- The caffeic acid moiety plays an essential role in attenuating lipid accumulation by chlorogenic acid and its analogues
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Chlorogenic acid (5-caffeoylquinic, CA) possesses distinct hypolipidemic properties in vivo and in vitro, yet the structure-activity relationship (SAR) of CA on lipid metabolism remains unknown. To achieve this aim, we designed and synthesized two sets of CA analogues and evaluated their efficacies to prevent oleic acid (OA)-elicited lipid accumulation in HepG2 cells. Blockage of all hydroxyl and carboxyl groups on the quinic acid moiety did not deteriorate the hypolipidemic effect of CA while blockage of all phenolic hydroxyl groups on the caffeic acid moiety abolished the activity of CA. Further replacement of the quinic acid moiety with cyclohexane and modification of individual phenolic hydroxyl groups on the caffeic acid moiety showed that the phenolic-hydroxyl-reserved analogues displayed a more potent hypolipidemic effect than CA, whereas the analogue with no phenolic hydroxyl displayed little effect on the OA-elicited lipid accumulation. In accordance, the modulating effects of CA on the transcription of the lipogenic gene sterol-regulatory element binding protein (SREBP)1c/1a, acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS) and peroxisome proliferator-activated receptor α (PPARα) were also abolished when the phenolic hydroxyl groups on the caffeic acid moiety were blocked. Our results suggest that the phenolic hydroxyl on the caffeic acid moiety is vital for the lipid-lowering activity of CA.
- Cao, Xiaoxue,Wu, Chongming,Tian, Yu,Guo, Peng
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Read Online
- 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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- Mizoroki-Heck Reaction of Unstrained Aryl Ketones via Ligand-Promoted C-C Bond Olefination
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Mizoroki-Heck reaction of unstrained aryl ketone with acrylate/styrene is accomplished via palladium-catalyzed ligand-promoted C-C bond cleavage. Various (hetero)aryl ketones are compatible in the reaction, affording the alkene product in good to excellent yields. Further applications in the late-stage olefination of some drugs, natural products, and fragrance-derived aryl ketones demonstrate the synthetic utility of this protocol. By employing ketone as both the directing group and the leaving group, 1,2-bifunctionalization is achieved via sequential ortho-C-H alkylation/ipso-Heck olefination.
- Wang, Mei-Ling,Xu, Hui,Li, Han-Yuan,Ma, Biao,Wang, Zhen-Yu,Wang, Xing,Dai, Hui-Xiong
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p. 2147 - 2152
(2021/04/05)
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- Ruthenium-Catalyzed Oxidative Cross-Coupling Reaction of Activated Olefins with Vinyl Boronates for the Synthesis of (E, E)-1,3-Dienes
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An oxidative cross-coupling reaction between activated olefins and vinyl boronate derivatives has been developed for the highly stereoselective construction of synthetically useful (E,E)-1,3-dienes. The highlight of this reaction is that exclusive stereoselectivity (only E,E-isomer) was achieved from a base-free, ligand-free, and mild catalytic condition with a less expensive [RuCl2(p-cymene)]2 catalyst.
- Dethe, Dattatraya H.,Beeralingappa, Nagabhushana C.,Uike, Amar
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p. 3444 - 3455
(2021/02/16)
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- Benzyne-Mediated Esterification Reaction
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A benzyne-mediated esterification of carboxylic acids and alcohols under mild conditions has been realized, which is made possible via a selective nucleophilic addition of carboxylic acid to benzyne in the presence of alcohol. After a subsequent transesterification with alcohol, the corresponding esters can be produced efficiently. This benzyne-mediated protocol can be used on the modification of Ibuprofen, cholesterol, estradiol, and synthesis of nandrolone phenylpropionate. In addition, benzyne can also be used to promote lactonization and amidation reaction.
- Li, Yang,Shi, Jiarong,Zhao, Jinlong
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supporting information
p. 7274 - 7278
(2021/10/01)
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- Novel multi-dentate phosphines for Pd-catalyzed alkoxycarbonylation of alkynes promoted by H2O additive
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A series of novel multi (bi-/tri-/tetra-)-dentate phosphines with good robustness against water and oxygen were synthesized and fully characterized. It was found that the developed ionic tri-dentate phosphine (L2′) enabled Pd-catalyzed alkoxycarbonylation of alkynes most efficiently while H2O was used as an additive instead of acid. As for L2′, its unique steric configuration with two types of potential P-P chelation modes (P?P distance of 4.31 ? and 4.36 ? respectively) to Pd-centre rendered the corresponding Pd-catalyst high activity and good stability for alkoxycarbonylation of alkynes. The in situ FT-IR analysis also verified that the formation and stability of Pd–H active species were greatly facilitated with the presence of L2′ as well as H2O additive. In addition, as an ionic phosphine, L2′ based PdCl2(MeCN)2 system immobilized in RTIL of [Bmim]NTf2 could be recycled for 7 runs without obvious activity loss or metal leaching.
- Yang, Da,Liu, Lei,Wang, Dong-Liang,Lu, Yong,Zhao, Xiao-Li,Liu, Ye
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p. 236 - 244
(2019/02/19)
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- Bioactivity and structure–activity relationship of cinnamic acid derivatives and its heteroaromatic ring analogues as potential high-efficient acaricides against Psoroptes cuniculi
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A series of cinnamic acid derivatives and its heteroaromatic ring analogues were synthesized and evaluated for acaricidal activity in vitro against Psoroptes cuniculi, a mange mite. Among them, eight compounds showed the higher activity with median lethal concentrations (LC50) of 0.36–1.07 mM (60.4–192.1 μg/mL) and great potential for the development of novel acaricidal agent. Compound 40 showed both the lowest LC50 value of 0.36 mM (60.4 μg/mL) and the smallest median lethal time (LT50) of 2.6 h at 4.5 mM, comparable with ivermectin [LC50 = 0.28 mM (247.4 μg/mL), LT50 = 8.9 h], an acaricidal drug standard. SAR analysis showed that the carbonyl group is crucial for the activity. The type and chain length of the alkoxy in the ester moiety and the steric hindrance near the ester group significantly influence the activity. The esters were more active than the corresponding thiol esters, amides, ketones or acids. Replacement of the phenyl group of cinnamic esters with α-pyridyl or α-furanyl significantly increase the activity. Thus, a series of cinnamic esters and its heteroaromatic ring analogues with excellent acaricidal activity emerged.
- Chen, Dong-Dong,Zhang, Bing-Yu,Liu, Xiu-Xiu,Li, Xing-Qiang,Yang, Xin-Juan,Zhou, Le
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p. 1149 - 1153
(2018/03/05)
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- Synthesis of (E)-cinnamyl ester derivatives via a greener Steglich esterification
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Cinnamic acid derivatives are known antifungal, antimicrobial, antioxidant, and anticancer compounds. We have developed a facile and mild methodology for the synthesis of (E)-cinnamate derivatives using a modified Steglich esterification of (E)-cinnamic acid. Using acetonitrile as the solvent, rather than the typical chlorinated solvent, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) as the coupling agent enables ester conversion in 45 min with mild heating (40–45 °C) and an average yield of 70% without need for further purification. These conditions were used to couple (E)-cinnamic acid with 1° and 2° aliphatic alcohols, benzylic and allylic alcohols, and phenols. This work demonstrates a facile and greener methodology for Steglich esterification reactions.
- Lutjen, Andrew B.,Quirk, Mackenzie A.,Barbera, Allycia M.,Kolonko, Erin M.
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p. 5291 - 5298
(2018/05/04)
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- General and Efficient Intermolecular [2+2] Photodimerization of Chalcones and Cinnamic Acid Derivatives in Solution through Visible-Light Catalysis
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[2+2] Photocycloaddition, for example, the dimerization of chalcones and cinnamic acid derivatives, is a unique strategy to construct cyclobutanes, which are building blocks for a variety of biologically active molecules and natural products. However, most attempts at the above [2+2] addition have focused on solid-state, molten-state, or host–guest systems under ultraviolet-light irradiation in order to overcome the competition of facile geometric isomerization of nonrigid olefins. We report a general and simple method to realize the intermolecular [2+2] dimerization reaction of these acyclic olefins to construct cyclobutanes in a highly regio- and diastereoselective manner in solution under visible light, which provides an efficient solution to a long-standing problem.
- Lei, Tao,Zhou, Chao,Huang, Mao-Yong,Zhao, Lei-Min,Yang, Bing,Ye, Chen,Xiao, Hongyan,Meng, Qing-Yuan,Ramamurthy, Vaidhyanathan,Tung, Chen-Ho,Wu, Li-Zhu
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p. 15407 - 15410
(2017/11/13)
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- An ionic liquid catalyzed probase method for one-pot synthesis of α,β-unsaturated esters from esters and aldehydes under mild conditions
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A one-pot synthesis of α,β-unsaturated esters from unactivated esters and aldehydes using strong bases, such as sodium alkoxide and potassium tert-butoxide, was reported. However, the ionic liquid (IL) catalyzed probase method for producing α,β-unsaturated esters was not reported until now. In this work, a series of ILs with fluoride anions were firstly prepared and used as catalysts in combination with the probase N,O-bis(trimethylsilyl) acetamide (BSA) for the α,β-unsaturated esters synthesis. This process could also be promoted through the introduction of another IL with Lewis acid sites. The yield and selectivity of the product could reach up to 84.2% and 95.0%, respectively, when [Bmim]F was used in combination with [Bmim]Cl/AlCl3 (the molar fraction of AlCl3 is 0.67). The mechanism investigation through GC-MS indicates that BSA would convert into onium amide, which acted as a strong base for α-H abstraction, with the catalysis of [Bmim]F. Meanwhile, [Bmim]Cl/AlCl3 played an important role in the condensation step between enolates and aldehydes. On the basis of mechanism insights, kinetic and thermodynamic studies were also carried out for a better understanding of this new route.
- Wang, Gang,Xu, Yiming,Zhang, Suojiang,Li, Zengxi,Li, Chunshan
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p. 4838 - 4848
(2017/10/23)
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- Bioactivity and structure-activity relationship of cinnamic acid esters and their derivatives as potential antifungal agents for plant protection
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A series of cinnamic acid esters and their derivatives were synthesized and evaluated for antifungal activities in vitro against four plant pathogenic fungi by using the mycelium growth rate method. Structure-activity relationship was derived also. Almost all of the compounds showed some inhibition activity on each of the fungi at 0.5 mM. Eight compounds showed the higher average activity with average EC50 values of 17.4-28.6 μg/mL for the fungi than kresoxim-methyl, a commercial fungicide standard, and ten compounds were much more active than commercial fungicide standards carbendazim against P. grisea or kresoxim-methyl against both P. grisea and Valsa Mali. Compounds C1 and C2 showed the higher activity with average EC50 values of 17.4 and 18.5 μg/mL and great potential for development of new plant antifungal agents. The structure-activity relationship analysis showed that both the substitution pattern of the phenyl ring and the alkyl group in the alcohol moiety significantly influences the activity. There exists complexly comprehensive effect between the substituents on the phenyl ring and the alkyl group in the alcohol moiety on the activity. Thus, cinnamic acid esters showed great potential the development of new antifungal agents for plant protection due to high activity, natural compounds or natural compound framework, simple structure, easy preparation, low-cost and environmentally friendly.
- Zhou, Kun,Chen, Dongdong,Li, Bin,Zhang, Bingyu,Miao, Fang,Zhou, Le
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- MYOGLOBIN-BASED CATALYSTS FOR CARBENE TRANSFER REACTIONS
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Methods are provided for carrying out carbene transfer transformations such as olefin cyclopropanation reactions, carbene heteroatom-H insertion reactions (heteroatom = N, S, Si), sigmatropic rearrangement reactions, and aldehyde olefination reactions with high efficiency and selectivity by using a novel class of myoglobin-based biocatalysts. These methods are useful for the synthesis of a variety of organic compounds which contain one or more new carbon-carbon or carbon-heteroatom (N, S, or Si) bond. The methods can be applied for conducting these transformations in vitro (i.e., using the biocatalyst in isolated form) and in vivo (i.e., using the biocatalyst in a whole cell system).
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Paragraph 0090; 00367
(2016/06/14)
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- Myoglobin-catalyzed olefination of aldehydes
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The olefination of aldehydes constitutes a most valuable and widely adopted strategy for constructing carbon-carbon double bonds in organic chemistry. While various synthetic methods have been made available for this purpose, no biocatalysts are known to mediate this transformation. Reported herein is that engineered myoglobin variants can catalyze the olefination of aldehydes in the presence of α-diazoesters with high catalytic efficiency (up to 4,900 turnovers) and excellent Ediastereoselectivity (92-99.9 % de). This transformation could be applied to the olefination of a variety of substituted benzaldehydes and heteroaromatic aldehydes, also in combination with different alkyl α-diazoacetate reagents. This work provides a first example of biocatalytic aldehyde olefination and extends the spectrum of synthetically valuable chemical transformations accessible using metalloprotein-based catalysts.
- Tyagi, Vikas,Fasan, Rudi
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supporting information
p. 2512 - 2516
(2016/02/18)
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- Using non-covalent interactions to direct regioselective 2+2 photocycloaddition within a macrocyclic cavitand
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The relative orientation of guests within ternary inclusion complexes is governed by the host-guest and guest-guest supramolecular interactions. Selectivity in 2+2 photocycloaddition between two alkenes included within a macrocyclic cavitand (γ-cyclodextrin) can be controlled using non-covalent interactions. In this manuscript, we report cavitand-mediated control of regioselectivity between alkyl cinnamates using non-covalent interactions. Using this method, we have shown that regioselectivity can be switched completely from a head-to-head dimer to a head-to-tail dimer. The reactions were also stereoselective in most cases. Stoichiometry experiments were performed to explore relative stabilities of the complexes, which indicate that the ternary complex is more stable than others. Selectivity in the photocycloaddition reaction was also applied retrospectively to deduce intermolecular orientations. Time-dependent conversion study we performed indicates that the observed reactivity of alkenes is representative of the intermolecular orientations in the bulk of the complex medium. Experimental observations and computational studies were used to qualitatively understand the complex structures, and relative magnitudes of the weak interactions. The reactions of complexes were studied in slurry form, and the extent of reaction control suggests a solid-state-like behavior.
- Nguyen, Nga,Clements, Aspen Rae,Pattabiraman, Mahesh
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p. 2433 - 2443
(2016/03/19)
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- Borane-Catalyzed Reductive α-Silylation of Conjugated Esters and Amides Leaving Carbonyl Groups Intact
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Described herein is the development of the B(C6F5)3-catalyzed hydrosilylation of α,β-unsaturated esters and amides to afford synthetically valuable α-silyl carbonyl products. The α-silylation occurs chemoselectively, thus leaving the labile carbonyl groups intact. The reaction features a broad scope of both acyclic and cyclic substrates, and the synthetic utility of the obtained α-silyl carbonyl products is also demonstrated. Mechanistic studies revealed two operative steps: fast 1,4-hydrosilylation of conjugated carbonyls and then slow silyl group migration of a silyl ether intermediate.
- Kim, Youngchan,Chang, Sukbok
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supporting information
p. 218 - 222
(2016/01/25)
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- Palladium-Catalyzed Arylation of Olefins by Triarylphosphines via C-P Bond Cleavage
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C-H Arylation of olefins by triarylphosphines via C-P bond cleavage has been achieved with either Pd0 or PdII catalysts. A variety of olefins and triarylphosphines are tolerated, and we inferred that both Pd0 and PdII could function directly without pre-oxidation or pre-reduction.
- Lu, Dapeng,Xu, Yu,Liu, Wenjing,Guo, Lijuan,Sun, Xingxia
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p. 116 - 122
(2015/10/19)
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- Antileishmanial lead structures from nature: Analysis of structure-activity relationships of a compound library derived from caffeic acid bornyl ester
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Bioassay-guided fractionation of a chloroform extract of Valeriana wallichii (V. wallichii) rhizomes lead to the isolation and identification of caffeic acid bornyl ester (1) as the active component against Leishmania major (L. major) promastigotes (IC50 = 48.8 μM). To investigate the structure-activity relationship (SAR), a library of compounds based on 1 was synthesized and tested in vitro against L. major and L. donovani promastigotes, and L. major amastigotes. Cytotoxicity was determined using a murine J774.1 cell line and bone marrow derived macrophages (BMDM). Some compounds showed antileishmanial activity in the concentration range of pentamidine and miltefosine which are the standard drugs in use. In the L. major amastigote assay compounds 15, 19 and 20 showed good activity with relatively low cytotoxicity against BMDM, resulting in acceptable selectivity indices. Molecules with adjacent phenolic hydroxyl groups exhibited elevated cytotoxicity against murine cell lines J774.1 and BMDM. The Michael system seems not to be essential for antileishmanial activity. Based on the results compound 27 can be regarded as new lead structure for further structure optimization.
- Glaser, Jan,Schultheis, Martina,Hazra, Sudipta,Hazra, Banasri,Moll, Heidrun,Schurigt, Uta,Holzgrabe, Ulrike
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p. 1394 - 1410
(2014/03/21)
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- Facile formation of stable tris(imido)phosphate trianions as their tri- and hexanuclear Pd(II) complexes in protic solvents
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Employing Pd(OAc)2, a facile deprotonation route to access the highly basic tris(alkylimido)phosphate trianions, [(RN)3PO] 3- (R = tBu, cHex, or iPr), analogous to the orthophosphate (PO43-) ion in polar and in protic solvents has been achieved. Trinuclear and prismatic Pd(II) clusters of these imido trianions having the formula {Pd3[(NR) 3PO](OAc)3}n (n = 1 or 2) or as mixed-bridged clusters of the type {Pd3[(NiPr)3PO](OAc) 2(OR′)}2 (R′ = Me or H) were isolated exclusively in all these reactions in which the trianionic species acts as a tripodal chelating ligand to the trinuclear Pd3 unit. Reactivity studies aiming at the Pd(II) atoms in these clusters with nucleophilic reagents, such as primary amines (R″NH2), have led to a new trimeric cluster with the formula {Pd3[(NR)3PO](OAc) 3(R″NH2)3} in which the tripodal coordination of the Pd-Nimido moieties remained unaffected, exemplifying the robustness of the Pd3 unit in all these clusters. We have also shown the catalytic activity of these Pd(II) complexes in Mizoroki-Heck type coupling reactions in the presence of Cu(OAc)2.
- Gupta, Arvind K.,Reddy, S. Arun Dixith,Boomishankar, Ramamoorthy
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p. 7608 - 7614
(2013/07/26)
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- Macrocellular Pd@ionic liquid@organo-Si(HIPE) heterogeneous catalysts and their use for Heck coupling reactions
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Supported ionic liquid phases (SILPs) within macrocellular silica-based foams are prepared by a simple impregnation in organic solvents. Thin ionic liquid layers with thicknesses of 6 to 12 nm were obtained. The SILs mobility has been evidenced through NMR solid state spectroscopy. Subsequently, palladium salts are efficiently trapped within the SILPs, while an in situ palladium hydrogenation allowed an efficient reduction and formation of 10 nm diameter palladium metal nanoparticles. These hybrid foams are used as heterogeneous macrocellular catalysts for the Heck coupling reaction of iodobenzene and cyclohexyl acrylate, where palladium leaching appears to be very low. Despite recyclability minimized through the entrapment of detrimental ammonium salts within the macroporous network during the reaction, competitive TONs and TOFs were reached, while separation of the products can be reached at ease, due to the fact that both palladium species and by-products are trapped within the monolithic foams.
- Brun, Nicolas,Hesemann, Peter,Laurent, Guillaume,Sanchez, Clement,Birot, Marc,Deleuze, Herve,Backov, Renal
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p. 157 - 168
(2013/02/22)
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- Nucleophilic carbene-catalyzed redox-esterification reaction of α-halo-α,β-unsaturated aldehyde
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A nucleophilic carbene catalyzed redox esterification between α-halo-α,β-unsaturated aldehydes and various alcohols has been developed. Interestingly, the reaction provided α,β-unsaturated esters instead of the saturated α-halo substituted esters as the only product in good to high yield with excellent trans-selectivity, presumably via the umpolung-halo-elimination pathway.
- Wang, Xiang-Bo,Zou, Xiao-Lei,Du, Guang-Fen,Liu, Zhi-Yong,Dai, Bin
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p. 6498 - 6503
(2012/08/27)
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- NHC-catalyzed C-O or C-N bond formation: Efficient approaches to α,β-unsaturated esters and amides
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Simple and efficient NHC-catalyzed transformations of bromoenal or α,β-dibromoenal into α,β-unsaturated esters or amides with high stereoselectivity through C-O or C-N bond formation have been demonstrated. The NHC-catalyzed processes occur under mild con
- Zhang, Bo,Feng, Peng,Cui, Yuxin,Jiao, Ning
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supporting information; experimental part
p. 7280 - 7282
(2012/07/28)
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- Design, synthesis, and preliminary evaluation of substituted cinnamic acid esters as selective matrix metalloproteinase inhibitors
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Strategy, Management and Health Policy Preclinical Research Substituted cinnamic acid esters with extended P1' groups were synthesized using microwave irradiation and tested for their inhibitory activities on matrix metalloproteinase (MMP)-1, MMP-2, and MMP-9. Preliminary structure-activity relationship analysis and docking studies showed that hydroxyl groups in the benzene ring and the presence of extended spatial structures in the carboxylic acid played key roles in the MMP-2 and MMP-9 inhibitory activity and selectivity over MMP-1.
- Shi, Zhi-Hao,Li, Nian-Guang,Shi, Qian-Ping,Hao-Tang,Tang, Yu-Ping
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p. 317 - 324,8
(2020/07/30)
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- Surfactant-free synthesis of palladium nanoclusters for their use in catalytic cross-coupling reactions
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Surfactant-free Pd nanoclusters (Pd NCs) (size: 1-1.5 nm) showed high catalytic activity in the Suzuki-Miyaura cross-coupling and Mizoroki-Heck reactions. The Pd NCs had a high turnover number, up to 6.0 × 10 8, which can be recycled at least five times without loss of catalytic activity.
- Hyotanishi, Megumi,Isomura, Yuto,Yamamoto, Hiroko,Kawasaki, Hideya,Obora, Yasushi
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supporting information; experimental part
p. 5750 - 5752
(2011/06/22)
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- Nucleophilic iron catalysis in transesterifications: Scope and limitations
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Figure presented The ester bond is one of the most common structural motifs found in nature. Apart from the condensation between an acid and an alcohol, transesterifications represent another mechanistic alternative for the preparation of this compound class. The present paper summarizes our most recent investigations in this field, using nucleophilic iron complexes as catalysts for transesterifications under neutral conditions. This new type of metal catalyst complements the existing methodologies, which rely on Lewis acidic metal complexes. Investigations on scope and limitations, stereochemical course, and chemoselectivities will be presented.
- Magens, Silja,Plietker, Bernd
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supporting information; experimental part
p. 3715 - 3721
(2010/08/07)
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- ACYLATION REACTION OF HYDROXYL GROUP
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Disclosed is a selective ester production process of an alcoholic hydroxyl group, which proceeds under chemically mild conditions, while having adequate environmental suitability, operability and economical efficiency. Specifically disclosed is a process for producing an ester compound, which is characterized in that an alcohol and a carboxylic acid ester compound are reacted in the presence of a compound containing zinc element, thereby selectively acylating a hydroxyl group of the alcohol.
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Page/Page column 12; 14
(2010/07/03)
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- Glycerol as a cheap, safe and sustainable solvent for the catalytic and regioselective β,β-diarylation of acrylates over palladium nanoparticles
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Herein we show that glycerol can be considered as a promising cheap and green solvent for the regioselective β,β-diarylation of alkenes. Whereas this reaction is generally catalyzed under an inert atmosphere by expensive phosphine or carbene-palladium complexes, we show here that the diarylation of alkenes can be conveniently achieved in glycerol in the presence of air-stable palladium nanoparticles. These palladium nanoparticles were stabilized over a sugar-based surfactant derived from biomass. By an adjustment of the reaction temperature, we were able to control the mono- and diarylation step of alkenes, thus offering a convenient route to unsymmetrical diarylated alkenes. At the end of the reaction, the diarylated alkenes were cleanly and selectively extracted from the glycerol-palladium catalytic phase using supercritical carbon dioxide, thus affording a convenient purification work-up. Within the framework of green chemistry, this work combines (i) catalysis in a cheap, safe and sustainable medium, (ii) easily made and air-stable palladium nanoparticles as the catalyst, and (iii) a clean and selective extraction of the reaction products with supercritical carbon dioxide.
- Delample, Mathieu,Villandier, Nicolas,Douliez, Jean-Paul,Camy, Severine,Condoret, Jean-Stephane,Pouilloux, Yannick,Barrault, Joel,Jerome, Franois
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experimental part
p. 804 - 808
(2010/09/11)
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- Flavonoids and cinnamic acid esters as inhibitors of fungal 17β-hydroxysteroid dehydrogenase: A synthesis, QSAR and modelling study
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The 17β-hydroxysteroid dehydrogenases (17β-HSDs) modulate the biological potency of estrogens and androgens by interconversion of inactive 17-keto-steroids and their active 17β-hydroxy- counterparts. We have shown previously that flavonoids are potentially useful lead compounds for developing inhibitors of 17β-HSDs. In this paper, we describe the synthesis and biochemical evaluation of structurally analogous inhibitors, the trans-cinnamic acid esters and related compounds. Additionally, quantitative structure-activity relationship (QSAR) and modelling studies were performed to rationalize the results and to suggest further optimization. The results stress the importance of a hydrogen bond with Asn154 and hydrophobic interactions with the aromatic side chain of Tyr212 for optimal molecular recognition.
- Sova, Matej,Perdih, Andrej,Kotnik, Miha,Kristan, Katja,Rizner, Tea Lanisnik,Solmajer, Tom,Gobec, Stanislav
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p. 7404 - 7418
(2008/02/01)
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- Sustainable Mizoroki-Heck reaction in water: Remarkably high activity of Pd(OAc)2 immobilized on reversed phase silica gel with the aid of an ionic liquid
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Palladium acetate immobilized on reversed phase amorphous silica gel with the aid of an ionic liquid, [bmim]PF6, was highly efficient in the promotion of the Mizoroki-Heck reaction in pure water without a ligand up to the sixth re-use, in 95% average yield with TON and TOF 1,600,000 and 71,000 (h-1), respectively. The Royal Society of Chemistry 2005.
- Hagiwara, Hisahiro,Sugawara, Yoshitaka,Hoshi, Takashi,Suzuki, Toshio
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p. 2942 - 2944
(2007/10/03)
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- Immobilization of Pd(OAc)2 in ionic liquid on silica: Application to sustainable Mizoroki-Heck reaction
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(Equation Presented) Palladium acetate was supported on amorphous silica with the aid of an ionic liquid, [bmim]PF6. The immobilized catalyst was highly efficient in promoting the Mizoroki-Heck reaction without a ligand in n-dodecane for at least six reuses, in 89-98% yields. The TON and TOF reached 68 400 and 8000, respectively.
- Hagiwara, Hisahiro,Sugawara, Yoshitaka,Isobe, Kohei,Hoshi, Takashi,Suzuki, Toshio
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p. 2325 - 2328
(2007/10/03)
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- Chemistry of Silylketenes: a Simple Preparation of α-Silyl-α-stannylacetic Esters and Their Stereoselective Reformatsky-type Reaction with Aldehydes or Aldimines
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Silylketenes 1a, b reacted smoothly with alkoxystannanes 3 to give the corresponding α-silyl-α-stannylacetates 4 almost quantitatively.Treatment of 4 with TiCl4 caused selective cleavage of the C-Sn bond to bring about Reformatsky-type reaction with aldehydes 6 giving β-hydroxy-α-silyl esters 7.These two steps were carried out by one-pot operation, and variously substituted compounds 7 were obtained with high syn-selectivity (52-96percent d.e.) in 41-89percent yields.A similar one-pot procedure starting from 1a-c, 3, and aldimines 11 also provided the corresponding β-amino-α-silyl esters 12 with excellent syn-selectivity (96percent d.e. ) in 64-94percent yields.Stereocontrolled preparation of both (E)- and (Z)-α,β-unsaturated esters 8 and a syn-amino diol derivative 17 from syn-7 and syn-12, respectively, is also described.
- Akai, Shuji,Tsuzuki, Yasunori,Matsuda, Satoshi,Kitagaki, Shinji,Kita, Yasuyuki
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p. 2813 - 2820
(2007/10/02)
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- A highly active and stereoselective montmorillonite catalyst for arylation of conjugated alkenes
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A highly active and stereoselective heterogenised homogeneous catalyst montmorilloniteethylsilydiphenylphosphinepalladium (II) chloride complex (Pd/P is 1:1) for arylation of conjugated alkenes is reported.
- Choudary, Boyapati M.,Sarma, Ravichandra M.,Rao, Koteswara K.
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p. 719 - 726
(2007/10/02)
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- A NOVEL MOLECULAR RECOGNITION IN MONTMORILLONITE IN THE ARYLATION OF ACRYLATES
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A novel sequential and preferential substrate selectivity in arylation of acrylates with iodobenzenes by intralamellar montmorilloniteethylsilyldiphenylphosphinepalladium(II) chloride catalyst is reported for the first time.
- Choudary, B. M.,Sarma, M. Ravichandra,Rao, K. Koteswara
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p. 5781 - 5784
(2007/10/02)
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- REACTION OF BENZYLIDENEBENZYLAMINE WITH CINNAMIC ACID DERIVATIVES UNDER CONDITIONS OF PHASE-TRANSFER CATALYSIS. I. SYNTHESIS OF β-ARYL-γ-PHENYL-γ-AMINOBUTYRIC ACIDS AND THEIR DERIVATIVES
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The reaction of benzylidenebenzylamine with the esters of substituted cinnamic acids under the conditions of phase-transfer catalysis gives high yields of β-aryl-γ-phenyl-γ-aminobutyric acids and their derivatives (hydrochlorides, 4-aryl-5-phenyl-2-pyrrolidones).
- Potapov, V. M.,Gracheva, R. A.,Sivov, N. A.,Savina, S. A.,Sivova, L. A.
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p. 1694 - 1699
(2007/10/02)
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