- 2-Phenylcyclopropylmethylamine Derivatives as Dopamine D2Receptor Partial Agonists: Design, Synthesis, and Biological Evaluation
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Partial agonist activity at the dopamine D2 receptor (D2R) is the primary pharmacological feature of the third-generation antipsychotics─aripiprazole, brexpiprazole, and cariprazine. However, all these drugs share a common phenyl-piperazine moiety as the primary pharmacophore. In this study, we designed and synthesized a series of novel compounds based on the 2-phenylcyclopropylmethylamine (PCPMA) scaffold and studied their pharmacological activity at the D2R. A number of potent D2R partial agonists were identified through binding affinity screening and functional activity profiling in both G protein and β-arrestin assays. The structure-functional activity relationship results showed that the spacer group is crucial for fine-tuning the intrinsic activity of these compounds. Compounds (+)-14j and (+)-14l showed good pharmacokinetic properties and an unexpected selectivity against the serotonin 2A (5-HT2A) receptor. Preliminary suppressive effects in a mouse hyperlocomotion model proved that these PCPMA-derived D2R partial agonists are effective as potential novel antipsychotics.
- Cheng, Jianjun,Fan, Luyu,Liu, Ruiquan,Tan, Liang,Wang, Huan,Wang, Sheng,Yan, Wenzhong,Yu, Jing
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p. 17239 - 17258
(2021/12/06)
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- Efficient synthesis of acrylates bearing an aryl or heteroaryl moiety: One-pot method from aromatics and heteroaromatics using formylation and the horner-wadsworth-emmons reaction
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Acrylates bearing an aryl or heteroaryl moiety were efficiently prepared by a one-pot process employing a sequence of lithiation, formylation and the Horner-Wadsworth-Emmons reaction starting from aromatic and heteroaromatic compounds. This method can efficiently introduce an acrylate moiety into aromatic and heteroaromatic compounds.
- Yasukata, Tatsuro,Matsuura, Takaharu
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p. 527 - 533
(2021/03/22)
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- Reduction of Electron-Deficient Alkenes Enabled by a Photoinduced Hydrogen Atom Transfer
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Direct hydrogen atom transfer from a photoredox-generated Hantzsch ester radical cation to electron-deficient alkenes has enabled the development of an efficient formal hydrogenation under mild, operationally simple conditions. The HAT-driven mechanism is supported by experimental and computational studies. The reaction is applied to a variety of cinnamate derivatives and related structures, irrespective of the presence of electron-donating or electron-withdrawing substituents in the aromatic ring and with good functional group compatibility. (Figure presented.).
- Larionova, Natalia A.,Ondozabal, Jun Miyatake,Cambeiro, Xacobe C.
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supporting information
p. 558 - 564
(2020/12/07)
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- A Photocatalytic Regioselective Direct Hydroaminoalkylation of Aryl-Substituted Alkenes with Amines
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A photocatalytic method for the α-selective hydroaminoalkylation of cinnamate esters has been developed. The reaction involves the regioselective addition of α-aminoalkyl radicals generated from aniline derivatives or aliphatic amines to the α-position of unsaturated esters. The scope of aromatic alkenes was extended to styrenes undergoing hydroaminoalkylation with anti-Markovnikov selectivity, which confirms the importance of the aromatic group at the β-position. Simple scale-up is demonstrated under continuous flow conditions, highlighting the practicality of the method.
- Larionova, Natalia A.,Ondozabal, Jun Miyatake,Smith, Emily G.,Cambeiro, Xacobe C.
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supporting information
p. 5383 - 5388
(2021/07/26)
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- C–C Cross-Coupling Reactions of Organosilanes with Terminal Alkenes and Allylic Acetates Using PdII Catalyst Supported on Starch Coated Magnetic Nanoparticles
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Starch coated magnetic nanoparticles supported palladium catalyst has been explored to perform C–C cross coupling reactions, such as oxidative Heck coupling and Tsuji–Trost allylic coupling using organosilicon compounds as one of the coupling partners. The biopolymer coated magnetic catalyst was very easy to recover magnetically and was efficiently recycled in the subsequent batches. All the reactions were performed in air and thus the necessity of air and moisture free reaction condition is avoided. The present protocols show wide substrate scope and good yields of the products.
- Patra, Debabrata,Panja, Subir,Saha, Amit
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supporting information
p. 878 - 883
(2020/02/13)
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- Dual ligand-promoted palladium-catalyzed nondirected C-H alkenylation of aryl ethers
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Direct C-H functionalization of aryl ethers remains challenging owing to their low reactivity and selectivity. Herein, a novel strategy for nondirected C-H alkenylation of aryl ethers promoted by a dual ligand catalyst was demonstrated. This catalytic system readily achieved the highly efficient alkenylation of alkyl aryl ethers (anisole, phenetole, n-propyl phenyl ether, n-butyl phenyl ether and benzyl phenyl ether), cyclic aryl ethers (1,4-benzodioxan, 2,3-dihydrobenzofuran, dibenzofuran), and diphenyl oxides. Moreover, the proposed methodology was successfully employed for the late-stage modification of complex drugs containing the aryl ether motif. Interestingly, the compounds developed herein displayed fluorescent properties, which would facilitate their biological applications.
- Fu, Manlin,Liu, Jiang,Wang, Lei,Yin, Biao,Zhu, Qing
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supporting information
p. 3293 - 3296
(2020/04/02)
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- Finely dispersed palladium on silk-fibroin as an efficient and ligand-free catalyst for Heck cross-coupling reaction
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A palladium–fibroin complex (Pd/Fib.) was prepared by the addition of sonicated fibroin fiber in water to palladium acetate solution. Pd (OAc)2 was absorbed by fibroin and reduced with NaBH4 at room temperature to the Pd(0) nanoparticles. Powder-X-ray diffraction, scanning electron microscopy–energy-dispersive X-ray spectroscopy, Fourier transform-infrared, CHN elemental analysis and inductively coupled plasma-atomic emission spectroscopy were carried out to characterize the Pd/Fib. catalyst. Catalytic activity of this finely dispersed palladium was examined in the Heck coupling reaction. The catalytic coupling of aryl halides (-Cl, -Br, -I) and olefins led to the formation of the corresponding coupled products in moderate to high yields under air atmosphere. A variety of substrates, including electron-rich and electron-poor aryl halides, were converted smoothly to the targeted products in simple procedure. Heterogeneous supported Pd catalyst can be recycled and reused several times.
- Mirzaei, Hakimeh,Eshghi, Hossein,Seyedi, Seyed Mohammad
-
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- Bis(pyrazolyl)palladium(II) complexes as catalysts for Mizoroki–Heck cross-coupling reactions
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Recent progress in carbon–carbon cross-coupling reactions has resulted in the discovery of highly active catalysts for carrying out such transformations. However, due to the wide array of applications of the products from cross-coupling reactions, there is the need to design suitable catalysts that permit the practical and economical synthesis of the cross-coupled products. Palladium complexes with bulky and electron-donating ligands have served as excellent (pre)catalysts for the Mizoroki–Heck cross-coupling reaction. By using bulky pyrazole-based ligands, we have prepared palladium(II) complexes with controlled steric and electronic properties of the metal center. We have used these bulky bis(pyrazolyl)palladium(II) complexes as (pre)catalysts for the Mizoroki–Heck cross-coupling reaction. The (pre)catalysts displayed high activity and selectivity, giving high catalytic conversions at a low (pre)catalyst loading and short reaction times. A mercury poisoning test confirmed that the (pre)catalysts promoted the Mizoroki–Heck cross-coupling homogenously and do not decompose into palladium black during the reactions. The catalytic systems were also tolerant to the presence of functional groups, such as 4-CF3, 4-CH3, 4-CO2Me and 4-CO2Et, on the alkene substrates.
- Ocansey, Edward,Darkwa, James,Makhubela, Banothile C.E.
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- Magnetic dendritic polymer nanocomposites as supports for palladium: A highly efficient and reusable catalyst for Mizoroki-Heck and Suzuki-Miyaura coupling reactions
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A novel catalyst Fe3O4@SiO2-Dendrimer-Pd based on palladium immobilized on magnetic dendritic polymer nanocomposites was successfully synthesized and characterized by FT-IR, EA, XRD, TEM, EDX, VSM and XPS. This nanocatalyst showed excellent catalytic activity for solvent-free Mizoroki-Heck reaction and Suzuki-Miyaura reaction in EtOH/H2O at a palladium loading of only 0.009 mol%. Moreover, the Fe3O4@SiO2-Dendrimer-Pd catalyst could be conveniently recovered by an external magnet and used consecutively five times with excellent yields. The remarkable catalytic performances and convenient magnetic separability of the Fe3O4@SiO2-Dendrimer-Pd catalyst make it promising for practical application.
- Ma, Rong,Yang, Pengbo,Bian, Fengling
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p. 4748 - 4756
(2018/03/21)
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- Kryptofix 5 as an inexpensive and efficient ligand for the palladium-catalyzed Mizoroki-Heck reaction
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A novel complex of PdCl2 with a multidentate cryptand ligand, Kryptofix 5, has been prepared and characterized by various techniques including 1H- and 13C NMR spectroscopy, Fourier transform infrared (FT-IR), Raman, ultraviolet and visible (UV-VIS) spectroscopy, inductively coupled plasma (ICP), CHN elemental and energy dispersive X-ray analysis (EDX). This heat- and air-stable complex was utilized as a highly active catalyst for the Mizoroki-Heck reaction of aryl halides with various olefins. Interestingly, it was found that aryl bromides as well as aryl iodides were efficiently cross-coupled with terminal alkenes at 130?°C in 10?min. Furthermore, the least reactive aryl chlorides reacted with styrene to obtain the desired products in acceptable yields.
- Movassagh, Barahman,Ranjbari, Shabnam
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- Discovery of novel piperonyl derivatives as diapophytoene desaturase inhibitors for the treatment of methicillin-, vancomycin- and linezolid-resistant Staphylococcus aureus infections
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Inhibition of S. aureus diapophytoene desaturase (CrtN) could serve as an alternative approach for addressing the tricky antibiotic resistance by blocking the biosynthesis of carotenoid pigment which shields the bacterium from host oxidant killing. In this study, we designed and synthesized 44 derivatives with piperonyl scaffold targeting CrtN and the structure-activity relationships (SARs) were examined extensively to bring out the discovery of 21b with potent efficacy and better hERG safety profile compared to the first class CrtN inhibitor benzocycloalkane derivative 2. Except the excellent pigment inhibitory activity against wild-type S. aureus, 21b also showed excellent pigment inhibition against four pigmented MRSA strains. In addition, H2O2 killing and human whole blood killing assays proved 21b could sensitize S. aureus to be killed under oxidative stress conditions. Notably, the murine study in vivo validated the efficacy of 21b against pigmented S. aureus Newman, vancomycin-intermediate S. aureus Mu50 and linezolid-resistant S. aureus NRS271.
- Wei, Hanwen,Mao, Fei,Ni, Shuaishuai,Chen, Feifei,Li, Baoli,Qiu, Xiaoxia,Hu, Linghao,Wang, Manjiong,Zheng, Xinyu,Zhu, Jin,Lan, Lefu,Li, Jian
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p. 235 - 251
(2018/01/17)
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- Oxidative Functionalization of Cinnamaldehyde Derivatives: Control of Chemoselectivity by Organophotocatalysis and Dual Organocatalysis
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The catalytic and chemoselective oxidation of cinnamaldehyde derivatives having a C=C bond and formyl group was studied by using two organocatalysts. The visible-light-induced catalysis using rhodamine 6G as an organophotocatalyst promoted the methoxyhydr
- Yoshioka, Eito,Inoue, Maika,Nagoshi, Yuka,Kobayashi, Ayumi,Mizobuchi, Rumiko,Kawashima, Akira,Kohtani, Shigeru,Miyabe, Hideto
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p. 8962 - 8970
(2018/07/15)
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- Syntheses, characterization, solution behavior and catalytic activity of trans-[(guanidine)2PdX2] (X?=?Cl and OC(O)R; R?=?Me, Ph and tBu) in Heck–Mizoroki coupling reactions involving chloroarenes/methyl acrylate
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Trans-[{(ArNH)2C[dbnd]NAr}2PdX2] (Ar = 2,5-Me2C6H3; X = Cl (1) and OC(O)R; R = Me (2), Ph (3), and tBu (4)) were isolated in high yields and characterized by elemental analysis, IR, and NMR (1H and 13C) spectroscopy. The molecular structures of the aforementioned complexes were determined by single crystal X-ray diffraction which revealed trans syn anti-anti (1·CHCl3), trans anti anti-syn (2·CHCl3 and 3·C7H8) and trans anti anti-anti (4) stereochemistry in solid state. Complexes 2·CHCl3, 3·C7H8 and 4 contain a pair of R11(8) rings stabilized by an intramolecular N–H?O hydrogen bond between the guanidine ligand and the carboxylate moiety. The influence of shape and size of the anion upon the stereochemistry of the complexes in the solid state and in solution are discussed. VT 1H NMR spectroscopic studies carried out on samples of 1 and 3 revealed the presence of a mixture of two rotamers in solution which arise due to the restricted [dbnd]C–N(H)Ar single bond rotation of the guanidine ligand in both complexes. Complexes 1–4 were shown to be active catalysts even when used in 0.001 mol% in Heck–Mizoroki coupling reactions involving chlorobenzene and methyl acrylate. The scope of 1 in Heck–Mizoroki coupling reactions involving methyl acrylate and nine distinct chloroarenes were explored at 0.01 mol% which afforded the coupling products in 81?96% yields.
- Elumalai, Palani,Ujjval, Rishabh,Nethaji, Munirathinam,Thirupathi, Natesan
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p. 313 - 322
(2018/06/20)
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- Direct C-H Cyanation of Arenes via Organic Photoredox Catalysis
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Methods for the direct C-H functionalization of aromatic compounds are in demand for a variety of applications, including the synthesis of agrochemicals, pharmaceuticals, and materials. Herein, we disclose the construction of aromatic nitriles via direct C-H functionalization using an acridinium photoredox catalyst and trimethylsilyl cyanide under an aerobic atmosphere. The reaction proceeds at room temperature under mild conditions and has proven to be compatible with a variety of electron-donating and -withdrawing groups, halogens, and nitrogen- and oxygen-containing heterocycles, as well as aromatic-containing pharmaceutical agents.
- McManus, Joshua B.,Nicewicz, David A.
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supporting information
p. 2880 - 2883
(2017/03/11)
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- Diastereoselective Synthesis of trans-2,3-Diaryl(heteroaryl)-3,6-dihydropyrans by an Allylboration/Ring-Closing-Metathesis Sequence
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trans-2,3-Diaryl(heteroaryl)-dihydropyrans were synthesized by an allylboration/ring-closing-metathesis sequence, using allylboranes formed in situ from the corresponding allylic alcohols. Aryl(heteroaryl) substituents were thus installed diastereoselectively onto dihydropyran rings in a trans fashion. These disubstituted dihydropyrans were further transformed into monosaccharide-like tetrahydropyrans.
- Nocquet, Pierre-Antoine,Corbu, Andrei,Meerpoel, Lieven,Stansfield, Ian,Berthelot, Didier,Angibaud, Patrick,Cossy, Janine
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supporting information
p. 3343 - 3354
(2017/06/29)
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- Microwave-Assisted Synthesis of Phenylpropanoids and Coumarins: Total Synthesis of Osthol
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Herein we describe a one-pot microwave-assisted method for the synthesis of cinnamic acid and coumarin derivatives. The synthesis begins with an aldehyde synthon, and the chosen reaction conditions determine whether a cinnamic acid or coumarin derivative is formed. A regioselective Claisen rearrangement was also efficiently incorporated into the synthetic sequence to further increase the complexity of the product. Notably, this approach provides high product yields and selectivities without the need of a phenol protecting group.
- Konrádová, Daniela,Kozubíková, Hana,Dole?al, Karel,Pospí?il, Ji?í
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supporting information
p. 5204 - 5213
(2017/09/29)
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- Synthesis of olefins via a Wittig reaction mediated by triphenylarsine
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An arsine-mediated Wittig reaction for the synthesis of olefins is described. After heating triphenylarsine in the presence of an activated alkyl bromide for 30?min, the resulting arsonium salt condensed with aldehydes in as little as 5?min at room temperature, yielding the olefins in high yields. Aromatic, heteroaromatic, and alkyl aldehydes were all suitable substrates for this process.
- Li, Lun,Stimac, Jared C.,Geary, Laina M.
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supporting information
p. 1379 - 1381
(2017/03/17)
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- Oxidative coupling of Michael acceptors with aryl nucleophiles produced through rhodium-catalyzed C-C bond activation
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Utilizing rhodium catalysis, aryl nucleophiles generated via carbon-carbon single bond activation successfully undergo oxidative coupling with Michael acceptors. The reaction scope encompasses a broad range of nucleophiles generated from quinolinyl ketones as well as a series of electron deficient terminal alkenes, illustrating the broad potential of intersecting carbon-carbon bond activation with synthetically useful coupling methodologies. The demonstrated oxidative coupling produces a range of cinnamyl derivatives, several of which are challenging to prepare via conventional routes.
- Gregerson, Caroline E.,Trentadue, Kathryn N.,Phipps, Erik J. T.,Kirsch, Janelle K.,Reed, Katherine M.,Dyke, Gabriella D.,Jansen, Jacob H.,Otteman, Christian B.,Stachowski, Jessica L.,Johnson, Jeffrey B.
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p. 5944 - 5948
(2017/07/25)
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- An in Situ Generated Palladium on Aluminum Oxide: Applications in Gram-Scale Matsuda-Heck Reactions
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In situ generated palladium on aluminum oxide provides an active catalytic system for Matsuda-Heck reactions in gram-scale. The novel catalyst proceeded through a significantly higher catalytic activity compared to the classical Pd/C system. Based on the high catalytic activity the first α,β,β-triarylation of methyl acrylate in good yields could be provided in one-step.
- Pape, Simon,Dauk?ait?, Lauryna,Lucks, Sandra,Gu, Xiaoting,Brunner, Heiko
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supporting information
p. 6376 - 6379
(2016/12/23)
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- Palladium supported on poly (ionic liquid) entrapped magnetic nanoparticles as a highly efficient and reusable catalyst for the solvent-free Heck reaction
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A novel palladium catalyst supported on poly (1-aminoethyl-3-vinylimidazolium bromide) entrapped magnetic nanoparticles (Pd/Fe3O4@PIL-NH2) was prepared. The catalyst was characterized by TEM, FT-IR, VSM, XRD, and XPS. The Pd loading on the catalyst was 0.23 wt % as measured by AAS. The catalyst showed excellent activity for the solvent-free Heck reaction. In addition, this novel Pd catalyst could be simply recovered with an external magnet and run five times with excellent yields achieved.
- Liu, Wendong,Wang, Dongfang,Duan, Yajing,Zhang, Yahui,Bian, Fengling
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supporting information
p. 1784 - 1789
(2015/03/30)
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- Matsuda-Heck reaction with arenediazonium tosylates in water
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An environmentally friendly Matsuda-Heck reaction with arenediazonium tosylates has been developed for the first time. A range of alkenes was arylated in good to quantitative yields in water. The reaction is significantly accelerated when carried out under microwave heating. The arylation of haloalkylacrylates with diazonium salts has been implemented for the first time.
- Kutonova, Ksenia V.,Trusova, Marina E.,Stankevich, Andrey V.,Postnikov, Pavel S.,Filimonov, Victor D.
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supporting information
p. 358 - 362
(2015/06/16)
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- Phospholane-catalyzed wittig reaction
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We identified 2-phenylisophosphindoline 2-oxide as a suitable and potentially tunable catalyst for the catalytic Wittig reaction of aldehydes with activated organohalides. This catalyst was obtained by a straightforward two-step synthesis. Trimethoxysilane proved to be an efficient reducing agent for the in situ generation and regeneration of the catalyst from the corresponding phosphane oxide. Sodium carbonate was identified as a suitable base for the transformation. It is noteworthy that the particle size of the sodium carbonate had a tremendous effect on the outcome of the reaction. Under the optimized reaction conditions, 23 aldehydes were converted into the corresponding alkenes in high isolated yields of up to 88%. Moreover, an asymmetric catalytic Wittig reaction was performed for the desymmetrization of a prochiral diketone.
- Werner, Thomas,Hoffmann, Marcel,Deshmukh, Sunetra
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p. 3286 - 3295
(2015/05/20)
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- Scope and Limitation of the Microwave-Assisted Catalytic Wittig Reaction
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We have developed a microwave-assisted catalytic Wittig reaction. In this paper, we give full account of the scope and limitations of this reaction. A screening of various commercially available phosphine oxides as precatalysts revealed Bu3P=O to be the most promising candidate. We tested 10 silanes for the in situ reduction of the phosphine oxide to generate Bu3P as the actual catalyst. Different epoxides were tested as masked bases. In this context, cyclohexene oxide as well as butylene oxide proved to be suitable. The reaction could be carried out at 125 C, but higher yields and E/Z selectivities were obtained at 150 °C. Under the optimised reaction conditions, more than 40 examples for the conversion of various aldehydes into the corresponding alkenes are reported. The products were obtained in yields of up to 88 with high E selectivities. Moreover, we also describe the further screening of several chiral phosphines as catalysts for the microwave-assisted enantioselective catalytic Wittig reaction. The scope and limitations of the microwave-assisted catalytic Wittig reaction have been evaluated with respect to the catalyst, silane, solvent, reaction conditions, and substrates.
- Hoffmann, Marcel,Deshmukh, Sunetra,Werner, Thomas
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p. 4532 - 4543
(2015/07/27)
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- Mild synthesis of mesoporous silica supported ruthenium nanoparticles as heterogeneous catalysts in oxidative Wittig coupling reactions
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A new efficient approach for the in situ synthesis of anchored ruthenium nanoparticles (RuNP) in three different kinds of mesoporous silica materials, MCM-41, SBA-15 and HMS, has been developed. Solids have been synthesized under very mild conditions from RuCl3·H2O salt reduced in one hour at room temperature in the mesoporous silicas previously grafted with aminopropyltriethoxysilane (APTES). Well-dispersed ruthenium nanoparticles, with an average size of 3 nm, anchored into the silica network by the APTES were obtained. These materials, with a molar ratio of Si/Ru = 40, were found to be catalytically active and selective in the alcohol oxidation-Wittig olefination. Interestingly, while the reaction occurs from the alcohol, control experiments suggest that the aldehyde (the common Wittig substrate) is not involved. The Royal Society of Chemistry.
- Carrillo, Adela I.,Schmidt, Luciana C.,Marin, M. Luisa,Scaiano, Juan C.
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supporting information
p. 435 - 440
(2014/02/14)
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- Pd nanoparticles in the thermoregulated ionic liquid and organic biphasic system: An efficient and recyclable catalyst for heck reaction
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A thermoregulated ionic liquid and organic biphasic system composed of ionic liquid [CH3(OCH2CH2)16N +Et3][CH3SO3 -] (IL PEG750) with ILPEG750-stabilized Pd nanoparticles and organic solvents, which allows for not only a highly efficient homogeneous catalytic reaction, but also an easy biphasic separation and reuse of catalyst attributed to the thermoregulated phase-transition property of the system, was employed for Heck reaction. The ILPEG750-stabilized Pd nanoparticle catalyst exhibited high efficiency, more importantly, after reaction the Pd nanoparticle catalyst could be separated from products by simple phase separation and recycled for six times without evident loss of activity. Graphical Abstract: A thermoregulated ionic liquid and organic biphasic system containing [CH3(OCH2CH2)16N +Et3][CH3SO 3 - ] (ILPEG750)-stabilized Pd nanoparticles was applied to Heck reaction for the first time. The Pd nanoparticle catalyst exhibited high efficiency and good recyclability.[Figure not available: see fulltext.]
- Zeng, Yan,Wang, Yanhua,Xu, Yicheng,Song, Ying,Jiang, Jingyang,Jin, Zilin
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p. 200 - 205
(2013/03/13)
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- A robust first-pass protocol for the heck-mizoroki reaction
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The Heck-Mizoroki (HM) reaction is one of the most widely used C-C bond-forming methods of contemporary synthesis. Notwithstanding this, these reactions frequently require significant optimization before efficient transformations can be obtained. We describe here the results of a study that aimed to establish a generic experimental protocol for HM reactions which enables acceptable yields from first-pass experiments. The methodology utilizes readily available stable catalysts and can be applied to a broad range of coupling partners.
- Murray, Paul M.,Bower, John F,Cox, David K,Galbraith, Ewan K,Parker, Jeremy S,Sweeney, Joseph B.
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p. 397 - 405
(2013/04/24)
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- One-pot access to cinnamates via direct oxidative c-h transformation of allylarenes
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A highly selective combination of ruthenium complex and oxidant, which catalyzes the oxidative C-H esterification of allylarenes to the corresponding bis-(E)-cinnamates and (E)-cinnamates, is described. The one-pot route was carried out by olefinic migration of allylarenes with RuCl2(PPh 3)3 and DDQ-mediated allylic oxidation of the resulting internal alkenes with various alcohols in good yields. Georg Thieme Verlag Stuttgart · New York.
- Chang, Meng-Yang,Lin, Shin-Ying,Chan, Chieh-Kai
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p. 487 - 490
(2013/04/10)
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- Synthesis of new N-(arylcyclopropyl)acetamides and N-(arylvinyl)acetamides as conformationally-restricted ligands for melatonin receptors
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N-(Arylcyclopropyl)acetamides and N-(arylvinyl)acetamides or methyl ureas have been prepared as constrained analogues of melatonin. The affinity of these new compounds for chicken brain melatonin receptors and recombinant human MT1 and MT2 receptors was evaluated using 2-[ 125I]-iodomelatonin as radioligand. Strict ethylenic or cyclopropyl analogues of the commercialized agonist agomelatine (Valdoxan) were equipotent to agomelatine in binding bioassays. However, the ethylenic analogue was more effective than the cyclopropyl one in the melanophore aggregation bioassay, but was still less potent than the disubstituted 2,7-dimethoxy- naphtalenic compounds.
- Morellato, Laurence,Lefas-Le Gall, Marie,Langlois, Michel,Caignard, Daniel-Henri,Renard, Pierre,Delagrange, Philippe,Mathe-Allainmat, Monique
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p. 430 - 434
(2013/02/23)
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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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- The ligand and base-free Pd-catalyzed oxidative Heck reaction of arylboronic acids and olefins
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Highly effective Pd-catalyzed Heck-type oxidative couplings between arylboronic acids and terminal olefins were reported. It is noteworthy that such reactions could be carried out in the absence of the base and the ligand.
- Sun, Peng,Zhu, Yan,Yang, Hailong,Yan, Hong,Lu, Linhua,Zhang, Xiang,Mao, Jincheng
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supporting information; experimental part
p. 4512 - 4515
(2012/07/14)
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- Pd nanosized particles supported on chitosan and 6-deoxy-6-amino chitosan as recyclable catalysts for Suzuki-Miyaura and Heck cross-coupling reactions
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Several chitosan and 6-deoxy-6-amino chitosan-Schiff base ligands (1-4) were prepared by condensation of either 2-pyridinecarboxaldehyde or 2-(diphenylphosphino)benzaldehyde with the amino group(s) on chitosan and its derivative (6-deoxy-6-amino chitosan). The supported ligands were reacted with [PdCl2(COD)] to form chitosan-supported PdII catalysts (5-8). All the supported catalysts were air- and moisture-stable and have been characterized using elemental analysis, ICP-MS, UV-vis, FT-IR, PXRD, TGA, 31P solid state NMR and TEM. As models for the heterogenized catalysts (5 and 6), mononuclear PdII complexes (9 and 10) were also prepared via the Schiff-base condensation reaction of 1,3,4,6-tetra-O-acetyl- β-d-glucosamine hydrochloride to form 1,3,4,6-tetra-O-acetyl-β-d- glucos-2-pyridylimine and 1,3,4,6-tetra-O-acetyl-β-d-glucos-2- (diphenylphosphino)imine which were subsequently reacted with [PdCl 2(COD)]. Complexes (9 and 10) and their precursors were characterized by 1H and 31P NMR, UV-vis, FT-IR spectroscopy and elemental analysis. Catalytic Suzuki-Miyaura and Heck carbon-carbon cross-coupling reactions were carried out using the supported Pd catalysts and their mononuclear analogues. The immobilized and homogeneous catalysts showed high activity for both the Suzuki-Miyaura and Heck cross-coupling reactions in organic and aqueous media. Homogeneous catalysts (9 and 10) decomposed during the first run, while the supported catalysts could be recycled and reused up to five times.
- Makhubela, Banothile C.E.,Jardine, Anwar,Smith, Gregory S.
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scheme or table
p. 231 - 241
(2011/11/07)
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- Emission wavelength prediction of a full-color-tunable fluorescent core skeleton, 9-aryl-1,2-dihydropyrrolo[3,4-b]indolizin-3-one
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In this paper we report on a novel fluorescent core skeleton, 9-aryl-1,2-dihydropyrrolo[3,4-b]indolizin-3-one, which we named Seoul-Fluor, having tunable and predictable photophysical properties. Using a concise and practical one-pot synthetic procedure, a 68-member library of new fluorescent compounds was synthesized with diverse substituents. In Seoul-Fluor, the electronic characteristics of the substituents, as well as their positional changes, have a close correlation with their photophysical properties. The systematic perturbation of electronic densities on the specific positions of Seoul-Fluor, guided with the Hammett constant, allows emission wavelength tunability covering the full color range. On the basis of these observations and a computational analysis, we extracted a simple first-order correlation of photophysical properties with the theoretical calculation and accurately predicted the emission wavelength of Seoul-Fluors through the rational design. In this study, we clearly demonstrate that Seoul-Fluor can provide a powerful gateway for the generation of desired fluorescent probes without the need for a tiresome synthesis and trial-and-error process.
- Kim, Eunha,Koh, Minseob,Lim, Byung Joon,Park, Seung Bum
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supporting information; experimental part
p. 6642 - 6649
(2011/06/19)
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- In situ generated bulky palladium hydride complexes as catalysts for the efficient isomerization of olefins. Selective transformation of terminal alkenes to 2-alkenes
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Application of an in situ generated bulky palladium(II) hydride catalyst obtained from a 1:1:1 mixture of Pd(dba)2, P(tBu)3, and isobutyryl chloride provides an efficient protocol for the isomerization and migration of a variety of olefins. In addition to the isomerization of (Z)- to (E)-olefins, the conjugative migration of allylbenzenes, allyl ethers, and amines was effectively achieved in near-quantitative yields and with excellent functional group tolerance. Catalyst loadings in the range of 0.5-1.0 mol % were typically applied, but even loadings as low as 0.25 mol % could be achieved when the reactions were performed under neat conditions. More interestingly, the investigated catalyst proved to be selective for converting terminal alkenes to 2-alkenes. This one-carbon migration process for monosubstituted olefins provides an alternative catalyst, which bridges the gap between the allylation and propenylation/vinylation protocols. Several substrates, including homoallylic alcohols and amines, were selectively transformed into their corresponding 2-alkenes, and examples using enantiomerically enriched substrates provided products without epimerization at the allylic stereogenic carbon centers. Finally, some mechanistic investigations were undertaken to understand the nature of the active in situ generated Pd-H catalyst. These studies revealed that the catalytic system is highly dependent on the large steric demand of the P(tBu)3 ligand. The use of an alternative ligand, cataCXium PinCy, also proved effective for generating an active catalyst, and it was demonstrated in some cases to display better selectivity for the one-carbon shifts of terminal olefins. A possible intermediate involved in the preparation of the active catalyst was characterized by its single-crystal X-ray structure, which revealed a monomeric tricoordinated palladium(II) acyl complex, bearing a chloride ligand.
- Gauthier, Delphine,Lindhardt, Anders T.,Olsen, Esben P. K.,Overgaard, Jacob,Skrydstrup, Troels
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supporting information; experimental part
p. 7998 - 8009
(2010/08/04)
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- Sodium 2-(2-pyridin-3-ylethylamino)sulfonate: an efficient ligand and base for palladium-catalyzed Heck reaction in aqueous media
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The first successful Pd(OAc)2, N-donor ligand and base mediated Heck coupling reaction of aryl halides and alkenes in water is described. The corresponding Heck products were obtained in good to excellent yields.
- Pawar, Shivaji S.,Dekhane, Deepak V.,Shingare, Murlidhar S.,Thore, Shivaji N.
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p. 4252 - 4255
(2008/09/21)
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- Templating photodimerization of trans-cinnamic acid esters with a water-soluble Pd nanocage
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A water-soluble octahedral Pd nanocage acting as a reaction vessel templates the photodimerization of substituted trans-cinnamic acid methyl esters in water. Irradiation of the host-guest complexes of trans-cinnamic acid methyl esters with the Pd nanocage resulted in selective formation of a syn head-head dimer in addition to the corresponding cis isomer. These results suggest that the guest molecules are preoriented in a selective fashion with the hydrophilic ester group facing water and the hydrophobic aryl group tucked within the cavity of the host. Such an orientation occurs at the hydrophobic-hydrophilic interface between the nanocage exterior and interior. Weak intermolecular C-H-π and π-π interactions between the host and the guest(s) are likely to be responsible for the lack of mobility of the reactant olefins during their short excited-state lifetime.
- Karthikeyan,Ramamurthy
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p. 452 - 458
(2007/10/03)
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- Wittig reactions in water media employing stabilized ylides with aldehydes. Synthesis of α,β-unsaturated esters from mixing aldehydes, α-bromoesters, and Ph3P in aqueous NaHCO3
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(Chemical Equation Presented) Water is demonstrated to be an effective medium for the Wittig reaction over a wide range of stabilized ylides and aldehydes. Despite sometimes poor solubility of the reactants, good chemical yields normally ranging from 80 to 98% and high E-selectivities (up to 99%) are achieved, and the rate of the reactions in water is unexpectedly accelerated. The efficiency of water as a medium in the Wittig reaction is compared to conventional organic solvents ranging from carbon tetrachloride to methanol. The aqueous Wittig reaction works best when large hydrophobic entities are present, such as aromatic, heterocyclic aromatic carboxaldehydes, and long-chain aliphatic aldehydes with triphenylphosphoranes. The E/Z-isomeric ratio of the Wittig products appears dependent on the electron-accepting/donating capacity and the location of the substituents present in the aromatic ring. The effect of additives, such as benzoic acid, LiCl, and sodium dodecyl sulfate (SDS), on the Wittig reaction has been explored. The Wittig reaction can also be conducted in the presence of acidic entities, such as phenols and carboxylic acids. In addition, large α-substituents in the aliphatic aldehydes do not jeopardize the reaction. It is also demonstrated that hydrates of aldehydes can be used directly in the aqueous Wittig reaction as substrates. The scope of the aqueous Wittig reaction is extended to 24 examples of one-pot mixtures of Ph3P, α-bromoesters, and aldehydes in sodium bicarbonate solution (at 20°C for 40 min to 3 h) to provide Wittig products of up to 99% yield and up to 98% E-selectivity. Since water is inexpensive, extremely easy to handle, and represents no environmental concerns, it should be considered a possible medium for new organic reactions.
- El-Batta, Amer,Jiang, Changchun,Zhao, Wen,Anness, Robert,Cooksy, Andrew L.,Bergdahl, Mikael
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p. 5244 - 5259
(2008/02/07)
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- Inhibition of chitin synthases and antifungal activities by 2′-benzoyloxycinnamaldehyde from Pleuropterus ciliinervis and its derivatives
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In the course of search for potent chitin synthase inhibitors from natural resources, a novel chitin synthases inhibitor, 2′-benzoyloxycinnamaldehyde (2′-BCA) (I), was isolated from the aerial parts of Pleuropterus ciliinervis NAKAI. 2′-BCA inhibited chit
- Kang, Tae Hoon,Hwang, Eui Il,Yun, Bong Sik,Park, Ki Duk,Kwon, Byoung Mog,Shin, Chul Soo,Kim, Sung Uk
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p. 598 - 602
(2008/02/02)
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- Solvent-free, open-vessel microwave-promoted Heck couplings: From the mmol to the mol scale
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The rapid, microwave-promoted Heck coupling of aryl iodides in open reaction vessels is presented and scale-up of the reactions to the mol scale demonstrated. Reactions are performed using 0.1 mol% palladium acetate as the catalyst, sodium carbonate and tributylamine as bases and tetrabutylammonium bromide as an additive. Georg Thieme Verlag Stuttgart.
- Leadbeater, Nicholas E.,Williams, Victoria A.,Barnard, Thomas M.,Collins Jr., Michael J.
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p. 2953 - 2958
(2008/02/13)
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- Diastereoselective method of preparing olefins by means of the horner-wadsworthemmons reaction, comprising the addition of a tris-(polyoxaalkyl)-amine sequestering agent
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The invention relates to a process for the diastereoselective preparation of olefins via the Homer-Wadsworth-Emmons reaction, which consists in reacting at low temperature a phosphonate with a carbonyl derivative in the presence of a base in a suitable solvent, characterized in that a tris(polyoxaalkyl)amine sequestering reagent of formula (I): N—[CHR1—CHR2—O—(CHR3—CHR4—O)n—R5]3 (I), wherein: n is an integer between 0 and 10; R1, R2, R3 and R4 may be identical or different, and represent a hydrogen atom or an alkyl radical containing from 1 to 4 carbon atoms; R5 represents a hydrogen atom, an alkyl or cycloalkyl radical containing up to 12 carbon atoms, a phenyl radical or a radical of formula —CμH2μ-Φ, or CmH2m+1-Φ-, with m being an integer between 1 and 12 and Φ being a phenyl radical; is added in an amount that is sufficient to increase the diastereoselectivity of the olefin.
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Page/Page column 5-6
(2010/11/08)
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- Assembled catalyst of palladium and non-cross-linked amphiphilic polymer ligand for the efficient heterogeneous Heck reaction
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The efficient heterogeneous Heck reaction was achieved by a new networked and supramolecular catalyst PdAS-V (1b). Employing of PdAS-V in 5.0×10-5molequiv. efficiently progressed the heterogeneous Heck reaction of a series of aryl iodides with acrylates, styrenes and acrylic acid. PdAS-V was successfully recycled five times without any decrease in its activity, and showed good stability in toluene and water, and hence the Heck reaction was efficiently performed in both reaction media. The use of 8.0×10-7molequiv. of PdAS-V resulted in the coupling product in 92% yield with the turnover number (TON) and the turnover frequency (TOF) of PdAS-V reached up to 1,150,000 and 12,000, respectively. The efficient synthesis of resveratrol was achieved via the PdAS-V-promoted Heck reaction.
- Yamada, Yoichi M. A.,Takeda, Koji,Takahashi, Hideyo,Ikegami, Shiro
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p. 4097 - 4105
(2007/10/03)
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- A catalytic asymmetric synthesis of chiral glycidic acid derivatives through chiral dioxirane-mediated catalytic asymmetric epoxidation of cinnamic acid derivatives
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A novel and practical asymmetric synthesis of chiral glycidic acid derivatives involving methyl (2R,3S)-3-(4-methoxyphenyl)glycidate ((2R,3S)-2a), a key intermediate for diltiazem hydrochloride (1), was developed. Treatment of methyl (E)-4-methoxycinnamate ((E)-3a) with chiral dioxirane, generated in situ from a catalytic amount (5 mol %) of an 11-membered C2-symmetric binaphthyl ketone (R)-7a, provided (2R,3S)-2a in 92% yield and 80% ee. Other cinnamic acid esters and amides were epoxidized by the use of the same procedure to give the corresponding chiral glycidic acid derivatives with up to 95% yield and 92% ee. Higher enantioselectivities in the asymmetric epoxidation of (E)-cinnamates than that of (E)-stilbene derivatives were observed and were proposed to be attributed to a dipole-dipole repulsion between oxygen atoms of an ester group in the cinnamates and those of the lactone moieties in the binaphthyl dioxirane.
- Imashiro, Ritsuo,Seki, Masahiko
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p. 4216 - 4226
(2007/10/03)
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- Palladium-Imidazolium Carbene Catalyzed Mizoroki-Heck Coupling with Aryl Diazonium Ions
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(Matrix Presented) Catalyst formed from N,N-bis(2,6-diisopropylphenyl)dihydroimidazolium chloride and palladium(II) acetate (2 mol %) was used, without added base, to efficiently produce Heck coupled products with olefins and aryl diazonium tetrafluoroborate substrates. The reactions were performed at room temperature, giving product in 2-4 h with 80-90% yields for isolated materials. Diazonium ions, formed in situ directly from anilines, also couple under these conditions.
- Andrus, Merritt B.,Song, Chun,Zhang, Jiuqing
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p. 2079 - 2082
(2007/10/03)
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- Pd-Cu-Exchanged montmorillonite K10 clay: An efficient and reusable heterogeneous catalyst for vinylation of aryl halides
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Palladium and copper exchanged montmorillonite K10 clay has been found to catalyse very efficiently the reaction between aryl halides (X = Br, I) and acrylates, and styrenes affording alkyl (E)-cinnamates and (E)-stilbenes respectively in high yields.
- Ramchandani,Uphade,Vinod,Wakharkar,Choudhary,Sudalai
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p. 2071 - 2072
(2007/10/03)
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- Palladium complexes supported on hybrid organic-inorganic zirconium phosphite: Selectivity in the Heck reaction
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Supported palladium complex on zirconium phosphite-phosphonate was made from triphenylphosphine phosphonic acid. The supported catalyst showed significant selectivity in the competitive Heck reaction between iodobenzene and different iodobenzoates. The re
- Villemin, Didier,Jaffres, Paul-Alain,Nechab, Belkacem,Courivaud, Frederic
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p. 6581 - 6584
(2007/10/03)
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- Synthesis and biological activity of cinnamaldehydes as angiogenesis inhibitors
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A series of 2-hydroxycinnamaldehyde derivatives was synthesized for examing a structure-activity relationship for inhibition of angiogenesis. The anti-angiogenic effects of 2'-substituted cinnamaldehydes and related analogs were determined in a chick embryo chorioallantoic membrane assay system.
- Kwon, Byoung-Mog,Lee, Seung-Ho,Cho, Young-Kwon,Bok, Song-Hae,So, Seung-Ho,Youn, Mi-Ran,Chang, Soo-Ik
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p. 2473 - 2476
(2007/10/03)
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- Derivatives of 2-arylcyclopropylamine: Synthesis and interactions with 5-HT1A receptors
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A series of cis- and trans-derivatives of 2-aryl-N,N-dipropylcyclopropylamines and 1-(2-arylcyclopropyl)-N,N-dipropylmethylamines were synthesized and evaluated for affinity at the 5-HT1A receptor. The key step in the syntheses was a cyclopropanation of cis- and trans-3-arylpropenoic esters with diazomethane which proceeds with retention of the stereochemistry. cis-1-[2-(3-Methoxyphenyl)cyclopropyl]-N,N-dipropylmethylamine (32) had the highest 5-HT1A-receptor affinity (Ki= 58 nM) of the novel derivatives.
- Appelberg, Ulf,Mohell, Nina,Hacksell, Uli
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p. 415 - 420
(2007/10/03)
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- Synthesis of new 3,4-disubstituted pyrrolidines as thromboxane A2/prostaglandin H2 (TP) receptor antagonists
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The synthesis and TP-receptor antagonistic activity of a series of 3,4-disubstituted pyrrolidines is described. The sulfonamide 1h was the most potent TP-receptor antagonist in this series with a pA2 value of 9.5 in isolated guinea pig trachea.
- Dubuffet, Thierry,Muller, Olivier,Simonet, Serge S.,Descombes, Jean-Jacques,Laubie, Michel,Verbeuren, Tony J.,Lavielle, Gilbert
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p. 349 - 352
(2007/10/03)
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- Photocyclization of Ortho-Substituted Cinnamic Acids
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Mono and di (i.e. 2,6) o-chloro- and o-methoxycinnamic acids undergo photocyclization to give the corresponding coumarins.The reaction occurs in aqueous and organic media, with a prototypical reaction giving evidence of being favored at pH > 6.Cyclization of the dimethoxy acid is relatively inefficient (Φ for the PSS = 0.0015), and a photostationary state of the cis/trans acids is formed early into the reaction.The photocyclization of the dichloro analog is more efficient (Φ exceeds 0.04) and therefore time dependent since product formation competes with trans/cis isomerization.Methyl o-chlorocinnamate also photocyclizes (Φ for the PSS = 0.0022 in acetonitrile) but the o-methoxy ester is virtually photoinert.It is proposed that the acid photocyclizes through intramolecular nucleophilic attack by the carboxylate group followed by heterolysis of the nucleofuge.Methyl o-chlorocinnamate appears to photocyclize through a cycloaddition of the carbonyl group followed by homolysis of the Cl and Me moieties, possibly through the intermediacy of a ketene as proposed by earlier workers.
- Terrian, Deborah L.,Mohammad, Taj,Morrison, Harry
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p. 1981 - 1984
(2007/10/02)
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- Electrocyclization of 3-azahexa-1,3,5-trienes: A convenient iminophosphorane-mediated preparation of 4-arylpyridines
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Aza Wittig reaction of iminophosphoranes 1, derived from α-azido- α,β-unsaturated esters and β-arylpropenals 2 leads to 4-arylpyridines in moderate to good yields.
- Molina, Pedro,Pastor, Aurelia,Vilaplana, Maria Jesus
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p. 3773 - 3776
(2007/10/02)
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