ligated by all six donor atoms of two iminophenolate ligands. The heteroleptic magnesium complexes 1a-8a and calcium complex 4b proved to be efficient initiators for the ring-opening polymerization of rac-lactide at ambient temperature in THF or at 70 C in toluene, and the polymerizations were better controlled in the presence of 2-propanol. The introduction of a bulky ortho substituent on the phenoxy unit of the ligand resulted in an increase of the catalytic activity of the corresponding metal complex. Microstructure analysis of the resultant poly(rac-lactide) samples via homonuclear-decoupled 1H NMR spectroscopy revealed Pr values ranging from 0.60 to 0.81, which closely depended on the employed catalyst and polymerization conditions.
- Yi, Wei,Ma, Haiyan
-
p. 11821 - 11835
(2013/11/19)
-
- SYNTHESIS OF BORONIC ESTERS AND BORONIC ACIDS USING GRIGNARD REAGENTS
-
Boronic esters and boronic acids are synthesized at ambient temperature in an ethereal solvent by the reaction of Grignard reagents with a boron-containing substrate. The boron-containing substrate may be a boronic ester such as pinacolborane, neopentylglycolborane, or a dialkylaminoborane compound such as diisopropylaminoborane. The Grignard reagents may be preformed or generated from an alkyl, alkenyl, aryl, arylalkyl, heteroaryl, vinyl, or allyl halide compound and Mg°. When the boron-containing substrate is a boronic ester, the reactions generally proceed at room temperature without added base in about 1 to 3 hours to form a boronic ester compound. When the boron-containing substrate is a dialkylaminoborane compound, the reactions generally proceed to completion at 0°C in about 1 hour to form a boronic acid compound.
- -
-
Paragraph 0102-0103; 0109
(2013/03/26)
-
- Synthesis of phenylboronic acids in continuous flow by means of a multijet oscillating disc reactor system operating at cryogenic temperatures
-
A multijet oscillating disk (MJOD) millireactor system suitable for operating at cryogenic temperatures has been developed, assembled, and investigated. This new reactor system (cryoMJOD) was realized with the purpose to prepare various phenylboronic acids in a continuous two (three)-step telescoped synthetic process at temperatures in the interval -50 to -75 °C. In this process, n-butyllithium was reacted with a phenylbromide to provide the corresponding phenyllithium derivative, whereupon a borate was added under the formation of target product phenylboronic acid in good selectivity and medium-to-good yield (50-75%). These results were competitive with results previously revealed in the literature. The residence times of the telescoped two-step process were considerably shorter compared to those of batch mode operations for the identical syntheses. The flow process was optimized by means of statistical experimental design and multivariate regression, upon which the process was utilized for the production of a series of phenylboronic acid derivatives, all in medium-to-good yield. One of the substrates, 4-methoxyphenylboronic acid, was submitted for throughput improvements, resulting in a process with capability to produce the product phenylboronic acid in a quantity of 2.0 kg × day-1.
- Sleveland, Dagfinn,Bjorsvik, Hans-Rene
-
experimental part
p. 1121 - 1130
(2012/08/27)
-
- Scope of the palladium-catalyzed aryl borylation utilizing bis-boronic acid
-
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.
-
supporting information; experimental part
p. 11667 - 11673
(2012/09/05)
-
- Terphenyl crowns: A new family of receptors containing ethereal canopies that direct potassium cation onto benzenoid platforms for cation-π interactions
-
We have synthesized three simple and versatile terphenyl crowns (TC) receptors containing ethereal canopies that direct a potassium cation for efficient cation-π interactions as established by 1H NMR spectroscopy and by isolation and X-ray crystallography of their K+ salts.
- Shukla, Ruchi,Lindeman, Sergey V.,Rathore, Rajendra
-
supporting information; experimental part
p. 5600 - 5602
(2010/01/31)
-
- Introduction of allyi and prenyl side-chains into aromatic systems by suzuki cross-coupling reactions
-
This paper reports some studies aiming at the developement of a general protocol useful for the synthesis of allyl- and prenylaromatic compounds. The first part deals with, the preparation of boron reagents like arylboronic acids and their pinacol esters as well as of pinacol allyl- and prenylboronates. The second part of the paper is devoted to the use of these boron reagents in Suzuki-Miyaura cross-coupling reactions leading to allylation and prenylation of aromatic compounds. Of the six methods studied, the most promising re-suits were obtained by using the Pd2(dba)3-catalyzed reactions of arylboronic acids with allyl and prenyl bromides, that lead to the products of cross coupling in high yields (average 87%), and the reactions of aryl trifluoroborates with allyl and prenyl bromides catalyzed by Pd(OAc)2 that lead to the products of coupling in all cases in high yields (average 82%).
- Gerbino, Dario C.,Mandolesi, Sandra D.,Schmalz, Hans-Guenther,Podesta, Julio C.
-
scheme or table
p. 3964 - 3972
(2010/02/27)
-
- Efficient hydrolysis of organotrifluoroborates via silica gel and water
-
(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.
-
supporting information; experimental part
p. 7364 - 7369
(2010/01/16)
-
- Palladium-catalyzed cross-coupling of N-benzenesulfonyl-3,4-dibromopyrrole and its application to the total syntheses of lamellarins O, P, Q, and R
-
Palladium-catalyzed Suzuki-Miyaura coupling of N-benzenesulfonyl-3,4-dibromopyrrole with a variety of arylboronic acids gave the corresponding 3,4-diarylpyrroles in high yields. The 3,4-differentially arylated pyrroles could also be prepared by stepwise cross-coupling approach. The total syntheses of lamellarins O, P, Q, and R have been achieved by using the cross-coupling and the directed lithiation as key reactions.
- Fukuda, Tsutomu,Sudo, Ei-ichi,Shimokawa, Kozue,Iwao, Masatomo
-
p. 328 - 338
(2008/04/01)
-
- Substituent effects on aryltrifluoroborate solvolysis in water: Implications for Suzuki-Miyaura coupling and the design of stable 18F-labeled aryltrifluoroborates for use in PET imaging
-
(Chemical Equation Presented) Whereas electron withdrawing substituents retard the rate of aryltrifluoroborate solvolysis, electron-donating groups enhance it. Herein is presented a Hammett analysis of the solvolytic lability of aryltrifluoroborates where log(Ksolv) values correlate to a values with a ρ value of approximately -1. This work provides a predictable rubric for tuning the reactivity of boron for several uses including 18F-labeled PET reagents and has mechanistic implications for ArBF3-enhanced ligandless metal-mediated cross coupling reactions with aryltrifluoroborates.
- Ting, Richard,Harwig, Curtis W.,Lo, Justin,Li, Ying,Adam, Michael J.,Ruth, Thomas J.,Petrin, David M.
-
p. 4662 - 4670
(2008/09/20)
-
- Efforts directed toward the synthesis of colchicine: Application of palladium-catalyzed siloxane cross-coupling methodology
-
Colchicine is an important and synthetically challenging natural product. The key synthetic step in this approach to the synthesis of colchicine involved a palladium-catalyzed cross-coupling reaction between 5-bromotropolone (4) and an aryl siloxane to form the aryl-tropolone bond. The coupling of a variety of highly functionalized aryl siloxane derivatives was investigated and optimized coupling conditions were developed. It was discovered that a palladium catalyst with a high degree of phosphine ligand coordination (5 equiv of phosphine/mol Pd) was necessary to efficiently couple aryl siloxanes with 5-bromotropolone (4). In addition, the coupling approach has provided a direct comparison between siloxane and boronic acid coupling technologies that demonstrated that aryl siloxanes and boronic acids produce similar yields of highly functionalized biaryl products.
- Seganish, W. Michael,Handy, Christopher J.,DeShong, Philip
-
p. 8948 - 8955
(2007/10/03)
-
- Deprotection of pinacolyl boronate esters via hydrolysis of intermediate potassium trifluoroborates
-
An efficient two-step procedure for the deprotection of pinacolyl organoboronate esters is described. Reaction with excess potassium hydrogen fluoride produces the corresponding stable, crystalline potassium organotrifluoroborate salts. Treatment of the trifluoroborates with either inorganic base or trimethylsilyl chloride and water affords the corresponding organoboronic acid in high yield.
- Yuen, Alexander K.L.,Hutton, Craig A.
-
p. 7899 - 7903
(2007/10/03)
-
- Carbazole containing compound and organic electroluminescent display device using the same
-
The present invention is directed to a carbazole containing compound and an organic electroluminescent display device using the same. In particular, the carbazole containing compound may be a blue phosphorescent host material having a large triplet energy
- -
-
-
- Benzoxepin-derived estrogen receptor modulators: A novel molecular scaffold for the estrogen receptor
-
We present and examine the efficacy of a novel benzoxepin-based scaffold for modulation of the human estrogen receptor. Receptor tolerance of this new molecular scaffold is examined through presentation of experimentally determined antiproliferative effects on human MCF-7 breast tumor cells and measured binding affinities. The effect of functional group substitution on the benzoxepin scaffold is explored through a brief computational structure - activity relationship investigation with molecular simulation.
- Lloyd, David G.,Hughes, Rosario B.,Zisterer, Daniela M.,Williams, D. Clive,Fattorusso, Caterina,Catalanotti, Bruno,Campiani, Giuseppe,Meegan, Mary J.
-
p. 5612 - 5615
(2007/10/03)
-
- Orientation and alkylation effects on cation-π interactions in aqueous solution
-
We have investigated the orientation dependence of the cation-π interaction between a phenyl ring and a pyridinium ring in the context of a flexible model system in water. Of the four possible positions of the pyridinium nitrogen, ipso, ortho, meta, and para, we found a variation in the interaction energy of about 0.75 kcal mol-1, with the stacking of the ipso-pyridinium ring providing the strongest interaction. The observed stability is attributed to the maximization of the electrostatic interaction, minimization of rotamers, and possible differences in hydration phenomena arising from alkylation.
- Rashkin, Mark J.,Hughes, Robert M.,Calloway, Nathaniel T.,Waters, Marcey L.
-
p. 13320 - 13325
(2007/10/03)
-
- Novel fragmentation reaction of 2-alkyl- and 2,4-dialkyl-3-iodo-1- oxocyclohexan-2,4-carbolactones
-
2-Alkyl- and 2,4-dialkyl-3-iodo-1-oxocyclohexan-2,4-carbolactones undergo lithium hydroxide- and lithium alkoxide-induced fragmentation reactions to provide butenolides, γ-hydroxycyclohexenones, and/or γ- butyrolactones. In general, product distribution is governed by two factors: (1) the nature of nucleophiles and (2) the steric bulkiness of the substituents at C-2 and C-4 of the cyclohexanones. Lithium hydroxide-induced fragmentation provides butenolides and γ-hydroxycyclohexenones. In contrast, lithium alkoxide-promoted fragmentation results in predominantly 5-substituted γ-butyrolactones along with a small amount of butenolides in limited cases. Fragmentation products induced by lithium hydroxide are largely influenced by the steric bulkiness of the substituents at C-2 and C-4 of the cyclohexanone ring. The bulky substituents render the exclusive formation of butenolides.
- Khim, Seock-Kyu,Dai, Mingshi,Zhang, Xuqing,Chen, Lei,Pettus, Liping,Thakkar, Kshitij,Schultz, Arthur G.
-
p. 7728 - 7733
(2007/10/03)
-
- Deprotection of pinacolyl boronate esters by transesterification with polystyrene-boronic acid
-
A mild, efficient method for the deprotection of pinacolyl organoboronate esters is described. Treatment of the organoboronate ester with excess polystyrene-boronic acid followed by filtration and evaporation of the solvent provides the corresponding organoboronic acid. Mild deprotection of pinacolyl boronate esters to the corresponding boronic acids was achieved in the presence of excess polystyrene-boronic acid via a transesterification process. The procedure allows for the cleavage of pinacolyl boronate esters in the presence of sensitive functional groups. Crown Copyright
- Pennington, Thomas E.,Kardiman, Cynantya,Hutton, Craig A.
-
p. 6657 - 6660
(2007/10/03)
-
- Short and flexible route to 3,4-diarylpyrrole marine alkaloids: Syntheses of permethyl storniamide A, ningalin B, and lamellarin G trimethyl ether
-
A highly efficient route to 3,4-diarylpyrrole marine alkaloids has been developed using Hinsberg-type pyrrole synthesis and palladium-catalyzed Suzuki cross-coupling of the 3,4-dihydroxypyrrole bis-triflate derivatives as key reactions. Based on this approach, formal syntheses of permethyl storniamide A and ningalin B, and a total synthesis of lamellarin G trimethyl ether have been achieved.
- Iwao, Masatomo,Takeuchi, Toshiro,Fujikawa, Naotaka,Fukuda, Tsutomu,Ishibashi, Fumito
-
p. 4443 - 4446
(2007/10/03)
-
- Novel synthesis of arylboronic acids by electroreduction of aromatic halides in the presence of trialkyl borates
-
A novel preparation of aryl and heteroarylboronic acids by an electrochemical coupling reaction is described. It is based on the reductive coupling between aromatic or heteroaromatic halides and a trialkyl borate. The reactions are carried out in DMF or THF with the use of sacrificial aluminium or magnesium anodes in a single-compartment cell. Arylboronic acids are obtained with moderate to good selectivities and isolated yields.
- Laza, Carine,Dunach, Elisabet,Serein-Spirau, Francoise,Moreau, Joel J. E.,Vellutini, Luc
-
p. 373 - 375
(2007/10/03)
-
- Substituted 3-amino biaryl propionic acids as potent VLA-4 antagonists.
-
A series of substituted N-(3,5-dichlorobenzenesulfonyl)-(L)-prolyl- and (L)-azetidyl-beta-biaryl beta-alanine derivatives was prepared as selective and potent VLA-4 antagonists. The 2,6-dioxygenated biaryl substitution pattern is important for optimizing potency. Oral bioavailability was variable and may be a result of binding to circulating plasma proteins.
- Kopka, Ihor E,Lin, Linus S,Mumford, Richard A,Lanza Jr., Thomas,Magriotis, Plato A,Young, David,DeLaszlo, Stephen E,MacCoss, Malcolm,Mills, Sander G,Van Riper, Gail,McCauley, Ermengilda,Lyons, Kathryn,Vincent, Stella,Egger, Linda A,Kidambi, Usha,Stearns, Ralph,Colletti, Adria,Teffera, Yohannes,Tong, Sharon,Owens, Karen,Levorse, Dorothy,Schmidt, John A,Hagmann, William K
-
p. 2415 - 2418
(2007/10/03)
-
- Synthesis of a Sialyl LewisX mimetic conjugated with DTPA, potential ligand of new contrast agents for medical imaging
-
The structure of a mimetic of sialyl LewisX, namely 3-[2-(α-D-mannopyranosyloxy)phenyl]phenylacetic acid, was coupled to diethylenetriaminepentaacetic acid (DTPA) via a flexible alkyl spacer and the amide linkage. The overall yield of the eleven-step synthesis starting from 3-bromophenylacetic acid was 4-8%. This new ligand is expected to target inflammation sites through specific interactions with selectins, the adhesion molecules expressed on the vascular endothelium in pathological conditions. In particular, complexation of the DTPA moiety with gadolinium or radionuclides could produce contrast agents for medical imaging. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
- Fu, Yanjun,Laurent, Sophie,Muller, Robert N.
-
p. 3966 - 3973
(2007/10/03)
-
- Suzuki cross-coupling reaction of sterically hindered aryl boronates with 3-iodo-4-methoxybenzoic acid methylester
-
The cross-coupling reaction of 3-iodo-4-methoxybenzoic acid methylester with sterically hindered arylboronic esters and especially 5,5-dimethyl-2-mesityl-1,3,2-dioxaborinane, is reported. The optimisation of the process in order to obtain biaryls in good yield by using anhydrous benzene at reflux and sodium phenoxide in the presence of 0.06 equiv. of Pd(PPh3)4 is described. (C) 2000 Elsevier Science Ltd.
- Chaumeil,Signorella,Le Drian
-
p. 9655 - 9662
(2007/10/03)
-
- Syntheses, structures, and luminescence/electroluminescence of BPh2(mqp), Al(CH3)(mqp)2, and Al(mqp)3 (mqp = 2-(4′-Methylquinolinyl)-2-phenolato)
-
Three new complexes BPh2(mqp) (1), Al(CH3)(mqp)2 (2), and Al(mqp)3 (3) have been synthesized and characterized, where mqp = 2-(4′-methylquinolinyl)-2-phenolato. The mqp ligand in compounds 1 and 2 act as a chelate ligand, while in compound 3 it acts as both a chelate ligand and a terminal ligand. The boron center in 1 has tetrahedral geometry, while the aluminum ion in 2 and 3 has trigonal-bipyramidal geometry. In CH2Cl2 solution, these compounds emit a green, a green-blue, and a whitish blue color (λ = 514, 515, 497 nm), respectively, when irradiated by UV light. In the solid state, these three compounds emit a green, a blue, and a whitish blue color, respectively (λ = 520, 474, 500 nm). Electroluminescent devices using compound 3 as an emitter have been fabricated.
- Liu, Shi-Feng,Seward, Corey,Aziz, Hany,Hu, Nan-Xing,Popovi?, Zoran,Wang, Suning
-
p. 5709 - 5714
(2008/10/08)
-
- Transmetallations between aryltrialkyltins and borane: Synthesis of arylboronic acids and organotin hydrides
-
Aryltrialkyltin compounds react with borane in THF to give mixtures of trialkyltin hydrides and arylboranes, which on hydrolysis give arylboronic acid in high yields. The arylboronic acids are easily separated and obtained free of organotins.
- Faraoni,Koll,Mandolesi,Zú?iga,Podestá
-
p. 236 - 238
(2007/10/03)
-
- The use of a modified Suzuki reaction for the synthesis of monoarylferrocenes
-
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.
-
p. 2513 - 2523
(2007/10/03)
-
- Towards New Iron(III) Chelators: Synthesis and Complexing Ability of a Water-Soluble Tripodal Ligand Based on 2,2′-Dihydroxybiphenyl Subunits
-
A new water-soluble iron(III) sequestering agent has been designed. The tris-bidentate tripodal ligand consists of three 2,2′-dihydroxybiphenyl subunits connected via amide linkages at their meta (4-) positions to a framework of the "tren" type. The key step of the synthesis involves the coupling of suitably substituted monophenyl moieties in order to obtain the biphenyl precursor. The deprotonation constants of the ligand, and the formation and deprotonation constants of the FeIII complex have been determined from potentiometric and spectrophotometric measurements. The results are compared with those of a previously described homologous ligand in which the chelating subunits are attached to the tren framework via the ortho (3-) position of the biphenyl rather than the 4-position.
- Baret, Paul,Beaujolais, Virginie,Beguin, Claude,Gaude, Didier,Pierre, Jean-Louis,Serratrice, Guy
-
p. 613 - 619
(2007/10/03)
-
- ISOPRENYL TRANSFERASE INHIBITORS
-
Peptidomimetic compounds useful in the treatment of Ras-associated human cancers, and other conditions mediated by farnesylated or geranylgeranylated proteins; and synthetic intermediates thereof
- -
-
-
- Compositions and methods of inhibiting the binding of E-selectin or P-selectin or sialyl-Lewisx or sialyl-Lewisa
-
This invention relates to compounds that inhibit the binding of E-selectin or P-selectin to sialyl-Lewisx or sialyl-Lewisa presented on a cell surface having the general structure: STR1 This invention also relates to methods of inhibiting the binding of E-selectin or P-selectin to sialyl-Lewisx or sialyl-Lewisa presented on a cell surface using said compounds and to pharmaceutically active compositions comprising compounds that inhibit the binding of E-selectin to sialyl-Lewisx and to methods of treatment of septic shock, ARDS, Crohn's disease, chronic inflammatory diseases, such as psoriasis and rheumatoid arthritis, and reperfusion injuries that occurs following heart attacks, strokes and organ transplants and to the treatment of cancer.
- -
-
-
- 17b-aryl-4-aza-steroid derivatives useful as 5-alpha-reductase inhibitors
-
Compounds of the formula STR1 are inhibitors of 5α-reductase and are useful alone or in combination with other active agents for the treatment of hyperandrogenic disorders such as acne vulgaris, seborrhea, female hirsutism, male pattern baldness, and benign prostatic hyperplasia.
- -
-
-
- Reaction of Arylboronic Acids and their Derivatives with Lead Tetra-acetate. The Generation of Aryl-lead Triacetates, and meta- and para-Phenylenebis(lead triacetate), in situ for Electrophilic Arylation
-
Arylboronic acids and some of their derivatives have been found to undergo a rapid boron-lead exchange with lead tetra-acetate.In the presence of a catalytic amount of mercury(II) acetate, the reaction produces mainly the aryl-lead triacetate, and it has been developed as a convenient method for in situ generation of these useful electrophilic C-arylating reagents.The reaction allows the generation for the first time of meta- and para-phenylenebis(lead triacetate), compounds which behave as meta- and para-phenylene dication equivalents.
- Morgan, Jacqueline,Pinhey, John T.
-
p. 715 - 720
(2007/10/02)
-
- REACTIONS OF DIBORANE WITH LITHIUM DIARYLCUPRATES AND ORGANOCADMIUM COMPOUNDS
-
Lithium diarylcuprates react with diborane to form as intermediates organoboron compounds, which can be converted into phenols, arylboronic acids and arylamines; complexes of triarylboron compounds can also be isolated.Preliminary studies show that organo
- Bullen, N. P.,Chiheru, K. S.,Thorpe, F. G.
-
p. 147 - 154
(2007/10/02)
-