- Hypervalent iodine(iii) induced oxidative olefination of benzylamines using Wittig reagents
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We have developed hypervalent iodine(iii) induced oxidative olefination of primary and secondary benzylamines using 2C-Wittig reagents, which provides easy access to α,β-unsaturated esters. Mild reaction conditions, good to excellent yields with high (E) selectivity, and a broad substrate scope are the key features of this reaction. We have successfully carried out the gram-scale synthesis of α,β-unsaturated esters.
- Ramavath, Vijayalakshmi,Rupanawar, Bapurao D.,More, Satish G.,Bansode, Ajay H.,Suryavanshi, Gurunath
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p. 8806 - 8813
(2021/05/26)
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- Larvicidal activity and in silico studies of cinnamic acid derivatives against Aedes aegypti (Diptera: Culicidae)
-
Cinnamic acid derivatives (CAD's) represent a great alternative in the search for insecticides against Aedes aegypti mosquitoes since they have antimicrobial and insecticide properties. Ae. aegypti is responsible for transmitting Dengue, Chikungunya, and Zika viruses, among other arboviruses associated with morbimortality, especially in developing countries. In view of this, in vitro analyses of n-substituted cinnamic acids and esters were performed upon 4th instar larvae (L4) of Ae. aegypti, as well as, molecular docking studies to propose a potential biological target towards this mosquitoes species. The larvicide assays proved that n-substituted ethyl cinnamates showed a more pronounced activity than their corresponding acids, in which p-chlorocinnamate (3j) presented a LC50 value of 8.3 μg/mL. Thusly, external morphologic alterations (rigid and elongated body, curved bowel, and translucent or darkened anal papillae) of mosquitoes’ group exposed to compound 3j, were observed by microscopy. In addition, an analytical method was developed for the quantification of the most promising analog by using high-performance liquid chromatography with UV detection (HPLC-UV). Molecular docking studies suggested that the larvicide action is associated with inhibition of acetylcholinesterase (AChE) enzyme. Therefore, expanding the larvicidal study with the cinnamic acid derivatives against the vector Ae. aegypti is important for finding search for more effective larvicides and with lower toxicity, since they have already shown good larvicidal properties against Ae. aegypti.
- Bezerra Fran?a, Saraliny,Carine Barros de Lima, Luana,Rychard da Silva Cunha, Cristhyan,Santos Anuncia??o, Daniela,Ferreira da Silva-Júnior, Edeildo,Ester de Sá Barreto Barros, Maria,José da Paz Lima, Dimas
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- 1,3-Diphenyldisiloxane Enables Additive-Free Redox Recycling Reactions and Catalysis with Triphenylphosphine
-
The recently reported chemoselective reduction of phosphine oxides with 1,3-diphenyldisiloxane (DPDS) has opened up the possibility of additive-free phosphine oxide reductions in catalytic systems. Herein we disclose the use of this new reducing agent as an enabler of phosphorus redox recycling in Wittig, Staudinger, and alcohol substitution reactions. DPDS was successfully utilized in ambient-temperature additive-free redox recycling variants of the Wittig olefination, Appel halogenation, and Staudinger reduction. Triphenylphosphine-promoted catalytic recycling reactions were also facilitated by DPDS. Additive-free triphenylphosphine-promoted catalytic Staudinger reductions could even be performed at ambient temperature due to the rapid nature of phosphinimine reduction, for which we characterized kinetic and thermodynamic parameters. These results demonstrate the utility of DPDS as an excellent reducing agent for the development of phosphorus redox recycling reactions.
- Buonomo, Joseph A.,Cole, Malcolm S.,Eiden, Carter G.,Aldrich, Courtney C.
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p. 3583 - 3594
(2020/09/15)
-
- Systematic Study on the Catalytic Arsa-Wittig Reaction
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Efficient catalytic arsa-Wittig reactions have been developed by using 1-phenylarsolane as a catalyst. A wide array of aldehydes was converted to the corresponding olefins in high yields with moderate to excellent E stereoselectivity in the presence of a catalytic amount of 1-phenylarsolane. Moreover, density functional theory calculations were carried out to afford insight into the E/Z selectivity.
- Inaba, Ryoto,Kawashima, Ikuo,Fujii, Toshiki,Yumura, Takashi,Imoto, Hiroaki,Naka, Kensuke
-
supporting information
p. 13400 - 13407
(2020/09/21)
-
- Gold-catalyzed partial hydrogenation of activated alkynes mediated by triphenylphosphine
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Gold(I) can exhibit a cooperative effect with triphenylphosphine, accelerating the triphenylphosphine-mediated partial hydrogenation of activated alkynes. In this protocol, 3-arylpropiolates are selectively reduced to the Z -isomer when the aryl ring bears an electron-donor substituent, whereas 3-arylpropynones are reduced to the E-isomers.
- Cocoletzi-Xochitiotzi, Ana Patricia,Hernández-Hernández, Miguel,Medina-Mercado, Ignacio,Jiménez-Martínez, Williams De Jesús,Mastranzo, Virginia Maricela,Porcel, Susana
-
supporting information
p. 2379 - 2386
(2020/08/19)
-
- A de novo peroxidase is also a promiscuous yet stereoselective carbene transferase
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By constructing an in vivo-assembled, catalytically proficient peroxidase, C45, we have recently demonstrated the catalytic potential of simple, de novo-designed heme proteins. Here, we show that C45's enzymatic activity extends to the efficient and stereoselective intermolecular transfer of carbenes to olefins, heterocycles, aldehydes, and amines. Not only is this a report of carbene transferase activity in a completely de novo protein, but also of enzyme-catalyzed ring expansion of aromatic heterocycles via carbene transfer by any enzyme.
- Stenner, Richard,Steventon, Jack W.,Seddon, Annela,Anderson, J.L. Ross
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p. 1419 - 1428
(2020/01/28)
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- Effect of Reaction Media on Photosensitized [2+2]-Cycloaddition of Cinnamates
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The outcome of photosensitized [2+2]-cycloaddition reactions of various cinnamates has been compared in different reaction media, including homogeneous organic solutions under inert conditions, degassed water, and aerated physical gels. The reactions were performed under LED blue light (λmax=455 nm) irradiation and [Ir{dF(CF3)ppy}2(dtb-bpy)]PF6 (1.0 mol%) as photocatalyst. The processes were optimized taking into consideration solvent, gelator, and substrate. Comparative kinetics analyses, as well as the effect of the reaction media on the diastereoselectivity of the process, were evaluated during this investigation. In a number of cases, carrying out the reaction in a less polar solvent, like toluene or highly polar solvent, like water had a tremendous impact on the diastereoselectivity of the process, pointing towards an effect on the stabilization of the putative diradical intermediate in this medium. Moreover, while for reactions run in homogeneous solution oxygen needs to be excluded, no erosion in yield is observed when the photoadditions were run in aerated gel media.
- Abramov, Alex,Reiser, Oliver,Díaz Díaz, David
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p. 649 - 656
(2020/05/25)
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- Copper-catalyzed Mizoroki-Heck coupling reaction using an efficient and magnetically reusable Fe3O4@SiO2@PrNCu catalyst
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This study intends to design and prepare a new magnetic copper catalyst and its activity was assessed by carbon-carbon coupling reactions. For this purpose, 1-[3-(trimethoxysilyl) propyl] urea (TMSPU), hydrazine and CuI were used sequentially to modify Fe3O4@SiO2 core-shell magnetic nanoparticles to obtain an efficient magnetic transition metal catalyst. Various analytical techniques were used to characterize the catalyst to show that the achieved structure and its properties are well-suited for coupling reactions. Finally, Mizoroki-Heck and Ullmann coupling reactions were performed using Fe3O4@SiO2@PrNCu catalyst. The new catalyst offer simple synthetic procedure, convenient use for routine casework and low price. The Fe3O4@SiO2@PrNCu catalyst was easily separated by means of a permanent and ordinary magnet and the recovered catalyst was reused in six cycles without any significant loss of activity.
- Yavari, Issa,Mobaraki, Akbar,Hosseinzadeh, Zhila,Sakhaee, Nader
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supporting information
p. 236 - 246
(2019/07/19)
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- PdII Immobilized on Ferromagnetic Multi-Walled Carbon Nanotubes Functionalized by Aminated 2-Chloroethylphosphonic Acid with S -Methylisothiourea (FMMWCNTs@CPA@SMTU@PdII NPs) Applied as a Highly Efficient and Recyclable Nanostructured Catalyst for Suzuki-Miyaura and Mizoroki-Heck Cross-Coupling Reactions in Solvent-Free Conditions
-
The new ferromagnetic nanostructured FMMWCNTs@CPA@SMTU@PdII NPs (IV) as an eco-friendly heterogeneous nanocatalyst with a particle size of ~20-30 nm reported earlier by our group has been found to be very effective for Suzuki-Miyaura and Mizoroki-Heck cross-coupling reactions at ambient temperature. The procedure has been applied for a wide range of aryl halides, arylboronic acids, and alkenes. The magnetic separation by an external magnetic field, mild reaction conditions, and catalyst reusability up to four times without significant decrease in catalytic activity (reduced catalytic activity from 11 to 18 % in the fifth, sixth, and seventh cycles) made the present method sustainable and economically viable for C-C cross-coupling reactions.
- Ghasemzadeh, Maryam Sadat,Akhlaghinia, Batool
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p. 674 - 692
(2019/07/12)
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- Metallosurfactant based Pd-Ni alloy nanoparticles as a proficient catalyst in the Mizoroki Heck coupling reaction
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A highly efficient, operationally simple and green catalytic approach involving Pd-Ni alloy nanoparticles (NPs) has been developed using microwaves (MWs) as an energy source and water-ethanol as a solvent system. Metallosurfactants were synthesized and used as precursors to fabricate Pd-Ni alloy NPs with a good control over the size and morphology. Surfactant capped zerovalent Pd-Ni alloy NPs were fabricated in the metallomicellar cores by a two-phase reduction method. The synthesized NPs exhibited the highest catalytic efficiency for the stereoselective Mizoroki Heck coupling featuring short reaction time, mild reaction conditions, wide substrate scope, preclusion of toxic organic solvents, easy recovery and recyclability of the catalyst.
- Kaur, Navneet,Kaur, Gurpreet,Bhalla, Aman,Dhau, Jaspreet S.,Chaudhary, Ganga Ram
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p. 1506 - 1514
(2018/04/12)
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- Silica-coated nano-Fe3O4-supported iminopyridine palladium complex as an active, phosphine-free and magnetically separable catalyst for Heck reactions
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A novel magnetic nanoparticle-supported iminopyridine palladium complex was successfully prepared by attaching palladium acetate to iminopyridine ligand-functionalized silica-coated nano-Fe3O4. The as-prepared catalyst was well characterized and was evaluated in Heck reactions in terms of activity and recyclability. It was found to be highly efficient for the reactions of various aryl iodides and aryl bromides having electron-withdrawing groups with olefins under phosphine-free and inert atmosphere-free conditions. Moreover, the catalyst could be conveniently recovered using an external magnet, and the recyclability was influenced by the base in the Heck reaction. The catalyst could be reused at least six times with no significant loss in activity when triethylamine acted as the base.
- Zhang, Qiang,Zhao, Xin,Wei, Huai-Xin,Li, Ji-Hang,Luo, Jun
-
-
- N-heterocyclic carbene-catalysed Peterson olefination reaction
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N-heterocyclic carbenes (NHCs) have been utilised as highly efficient organocatalysts to catalyse Peterson olefination reaction of aldehydes with trimethylsilylketene ethyl trimethylsilyl acetal or fluoro(trimethylsilyl)ketene ethyl trimethylsilyl acetal to produce the corresponding functionalized olefines in 34-93% yields with excellent stereoselectivities.
- Wang, Ying,Du, Guang-Fen,Gu, Cheng-Zhi,Xing, Fen,Dai, Bin,He, Lin
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p. 472 - 478
(2015/12/31)
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- Palladium immobilized on Fe3O4/ZnO nanoparticles: A novel magnetically recyclable catalyst for Suzuki-Miyaura and heck reactions under ligand-free conditions
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Magnetically separable Pd(0)/Fe3O4/ZnO catalyst was easily synthesized by immobilizing Pd on the surface of magnetic Fe3O4-ZnO nanoparticles. The nano-Pd/Fe3O4/ZnO was found as a magnetically separable and highly active catalyst for Suzuki-Miyaura as well as Heck cross-coupling reactions under ligand-free conditions. Under appropriate conditions, all reactions afforded the desired products in moderate to excellent yields. Moreover, this catalyst can be easily recovered using simple magnet and directly reused without significant loss of its activity.
- Hosseini-Sarvari, Mona,Khanivar, Ameneh,Moeini, Fatemeh
-
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- HETEROCYCLIC AMIDES AS KINASE INHIBITORS
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Disclosed are compounds having the formula: (I) wherein R1, R2, and R3 are as defined herein, and methods of making and using the same.
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Page/Page column 81
(2016/12/07)
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- Ligand-Free Heck Reactions of Aryl Iodides: Significant Acceleration of the Rate through Visible Light Irradiation at Ambient Temperature
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A mild Heck reaction of aryl iodides and olefins was realized by the cooperation of a palladium and a photoredox catalyst under the irradiation of visible light. This protocol works well to synthesize stilbenes with high Z/E ratios and (E)-cinnamates in the absence of ligands at ambient temperature. Control experiments revealed that palladium salt, visible light and photoredox catalyst were all crucial for the achievement of this cross-coupling under mild conditions. (Figure presented.).
- Zhang, Heng,Huang, Xueliang
-
supporting information
p. 3736 - 3742
(2016/12/16)
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- C(sp2)-C(sp2) cross coupling reaction catalyzed by a palladacycle phosphine complex: A simple and sustainable protocol in aqueous media
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The Heck reactions of various aryl halides with olefins using {[Ph2PCH2PPh2CH = C(O)(C10H7)] PdCl2} as efficient catalyst has been investigated. The mononuclear palladacycle complex showed excellent activity in aqueous phase including the C(sp 2)-C(sp 2) cross coupling reactions. The advantages of the protocol are high yields, short reaction time, a cleaner reaction profile and notable simplicity.
- Sabounchei, Seyyed Javad,Hosseinzadeh, Marjan
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p. 1919 - 1926
(2015/12/30)
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- Quantitative Structure-Property Relationship (QSPR) models for a local quantum descriptor: Investigation of the 4- and 3-substituted-cinnamic acid esterification
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In this work, the theoretical description of the 4- and 3-substituted-cinnamic acid esterification with different electron donating and electron withdrawing groups was performed at the B3LYP and M06-2X levels, as a two-step process: the O-protonation and the nucleophile attack by ethanol. In parallel, an experimental work devoted to the synthesis and characterization of the substituted-cinnamate esters has also been performed. In order to quantify the substituents effects, quantitative structure-property relationship (QSPR) models based on the atomic charges, Fukui functions and the Frontier Effective-for-Reaction Molecular Orbitals (FERMO) energies were investigated. In fact, the Fukui functions, f+C and f-O, indicated poor correlations for each individual step, and in contrast with the general literature, the O-protonation step is affected both by the FERMO energies and the O-charges of the carbonyl group. Since the process was shown to not be totally described by either charge- or frontier-orbitals, it is proposed to be frontier-charge-miscere controlled. Moreover, the observed trend for the experimental reaction yields suggests that the electron withdrawing groups favor the reaction and the same was observed for Step 2, which can thus be pointed out as the determining step.
- Rodrigues-Santos, Cláudio E.,Echevarria, Aurea,Sant'Anna, Carlos M.R.,Bitencourt, Thiago B.,Nascimento, Maria G.,Bauerfeldt, Glauco F.
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supporting information
p. 17493 - 17510
(2015/12/01)
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- N,N,N′,N′-Tetramethylenediamine dioxide (TMEDAO2) facilitates atom economical/open atmosphere Ley-Griffith (TPAP) tandem oxidation-Wittig reactions
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N,N,N′,N′-Tetramethylethylenediamine dioxide (TMEDAO2) was explored as a more atom economical co-oxidant for the Ley-Griffith oxidation of alcohols to aldehydes. TMEDAO2 was found to selectivity oxidise benzylic and allylic alcohols in comparable yields to that of the standard Ley-Griffith co-oxidant (NMO). Importantly TMEDAO2 facilitated tandem Ley-Griffith-Wittig reactions with stabilised ylides, in good to excellent yields, without the requirement of anhydrous conditions.
- Read, Christopher D. G.,Moore, Peter W.,Williams, Craig M.
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supporting information
p. 4537 - 4540
(2015/09/15)
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- Iron(IV)-Corrole Catalyzed Stereoselective Olefination of Aldehydes with Ethyl Diazoacetate
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Iron(IV)-corrole complexes were first investigated as catalysts for olefination of aldehydes with ethyl diazoacetate in the presence of triphenylphosphine. Efficient olefination of aromatic aldehydes with high trans-selectivity was observed, showing iron corrole is a new kind of promising catalyst for olefination reaction. Transformation of the phosphazine to ylide by iron(IV) corrole was proved to be the key step in the present system.
- Zou, Huai-Bo,Yang, Hong,Liu, Ze-Yu,Mahmood, Mian H.R.,Mei, Guang-Quan,Liu, Hai-Yang,Chang, Chi-Kwong
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supporting information
p. 2791 - 2795
(2015/06/30)
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- OMS-2 for aerobic, catalytic, one-pot alcohol oxidation-wittig reactions: Efficient access to α,β-unsaturated esters
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Manganese oxide octahedral molecular sieve (OMS) materials with well-defined pores have been extensively studied over two decades due to their intriguing chemical and physical properties. OMS-2, the synthetic cryptomelane form of manganese oxide, was synthesized by a modified reflux method and was found to be highly active for obtaining α,β-unsaturated esters (up to 95 % yield and with high diastereoselectivities) from a variety of benzyl, heteroaryl, allyl and alkyl alcohols via one-pot alcohol oxidation-Wittig reaction. The transformation utilizes air as the stoichiometric oxidant, and the inexpensive catalyst can be recovered and reused. Filter and use again! Porous manganese oxide molecular sieve based catalysts were found to efficiently promote the oxidation of a variety of alcohols to the aldehydes, which reacted insitu with stabilized Wittig reagent, providing almost exclusively E-α,β-unsaturated esters in good to excellent yields. The heterogeneous catalyst used was made from inexpensive starting materials, and the recovered catalyst was found to be reusable with a modest loss in activity.
- Kona, Jagadeswara R.,King'Ondu, Cecil K.,Howell, Amy R.,Suib, Steven L.
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p. 749 - 752
(2014/03/21)
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- SINGLE STEP ENANTIOSELECTIVE PROCESS FOR THE PREPARATION OF 3-SUBSTITUTED CHIRAL PHTHALIDES
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The present invention discloses single step, highly enantioselective catalytic oxidative cyclization process for the synthesis of 3-substituted chiral phthalides. In particular, the invention discloses asymmetric synthesis of chiral phthalides via synergetic nitrile accelerated oxidative cyclization of o-cyano substituted aryl alkenes in high yield and enantiomeric excess (ee) in short reaction time. Also, disclosed herein is “one-pot” asymmetric synthesis of biologically important natural compounds having 3-substituted chiral phthalide structural framework in the molecule.
- -
-
Paragraph 0150; 0151
(2014/11/13)
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- Modification of silica using piperazine for immobilization of palladium nanoparticles: A study of its catalytic activity as an efficient heterogeneous catalyst for Heck and Suzuki reactions
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An efficient heterogeneous palladium catalyst system has been developed based on immobilization of Pd nanoparticles on silica-bonded N-propylpiperazine (SBNPP) substrate. SBNPP substrate can stabilize the Pd nanoparticles effectively so that it can improve their stability against aggregation. Also, grafted piperazine species onto the silica backbone prevents the removing of Pd nanoparticles from the substrate surface. It seems that the high recyclable capability of Pd-SBNPP catalysts is resulted from these two characteristics. Transmission electron microscopy (TEM) of catalyst is shown the size of Pd nanoparticles in Pd-SBNPP average of 20 nm. Furthermore, X-ray photoelectron spectroscopy (XPS) of Pd-SBNPP is shown the presence of Pd(0) in the structure of this catalyst. Overall, TEM, XPS and XRD experiments strongly suggested that Pd nanoparticles were formed and immobilized on silica-functionalized piperazine. The catalytic activity of this catalyst was investigated in the Heck and Suzuki reactions. The catalyst could be recycled several times without appreciable loss in catalytic activity.
- Niknam, Khodabakhsh,Habibabad, Maryam Sadeghi,Deris, Abdollah,Panahi, Farhad,Reza Hormozi Nezhad, Mohammad
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p. 527 - 534
(2013/07/27)
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- Oxidative alkoxycarbonylation of terminal alkenes with carbazates
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A range of terminal alkenes smoothly underwent palladium-catalyzed oxidative alkoxycarbonylation with carbazates under an oxygen atmosphere to afford structurally diverse α,β-unsaturated esters in moderate to good yields with excellent regioselectivity and E selectivity.
- Su, Yu-Han,Wu, Zhao,Tian, Shi-Kai
-
supporting information
p. 6528 - 6530
(2013/07/26)
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- A SINGLE STEP ENANTIOSELECTIVE PROCESS FOR THE PREPARATION OF 3-SUBSTITUTED CHIRAL PHTHALIDES
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The present invention discloses single step, highly enantioselective catalytic oxidative cyclization process for the synthesis of 3-substituted chiral phthalides. In particular, the invention discloses asymmetric synthesis of chiral phthalides via synergetic nitrile accelerated oxidative cyclization of o-cyano substituted aryl alkenes in high yield and enantiomeric excess (ee) in short reaction time. Also, disclosed herein is "one -pot" asymmetric synthesis of biologically important natural compounds having 3-substituted chiral phthalide structural framework in the molecule.
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- Synthesis of a novel 8-hydroxyquinoline functionalized poly (ethylene glycol) bridged dicationic ionic liquid and its application in palladium-catalyzed Heck reaction under solvent-free conditions
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A novel 8-hydroxyquinoline functionalized poly (ethylene glycol) bridged dicationic ionic liquid ([HQ-PEG1000-DIL][BF4]) was synthesized and characterized. It was applied as an efficiently recyclable ligand for Pd-catalyzed Heck reaction under solvent-free conditions. It is noteworthy that the Pd(OAc)2/[HQ-PEG1000-DIL][BF 4] catalytic system could be easily recovered and reused without obvious loss of catalytic activity after five recycling runs.
- Wang, Yinglei,Luo, Jun,Liu, Zuliang
-
-
- Sustainable carbonecarbon bond formation catalyzed by new oxamate-containing palladium(II) complexes in ionic liquids
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New and versatile bis(oxamato)palladate(II) complexes of formula (n-Bu 4N)2[Pd(2-Mepma)2]·4H2O (1a) and (n-Bu4N)2[Pd(4-Mepma)2]·2H 2O·MeCN (1b) (n-Bu4N+ = tetra-n-buthylammonium, 2-Mepma = N- 2-methylphenyloxamate and 4-Mepma = N-4-methylphenyloxamate) have been synthesized and characterized by spectroscopic methods and single crystal X-ray diffraction. Each palladium(II) ion in 1a and 1b is four-coordinate with two oxygen and two nitrogen atoms from two fully deprotonated oxamate ligands building a centrosymmetric square planar surrounding. Their catalytic role has been investigated for both Heck and Suzuki coupling reactions using a series of aryl iodide/bromide derivatives in tetra-n-butylammonium bromide (n-Bu 4NBr) as ionic liquid, i.e. molten salt. These precatalysts appear as highly efficient, easily recovered and reused at least eight times without any drastic loss of their exceptional reactivity or leaching from the ionic liquid medium.
- Fortea-Pérez, Francisco Ramón,Schlegel, Isabel,Julve, Miguel,Armentano, Donatella,De Munno, Giovanni,Stiriba, Salah-Eddine
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p. 102 - 108
(2013/10/08)
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- Synthesis of substituted nitroolefins: A copper catalyzed nitrodecarboxylation of unsaturated carboxylic acids
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A novel, mild and convenient method for the nitrodecarboxylation of substituted cinnamic acid derivatives to their nitroolefins is achieved using a catalytic amount of CuCl (10 mol%) and tert-butyl nitrite (2 equiv.) as a nitrating agent in the presence of air. This reaction provides a useful method for the synthesis of β,β-disubstituted nitroolefin derivatives, which are generally difficult to access from other conventional methods. Additionally, this reaction is selective as the E-isomer of the acid derivatives furnishes the corresponding E-nitroolefins. One more salient feature of the method is, unlike other methods, no metal nitrates or HNO3 are employed for the transformation.
- Rokade, Balaji V.,Prabhu, Kandikere Ramaiah
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supporting information
p. 6713 - 6716
(2013/10/01)
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- PYRIMIDINONE COMPOUNDS FOR USE IN THE TREATMENT OF DISEASES OR CONDITIONS MEDIATED BY LP - PLA2
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The present invention relates to novel compounds that inhibit Lp-PLA2 activity, processes for their preparation, to compositions containing them and to their use in the treatment of diseases associated with the activity of Lp-PLA2, for example atherosclerosis, Alzheimer's disease, and/or diabetic macular edema (I).
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Page/Page column 37-38
(2012/06/30)
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- Stereoselective olefination and regiospecific vicinal difunctionalization of imines with α-(benzothiazol-2-ylsulfonyl) carbonyl compounds
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Depending on their structures, imines are able to undergo either olefination or vicinal difunctionalization with various α-(benzothiazol-2- ylsulfonyl) carbonyl compounds in the absence of external bases. The olefination reaction of aromatic imines with α-(benzothiazol-2-ylsulfonyl) carbonyl compounds proceeds smoothly in tetrahydrofuran at 70 °C to give structurally diverse α,β-unsaturated esters, amides, and ketones in good to excellent yields and with extremely high (E) selectivity. In contrast, the carbon-nitrogen double bonds of cyclic imines and the carbon-carbon double bonds of α,β-unsaturated imines are subjected to regiospecific vicinal difunctionalization with α-(benzothiazol-2-ylsulfonyl) carbonyl compounds under the same reaction conditions to give a variety of benzothiazole derivatives in good to excellent yields. It is noteworthy that the benzothiazole moiety is present in a number of antitumor agents and bioluminescent molecules. In addition, plausible reaction pathways have been proposed to account for these transformations, and these are substantially supported by ESI-MS analysis of the reaction mixtures.
- Shao, You-Dong,Wu, Xue-Song,Tian, Shi-Kai
-
supporting information; experimental part
p. 1590 - 1596
(2012/05/07)
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- A newly-designed PE-supported arsine for efficient and practical catalytic Wittig olefination
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A newly designed PE-supported arsine has been developed as an excellent catalyst for catalytic Wittig-type olefination. Simple ketones, in particular inactive ketones prove to be suitable substrates for the first time. This reaction provides an easy access to di-, tri-, and tetra-substituted olefins in high yield.
- Wang, Peng,Liu, Chun-Rong,Sun, Xiu-Li,Chen, Shuai-Shuai,Li, Jun-Fang,Xie, Zuowei,Tang, Yong
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supporting information; experimental part
p. 290 - 292
(2012/01/06)
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- Solid supported palladium(0) nano/microparticle: A ligand-free efficient recyclable heterogeneous catalyst for mono- and β,β-double-Heck reaction
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Solid supported palladium nano/microparticles were found to be active catalysts to perform mono- and β,β-double-Heck reactions. Different β-unsubstituted and substituted alkenes including acrylate, methacrylate, crotonate, styrene, acrylonitrile, and acrylamide were investigated successfully for mono- and β,β-double-Heck reactions with aryl iodide under milder reaction condition. One-pot β,β-double-Heck reaction of aryl iodides with α,β-unsaturated ester, amide, nitrile, and styrene derivatives were also performed under standard reaction conditions. Wide functional group tolerance, easy catalyst recovery, and recyclability up to twelve times without significant loss of catalytic activity added extra importance to the present process.
- Sharma, Dharminder,Kumar, Sandeep,Shil, Arun K.,Guha, Nitul Ranjan,Bandna,Das, Pralay
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supporting information
p. 7044 - 7051
(2013/01/15)
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- Organocatalytic decarboxylative Doebner-Knoevenagel reactions between arylaldehydes and monoethyl malonate mediated by a bifunctional polymeric catalyst
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A bifunctional polystyrene bearing both DMAP and piperidine groups has been prepared and used as an organocatalyst for decarboxylative Doebner-Knoevenagel reactions of arylaldehydes and monoethyl malonate. Isolated yields of the resulting cinnamates were very high, and in all cases only the E-isomer was detected. When a polystyrene catalyst functionalized with only DMAP or piperidine groups was used in these reactions, catalysis was much less efficient. Furthermore, catalysis using a combination of the monofunctional polymers was also less efficient than with the bifunctional polystyrene. Thus, it appears that there is a synergistic effect obtained by co-locating the two different catalytic amine groups on the same polymer backbone. Georg Thieme Verlag Stuttgart · New York.
- Lu, Jinni,Toy, Patrick H.
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supporting information; experimental part
p. 1723 - 1726
(2011/09/12)
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- Ruthenium-catalyzed regio- and enantioselective allylic substitution with water: Direct synthesis of chiral allylic alcohols
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Less is more: A new route to access chiral allylic alcohols through the regio- and enantioselective substitution of monosubstituted allylic chlorides with water has been developed. The reaction is catalyzed effectively by planar-chiral cyclopentadienyl ruthenium complexes (see scheme). Copyright
- Kanbayashi, Naoya,Onitsuka, Kiyotaka
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supporting information; experimental part
p. 5197 - 5199
(2011/06/26)
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- Contrasting reactivity of 2-mesityl-1,8-naphthyridine (Mes-NP) with singly-bonded [RhIIRhII] and [RuIRu I] compounds
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Reaction of cis-[Rh2(CH3COO) 2 (CH 3CN) 6](BF4)2 with two equivalents of 2-mesityl-1,8- naphthyridine (Mes-NP) affords trans-[Rh2(CH3COO) 2(Mes-NP) 2](BF4) 2 (1). X-ray structure reveals weak RhC(ipso) interaction, and a short RhRh distance. The same ligand, in contrast, oxidatively cleaves the RuRu bond in cis-[Ru2 (CO) 4 (CH3CN) 6](BF4)2 and results in trans-[Ru(Mes-NP) 2 (CH3CN) 2](BF4)2 (2). Both compounds adopt trans geometry to relieve the steric strain. Compound 2 exhibits moderate activity for the alcohol oxidation and aldehyde olefination reactions. CSIRO 2011.
- Saha, Biswajit,Rahaman, S. M. Wahidur,Sinha, Arup,Bera, Jitendra K.
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p. 583 - 589
(2012/01/30)
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- Site-directed anchoring of an N-heterocyclic carbene on a dimetal platform: Evaluation of a pair of diruthenium(i) catalysts for carbene-transfer reactions from ethyl diazoacetate
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Site-directed anchoring of naphthyridine-functionalized N-heterocylic carbene (NHC) is achieved on a metal-metal singly bonded diruthenium(I) platform. Room-temperature treatment of 1-isopropyl-3-(5,7-dimethyl-1,8- naphthyrid-2-yl)imidazolium bromide (PINA·HBr) with Ru 2(CH3COO)2(CO)4 in acetonitrile affords the unsupported compound Ru2(CO) 4(μ2C2,N1-PIN)2Br 2 (1). Judicious alteration in the NHC ligand resulted in the bridged compound Ru2(CO)4(CH3COO)(μ2- μ2C2,N1-BIN)Br (2) (BIN = 1-benzyl-3-(3-phenyl-1,8-naphthyrid-2-yl)imidazol-2-ylidene). X-ray analysis revealed the chelate binding of PIN on each ruthenium at equatorial sites for 1, and the bridge-chelate binding of BIN spanning the diruthenium core for 2. The catalytic utilities of the BArF (tetrakis(3,5-bis(trifluoromethyl) phenyl)borate) salts of these compounds are evaluated toward carbene-transfer reactions from ethyl diazoacetate including aldehyde olefination, cyclopropanation, and X-H (X = O, N) insertions. 1-BArF is clearly shown to be the superior catalyst. DFT calculations are undertaken to understand the influence of NHC binding on the electronic structures of the "Ru 2(CO)4" core and to rationalize the lower activity of 2-BArF.
- Saha, Biswajit,Ghatak, Tapas,Sinha, Arup,Rahaman, S. M. Wahidur,Bera, Jitendra K.
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scheme or table
p. 2051 - 2058
(2011/06/18)
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- A RuII-N-heterocyclic carbene (NHC) complex from metal-metal singly bonded diruthenium(I) precursor: Synthesis, structure and catalytic evaluation
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A mononuclear Ru(II)-N-heterocyclic carbene (NHC) complex [Ru II(CO)2(κ2C,N-BIN)(H2O)Br] [OTf] (OTf = trifluoromethane sulphonate) (1) has been synthesized in high-yield by the oxidative cleavage of the metal-metal singly-bonded diruthenium(I) precursor [Ru2(CO)4(CH3CN)6(OTf) 2] with 1,8-naphthyridine functionalized NHC precursor 1-benzyl-3-(5,7-dimethyl-1,8-naphthyrid-2-yl)imidazolium bromide (BIN·HBr) at room temperature. Compound 1 catalyzes transfer hydrogenation of ketones to alcohols, and carbene-transfer from ethyl diazoacetate to a variety of substrates. It is shown to be an excellent catalyst for the insertion of carbene into the O-H and N-H bonds of alcohols and amines.
- Sinha, Arup,Daw, Prosenjit,Rahaman, S.M. Wahidur,Saha, Biswajit,Bera, Jitendra K.
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experimental part
p. 1248 - 1257
(2011/04/22)
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- Bimetallic catalysis involving dipalladium(I) and diruthenium(I) complexes
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Dipalladium(I) and diruthenium(I) compounds bridged by two [{(5,7-dimethyl-1,8-naphthyridin-2-yl)amino}carbonyl]ferrocene (L) ligands have been synthesized. The X-ray structures of [Pd2L2][BF 4]2 (1) and [Ru2L2(CO) 4][BF4]2 (2) reveal dinuclear structures with short metal-metal distances. In both of these structures, naphthyridine bridges the dimetal unit, and the site trans to the metal-metal bond is occupied by weakly coordinating oxygen from the amido fragment. The catalytic utilities of these bimetallic compounds are evaluated. Compound 1 is an excellent catalyst for phosphine-free, Suzuki cross-coupling reactions of aryl bromides with arylboronic acids and provides high yields in short reaction times. Compound 1 is also found to be catalytically active for aryl chlorides, although the corresponding yields are lower. A bimetallic mechanism is proposed, which involves the oxidative addition of aryl bromide across the Pdi£ Pd bond and the bimetallic reductive elimination of the product. Compound 1 is also an efficient catalyst for the Heck cross-coupling of aryl bromides with styrenes. The mechanism for aldehyde olefination with ethyl diazoacetate (EDA) and PPh3, catalyzed by 2, has been fully elucidated. It is demonstrated that 2 catalyzes the formation of phosphorane utilizing EDA and PPh3, which subsequently reacts with aldehyde to produce a new olefin and phosphine oxide. The efficacy of bimetallic complexes in catalytic organic transformations is illustrated in this work. Good couple: Metal-metal singly bonded [PdIi£PdI] and [RuIi£RuI] complexes exhibit bimetallic synergy in the catalytic Ci£C bond-coupling and aldehyde-olefination reactions, respectively (see figure). Copyright
- Das, Raj K.,Saha, Biswajit,Rahaman, S. M. Wahidur,Bera, Jitendra K.
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scheme or table
p. 14459 - 14468
(2011/03/19)
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- Chromatography-free wittig reactions using a bifunctional polymeric reagent
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The first example of a polystyrene bearing two distinct reagent groups has been prepared. This phosphine and amine functionalized material was used in one-pot Wittig reactions with an aldehyde and either an α-halo-ester, -ketone, or -amide. Due to the heterogeneous nature of the polymer, the desired alkene product of these reactions could be isolated in excellent yield in essentially pure form after only filtration and solvent removal.
- Leung, Peter Shu-Wai,Teng, Yan,Toy, Patrick H.
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supporting information; experimental part
p. 4996 - 4999
(2010/12/25)
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- Palladium(II)/Cationic 2,2'-Bipyridyl system as a highly efficient and reusable catalyst for the Mizoroki-Heck reaction in water
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A water-soluble and air-stable Pd(NH3)2Cl 2/cationic 2,2'-bipyridyl system was found to be a highly-efficient and reusable catalyst for the coupling of aryl iodides and alkenes in neat water using Bu3N as a base. The reaction was conducted at 140 °C in a sealed tube in air with a catalyst loading as low as 0.0001 mol % for the coupling of activated aryl iodides with butyl and ethyl acrylates, providing the corresponding products in good to excellent yields with very high turnover numbers. In the case of styrene, Mizoroki-Heck coupling products were obtained in good to high yields by using a greater catalyst loading (1 mol %) and TBAB as a phase-transfer agent. After extraction, the residual aqueous solution could be reused several times with only a slight decrease in its activity, making the Mizoroki-Heck reaction "greener".
- Huang, Shao-Hsien,Chen, Jun-Rong,Tsai, Fu-Yu
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experimental part
p. 315 - 330
(2010/05/02)
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- P[N(i-Bu)CH2CH2]3N: Nonionic Lewis base for promoting the room-temperature synthesis of α,β-unsaturated esters, fluorides, ketones, and nitriles using Wadsworth - Emmons phosphonates
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The bicyclic triaminophosphine P(RNCH2CH2) 3N (R = i-Bu, 1c) serves as an effective promoter for the room-temperature stereoselective synthesis of α,β-unsaturated esters, fluorides, and nitriles from a wide array of aromatic, aliphatic, heterocyclic, and cyclic aldehydes and ketones, using a range of Wadsworth-Emmons (WE) phosphonates. Among the analogues of 1c [R = Me (1a), i-Pr (1b), Bn (1d)], 1a and 1b performed well, although longer reaction times were involved, and 1d led to poorer yields than 1c. Functionalities such as cyano, chloro, bromo, methoxy, amino, ester, and nitro were well tolerated. We were able to isolate and characterize (by X-ray means; see above) the reactive WE intermediate species formed from 2b and 1c.
- Chintareddy, Venkat Reddy,Ellern, Arkady,Verkade, John G.
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supporting information; experimental part
p. 7166 - 7174
(2010/12/25)
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- Task-specific ionic liquid as reagent and reaction medium for the one-pot Horner-Wadsworth-Emmons-type reaction under microwave irradiation
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A task-specific imidazolium-based phosphinite ionic liquid (IL-OPPh2) was used as the dual solvent-reagent for the synthesis of E-cinamates and coumarin derivatives via the one-pot Horner-Wadsworth-Emmons-type reaction. The ionic liquid containing its cor
- Valizadeh, Hassan,Shockravi, Abbas
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experimental part
p. 4341 - 4349
(2010/04/26)
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- Microwave-promoted heck reaction using Pd(OAc)2 as catalyst under ligand-free and solvent-free conditions
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A rapid and efficient microwave-promoted Heck reaction of aryl iodides and bromides with terminal olefins using a Pd(OAc)2 (0.05 mol%)/K3PO4 catalytic system under ligand-free and solvent-free conditions is described. Copyright Taylor & Francis Group, LLC.
- Du, Li-Hua,Wang, Yan-Guang
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p. 217 - 222
(2007/10/03)
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- Synthesis, characterization, and applications in Heck and Suzuki coupling reactions of amphiphilic cyclopalladated ferrocenylimines
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A series of novel amphiphilic ferrocenylimines and their cyclopalladated complexes of general formula [Fe(η5-C5H5)(η5-C5H4CR1{double bond, long}NR2)] (R1=H, R2=C12H25-n 4a, R1=H, R2=C16H33-n 4b, R1=CH3, R2=C12H25-n 4c, R1=CH3, R2=C16H33-n 4d), [PdCl{[(η5-C5H5)]Fe[(η5-C5H3)CR1{double bond, long}NR2]}]2 (5a-d), [PdCl{[(η5-C5H5)]Fe[(η5-C5H3)-CR1{double bond, long}NR2]}(PPh3)] (6a-d), were prepared and characterized by 1H NMR, 13C NMR, 31P NMR, IR, HRMS, and elemental analysis. The crystal structures of 5c,d were determined by X-ray crystallography. These amphiphilic cyclopalladated complexes are thermally stable and insensitive to oxygen and moisture. The redox properties of 4a-d, 5a-d, 6a-d were also investigated using cyclic voltammetric technique. Compounds 5a-d, 6a-d displayed good activity in the Heck reaction of a variety of aryl halides with ethyl acrylate or styrene and the Suzuki-Miyaura cross-coupling reaction of aryl bromides with phenylboronic acid in bulk solution. They are also suitable for formation of Langmuir-Blodgett (LB) films.
- Mu, Bing,Li, Tiesheng,Xu, Wenjian,Zeng, Guoliang,Liu, Pingping,Wu, Yangjie
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p. 11475 - 11488
(2008/03/12)
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- METHOD FOR THE PRODUCTION OF OLEFINS FROM CARBONYL COMPOUNDS
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A method for the production of a,?-unsaturated compounds of general formula (I) is disclosed, where R1 and R2 independently = H, substituted or unsubstituted alkyl or aryl, R3 = H, substituted or unsubstituted alkyl or aryl, or a functional group such as OR4, NR5R6, SR7, where R4, R5, R6 and R7 = common substituents in particular, alkyl- and/or aryl groups, or halogen, EWG = an electron withdrawing group such as for example, CO2H, CO2R8, CONR9R10, COSR11, CN, NO2, SO2R12, CHO, COR13, etc. where R8, R9, R10, R11, R12 and R13 = common substituents, in particular, alkyl- and/or aryl groups, in which a carbonyl compound of formula (II), in which R1 and R2 are as defined above, is reacted with a carboxylic acid of formula (III) in the presence of an amine or with the same acid generated in situ by the addition of an acid to the salt thereof in which R3 and EWG are as defined above. Under mild reaction conditions unsaturated esters with high (E)-stereoselectivity are obtained. The reaction typically occurs at room temperature or lower without particular requirements such as inert gas, exclusion of humidity, heat etc. CO2 and water are obtained as the only by-products.
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Page/Page column 8
(2008/06/13)
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- A practical, efficient, and atom economic alternative to the Wittig and Horner-Wadsworth-Emmons reactions for the synthesis of (E)-α,β- unsaturated esters from aldehydes
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We describe a highly efficient new methodology for the synthesis of (E)-α,β-unsaturated esters from aldehydes. In our DMAP-catalyzed reaction, both aromatic as well as aliphatic aldehydes furnish the desired products highly regio- and stereoselectively if treated with commercially available or synthetically easily accessible malonic acid half ester. A large scale application in the synthesis of p-methoxycinnamates, which are of use as sunscreen ingredients, is described.
- List, Benjamin,Doehring, Arno,Hechavarria Fonseca, Maria T.,Job, Andreas,Rios Torres, Ramon
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p. 476 - 482
(2007/10/03)
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- Tricyclohexylphosphine-cyclopalladated ferrocenylimine complexes: Synthesis, crystal structures and application in Suzuki and Heck reactions
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A series of novel tricyclohexylphosphine (PCy3)-cyclopalladated ferrocenylimine complexes 2c-2g have been easily synthesized. These new palladacycles are thermally stable and are not sensitive to air and moisture. Their detailed structures have been determined by single-crystal X-ray analysis and six different types of intermolecular hydrogen bonds are found to be existed in the crystals of these complexes. The use of 2c-2g as catalysts for Suzuki and Heck reactions was examined. They were found to be very efficient for the Suzuki reaction of aryl chlorides with phenylboronic acid. Typically, using 0.1 mol% of catalyst in the presence of 1.5 equivalent of Cs2CO 3 as base in dioxane at 100 °C provided coupled products in excellent yields. These complexes also displayed good activity in the Heck reaction of a range of aryl bromides with acrylic acid ethyl ester although they were not particularly useful for the activation of aryl chlorides. The Royal Society of Chemistry 2006.
- Xu, Chen,Gong, Jun-Fang,Yue, Su-Fang,Zhu, Yu,Wu, Yang-Jie
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p. 4730 - 4739
(2007/10/03)
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- Functionalized ionic liquid as an efficient and recyclable reaction medium for phosphine-free palladium-catalyzed heck reaction
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A functionalized ionic liquid, 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate ([HEmim][BF4]), was found to be as an efficient and recyclable reaction medium for palladium-catalyzed Heck reaction. The olefination of iodoarenes and bromoarenes with olefins generated the corresponding products in good to excellent yields under phosphine-free reaction conditions. The reaction involved the use of [HEmim][BF4] as the solvent, potassium phosphate as the base, and palladium acetate as the catalyst. In addition, palladium and ionic liquid could be recovered and recycled for six consecutive trials without significant loss of its reactivity. Georg Thieme Verlag Stuttgart.
- Zhou, Li,Wang, Lei
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p. 2653 - 2658
(2008/02/05)
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- Arenediazonium o-benzenedisulfonimides as efficient reagents for Heck-type arylation reactions
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Arenediazonium o-benzenedisulfonimides can be used as new and efficient reagents for Heck-type arylation reactions of some common substrates containing C-C multiple bonds, namely ethyl acrylate, acrylic acid, acroleyne, styrene and cyclopentene. The reactions were carried out in an organic solvent, in the presence of Pd(OAc)2 as pre-catalyst, and gave rise to arylated products, for example, ethyl cinnamates, cinnamic acids, cinnamic aldehydes and stilbenes, possessing an (E)-configuration, and 1-arylcyclopentenes, in good to excellent yields. It is noteworthy that all the reactions led to the recovery, in greater than 80% yield, of o-benzenedisulfonimide, recyclable for the preparation of other diazonium salts.
- Artuso, Emma,Barbero, Margherita,Degani, Iacopo,Dughera, Stefano,Fochi, Rita
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p. 3146 - 3157
(2007/10/03)
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- Two variations of solvent-reduced wittig olefination reactions - Comparison of solventless wittig reactions to wittig reactions under ultrasonication with minimal work-up
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Stabilized and semi-stabilized phosphoranes can be subjected to solventless Wittig reactions with carbaldehydes. Simple heating of a mixture of added components at 100°C in an electric oven gives the corresponding olefins in good yield. Alternatively, the Wittig reactions can be carried out in a biphasic medium under ultrasonication. In this case, the Wittig products can be isolated by simple evaporation of the organic phase without additional work-up.
- Watanabe, Masataka,Morais, Goreti Ribeiro,Mataka, Shuntaro,Ideta, Keiko,Thiemann, Thies
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p. 909 - 915
(2007/10/03)
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