- Synthesis, characterization and computational evaluation of bicyclooctadienes towards molecular solar thermal energy storage
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Molecular solar-thermal energy storage (MOST) systems are based on photoswitches that reversibly convert solar energy into chemical energy. In this context, bicyclooctadienes (BODs) undergo a photoinduced transformation to the corresponding higher energy
- Erdelyi, Mate,Ghasemi, Shima,Hillers-Bendtsen, Andreas Erbs,Kann, Nina,Mikkelsen, Kurt V.,Moth-Poulsen, Kasper,Muhammad, Lidiya M.,Quant, Maria,Wang, Zhihang
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p. 834 - 841
(2022/02/07)
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- 1,2,4-Triazole-3-thione compounds with a 4-ethyl alkyl/aryl sulfide substituent are broad-spectrum metallo-β-lactamase inhibitors with re-sensitization activity
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Metallo-β-lactamases (MBLs) are important contributors of Gram-negative bacteria resistance to β-lactam antibiotics. MBLs are highly worrying because of their carbapenemase activity, their rapid spread in major human opportunistic pathogens while no clinically useful inhibitor is available yet. In this context, we are exploring the potential of compounds based on the 1,2,4-triazole-3-thione scaffold as an original ligand of the di-zinc active sites of MBLs, and diversely substituted at its positions 4 and 5. Here, we present a new series of compounds substituted at the 4-position by a thioether-containing alkyl chain with a carboxylic and/or an aryl group at its extremity. Several compounds showed broad-spectrum inhibition with Ki values in the μM to sub-μM range against VIM-type enzymes, NDM-1 and IMP-1. The presence of the sulfur and of the aryl group was important for the inhibitory activity and the binding mode of a few compounds in VIM-2 was revealed by X-ray crystallography. Importantly, in vitro antibacterial susceptibility assays showed that several inhibitors were able to potentiate the activity of meropenem on Klebsiella pneumoniae clinical isolates producing VIM-1 or VIM-4, with a potentiation effect of up to 16-fold. Finally, a selected compound was found to only moderately inhibit the di-zinc human glyoxalase II, and several showed no or only moderate toxicity toward several human cells, thus favourably completing a promising behaviour.
- Becker, Katja,Benvenuti, Manuela,Bossis, Guillaume,Conde, Pierre-Alexis,Crowder, Michael W.,Dillenberger, Melissa,Docquier, Jean-Denis,Gavara, Laurent,Hernandez, Jean-Fran?ois,Legru, Alice,Mangani, Stefano,Pozzi, Cecilia,Sannio, Filomena,Tassone, Giusy,Thomas, Caitlyn A.,Verdirosa, Federica
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supporting information
(2021/10/12)
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- 4-Amino-1,2,4-triazole-3-thione-derived Schiff bases as metallo-β-lactamase inhibitors
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Resistance to β-lactam antibiotics in Gram-negatives producing metallo-β-lactamases (MBLs) represents a major medical threat and there is an extremely urgent need to develop clinically useful inhibitors. We previously reported the original binding mode of 5-substituted-4-amino/H-1,2,4-triazole-3-thione compounds in the catalytic site of an MBL. Moreover, we showed that, although moderately potent, they represented a promising basis for the development of broad-spectrum MBL inhibitors. Here, we synthesized and characterized a large number of 4-amino-1,2,4-triazole-3-thione-derived Schiff bases. Compared to the previous series, the presence of an aryl moiety at position 4 afforded an average 10-fold increase in potency. Among 90 synthetic compounds, more than half inhibited at least one of the six tested MBLs (L1, VIM-4, VIM-2, NDM-1, IMP-1, CphA) with Ki values in the μM to sub-μM range. Several were broad-spectrum inhibitors, also inhibiting the most clinically relevant VIM-2 and NDM-1. Active compounds generally contained halogenated, bicyclic aryl or phenolic moieties at position 5, and one substituent among o-benzoic, 2,4-dihydroxyphenyl, p-benzyloxyphenyl or 3-(m-benzoyl)-phenyl at position 4. The crystallographic structure of VIM-2 in complex with an inhibitor showed the expected binding between the triazole-thione moiety and the dinuclear centre and also revealed a network of interactions involving Phe61, Tyr67, Trp87 and the conserved Asn233. Microbiological analysis suggested that the potentiation activity of the compounds was limited by poor outer membrane penetration or efflux. This was supported by the ability of one compound to restore the susceptibility of an NDM-1-producing E. coli clinical strain toward several β-lactams in the presence only of a sub-inhibitory concentration of colistin, a permeabilizing agent. Finally, some compounds were tested against the structurally similar di-zinc human glyoxalase II and found weaker inhibitors of the latter enzyme, thus showing a promising selectivity towards MBLs.
- Baud, Damien,Bebrone, Carine,Becker, Katja,Benvenuti, Manuela,Cerboni, Giulia,Chelini, Giulia,Cutolo, Giuliano,De Luca, Filomena,Docquier, Jean-Denis,Feller, Georges,Fischer, Marina,Galleni, Moreno,Gavara, Laurent,Gresh, Nohad,Kwapien, Karolina,Legru, Alice,Mangani, Stefano,Mercuri, Paola,Pozzi, Cecilia,Sannio, Filomena,Sevaille, Laurent,Tanfoni, Silvia,Verdirosa, Federica,Berthomieu, Dorothée,Bestgen, Beno?t,Frère, Jean-Marie,Hernandez, Jean-Fran?ois
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supporting information
(2020/09/16)
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- Regioselective synthesis of substituted cyclohexa-1,3-dienes via the base-mediated cyclisation of α,β-unsaturated carbonyl compounds and γ-phosphonylcrotonates
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The base-mediated reaction of α,β-unsaturated carbonyl compounds and γ-phosphonylcrotonates under an argon atmosphere readily furnishes substituted cyclohexa-1,3-dienes. The cyclisation proceeds with complete regioselectivity to afford products that are r
- Chandra, Rajesh,Joshi, Prabhakar R.,Menon, Rajeev S.
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- Base-free Pd-MOF catalyzed the Suzuki-Miyaura cross-coupling reaction of arenediazonium tetrafluoroborate salts with arylboronic acids
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A convenient and environmental benign synthesis of biaryls has been demonstrated by a straightforward reaction catalyzed by the palladium-containing metal-organic framework (Pd-MOF) [Pd (2-pymo)2]n (2-pymo = 2-pyrimidinolate). A series of functionalized biaryl derivatives have been synthesized in good to excellent yields by the Suzuki-miyaura cross-couplings of sustainable arenediazonium salts with a variety of arylboronic acids and the reactions were catalyzed by the Pd-MOF using methanol as a benign solvent. Those base- and additive-free catalytic reactions proceeded smoothly under non-anhydrous and non-degassed condition. Such transformation avoided high reaction temperature, tolerated many functional groups and presented a wide substrate scope. The catalyst could be recovered by filtration and reused for four successive cycles before collapse of the MOF structure.
- Liu, Yangyang,Wang, Jie,Li, Tang,Zhao, Zesheng,Pang, Wan
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- Noncovalent Interactions in Ir-Catalyzed C-H Activation: L-Shaped Ligand for Para-Selective Borylation of Aromatic Esters
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An efficient strategy for the para-selective borylation of aromatic esters is described. For achieving high para-selectivity, a new catalytic system has been developed modifying the core structure of the bipyridine. It has been proposed that the L-shaped ligand is essential to recognize the functionality of the oxygen atom of the ester carbonyl group via noncovalent interaction, which provides an unprecedented controlling factor for para-selective C-H activation/borylation.
- Hoque, Md Emdadul,Bisht, Ranjana,Haldar, Chabush,Chattopadhyay, Buddhadeb
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supporting information
p. 7745 - 7748
(2017/06/21)
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- 1,2,4-Triazole-3-thione Compounds as Inhibitors of Dizinc Metallo-β-lactamases
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Metallo-β-lactamases (MBLs) cause resistance of Gram-negative bacteria to β-lactam antibiotics and are of serious concern, because they can inactivate the last-resort carbapenems and because MBL inhibitors of clinical value are still lacking. We previously identified the original binding mode of 4-amino-2,4-dihydro-5-(2-methylphenyl)-3H-1,2,4-triazole-3-thione (compound IIIA) within the dizinc active site of the L1 MBL. Herein we present the crystallographic structure of a complex of L1 with the corresponding non-amino compound IIIB (1,2-dihydro-5-(2-methylphenyl)-3H-1,2,4-triazole-3-thione). Unexpectedly, the binding mode of IIIB was similar but reverse to that of IIIA. The 3 D structures suggested that the triazole–thione scaffold was suitable to bind to the catalytic site of dizinc metalloenzymes. On the basis of these results, we synthesized 54 analogues of IIIA or IIIB. Nineteen showed IC50 values in the micromolar range toward at least one of five representative MBLs (i.e., L1, VIM-4, VIM-2, NDM-1, and IMP-1). Five of these exhibited a significant inhibition of at least four enzymes, including NDM-1, VIM-2, and IMP-1. Active compounds mainly featured either halogen or bulky bicyclic aryl substituents. Finally, some compounds were also tested on several microbial dinuclear zinc-dependent hydrolases belonging to the MBL-fold superfamily (i.e., endonucleases and glyoxalase II) to explore their activity toward structurally similar but functionally distinct enzymes. Whereas the bacterial tRNases were not inhibited, the best IC50 values toward plasmodial glyoxalase II were in the 10 μm range.
- Sevaille, Laurent,Gavara, Laurent,Bebrone, Carine,De Luca, Filomena,Nauton, Lionel,Achard, Maud,Mercuri, Paola,Tanfoni, Silvia,Borgianni, Luisa,Guyon, Carole,Lonjon, Pauline,Turan-Zitouni, Gülhan,Dzieciolowski, Julia,Becker, Katja,Bénard, Lionel,Condon, Ciaran,Maillard, Ludovic,Martinez, Jean,Frère, Jean-Marie,Dideberg, Otto,Galleni, Moreno,Docquier, Jean-Denis,Hernandez, Jean-Fran?ois
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p. 972 - 985
(2017/06/27)
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- Revisitation of Organoaluminum Reagents Affords a Versatile Protocol for C-X (X = N, O, F) Bond-Cleavage Cross-Coupling: A Systematic Study
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A revisit of organoaluminum reagents for cross-coupling reactions has opened up several types of C-C bond formation protocols through cleavage of phenolic/alcoholic C-O and C-F and ammonium C-N bonds. Catalyzed by the commercially available NiCl2(PCy3)2 catalyst, these reactions proceed smoothly with a wide range of substrates and broad functional group compatibility, providing a versatile methodology for organoaluminum-mediated cross-coupling processes.
- Ogawa, Hiroyuki,Yang, Ze-Kun,Minami, Hiroki,Kojima, Kumiko,Saito, Tatsuo,Wang, Chao,Uchiyama, Masanobu
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p. 3988 - 3994
(2017/06/19)
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- Cobalt-Catalyzed Biaryl Couplings via C-F Bond Activation in the Absence of Phosphine or NHC Ligands
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A highly general and selective Co-catalyzed biaryl coupling through C-F cleavage under phosphine or NHC-free conditions was described. A broad range of aryl fluorides including unactivated fluorides as well as those with sensitive functionalities could couple with various Ti(OEt)4-mediated aryl Grignard reagents with high selectivity under the catalysis of CoCl2/DMPU. Importantly, selective C-F bond activation couplings between two types of fluorines (difluorinated aromatics and on two different coupling partners) and in the presence of C-Cl or C-Br bonds could also be achieved.
- Wei, Juan,Liu, Kun-Ming,Duan, Xin-Fang
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p. 1291 - 1300
(2017/02/10)
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- An N-Heterocyclic Carbene-Nickel Half-Sandwich Complex as a Precatalyst for Suzuki-Miyaura Coupling of Aryl/Heteroaryl Halides with Aryl/Heteroarylboronic Acids
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A nickel half-sandwich complex supported by our original NHC ligand was developed as a robust precatalyst for Suzuki-Miyaura cross-coupling. The addition of PPh3 was a crucial element in the suppression of side reactions and in accelerating the cross-coupling reaction. By employing the optimal conditions, aryl-aryl, heteroaryl-aryl, and heteroaryl-heteroaryl couplings were achieved.
- Ando, Shin,Matsunaga, Hirofumi,Ishizuka, Tadao
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p. 1266 - 1272
(2018/06/18)
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- Synthesis method of 4'-halogenated methylbiphenyl-2-formic aid alkyl ester
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The invention discloses a synthesis method of a 4'-halogenated methylbiphenyl-2-formic acid alkyl ester compound, and belongs to the technical field of organic synthesis. The method includes the following steps that 1, biphenyl-2-formic acid (I) and low alkyl alcohol are subjected to an esterification reaction under an acid catalyst to prepare biphenyl-2-formic acid alkyl ester (II); 2, the temperature in a four-mouth bottle containing biphenyl-2-formic acid alkyl ester (II), paraformaldehyde and a solvent is controlled to be within 20-50 DEG C, zinc halide is added, a dehydrating agent is added drop by drop, liquid chromatography monitoring is performed till the raw materials disappear about 2-5 h later, the reaction is finished, the temperature is lowered to the room temperature, an oil layer is washed, crystallization is performed to prepare 4'-halogenated methylbiphenyl-2-formic acid alkyl ester (III), and recrystallization purification is performed to prepare a pure product of 4'-halogenated methylbiphenyl-2-formic acid alkyl ester (III). According to the method, with biphenyl-2-formic acid as the starting raw material, the sartan drug intermediate 4'-halogenated methylbiphenyl-2-formic acid alkyl ester is prepared; the process is simple, conditions are easy to control, the raw materials are cheap and easy to get, production cost is low, environmental pollution is small, and the method is suitable for industrial production.
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Paragraph 0041; 0042
(2016/12/01)
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- Cyanoborohydride-promoted radical arylation of benzene
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Radical biaryl coupling of iodoarenes and benzene can be effectively promoted by tetrabutylammonium cyanoborohydride with air under photoirradiation conditions using a Xe lamp. The utility of this methodology is highlighted by its functional group tolerance and chemoselectivity.
- Kawamoto, Takuji,Sato, Aoi,Ryu, Ilhyong
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supporting information
p. 2111 - 2113
(2014/05/06)
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- Photocatalysis in dimethyl carbonate green solvent: Degradation and partial oxidation of phenanthrene on supported TiO2
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Dimethyl carbonate (DMC) is here proposed-for the first time-as a green organic solvent for photocatalytic synthesis. In this work, the photocatalytic partial oxidation of phenanthrene in dimethyl carbonate (DMC) by using anatase TiO2as the photocatalyst is described as paradigmatic example of a green synthetic process starting from polycyclic aromatic hydrocarbons (PAHs). For comparison, the same reaction carried out also in ethanol, 1-propanol or 2-propanol is reported. The use of DMC as the solvent allowed us to achieve 19% and 23% selectivity towards 9-fluorenone and 6H-benzo[c]chromen-6-one, respectively. The proposed approach may represent both a new green synthetic process and an environmentally friendly route to degradation of PAHs. This journal is
- Bellardita,Loddo,Mele,Panzeri,Parrino,Pibiri,Palmisano
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p. 40859 - 40864
(2015/01/08)
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- Selective Co/Ti cooperatively catalyzed biaryl couplings of aryl halides with aryl metal reagents
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Various aryl bromides or chlorides, including those bearing a free COOH, OH, CONHR, and SO2NHR group, coupled with aryl magnesium or lithium reagents in the presence of 7.5 mol % CoCl2/15 mol % PBu3 and substoichiometric Ti(OEt)4 (40 mol % to ArM) at room temperature in high yields with high chemo- and regioslectivity. This simple reaction represents the first example of Co/Ti cooperative catalysis which plays a key role in suppressing undesired homocouplings.
- Zeng, Jing,Liu, Kun Ming,Duan, Xin Fang
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supporting information
p. 5342 - 5345
(2013/11/06)
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- Synthesis of fluorenone and anthraquinone derivatives from aryl- and aroyl-substituted propiolates
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Fluorenone derivatives were generated from aryl-substituted propiolates via a cobalt-catalyzed Diels-Alder reaction/DDQ-oxidation and Friedel-Crafts-type cyclization. Several functional groups are tolerated, and good to excellent overall yields (up to 89%) could be achieved. For the synthesis of anthraquinone derivatives, aroyl-substituted propiolates were applied in a zinc iodide catalyzed Diels-Alder reaction with 1,3-dienes. The subsequent DDQ oxidation and Friedel-Crafts-type cyclization led to symmetrical as well as some unsymmetrical anthraquinones in good to excellent yields of up to 87% over the three-step reaction sequence.
- Puenner, Florian,Schieven, Justin,Hilt, Gerhard
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supporting information
p. 4888 - 4891
(2013/10/08)
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- Palladium(II)-exchanged hydroxyapatite-catalyzed Suzuki-Miyaura-type cross-coupling reactions with potassium aryltrifluoroborates
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Palladium(II)-exchanged hydroxyapatite (PdHAP; Pd/Ca ratio = ca. 1/200) was prepared by ion-exchanging with Ca2+ from calcined hydroxyapatite (2.0 mmol) and Pd(NO3)2 (0.10 mmol) in water (150 mL) at 70 °C for 24 h. The PdHAP (1 mol% Pd to aryl bromides) functioned as a catalyst for the Suzuki-Miyaura-type cross-coupling reaction of aryl bromides and potassium aryltrifluoroborates with triphenylphosphine (1 mol%) and excess potassium carbonate at 50 °C in methanol under air. This cross-coupling reaction was found to proceed in water, while the rate was slow compared with that in methanol. The heterogeneous PdHAP catalyst was used ten times repeatedly at 50 °C in methanol under air, though its catalytic activity gradually declined. XRD and XRF analyses and TEM images revealed that most of palladium species would still be supported as isolated ions on the repeatedly used PdHAP, in spite of the changes of the structure and composition of PdHAP surface at the late stages in the repetitive uses and the partial leaching of Pd species at the initial stages in the repetitive uses. The gradual decline of the catalytic activity might be dependent on either the changes of PdHAP surface at the late stages or the partial leaching of Pd species at the initial stages. Still, heterogeneous PdHAP served as a reusable catalyst for Suzuki-Miyaura-type cross-coupling reaction with potassium aryltrifluoroborates.
- Masuyama, Yoshiro,Sugioka, Yutaka,Chonan, Shiori,Suzuki, Noriyuki,Fujita, Masahiro,Hara, Kenji,Fukuoka, Atsushi
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experimental part
p. 81 - 85
(2012/02/03)
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- STABILIZED ORGANOMETALLIC REAGENTS
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Compositions of stabilized forms of organometallic reagents, methods of preparing the stabilized forms, and methods of using the stabilized forms, are provided. Stabilized organometallic reagent compositions of the invention are sorbent solids permeated by the organometallic reagent. The reagent can be a Grignard reagent, a Reformatsky reagent, a zinc reagent of the type RZnX, R2Zn, Ar2Zn, R3ZnM, Ar3ZnM, and the like, an organolithium reagent such as n-butyllithium, a organocopper reagent, or other reactive, potentially pyrophoric reagent. The compositions are solids that can be weighed and dispensed in ambient air without requiring inert gas blanketing. The compositions can be prepared by contacting the sorbent solid, which can be silica, an alkyl silica, alumina, or other non-reactive sorbent solid with a solution of the organometallic reagent in a non-reactive solvent, then, removing the solvent, such as under vacuum. The stabilized composition can be used by extracting the organometallic reagent from the composition with a non-reactive solvent and contacting the solution with a reactant.
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Page/Page column 13
(2011/10/10)
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- Rapid nickel-catalyzed suzuki-miyaura cross-couplings of aryl carbamates and sulfamates utilizing microwave heating
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High-speed and scalable nickel-catalyzed cross-coupling of arylboronic acids with aryl carbamates and sulfamates is achieved by using sealed-vessel microwave processing.(Figure Presented)
- Baghbanzadeh, Mostafa,Pilger, Christian,Kappe, C. Oliver
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supporting information; experimental part
p. 1507 - 1510
(2011/04/26)
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- Umpolung direct arylation reactions: Facile process requiring only catalytic palladium and substoichiometric amount of silver salts
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An umpolung direct arylation process is described. The reaction requires only a catalytic amount of Pd(OAc)2 and a substoichiometric amount of silver salts, without any external base or ligand to proceed. The directed oxidative insertion of the transition metal followed by the coupling into the C-H bond of an unactivated arene has surprisingly not yet been reported, despite the clear advantages in the ease of starting material synthesis. The reaction is regioselective with regards to the arene partner, and the role of the acetate and carbonate groups has been elucidated. This methodology adds to the very few examples of benzene coupling without the inclusion of electron-withdrawing groups to increase acidity.
- Mousseau, James J.,Vallee, Frederic,Lorion, Melanie M.,Charette, Andre B.
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supporting information; experimental part
p. 14412 - 14414
(2010/12/24)
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- Revealing a second transmetalation step in the Negishi coupling and its competition with reductive elimination: Improvement in the interpretation of the mechanism of biaryl syntheses
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This paper presents an experimental and theoretical investigation of the Pd-catalyzed Negishi coupling reaction and reveals a novel second transmetalation reaction between an Ar1-Pd-Ar2 species and the organozinc reagent Ar2-ZnX. Understanding of this second step reveals how homocoupling and dehalogenation products are formed. Thus, the second transmetalation generates Ar2PdAr2 and Ar 1ZnCl, which upon reductive elimination and hydrolysis, respectively, give the homocoupling product Ar2-Ar2 and the dehalogenation product Ar1H. The ratio of the cross-coupling product Ar1-Ar2 and the homocoupling product Ar 2-Ar2 is determined by competition between the second transmetalation and reductive elimination steps. This mechanism is further supported by density functional theoretical calculations. Calculations on a series of reactions suggest a strategy in controlling the selectivity of cross-coupling and homocoupling pathways, which we have experimentally verified.
- Liu, Qiang,Lan, Yu,Liu, Jing,Li, Gang,Wu, Yun-Dong,Lei, Aiwen
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supporting information; experimental part
p. 10201 - 10210
(2009/12/08)
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- Iron or Cobalt-Catalyzed Carbon-Carbon Coupling Reaction of Aryls, Alkenes and Alkines With Copper Reagents
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The present invention relates to a process for the formation of carbon-carbon bonds starting from a copper compound of an aryl, heteroaryl, alkene or alkine and an aryl, heteroaryl, alkene or alkine compound having a suitable leaving group. The copper compounds can be prepared inter alia by means of transmetalliziation from a Grignard or lithium compound. Cross-coupling of these compounds with e.g. a halogen-substituted aryl compound is carried out by means of an iron or cobalt catalyst using suitable solvents and suitable additives.
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- Cobalt-catalyzed cross-coupling reactions of heterocyclic chlorides with arylmagnesium halides and of polyfunctionalized arylcopper reagents with aryl bromides, chlorides, fluorides and tosylates
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A range of aromatic organocopper or organomagnesium compounds undergo smooth cross-coupling reactions with aryl bromides, chlorides, fluorides and tosylates, leading to polyfunctionalized aromatics or heterocycles in the presence of cobalt salts (5-7.5 mol%) as catalysts. Very mild reaction conditions are needed and, in the case of cross-coupling with organocopper compounds, Bu4NI (1 equiv) and 4-fluorostyrene (20 mol%) are essential as promoters for successful couplings. Georg Thieme Verlag Stuttgart.
- Korn, Tobias J.,Schade, Matthias A.,Cheemala, Murthy N.,Wirth, Stefan,Guevara, Simon A.,Cahiez, Gerard,Knochel, Paul
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p. 3547 - 3574
(2008/03/14)
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- IRON OR COBALT-CATALYZED CARBON-CARBON COUPLING REACTION OF ARYLS, ALKENES AND ALKINES WITH COPPER REAGENTS
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The invention relates to a method for combining carbon-carbon bonds starting from a copper compound of an aryl, heteroaryl, alkene or alkine and an aryl, heteroaryl, alkene or alkine compound with a suitable nucleofuge. The copper compounds can be produced inter alia by transmetallization from a Gignard or lithium compound. The cross-coupling of said compounds is carried out with a halogen-substituted aryl compound with the aid of an iron or cobalt catalyst using a suitable solvent and suitable additives.
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Page/Page column 8
(2010/11/08)
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- Iron-catalyzed aryl-aryl cross-couplings with magnesium-derived copper reagents
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(Chemical Equation Presented) Well-matched couples: Functionalized aryl and heteroaryl copper species obtained from the corresponding magnesium derivatives undergo Fe-catalyzed cross-coupling reactions with aryl iodides that bear keto, ester, triflate, or nitrile groups (see scheme).
- Sapountzis, Ioannis,Lin, Wenwei,Kofink, Christiane C.,Despotopoulou, Christina,Knochel, Paul
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p. 1654 - 1657
(2007/10/03)
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- Cobalt(II)-catalyzed cross-coupling of polyfunctional aryl copper reagents with aryl bromides and chlorides
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(Chemical Equation Presented) Polyfunctionalized biphenyl and heteroaromatic compounds were formed in the presence of [Co(acac)2], Bu4Nl, and 4-fluorostyrene (3) through a smooth cross-coupling reaction between organocopper reagents 1, prepared by the transmetalation of functionalized aryl magnesium halides with CuCN·2 LiCl, and aryl halides 2 that bear electron-withdrawing substituents. acac = acetylacetonate, DME = 1,2-dimethoxyethane, DMPU = 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone.
- Korn, Tobias J.,Knochel, Paul
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p. 2947 - 2951
(2007/10/03)
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- Process for preparing (hetero) aromatic substituted benzene derivatives
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Three processes are described for preparing (hetero)aromatic substituted benzene derivatives which comprise aromatization of cyclohexenone derivatives via (chloro)cyclohexadiene derivatives.
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- Versatile palladium-catalyzed arylation of organomanganese chlorides by aryl bromides
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In THF, a palladium-catalyzed cross-coupling reaction of organomanganese reagents with various aryl bromides including unreactive deactivated or hindered aryl bromides was performed successfully in the presence of a new catalytic system 1% PdCl2(dppp)-four equivalents DME. The scope of the reaction is very broad since many functional groups are tolerated, moreover, even hindered O,O′-di- or trisubstituted diaryls were obtained in high yields. It is interesting to note that hindered aryl bromides are more reactive than the corresponding aryl iodides. Alkyl, alkenyl and alkynylmanganese chlorides also react under similar conditions.
- Riguet, Eric,Alami, Mouad,Cahiez, Gérard
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p. 376 - 379
(2007/10/03)
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- Process for preparing (hetero) aromatic substituted benzene derivatives
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Three processes are described for preparing (hetero)aromatic substituted benzene derivatives which comprise aromatization of cyclohexenone derivatives via (chloro)cyclohexadiene derivatives.
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- SYNTHESIS OF 1,2-DISUBSTITUTED BENZENES AND BIPHENYLS FROM PHTHALIC ACIDS THROUGH ELECTROREDUCTION FOLLOWED BY ELECTROCYCLIC REACTIONS WITH ALKYNES
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Various substituted 1,2-dihydrophthalic acids were synthesized by electroreduction of phthalic acids in excellent yields.The electrocyclic reaction of 1,2-dihydrophthalic acids or the methyl ester with alkynes gave 1,2-disubstituted benzenes and biphenyls in good yields together with fumaric acid or methyl fumarate.
- Ohno, Toshinobu,Ozaki, Masato,Inagaki, Atsuro,Hirashima, Tsuneaki,Nishiguchi, Ikuzo
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p. 2629 - 2632
(2007/10/02)
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- Desulfurization of Benzo- and Dibenzothiophenes with Nickel Boride
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Nickel boride, prepared from the reduction of nickel chloride hexahydrate with sodium borohydride in methanol-tetrahydrofuran, reduces benzothiophenes to alkylbenzenes and dibenzothiophenes to biphenyls.The reaction is rapid at or below room temperature and does not require protection from the atmosphere.Best results are obtained when the nickel boride is generated in situ in the presence of the sulfur compound.Hydroxyl, carboxyl, ester, and amino groups are unaffected while chloro, bromo, and nitro substituents are also reduced under these conditions.A short-livedintermediate, possibly a nickel hydride species, appears to be required in the desulfurization.Complexation of the substrate to the nickel boride surface, followed by stepwise reduction of the two C-S bonds, occurs.The faster disappearance of dibenzothiophene containing the lighter 32S isotope compared to that with 34S (k(32S)/k(34S) = 1.005 to 1.006) suggests that C-S bond cleavage is the rate-determining step.
- Back, Thomas G.,Yang, Kexin,Krouse, H. Roy
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p. 1986 - 1990
(2007/10/02)
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- Angiotensin II antagonist 1,3-imidazoles and use thereas
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This invention provides novel phenyl and heterocyclic derivatives, their pharmaceutical formulations and their use for antagonizing angiotensin II receptors in mammals.
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- Reactions of Vinylphosphonates. 2. Synthesis of Functionalized Dienes, Trienes, and Their Analogues. Synthetic Aplications to Regioselectively Functionalized Benzene Derivatives
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The phosphoryl-stabilized carboanions prepared from vinylphosphonates 1a,b and various carbanions 2a-c react with aldehydes 3 to give olefins having various functional groups.The dienes 5c-g produced by the reaction using α,β-unsaturated aldehydes and a methyl (methylsulfinyl)methyl sulfide carbanion (2b) easily undergo thermolysis to afford reactive intermediate 1-methylthio 1,3,5-trienes, which are converted into the 1,4-disubstituted benzenes 7a-e in 27-56percent overall isolated yields via the electrocyclic reaction into cyclohexadienes and subsequent elimination of methanethiol.Thermolysis of the reaction product using ethyl α-(diethylphosphono)acrylate (1a), 2b, and 1,4-bis(2-formylethenyl)benzene (3g) produces 4,4''-bis(ethoxycarbonyl)-1,1':4',1''-terphenyl (7f) in 16percent yield.The reaction using an ethyl (methylthio)acetate carbanion (2c) instead of 2b gives thermally stable dienes 5i-l in 38-52percent yields.Oxidation of the dienes 5i,k,l followed by thermolysis, leads to the 1,2,4-trisubstituted (8a,b) and 1,2-disubstituted benzenes (9).Similar treatment of the product 5m derived from 1a, 2c, and 3-phenylpropargylaldehyde (3f) produces a mixture of 2,4-bis(ethoxycarbonyl)biphenyl (8a) and ethyl 4-(ethoxycarbonyl)-7-phenylhepta-2,4-dien-6-ynoate (11) in 23percent and 32percent yields.
- Minami, Toru,Nishimura, Katsuhide,Hirao, Ichiro,Suganuma, Hiroyuki,Agawa, Toshio
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p. 2360 - 2363
(2007/10/02)
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