- Design of a facile fluorescent probe with a large Stokes shift for hydrogen peroxide imaging in vitro and in vivo
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By modifying 4′?hydroxybiphenyl?4?carbonitrile (BPN-OH) with 2?(4?(bromo?methyl)phenyl)?4,4,5,5?tetramethyl?1,3,2?dioxaborolane group, a facile fluorescent probe, BPN-TOB, for sensitively tracing H2O2 was designed and synthesized. BPN-TOB displayed a low detection limit (67 nM), fast response time (10 min), low cytotoxicity, a mega Stokes shift (170 nm) and a remarkable fluorescence enhancement (72-fold) in the detection of H2O2. Additionally, probe BPN-TOB could monitor exogenous and endogenous H2O2 in living MGC-803 cells (human gastric cancer cells) and RAW264.7 cells (leukemia cellsin mouse macrophage). In particular, this probe BPN-TOB was successfully utilized for imaging H2O2 in zebrafish.
- Chen, Song,Hou, Peng,Li, Hongmei,Liang, Guilin,Zhang, Hongguang
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Read Online
- Coordination networks based on nitrile-functionalized borate anions
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Salts of cyano borates bear potential of forming coordination polymers with solvent-filled voids as a source for porous materials. Herein we describe the synthesis and properties of novel cyano borates Na[H-B(O-C12H 8-CN)3], Na[B(O-C12H8-CN) 4] (C12H8 = biphenyl) and Na[B{O-C 6H3-(CN)2}4], as well as a new modification of Na[B(O-C6H4-CN)4]. Crystal structures of the sodium borates and the starting materials HO-C 6H3-(CN)2 and HO-C12H8-CN (new modification) are discussed as well. Data of nitrogen sorption experiments revealed a notable surface area in solvent-free Na[H-B(O-C12H 8-CN)3]. Copyright
- Harloff, Joerg,Karsch, Markus,Lund, Henrik,Schulz, Axel,Villinger, Alexander
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Read Online
- A simple but effective fluorescent probe with large stokes shift for specific detection of cysteine in living cells
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A novel 4′-hydroxybiphenyl-4-carbonitrile-based fluorescent probe, 1, for selective detection of cystein (Cys) over homocystein (Hcy) and glutathione (GSH) was developed. This probe had simple structure and could be easily synthesized with good yield from commercially available materials. Moreover, probe 1 showed a remarkable large Stokes shift (180 nm) and displayed a rapid (5 min) and highly sensitive response (the detection limit was 0.15 μM) for Cys with fluorescence turn-on signal changes (142-fold fluorescence enhancement). Importantly, probe 1 could be used to detect and image both exogenous and endogenous Cys in living A549 cells.
- Chen, Song,Hou, Peng,Wang, Jing,Fu, Shuang,Liu, Lei
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Read Online
- A synthetic approach to dimetalated arenes using flow microreactors and the switchable application to chemoselective cross-coupling reactions
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In spite of their potential utility, the chemistry of dimetalated arenes is still in its infancy because they are extremely difficult to synthesize. We report a novel method of synthesizing arenes bearing a boryl group and a metallic substituent, such as boryl, silyl, stannyl, or zincyl groups, in an integrated flow microreactor based on the generation and reactions of aryllithiums bearing a trialkyl borate moiety. The bimetallic arenes showed a remarkable chemoselectivity in palladium-catalyzed cross-coupling reactions. The selectivity was switched by the selection of the metal species that constitutes the dimetalated arenes as well as appropriate catalysts.
- Nagaki, Aiichiro,Ashikari, Yosuke,Kawaguchi, Tomoko,Mandai, Kyoko,Aizawa, Yoko
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p. 17039 - 17047
(2020/11/10)
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- A one-pot protocol for the fluorosulfonation and Suzuki coupling of phenols and bromophenols, streamlined access to biaryls and terphenyls
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A one-pot protocol for the fluorosulfation and Suzuki coupling of phenols is described. The tandem reaction proceeds efficiently at room temperature, and various biaryls and biaryl fluorosulfates were obtained in good to excellent yields. Furthermore, biaryl fluorosulfates were utilized as versatile building blocks for the preparation of terphenyls. The Royal Society of Chemistry 2020.
- Hu, Rui,Li, Xinmin,Ren, Changyue,Yuan, Zeli,Zhang, Hang,Zhang, Tingting
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supporting information
p. 4748 - 4753
(2020/08/17)
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- Iron-Catalyzed Room Temperature Cross-Couplings of Bromophenols with Aryl Grignard Reagents
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Herein we report a room temperature Fe-catalyzed coupling reaction of various bromophenols with aryl Grignard reagents, which exhibits a wide substrate scope and high functional group tolerance. For the first time, the combination of simple Fe(acac)3/PBu3/Ti(OEt)4 has been used as an effective catalyst for the biaryl couplings of bromophenols or their Na or K salts with debromination and etherification side reactions being well suppressed. Various biphenols including natural product garcibiphenyl C as well as pharmaceutical diflunisal and its ethyl ester were facilely synthesized using the present protocol. (Figure presented.).
- Xu, Li-Chen,Liu, Kun-Ming,Duan, Xin-Fang
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supporting information
p. 5421 - 5427
(2019/11/14)
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- Synthesis of Aryl Trimethylstannane via BF3·OEt2-Mediated Cross-Coupling of Hexaalkyl Distannane Reagent with Aryl Triazene at Room Temperature
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BF3·OEt2-mediated cross-coupling of (SnMe3)2 with aryl triazene offers a new strategy for the synthesis of aryl stannane. A variety of synthetically useful aryl trimethylstannanes were produced in moderate to good yields with this metal-free approach. One-pot sequential Stille cross-coupling with different aryl bromides provides a short entry to both symmetrical and unsymmetrical biaryl compounds.
- Mao, Shuai,Chen, Zhengkai,Wang, Lu,Khadka, Daulat Bikram,Xin, Minhang,Li, Pengfei,Zhang, San-Qi
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p. 463 - 471
(2019/01/10)
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- Follow on-based optimization of the biphenyl-DAPYs as HIV-1 nonnucleoside reverse transcriptase inhibitors against the wild-type and mutant strains
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The present work follows our preliminary discovery of biphenyl diarylpyrimidines (DAPYs) as HIV-1 nonnucleoside reverse transcriptase inhibitors. Further structural optimization of biphenyl-DAPYs led to the identification of a new series of biphenyl-substituted thiophene[3,2-d]pyrimidine analogues by a scaffold-hopping strategy. Biological evaluation of this series showed that these compounds possessed up to single-digit nanomolar potency (EC50 = 7.8–526.2 nM) and prominently low toxicity (CC50 = 18.5–280.8 μM) against wild-type (WT) HIV-1-infected cells. Furthermore, the results also demonstrated that compounds 29–32 exhibited high, broad-spectrum antiviral effects against clinically observed HIV-1 mutants. Specifically, compound 30, which had the highest selectivity index (SI = 16094) and the best anti-reverse transcriptase ability (IC50 = 39 nM), displayed marked inhibitory activity (EC50 = 13.5, 9.4, 17.0, 52.0, and 58.2 nM) against WT, K103N, E138K, L100I, Y181C mutants and moderate activity against double mutants. This study provides important avenues for the further design of HIV-1 inhibitors.
- Sang, Yali,Han, Sheng,Han, Shuwen,Pannecouque, Christophe,De Clercq, Erik,Zhuang, Chunlin,Chen, Fener
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- Synthetic method of 4-hydroxy-4'-biphenyl nitrile
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The invention discloses a preparation method of 4-hydroxy-4'-biphenyl nitrile. The method comprises: reacting 4-hydroxybiphenyl (2) with acetyl chloride to generate 4-acetic acid biphenyl (3), reacting 4-acetic acid biphenyl (3) with oxalyl chloride under aluminium trichloride catalysis to generate 4-chlorocarbonyl-4'-acetic acid biphenyl (4), reacting 4-chlorocarbonyl-4'-acetic acid biphenyl (4)with ammonia water to generate 4-formamido-4'-acetic acid biphenyl (5), dehydrating 4-formamido-4'-acetic acid biphenyl (5) under phosphorus oxychloride catalysis to generate 4-cyano-4'-acetic acid biphenyl (6), and deacetylating 4-cyano-4'-acetic acid biphenyl (6) in the presence of sodium hydroxide to generate 4-hydroxy-4'-biphenyl nitrile (1). The method is simple in process, is economic and eco-friendly, and is suitable for industrial amplification requirement.
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- Corresponding amine nitrile and method of manufacturing thereof
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The invention relates to a manufacturing method of nitrile. Compared with the prior art, the manufacturing method has the characteristics of significantly reduced using amount of an ammonia source, low environmental pressure, low energy consumption, low production cost, high purity and yield of a nitrile product and the like, and nitrile with a more complex structure can be obtained. The invention also relates to a method for manufacturing corresponding amine from nitrile.
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Paragraph 0150; 0151; 0152; 0158
(2018/05/07)
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- Nickel-Catalyzed Cyanation of Phenol Derivatives with Zn(CN)2 Involving C-O Bond Cleavage
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An efficient nickel-catalyzed cyanation of aryl sulfonates, fluorosulfonates, and sulfamates with Zn(CN)2 was developed, which provides a facile access to the nitrile products in generally good to excellent yields. The reaction is accomplished by using NiII complex as the precatalyst and DMAP as the additive. The method also displays wide functional group compatibility; for example, keto, methoxy, N,N-dimethylamino, cyano, ester, and pyridyl groups are well-tolerated during the reaction process.
- Gan, Yi,Wang, Gaonan,Xie, Xin,Liu, Yuanhong
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p. 14036 - 14048
(2018/11/03)
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- BIMESOGENIC COMPOUNDS AND MESOGENIC MEDIA
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The invention relates to bimesogenic compounds of formula I wherein R11, R12, MG11, MG12, X11, X12 and Sp1 have the meaning given in claim 1, to the use of bimesogenic compounds of formula I in liquid crystal media and particular to flexoelectric liquid crystal devices comprising a liquid crystal medium according to the present invention.
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- An acetatopalladium(II) complex with 1-benzyl-N-(3,5-di-tert-butylsalicylidene)piperidin-4-amine: Synthesis, structure and catalytic applications in Suzuki–Miyaura coupling of arylboronic acids with hydroxyaryl halides
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The Schiff base 1-benzyl-N-(3,5-di-tert-butylsalicylidene)piperidin-4-amine (HL) and its acetatopalladium(II) complex having the formula [Pd(L)(OAc)] were synthesized. Both HL and [Pd(L)(OAc)] were characterized using elemental analysis and various spectroscopic (infrared, UV–visible, 1H NMR and 13C NMR) and mass spectrometric measurements. The molecular structure of the complex was determined using X-ray crystallographic analysis. In the complex, the pincer-like NNO-donor L? and the monodenate OAc? provide a distorted square-planar N2O2 coordination environment around the metal centre. The physicochemical properties and the spectroscopic features of [Pd(L)(OAc)] are consistent with its molecular structure. The complex was found to be an effective catalyst for the Suzuki–Miyaura cross-coupling reactions of hydroxyaryl halides with arylboronic acids in predominantly aqueous media. The reactions afforded hydroxybiaryl products in good to excellent yields with a wide substrate scope.
- Keesara, Srinivas,Narendra Babu,Pal, Samudranil
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- 3-Hydroxypyrimidine-2,4-diones as Selective Active Site Inhibitors of HIV Reverse Transcriptase-Associated RNase H: Design, Synthesis, and Biochemical Evaluations
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Human immunodeficiency virus (HIV) reverse transcriptase (RT) associated ribonuclease H (RNase H) remains an unvalidated antiviral target. A major challenge of specifically targeting HIV RNase H arises from the general lack of selectivity over RT polymerase (pol) and integrase (IN) strand transfer (ST) inhibitions. We report herein the synthesis and biochemical evaluations of three novel 3-hydroxypyrimidine-2,4-dione (HPD) subtypes carefully designed to achieve selective RNase H inhibition. Biochemical studies showed the two subtypes with an N-1 methyl group (9 and 10) inhibited RNase H in low micromolar range without siginificantly inhibiting RT polymerase, whereas the N-1 unsubstituted subtype 11 inhibited RNase H in submicromolar range and RT polymerase in low micromolar range. Subtype 11 also exhibited substantially reduced inhibition in the HIV-1 INST assay and no significant cytotoxicity in the cell viability assay, suggesting that it may be amenable to further structure-activity relationship (SAR) for identifying RNase H inhibitors with antiviral activity.
- Tang, Jing,Liu, Feng,Nagy, Eva,Miller, Lena,Kirby, Karen A.,Wilson, Daniel J.,Wu, Bulan,Sarafianos, Stefan G.,Parniak, Michael A.,Wang, Zhengqiang
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p. 2648 - 2659
(2016/04/10)
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- Chemical programming of the domain of existence of liquid crystals
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This work illustrates how enthalpy and entropy changes responsible for successive phase transitions of cyanobiphenyl-based liquid crystals can be combined to give cohesive free energy densities. These new parameters are able to rationalize and quantify the demixing of the melting and clearing processes that occur in thermotropic liquid crystals. Minor structural variations at the molecular level can be understood as pressure increments that alter either the melting or clearing temperatures in a predictable way. This assessment of microsegregation operating in amphiphilic molecules paves the way for the chemical programming of the domain of existence of liquid-crystalline phases. Changing states: The cohesive free energy density concept (CFED) is applied to thermotropic cyanobiphenyl-based liquid crystals to establish predictive quantitative correlations between each antagonist segments of the amphiphilic molecules (flexible alkyl tail/rigid aromatic core) and their transition temperatures (solid→liquid crystalline/liquid crystalline→ isotropic liquid; see figure).
- Dutronc, Thibault,Terazzi, Emmanuel,Gune, Laure,Buchwalder, Kerry-Lee,Floquet, Sbastien,Piguet, Claude
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p. 1385 - 1391
(2016/01/25)
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- A modular synthesis of functionalised phenols enabled by controlled boron speciation
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A modular synthesis of functionalised biaryl phenols from two boronic acid derivatives has been developed via one-pot Suzuki-Miyaura cross-coupling, chemoselective control of boron solution speciation to generate a reactive boronic ester in situ, and oxidation. The utility of this method has been further demonstrated by application in the synthesis of drug molecules and components of organic electronics, as well as within iterative cross-coupling.
- Molloy, John J.,Law, Robert P.,Fyfe, James W. B.,Seath, Ciaran P.,Hirst, David J.,Watson, Allan J. B.
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p. 3093 - 3102
(2015/04/27)
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- Enthalpy-entropy compensation combined with cohesive free-energy densities for tuning the melting temperatures of cyanobiphenyl derivatives
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This work illustrates how minor structural perturbations produced by methylation of 4′-(dodecyloxy)-4-cyanobiphenyl leads to enthalpy-entropy compensation for their melting processes, a trend which can be analyzed within the frame of a simple intermolecular cohesive model. The transformation of the melting thermodynamic parameters collected at variable temperatures into cohesive free-energy densities expressed at a common reference temperature results in a novel linear correlation, from which melting temperatures can be simply predicted from molecular volumes. In tune with temperature! The transformation of the melting thermodynamic parameters into cohesive free-energy densities (CFED) for 4′-(n-oxy)-i′-methyl-j-methyl-4-cyanobiphenyl (CnLi′,j) provides a novel linear correlation for predicting melting temperatures in a simple way. Copyright
- Dutronc, Thibault,Terazzi, Emmanuel,Guenee, Laure,Buchwalder, Kerry-Lee,Spoerri, Aurore,Emery, Daniel,Mareda, Jiri,Floquet, Sebastien,Piguet, Claude
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p. 8447 - 8456
(2013/07/19)
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- Modulation of spectrokinetic properties of o-quinonoid reactive intermediates by electronic factors: Time-resolved laser flash and steady-state photolysis investigations of photochromic 6- and 7-arylchromenes
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A ready synthetic accessibility of a series of 6- and 7-arylchromenes via Pd0-catalyzed Suzuki coupling protocol has permitted a comprehensive investigation of the thermal decay behavior of a broad set of photogenerated o-quinonoid reactive intermediates. It is shown that substantial mesomeric effect between the benzopyran nucleus and the aryl ring at C6 or C7 position of the former renders significant absorption beyond 350 nm such that they are readily photoactivated to yield colored o-quinonoid intermediates. The absorption spectra of the latter are found to be strongly influenced by the substituents on C2-, C6- and C7-aryl rings; indeed the colored absorptions can be conveniently tuned by appropriate choice of substituents. The thermal decay (bleaching phenomenon), which is important from the point of view of their application in ophthalmic lenses, was investigated in each case by μs-ms as well as real-time absorption spec-troscopy. By careful experimentation, we have extracted the decay rate constants for Z,E and E,E o-quinonoid isomers of all 6- and 7-arylchromenes in an attempt to establish a correlation between the electronic attributes with their thermokinetic behavior. From a combined analysis of μs-ms (laser flash) and real-time kinetic data, it is shown that the colored o-quinonoid intermediates decay faster when the C2-aryl and C6-/C7-aryl rings contain electron-donating and electron-accepting groups, respectively. In the same vein, the decay was found to occur slowly for the reversed scenario, while intermediate decay rates are observed when both substituents are electron-donating. Thus, any substituent on the C2-aryl ring that contributes mesomerically to the development of charge on the quinonoid oxygen, and any substituent on the C6-/C7-aryl ring that exerts -I effect appear to expedite thermal decay. Furthermore, evidence is obtained for the first time from μs time-resolved laser-flash spectroscopy for the formation and characterization of the trans,cis (E,Z) o-quinonoid isomer, which has heretofore eluded spectral characterization in the photochromic phenomena of pyrans.
- Moorthy, Jarugu Narasimha,Koner, Apurba L.,Samanta, Subhas,Roy, Ankur,Nau, Werner M.
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supporting information; experimental part
p. 4289 - 4300
(2009/12/07)
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- ORGANOMETALLIC COMPLEXES
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Organometallic complexes are provided, methods for making the same, and their use in devices and sub-assemblies.
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Page/Page column 35
(2008/06/13)
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- General synthesis and catalytic applications of di(1-adamantyl) alkylphosphines and their phosphonium salts
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An improved synthesis of di(1-adamantyl)alkylphosphines by alkylation of di(1-adamantyl)phosphine followed by deprotonation of the resulting phosphonium halide is described. Compared to previous protocols for the synthesis of this class of compounds, the procedure does not require chlorination of the secondary phosphine by phosgene, or formation of sensitive lithium di(1-adamantyl) phosphide. Selected examples of the prepared phosphonium salts and phosphines are shown to be excellent ligands for the palladium-catalyzed cross-coupling reaction of chloroarenes with arylboronic acids.
- Tewari, Amit,Hein, Martin,Zapf, Alexander,Beller, Matthias
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p. 935 - 941
(2007/10/03)
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- ERbeta ligands. Part 1: the discovery of ERbeta selective ligands which embrace the 4-hydroxy-biphenyl template.
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The synthesis and structure-activity relationships of a series of simple biphenyls is described. Optimization of the 4-hydroxy-biphenyl template led to compounds with ERbeta selectivity on the order of 20-70-fold.
- Edsall Jr., Richard J,Harris, Heather A,Manas, Eric S,Mewshaw, Richard E
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p. 3457 - 3474
(2007/10/03)
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- Preparation of 4-cyano-4'-hydroxybiphenyl
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PCT No. PCT/FR98/00289 Sec. 371 Date Aug. 5, 1999 Sec. 102(e) Date Aug. 5, 1999 PCT Filed Feb. 16, 1998 PCT Pub. No. WO98/37059 PCT Pub. Date Aug. 27, 1998The invention relates to a preparation process for 4-cyano-4'-hydroxybiphenyl, the process comprising the protection of the aldehyde function of 4-bromo-benzaldehyde, the reaction of the protected 4-bromo-benzaldehyde with p-alkoxyphenyl magnesium halide, the deprotection of the formyl radical of the protected 4-alkoxy-4'-formyl-biphenyl and conversion of the formyl group into cyano and hydrolysis of the alkoxy group of the resulting 4-alkoxy 4'-cyano-biphenyl.
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- Preparation of 4-cyano-4'-hydroxybiphenyl
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PCT No. PCT/FR98/00290 Sec. 371 Date Aug. 5, 1999 Sec. 102(e) Date Aug. 5, 1999 PCT Filed Feb. 16, 1998 PCT Pub. No. WO98/37060 PCT Pub. Date Aug. 27, 1998The invention relates to a preparation process for 4-cyano-4'-hydroxybiphenyl, said process comprising the protection of the hydroxy group of 4-phenyl-phenol, acylation of the protected 4-phenyl-phenol group, conversion of the resulting ketone into an acid, amidification of the acid thus obtained, dehydration of the resulting amide and deprotection of the hydroxy group.
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- Mechanisms of the photochemical rearrangement of diphenyl ethers
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The mechanism of the photochemical rearrangement of diphenyl ether (1a) was studied. Irradiation of 1a in ethanol gave 2-phenylphenol (2, 42%) and 4-phenylphenol (3, 11%) as rearrangement products, in addition to phenol (4, 30%) and benzene (5, 25%) as diffusion products. Cross-coupling experiments employing [2H10]1a demonstrated that the formation of 2- and 4-phenylphenol was an intramolecular process. Irradiation of 1a in benzene or in toluene gave biphenyls in good yields. The combined yields of rearrangement products (2 and 3) increased with increase of solvent viscosity, with a concomitant decrease in the formation of 4. All the results can be rationalized in terms of excitation of 1a to the singlet state and dissociation to a radical pair intermediate involving phenoxy and phenyl radicals. Intramolecular recombination of these radicals gives rearrangement products, and escape followed by hydrogen abstraction from the solvent gives diffusion products. When position 4 of 1a was occupied by an electron-donating substituent (1b-e), aryloxy-phenyl bond cleavage to give the corresponding rearrangement products prevailed over phenoxy-aryl bond cleavage. The opposite was the case for substrates with an electron-withdrawing substituent at position 4 (1h,i).
- Haga, Naoki,Takayanagi, Hiroaki
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p. 735 - 745
(2007/10/03)
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- Tilt Angle Variation as a Function of Chain Length and Temperature in the Smectic C Phases of p,Alkoxyphenyl-p,Alkoxybenzoates
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The variation of the tilt angle with temperature in the smectic C phase has generally been shown to be non-existent or very slow for compounds or mixtures with the nematic-smectic C transition, while in the case of systems with the smectic A-smectic C transition, a relation between the steepness of this variation, near the transition, and the width of the smectic A domain has been observed.In this work, the variation of tilt angle in the smectic C phase is described for p-alkoxyphenyl-p-alkoxybenzoate homologous series, for which the evolution of polymorphism can be controlled systematically, by varying stepwise the length of the aliphatic chains, and for which large domains can be obtained for each type of phase sequence, nematic-, smectic A- and isotropic-smectic C.After completing the discussion made previously on the incidence of chain length on polymorphism, we confirm that the variation of tilt angle with temperature is slowest for compounds with intermediate chain lengths corresponding to the largest smectic A temperature range; this variation becomes continuously steeper when the smectic A domain becomes narrow.In addition, we show that the same description can be extended to the other types of phase sequences, by using the hypothesis of a virtual smectic A-smectic C transition above the observed nematic- or isotropic-smectic C transition.In fact, short chain lengths for homologues with a nematic/smectic C transition, or long chain lengths for homologues with an isotropic/smectic C transition, lead to an increase of the tilt angle at the phase transition and to a decrease of the amplitude of its variation with temperature; in our description, this behaviour corresponds to an increase of the temperature range between the real and virtual transitions.As a consequence, the homologues with very short and very long chain lengths show a quasi temperature-independent tilt angle, while the other homologues present a tilt angle variation similar to that observed for compounds exhibiting a smectic C/smectic A transition.This feature indicates that there is no need to distinguish between different types of smectic C phase.
- Heinrich, B.,Guillon, D.
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- Electrosynthesis of Unsymmetrical Polyaryls by a SRN1-Type Reaction
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Unsymmetrical polyaryls are electrosynthesized in liquid ammonia by a single-step SRN1 reaction in the presence of a redox mediator starting from aromatic halides and 2,6-di-tert-butyl phenoxide.With monoaryl halides activated by electron-withdrawing substituents (N of pyridyl or quinolyl, trifluoromethyl, cyano, sulfone, ester, ketone, alkyl sulfide, N(1+) of anilinium), biaryls are obtained in good yields (between 50 and 95percent).The yields of ter- and quateraryls are lower (40percent maximum).The reaction is extended to other ortho-disubstituted phenols.Elimination reactions of the tert-butyl groups from the products are achieved by a Friedel-Crafts reaction using either trifluoromethanesulfonic acid or aluminum trichloride as catalysts.
- Boy, P.,Combellas, C.,Suba, C.,Thiebault, A.
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p. 4482 - 4489
(2007/10/02)
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- SRN1C-arylation of potassium aryloxides by arylazo phenyl or tert- butyl sulfides in DMSO
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Aryloxide ions (Ar′O-) behave as C-nucleophiles towards diazosulfides (ArN = NSR; R = Ph, But) leading to imsymmetrical hydroxybiaryls (ArAr′OH) via C-C coupling. The reaction is particularly suited for the synthesis of terms which contain electron-withdrawing groups on the Ar moiety. The SRN1 mechanism is proposed on the grounds of experimental evidences.
- Petrillo, Giovanni,Novi, Marino,Dell Erba, Carlo,Tavani, Cinzia,Berta, Giovanni
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p. 7977 - 7990
(2007/10/02)
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- UNSYMMETRICAL BIARYLS FROM ARYLOXIDE ANIONS AND ARYLAZO PHENYL SULFIDES IN DMSO.
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Carbon-arylation of phenoxide and naphthoxide anions by arylazo phenyl sulfides represents a convenient synthesis of unsymmetrically substituted hydroxybiaryls.
- Petrillo, Giovanni,Novi, Marino,Dell'Erba, Carlo
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p. 6911 - 6912
(2007/10/02)
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- Activation of Reducing Agents. Sodium Hydride Containing Complex Reducing Agents. 32. NiCRAL's as Very Efficient Agents in Promoting Cross-Coupling of Aryl Halides
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Nickel-containing complex reducing agents NiCRA-bpy are shown to be the first nickel reagents able to efficiently perform cross-coupling of aryl halides.The presence of KI in the reaction medium generally improves the procedure.The mechanism and influence of the structures of the substrates are discused.
- Lourak, Mouhsine,Vanderesse, Regis,Fort, Yves,Caubere, Paul
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p. 4844 - 4848
(2007/10/02)
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- Selective Electrochemical and Photochemical Syntheses of Unsymmetrical Biaryls and Their Non-linear Optical Properties
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A selective synthesis of unsymmetrically substituted electron donor/electron acceptor biaryls is described which is based on an electrochemically or photochemically induced SRN1 reaction; the optical hyperpolarizability coefficients β are determined in solution for the various reaction products and found to be of the same order of magnitude as that of 4-nitro-aniline.
- Combellas, Catherine,Gautier, Helene,Simon, Jacques,Thiebault, Andre,Tournilhac, Francois,et al.
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p. 203 - 204
(2007/10/02)
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- Electrochemically Catalyzed Aromatic Nucleophilic Substitution. Phenoxide Ion as Nucleophile
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Cyclic voltammetry and preparative-scale electrolysis of aryl halides in the presence of phenoxide ions, a nucleophile reputed as unreactive SRN1 reactions, show the formation, in liquid ammonia or in dimethyl sulfoxide, of coupling products along an electrochemically catalyzed SRN1 aromatic substitution process.Coupling occurs at carbons of the phenyl ring rather than at the phenolic oxygen.The mechanism of the reaction is estabilished on kinetic grounds.Determination of the coupling rate constant between phenoxide ions and aryl radicals and comparison with other n ucleophiles shows that phenoxide ions are quite efficient nucleophiles in SRN1 reactions.The reaction can as well be viewed as an homolytic aromatic substitution.Mechanistic implications concerning the latter type of reaction are discussed.With mediated electrochemical induction of the substitution reaction, it is possible to raise the yield in coupling product up to about 80percent, which renders the reaction an attractive route to the synthesis of electron donor-electron acceptor biaryls.
- Alam, Nayat,Amatore, Christian,Comballas, Catherine,Pinson, Jean,Saveant, Jean-Michel,et al.
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p. 1496 - 1504
(2007/10/02)
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- ACTIVATION OF REDUCING AGENTS. SODIUM HYDRIDE CONTAINING COMPLEX REDUCING AGENTS 25. A ONE POT ONE REAGENT CROSS-COUPLING REACTION OF ARYL HALIDES
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The preparation of NiCRA in the presence of 2,2'-bipyridyl and KI leads to a reagent (termed NiCRA-bpy-KI) which is shown to be one of the most efficient Ni containing reagents reported so far for the cross-coupling of aryl halides.
- Lourak, M.,Vanderesse, R.,Fort, Y.,Caubere, P.
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p. 545 - 546
(2007/10/02)
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- SYNTHESIS OF 4-ALKOXY-4'-CYANOBIPHENYLS
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A preparative method was developed for the synthesis of liquid crystals of the 4-alkoxy-4'-cyanobiphenyl group.It involves the nitration of 4-cyanobiphenyl to 4-nitro-4'-cyanobiphenyl, reduction of the latter, diazotization of the obtained 4-amino-4'-cyanobiphenyl, and alkylation of the 4-hydroxy-4'-cyanobiphenyl formed during decomposition of the diazonium salt.
- Ruolene, Yu. I.,Adomenas, P. V.,Adomenene, O. K.,Denis, G. I.
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p. 1192 - 1195
(2007/10/02)
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- Liquid crystalline materials
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Novel liquid crystal materials which are trans-4-alkylcyclohexane-1-carboxylic acid esters are provided having the general formula: STR1 where R is a normal or branched chain alkyl group, which may also contain a chiral center, containing up to ten carbon atoms and X is selected from the groups: STR2 where A is a cyano group, a normal or branched chain alkyl group, which may also contain a chiral center, containing up to ten carbon atoms or an alkoxy group in which the alkyl group is as defined immediately above, and where Y is a halogen, preferably chlorine, or hydrogen.
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- Novel liquid crystal electro-optic devices
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Nematic liquid crystal compounds of the formula: SPC1 Wherein X can be hydrogen, alkyl (R-), alkoxy (RO-), acyloxy EQU1 or alkylcarbonato EQU2 wherein R is an alkyl group of 1-10 carbon atoms, have positive dielectric anisotropy and are useful in electro-optic cells which comprise a thin liquid crystal layer between two closely spaced parallel electrodes.
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