- NH2-MIL-125(Ti)-derived porous cages of titanium oxides to support Pt-Co alloys for chemoselective hydrogenation reactions
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The change of atom density induced structural collapse in the transformation process from metal-organic frameworks (MOFs) to their inorganic counterparts is a major challenge to the achievement of porous hollow structures. Herein, we develop an amino acid-mediated strategy for transformation of NH2-MIL-125(Ti) to successfully synthesize well-defined porous cages of titanium oxides (PCT) due to sheets serving as structural scaffolds. On this basis, PCT supported Pt-based nanoparticles are generated via a similar synthetic route, and are utilized to study the selective hydrogenation of carbonyl groups in α,β-unsaturated aldehydes, benefiting from the specific structures of PCT and tunable electronic structures of Pt mainly affected by doping with metal species such as Co. In this case, Pt-Co/PCT composites give 96% selectivity for cinnamyl alcohol at 100% conversion of cinnamaldehyde under 0.2 MPa H2 and 80 °C for 3 h. This research would offer a promising strategy for important organic transformations in academic and industrial research to selectively synthesize high-value-added products.
- Gu, Zhizhi,Chen, Liyong,Li, Xuezhao,Chen, Lin,Zhang, Yingyue,Duan, Chunying
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Read Online
- Ir nanoclusters confined within hollow MIL-101(Fe) for selective hydrogenation of α,β-unsaturated aldehyde
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Although the selective hydrogenation of α,β-unsaturated aldehyde to unsaturated alcohol (UOL) is an extremely important transformation, it is still a great challenge to achieve high selectivity to UOL due to thermodynamic favoring of the C[dbnd]C hydrogenation over the C[dbnd]O hydrogenation. Herein, we report that iridium nanoclusters (Ir NCs) confined within hollow MIL-101(Fe) expresses satisfied reaction activity (93.9%) and high selectivity (96.2%) for the hydrogenation of cinnamaldehyde (CAL) to cinnamyl alcohol (COL) under 1 bar H2 atmosphere and room temperature. The unique hollow structure of MIL-101(Fe) benefits for the fast transport of reactant, ensuring the comparable reaction activity and better recyclability of Ir@MIL-101(Fe) than the counterparts which Ir NCs were on the surface of MIL-101(Fe). Furthermore, The X-ray photoelectron spectroscopy data indicates the electropositive Ir NCs, owing to the electron transfer from Ir to MIL-101(Fe), can interact with oxygen lone pairs, and Fourier transform infrared spectrum shows the Lewis acid sites in MIL-101(Fe) can strongly interact with C[dbnd]O bond, which contributes to a high selectivity for COL. This work suggests the considerable potential of synergetic effect between hollow MOFs and metal nanoclusters for selective hydrogenation reactions.
- Liu, Qinglin,Liu, Qian,Chen, Yurong,Li, Yinle,Su, Hui,Liu, Qinghua,Li, Guangqin
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supporting information
p. 374 - 377
(2021/08/13)
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- Copper(i) pyrimidine-2-thiolate cluster-based polymers as bifunctional visible-light-photocatalysts for chemoselective transfer hydrogenation of α,β-unsaturated carbonyls
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The photoinduced chemoselective transfer hydrogenation of unsaturated carbonyls to allylic alcohols has been accomplished using cluster-based MOFs as bifunctional visible photocatalysts. Assemblies of hexanuclear clusters [Cu6(dmpymt)6] (1, Hdmpymt = 4,6-dimethylpyrimidine-2-thione) as metalloligands with CuI or (Ph3P)CuI yielded cluster-based metal organic frameworks (MOFs) {[Cu6(dmpymt)6]2[Cu2(μ-I)2]4(CuI)2}n (2), {[Cu6(dmpymt)6]2[Cu2(μ-I)2]4}n (3), respectively. Nanoparticles (NPs) of 2 and 3 served both as photosensitizers and photocatalysts for the highly chemoselective reduction of unsaturated carbonyl compounds to unsaturated alcohols with high catalytic activity under blue LED irradiation. The photocatalytic system could be reused for several cycles without any obvious loss of efficiency.
- Zhang, Meng Juan,Young, David James,Ma, Ji Long,Shao, Guo Quan
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p. 14899 - 14904
(2021/05/19)
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- Allylic alcohol synthesis by Ni-catalyzed direct and selective coupling of alkynes and methanol
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Methanol is an abundant and renewable chemical raw material, but its use as a C1 source in C-C bond coupling reactions still constitutes a big challenge, and the known methods are limited to the use of expensive and noble metal catalysts such as Ru, Rh and Ir. We herein report nickel-catalyzed direct coupling of alkynes and methanol, providing direct access to valuable allylic alcohols in good yields and excellent chemo- and regioselectivity. The approach features a broad substrate scope and high atom-, step- and redox-economy. Moreover, this method was successfully extended to the synthesis of [5,6]-bicyclic hemiacetals through a cascade cyclization reaction of alkynones and methanol.
- Chen, Herong,Kong, Wangqing,Zhou, Zhijun
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p. 9372 - 9378
(2021/07/25)
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- Intramolecular Sakurai Allylation of Geminal Bis(silyl) Enamide with Indolenine. A Diastereoselective Cyclization to Form Functionalized Hexahydropyrido[3,4- b]Indole
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A fluoride-promoted intramolecular Sakurai allylation of geminal bis(silyl) enamide with indolenine has been developed. The reaction facilitates an efficient cyclization to give hexahydropyrido[3,4-b]indoles in good yields with high diastereoselectivity. The resulted cis, trans-stereochemistry further enables the ring-closing metathesis (RCM) reaction of two alkene moieties, giving a tetracyclic N-hetereocycle widely found as the core structure in akuammiline alkaloids.
- Chen, Yi,Gao, Lu,Song, Xuanyi,Song, Zhenlei
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p. 124 - 128
(2021/01/13)
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- Microwave-heated γ-Alumina Applied to the Reduction of Aldehydes to Alcohols
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The development of cheap and robust heterogeneous catalysts for the Meerwein-Ponndorf-Verley (MPV) reduction is desirable due to the difficulties in product isolation and catalyst recovery associated with the traditional use of homogeneous catalysts for MPV. Herein, we show that microwave heated γ-Al2O3 can be used for the reduction of aldehydes to alcohols. The reaction is efficient and has a broad substrates scope (19 entries). The products can be isolated by simple filtration, and the catalyst can be regenerated. With the use of microwave heating, we can direct the heating to the catalyst rather than to the whole reaction medium. Furthermore, DFT was used to study the reaction mechanism, and we can conclude that a dual-site mechanism is operative where the aldehyde and 2-propoxide are situated on two adjacent Al sites during the reduction. Additionally, volcano plots were used to rationalize the reactivity of Al2O3 in comparison to other metal oxides.
- Dhokale, Bhausaheb,Susarrey-Arce, Arturo,Pekkari, Anna,Runemark, August,Moth-Poulsen, Kasper,Langhammer, Christoph,H?relind, Hanna,Busch, Michael,Vandichel, Matthias,Sundén, Henrik
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p. 6344 - 6355
(2020/10/28)
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- Regulating Hydrogenation Chemoselectivity of α,β-Unsaturated Aldehydes by Combination of Transfer and Catalytic Hydrogenation
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Two hydrogenation mechanisms, transfer and catalytic hydrogenation, were combined to achieve higher regulation of hydrogenation chemoselectivity of cinnamyl aldehydes. Transfer hydrogenation with ammonia borane exclusively reduced C=O bonds to get cinnamyl alcohol, and Pt-loaded metal–organic layers efficiently hydrogenated C=C bonds to synthesize phenyl propanol with almost 100 % conversion rate. The hydrogenation could be performed under mild conditions without external high-pressure hydrogen and was applicable to various α,β-unsaturated aldehydes.
- Zhou, Yangyang,Li, Zihao,Liu, Yanbo,Huo, Jia,Chen, Chen,Li, Qiling,Niu, Songyang,Wang, Shuangyin
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p. 1746 - 1750
(2020/02/25)
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- Ammonia borane enabled upgrading of biomass derivatives at room temperature
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Simplifying biomass conversion to valuable products with high efficiency is pivotal for the sustainable development of society. Herein, an efficient catalyst-free system using ammonia borane (AB) as the hydrogen donor is described, which enables controllable reaction selectivity towards four value-added products in excellent yield (82-100%) under very mild conditions. In particular, the system is uniquely efficient to produce γ-valerolactone (GVL) at room temperature. Combined in situ NMR and computational studies elucidate the hydrogen transfer mechanism of AB in methanol, the novel pathway of GVL formation from levulinate in water, and a competitive mechanism between reduction and reductive amination in the same system. Moreover, carbohydrates are converted directly into GVL in good yield, using a one-pot, two-step strategy. Products of a rather broad scope are prepared within a short reaction time of 30 min by using this catalyst-free strategy in methanol at room temperature. This journal is
- Meier, Sebastian,Riisager, Anders,Yang, Song,Zhao, Wenfeng
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supporting information
p. 5972 - 5977
(2020/11/03)
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- Enantioselective α-functionalization of 1,3-dithianes by iridium-catalyzed allylic substitution
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An iridium-catalyzed asymmetric allylic substitution reaction with 2-alkoxy carbonyl-1,3-dithianes has been achieved with high regio- and enantioselectivities. The transformation provides a new method for the enantioselective α-functionalization of dithianes. The corresponding dithiane-containing products are easily converted into many other derivatives with high yields and enantioselectivities.
- Xie, Xingang,Tang, Shouchu,Wang, Xiaolei,Wang, Panpan,Jiang, Qian,Zhao, Ruibo
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p. 12456 - 12467
(2020/11/09)
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- Aurovertin B derivative and preparation method and application thereof
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The invention relates to an aurovertin B derivative and a preparation method of the aurovertin B derivative, and application of the aurovertin B derivative in preparation of a medicine for treating triple-negative breast cancer. Compared with aurovertin B, the aurovertin B derivative disclosed by the invention has the advantages that the water solubility of the compound is improved, the bioavailability can be improved, and the preparation is convenient to prepare. Meanwhile, compared with aurovertin B, the aurovertin B derivative disclosed by the invention has the advantages that the derivative has obvious dose dependence, the toxicity of the compound to normal cells is reduced, and the druggability of the compound is improved. The aurovertin B derivative disclosed by the invention has a very strong inhibition effect on proliferation of triple-negative breast cancer cells, and the activity of the aurovertin B derivative is stronger than that of paclitaxel serving as a clinical drug.
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Paragraph 0040
(2020/09/23)
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- Diaminodiphosphine tetradentate ligand and ruthenium complex thereof, and preparation methods and applications of ligand and complex
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The invention discloses a diaminodiphosphine tetradentate ligand and a ruthenium complex thereof, and preparation methods and applications of the ligand and the complex, and provides a ruthenium complex represented by a formula I, wherein L is a diaminodiphosphine tetradentate ligand represented by a formula II, and X and Y are respectively and independently chlorine ion, bromine ion, iodine ion,hydrogen negative ion or BH4. According to the present invention, the ruthenium complex exhibits excellent catalytic activity in the catalytic hydrogenation reactions of ester compounds, has high yield and high chemical selectivity, is compatible with conjugated and non-conjugated carbon-carbon double bond, carbon-carbon triple bond, epoxy, halogen, carbonyl and other functional groups, and hasgreat application prospects.
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Paragraph 0320-0323
(2019/11/04)
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- Polypyridyl iridium(III) based catalysts for highly chemoselective hydrogenation of aldehydes
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Iridium-catalyzed transfer hydrogenation (TH) of carbonyl compounds using HCOOR (R = H, Na, NH4) as a hydrogen source is a pivotal process as it provides the clean process and is easy to execute. However, the existing highly efficient iridium catalysts work at a narrow pH; thus, does not apply to a wide variety of substrates. Therefore, the development of a new catalyst which works at a broad pH range is essential as it can gain a broader scope of utilization. Here we report highly efficient polypyridyl iridium(III) catalysts, [Ir(tpy)(L)Cl](PF6)2 {where tpy = 2,2′:6′,2′'-Terpyridine, L = phen (1,10-Phenanthroline), Me2phen (4,7-Dimethyl-1,10-phenanthroline), Me4phen (3,4,7,8-Tetramethyl-1,10-phenanthroline), Me2bpy (4,4′-Dimethyl-2–2′-dipyridyl)} for the chemoselective reduction of aldehydes to alcohols in aqueous ethanol and sodium formate as the hydride source. The reaction can be carried out efficiently in broad pH ranges, from pH 6 to 11. These catalysts are air stable, easy to prepare using commercially available starting materials, and are highly applicable for a wide range of substrates, such as electron-rich or deficient (hetero)arenes, halogens, phenols, alkoxy, ketones, esters, carboxylic acids, cyano, and nitro groups. Particularly, acid and hydroxy groups containing aldehydes were reduced successfully in basic and acidic reaction conditions, demonstrating the efficiency of the catalyst in a broad pH range with high conversion rates under microwave irradiation.
- Pandrala, Mallesh,Resendez, Angel,Malhotra, Sanjay V.
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p. 283 - 288
(2019/09/30)
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- Cobalt-Catalyzed Allylic Alkylation Enabled by Organophotoredox Catalysis
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Co-catalyzed allylic substitution reactions have received little attention, arguably because of the lack of any known advantage of Co catalysis over either Rh or Ir catalysis. Described here is a general and regioselective Co-catalyzed allylic alkylation using an in situ catalyst activation by organophotoredox catalysis. This noble-metal-free catalytic system exhibits unprecedentedly high reactivities and regioselectivities for the allylation with an allyl sulfone, for the first time, representing the unique synthetic utility of the Co-catalyzed method compared to the related Rh- and Ir-catalyzed reactions.
- Takizawa, Koji,Sekino, Tomoyuki,Sato, Shunta,Yoshino, Tatsuhiko,Kojima, Masahiro,Matsunaga, Shigeki
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supporting information
p. 9199 - 9203
(2019/06/04)
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- PHOTOCHEMICAL METHODS OF MAKING CYCLOBUTANE BORONATES AND RELATED COMPOUNDS
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The present technology relates generally cyclobutane boronates, including methods of preparation by exposing a mixture of a compound of Formula I in a solvent and a catalytic amount of a visible light sensitizer to provide a compound of Formula II, stereoisomers thereof, and/or salts of any of the foregoing. The cyclobutane boronate compounds are useful intermediates in the preparation of pharmaceutically active compounds as well as other other useful compounds.
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- Boron-Templated Dimerization of Allylic Alcohols to Form Protected 1,3-Diols via Acid Catalysis
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We report an unprecedented boron-templated dimerization of allylic alcohols that generates a 1,3-diol product with two stereogenic centers in high yield and diastereoselectivity. This acid-catalyzed reaction is achieved via in situ formation of a boronic ester intermediate that facilitates selective cyclization and formation of a cyclic boronic ester product. High yields are observed with a variety of allylic alcohols, and mechanistic studies confirm the role of boron as a template for the reaction.
- Nazari, S. Hadi,Forson, Kelton G.,Martinez, Erin E.,Hansen, Nicholas J.,Gassaway, Kyle J.,Lyons, Nathan M.,Kenney, Karissa C.,Valdivia-Berroeta, Gabriel A.,Smith, Stacey J.,Michaelis, David J.
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p. 9589 - 9593
(2019/12/02)
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- Arene Trifunctionalization with Highly Fused Ring Systems through a Domino Aryne Nucleophilic and Diels–Alder Cascade
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A convenient and efficient domino aryne process was developed under transition-metal-free conditions to generate a range of tetra- and pentacyclic ring systems. This transformation was realized via a 1,2-benzdiyne through a nucleophilic and Diels–Alder reaction cascade using styrene as the diene moiety. Three new chemical bonds, namely one C?N and two C?C bonds, and two benzofused rings could be constructed concomitantly, which was made possible by distinct chemoselective control at both the 1,2-aryne and 2,3-aryne stages. Moreover, in-depth studies were carried out on the domino aryne precursors and controlling the diastereoselectivity.
- He, Jia,Jia, Zizi,Tan, Hongcheng,Luo, Xiaohua,Qiu, Dachuan,Shi, Jiarong,Xu, Hai,Li, Yang
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p. 18513 - 18518
(2019/11/19)
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- Switchable Chemoselective Transfer Hydrogenations of Unsaturated Carbonyls Using Copper(I) N-Donor Thiolate Clusters
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Unsaturated alcohols and saturated carbonyls are important chemical, pharmaceutical, and biochemical intermediates. We herein report an efficient transfer hydrogenation protocol in which conversion of unsaturated carbonyl compounds to either unsaturated alcohols or saturated carbonyls was catalyzed by Cu(I) N-donor thiolate clusters along with changing hydrogen source (isopropanol or butanol) and base (NaOH or K2CO3). Mechanistic studies supported by DFT transition state modeling indicate that such a chemoselectivity can be explained by the relative concentrations of Cu(I) monohydride and protonated Cu(I) hydride complexes in each catalytic system.
- Zhang, Meng-Juan,Tan, Da-Wei,Li, Hong-Xi,Young, David James,Wang, Hui-Fang,Li, Hai-Yan,Lang, Jian-Ping
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p. 1204 - 1215
(2018/02/09)
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- Porous, Naturally Derived Hafnium Phytate for the Highly Chemoselective Transfer Hydrogenation of Aldehydes with Other Reducible Moieties
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Both the utilization of naturally occurring compounds to prepare functional materials and the selective conversion of aldehydes with other reducible moieties (ORMs) are very attractive topics. Herein, we synthesized a novel porous material, hafnium phytate (Hf-Phy), by using naturally derived sodium phytate as the building block. Hf-Phy has plenty of mesopores centered around 11.8 nm. Hf-Phy showed excellent performance for the transfer hydrogenation of aldehydes with ORMs by using 2-propanol as the hydrogen source with high selectivities (95–100 %) for alcohols without reducing ORMs. Systematic studies suggested that the oxophilicity of Hf4+ and the basicity and structure of Hf-Phy contributed significantly to the excellent performance. Additionally, Hf-Phy could be used over at least five cycles without any decrease in activity or selectivity.
- Song, Jinliang,Xue, Zhimin,Xie, Chao,Wu, Haoran,Liu, Shuaishuai,Zhang, Lujun,Han, Buxing
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p. 725 - 730
(2018/01/22)
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- Halogen Bond Catalyzed Bromocarbocyclization
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A halogen bond catalyzed bromo-carbocyclization of N-cinnamyl sulfonamides and O-cinnamyl phenyl ethers has been developed. N-methyl 4-iodopyridinium triflate is used as the halogen-bonding organocatalyst and the reaction is highly chemoselective. This report represents the first proof-of-concept for halogen-bonding organocatalyst-promoted electrophilic halogenation. Mechanistic study suggests the autocatalytic nature of this reaction.
- Chan, Yuk-Cheung,Yeung, Ying-Yeung
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p. 3483 - 3487
(2018/02/28)
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- A substituted cinnamic alcohol compound of preparation method
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The invention belongs to the field of medical and chemical intermediates and related chemical techniques, and relates to a preparation method of a substituted cinnamyl alcohol compound. Cinnamyl aldehyde and derivatives thereof are taken as raw materials, and nano-porous gold is taken as a catalyst, hydrogen is taken as a hydrogen source, organic alkali is taken as a solvent, and the hydrogen is selectively added to prepare substituted cinnamyl alcohol. Reaction temperature is -50 to 150 DEG C, reaction time is 12 to 36 h, and the hydrogen pressure is 1 to 50 bar; the molar ratio of the cinnamyl aldehyde and derivatives thereof to the catalyst is 1:0.01 to 0.1. The preparation method provided by the invention has the beneficial effects that the product selectivity is high, the repeatability of the catalyst is good, and the catalytic effect of the catalyst cannot obviously reduce after being reused for multiple times; the cheap green hydrogen is taken as the hydrogen source so as to meet the atom economy, and the possibility of industrialization is provided.
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Paragraph 0031; 0032; 0033; 0034; 0035; 0036; 0037-0042
(2017/08/25)
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- Stereoselective and Site-Specific Allylic Alkylation of Amino Acids and Small Peptides via a Pd/Cu Dual Catalysis
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We report a stereoselective and site-specific allylic alkylation of Schiff base activated amino acids and small peptides via a Pd/Cu dual catalysis. A range of noncoded α,α-dialkyl α-amino acids were easily synthesized in high yields and with excellent enantioselectivities (up to >99% ee). Furthermore, a direct and highly stereoselective synthesis of small peptides with enantiopure α-alkyl or α,α-dialkyl α-amino acids residues incorporated at specific sites was accomplished using this dual catalyst system.
- Huo, Xiaohong,He, Rui,Fu, Jingke,Zhang, Jiacheng,Yang, Guoqiang,Zhang, Wanbin
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supporting information
p. 9819 - 9822
(2017/08/02)
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- Gold-Catalyzed [2,3]-Sigmatropic Rearrangement: Reaction of Aryl Allyl Alcohols with Diazo Compounds
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A gold-catalyzed [2,3]-sigmatropic rearrangement reaction has been developed. The intermolecular rearrangement occurs between in situ generated donor-acceptor gold-carbenes and cinnamyl alcohols via tandem oxonium ylide formation. The desired rearranged product has been accomplished selectively over more conventional O-H insertion, cyclopropanation, cycloaddition, and C-H functionalization products under mild, open-air conditions. The scope of the work has been illustrated by synthesizing a new class of substrates that can be used for constructing complex molecular targets.
- Rao, Santhosh,Prabhu, Kandikere Ramaiah
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p. 846 - 849
(2017/02/26)
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- Stereodivergent allylic substitutions with aryl acetic acid esters by synergistic iridium and lewis base catalysis
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The preparation of all possible stereoisomers of a given chiral molecule bearing multiple stereocenters by a simple and unified method is a significant challenge in asymmetric catalysis. We report stereodivergent allylic substitutions with aryl acetic acid esters catalyzed synergistically by a metallacyclic iridium complex and benzotetramisole. Through permutations of the enantiomers of the two chiral catalysts, all four stereoisomers of the products bearing two adjacent stereocenters are accessible with high diastereoselectivity and enantioselectivity. The resulting chiral activated ester products can be converted readily to enantioenriched amides, unactivated esters, and carboxylic acids in a onepot manner.
- Jiang, Xingyu,Beiger, Jason J.,Hartwig, John F.
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- Iridium-Catalyzed Enantioselective Allylic Substitution of Aliphatic Esters with Silyl Ketene Acetals as the Ester Enolates
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Enantioselective allylic substitution with enolates derived from aliphatic esters under mild conditions remains challenging. Herein we report iridium-catalyzed enantioselective allylation reactions of silyl ketene acetals, the silicon enolates of esters, to form products containing a quaternary carbon atom at the nucleophile moiety and a tertiary carbon atom at the electrophile moiety. Under relatively neutral conditions, the allylated aliphatic esters were obtained with excellent regioselectivity and enantioselectivity. These products were readily converted into primary alcohols, carboxylic acids, amides, isocyanates, and carbamates, as well as tetrahydrofuran and γ-butyrolactone derivatives, without erosion of enantiomeric purity.
- Jiang, Xingyu,Hartwig, John F.
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p. 8887 - 8891
(2017/07/17)
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- A class of 1, 2, 5 - oxadiazole - 2 oxide analogs, its preparation and use
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The invention provides 1,2,5-oxadiazole-2 oxide analogue with a structure shown as general formula I, and a preparation method and an application thereof. The 1,2,5-oxadiazole-2 oxide analogue has the activity for resisting schistosome thioredoxin glutathione reductase, kills schistosome by blocking a normal redox equilibrium physiological metabolism process of schistosome cells, can be used as a drug lead for development of drugs for treating schistosomiasis, and provides novel means for preventing and treating schistosomiasis. The general formula I is shown in the description.
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Paragraph 0079; 0080; 0081; 0082
(2017/04/21)
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- Synthesis of two phloroglucinol derivatives with cinnamyl moieties as inhibitors of the carbonic anhydrase isozymes I and II: an in vitro study
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Two cinnamyl-substituted phloroglucinols, 4-p-methoxycinnamyl phloroglucinol (9) and 4,6-bis-p-methoxycinnamyl phloroglucinol (10) were synthesized. Two carbonic anhydrases, human carbonic anhydrase I and II (hCA I and II), were purified. Kinetic interact
- Burmao?lu, Serdar,Dilek, Esra,Y?lmaz, Ali Osman,Supuran, Claudiu T.
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p. 208 - 212
(2016/12/14)
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- Discovery of Potent Benzofuran-Derived Diapophytoene Desaturase (CrtN) Inhibitors with Enhanced Oral Bioavailability for the Treatment of Methicillin-Resistant Staphylococcus aureus (MRSA) Infections
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Blocking the staphyloxanthin biosynthesis process has emerged as a new promising antivirulence strategy. Previously, we first revealed that CrtN is a druggable target against infections caused by pigmented Staphylococcus aureus (S. aureus) and that naftifine was an effective CrtN inhibitor. Here, we identify a new type of benzofuran-derived CrtN inhibitor with submicromolar IC50 values that is based on the naftifine scaffold. The most potent analog, 5m, inhibits the pigment production of S. aureus Newman and three MRSA strains, with IC50 values of 0.38-5.45 nM, without any impact on the survival of four strains (up to 200 μM). Notably, compound 5m (1 μM) could significantly sensitize four strains to immune clearance and could effectively attenuate the virulence of three strains in vivo. Moreover, 5m was determined to be a weak antifungal reagent (MIC > 16 μg/mL). Combined with good oral bioavailability (F = 42.2%) and excellent safety profiles, these data demonstrate that 5m may be a good candidate for the treatment of MRSA infections.
- Wang, Youxin,Chen, Feifei,Di, Hongxia,Xu, Yong,Xiao, Qiang,Wang, Xuehai,Wei, Hanwen,Lu, Yanli,Zhang, Lingling,Zhu, Jin,Sheng, Chunquan,Lan, Lefu,Li, Jian
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p. 3215 - 3230
(2016/05/19)
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- Unsupported Nanoporous Gold Catalyst for Chemoselective Hydrogenation Reactions under Low Pressure: Effect of Residual Silver on the Reaction
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For the first time, H-H dissociation on an unsupported nanoporous gold (AuNPore) surface is reported for chemoselective hydrogenation of C=C, C=C, C=N, and C=O bonds under mild conditions (8 atm H2 pressure, 90 °C). Silver doping in AuNPore, which was inevitable for its preparation through a process of dealloying of Au-Ag alloy, exhibited a remarkable difference in catalytic activity between two catalysts, Au>99Ag1NPore and Au90Ag10NPore.The former was more active and the latter less active in H2 hydrogenation, while the reverse tendency was observed for O2 oxidation. This marked contrast between H2 reduction and O2 oxidation is discussed. Further, Au>99Ag1NPore showed a high chemoselectivity toward reduction of terminal alkynes in the presence of internal alkynes which was not achieved using supported gold nanoparticle catalysts and other previously known methods. Reductive amination, which has great significance in synthesis of amines due to its atom-economical nature, was also realized using Au>99Ag1NPore, and the Au>99Ag1NPore/H2 system showed a preference for the reduction of aldehydes in the presence of imines. In addition to this high chemoselectivity, easy recovery and high reusability of AuNPore make it a promising heterogeneous catalyst for hydrogenation reactions.
- Takale, Balaram S.,Feng, Xiujuan,Lu, Ye,Bao, Ming,Jin, Tienan,Minato, Taketoshi,Yamamoto, Yoshinori
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supporting information
p. 10356 - 10364
(2016/08/31)
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- Electronic interactions between a stable electride and a nano-alloy control the chemoselective reduction reaction
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Controlling the electronic structure of heterogeneous metal catalysts is considered an efficient method to optimize catalytic activity. Here, we introduce a new electronic effect induced by the synergy of a stable electride and bimetallic nanoparticles for a chemoselective reduction reaction. The electride [Ca24Al28O64]4+·(e-)4, with extremely low work function, promotes the superior activity and selectivity of a Ru-Fe nano-alloy for the conversion of α,β-unsaturated aldehydes to unsaturated alcohols in a solvent-free system. The catalyst is easily separable from the product solution and reusable without notable deactivation. Mechanistic studies demonstrate that electron injection from the electride to the Ru-Fe bimetallic nanoparticles promotes H2 dissociation on the highly charged active metal and preferential adsorption of CO bonds over CCs bond of the unsaturated aldehydes, to obtain the thermodynamically unfavorable but industrially important product.
- Ye, Tian-Nan,Li, Jiang,Kitano, Masaaki,Sasase, Masato,Hosono, Hideo
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p. 5969 - 5975
(2016/08/31)
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- Green, Multi-Gram One-Step Synthesis of Core–Shell Nanocomposites in Water and Their Catalytic Application to Chemoselective Hydrogenations
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We devise a new and green route for the multi-gram synthesis of core–shell nanoparticles (NPs) in one step under organic-free and pH-neutral conditions. Simply mixing core and shell metal precursors in the presence of solid metal oxides in water allowed for the facile fabrication of small CeO2-covered Au and Ag nanoparticles dispersed on metal oxides in one step. The CeO2-covered Au nanoparticles acted as a highly efficient and reusable catalyst for a series of chemoselective hydrogenations, while retaining C=C bonds in diverse substrates. Consequently, higher environmental compatibility and more efficient energy savings were achieved across the entire process, including catalyst preparation, reaction, separation, and reuse.
- Urayama, Teppei,Mitsudome, Takato,Maeno, Zen,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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supporting information
p. 17962 - 17966
(2016/12/16)
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- An expedient synthesis of new 2-(furoxan-3-yl)thiazolidin-4-one derivatives
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A series of new biologically interesting furoxan-3-thiazolidinones have been synthesized via one-pot three-component reaction of furoxan aldehydes, anilines and mercaptoacetic acid. The multi-component reaction involves condensation of furoxan aldehyde with aniline to give imine; the formed imine undergoes nucleophilic addition with mercaptoacetic acid, followed by cyclisation with loss of H2O to obtain the desired products. All the synthesized compounds were well characterized using spectral techniques and confirmed by an X-ray crystal structure for one compound.
- Kumar, Singam Naveen,Kumar, Chebolu Naga Sesha Sai Pavan,Anudeep, Sri Ranga Vanarasi,Sharma, Kirti Kumari,Rao, Vaidya Jayathirtha,Babu, Nanubolu Jagadeesh
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- SnO2-isolated Pt3Sn alloy on reduced graphene oxide: An efficient catalyst for selective hydrogenation of CO in unsaturated aldehydes
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In this communication, a pyramid shaped alloy-metal oxide-graphene hybrid was synthesized by a facile procedure, in which SnO2 nanoparticles (NPs) (4.8-5.8 nm) were first coated onto the surface of reduced graphene oxide (rGO), and then very fine Pt3Sn NPs (0.6-1.2 nm) were fabricated on the SnO2 NPs on rGO sheets under microwave irradiation in a few minutes. Characterizations disclosed that the SnO2 NPs on rGO were more favorable for the dispersion of Pt, and Pt3Sn formed mainly on the surface of SnO2 NPs. This pyramid shaped Pt3Sn/SnO2/rGO hybrid was highly active, selective and stable for the hydrogenation of the CO bond in unsaturated aldehydes to unsaturated alcohols under mild conditions.
- Shi, Juanjuan,Zhang, Mengyuan,Du, Weichen,Ning, Wensheng,Hou, Zhaoyin
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p. 3108 - 3112
(2015/06/08)
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- Chiral primary amine/palladium dual catalysis for asymmetric allylic alkylation of β-ketocarbonyl compounds with allylic alcohols
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An efficient dual catalytic system composed of a chiral primary amine and a palladium complex was developed to promote the direct asymmetric allylic alkylation (AAA) of β-ketocarbonyl compounds. In particular, the synergistic dual catalytic system enabled
- Zhou, Han,Zhang, Long,Xu, Changming,Luo, Sanzhong
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supporting information
p. 12645 - 12648
(2015/10/28)
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- Titanocene(III) chloride mediated radical-induced opening of monosubstituted epoxy acetates for the synthesis of primary allylic alcohols
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A simple and efficient method for the synthesis of primary allylic alcohols from monosubstituted epoxy acetates has been developed using titanocene(III) chloride mediated epoxide ring opening via acetate elimination.
- Chakraborty,Mandal,Roy
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p. 893 - 901
(2015/08/18)
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- Multifunctional novel Diallyl disulfide (DADS) derivatives with β-amyloid-reducing, cholinergic, antioxidant and metal chelating properties for the treatment of Alzheimer's disease
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A series of novel Diallyl disulfide (DADS) derivatives were designed, synthesized and evaluated as chemical agents, which target and modulate multiple facets of Alzheimer's disease (AD). The results showed that the target compounds 5a-l and 7e-m exhibited significant anti-Aβ aggregation activity, considerable acetylcholinesterase (AChE) inhibition, high selectivity towards AChE over butyrylcholinesterase (BuChE), potential antioxidant and metal chelating activities. Specifically, compounds 7k and 7l exhibited highest potency towards self-induced Aβ aggregation (74% and 71.4%, 25 μM) and metal chelating ability. Furthermore, compounds 7k and 7l disaggregated Aβ fibrils generated by Cu2+-induced Aβ aggregation by 80.9% and 78.5%, later confirmed by transmission electron microscope (TEM) analysis. Besides, 7k and 7l had the strongest AChE inhibitory activity with IC50 values of 0.056 μM and 0.121 μM, respectively. Furthermore, molecular modelling studies showed that these compounds were capable of binding simultaneously to catalytic active site (CAS) and peripheral anionic site (PAS) of AChE. All the target compounds displayed moderate to excellent antioxidant activity with ORAC-FL values in the range 0.546-5.86 Trolox equivalents. In addition, absorption, distribution, metabolism and excretion (ADME) profile and toxicity prediction (TOPKAT) of best compounds 7k and 7l revealed that they have drug like properties and possess very low toxic effects. Collectively, the results strongly support our assertion that these compounds could provide good templates for developing new multifunctional agents for AD treatment.
- Manral, Apra,Saini, Vikas,Meena, Poonam,Tiwari, Manisha
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p. 6389 - 6403
(2015/10/05)
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- Palladium-catalyzed allylic alkylation of simple ketones with allylic alcohols and its mechanistic study
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Allylic alcohols were directly used in Pd-catalyzed allylic alkylations of simple ketones under mild reaction conditions. The reaction proceeded smoothly at 20°C by the concerted action of a Pd catalyst, a pyrrolidine co-catalyst, and a hydrogen-bonding solvent, and does not require any additional reagents. A computational study suggested that methanol plays a crucial role in the formation of the π-allylpalladium complex by lowering the activation barrier. Concerted action: Allylic alcohols were directly used in the title reaction under mild conditions. The reaction smoothly proceeds by the concerted action of a Pd catalyst, a pyrrolidine co-catalyst, and a hydrogen-bonding solvent, and does not require any additional reagents. A computational study suggested that methanol plays a crucial role in the formation of the π-allylpalladium complex by lowering the activation barrier.
- Huo, Xiaohong,Yang, Guoqiang,Liu, Delong,Liu, Yangang,Gridnev, Ilya D.,Zhang, Wanbin
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supporting information
p. 6776 - 6780
(2014/07/08)
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- 2-Arylcyclopropylmethanol as a substitute for homoallyl aryl alcohol in the construction of cis-2,6-disubstituted tetrahydropyran: Synthesis of (±)-centrolobine
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The application of 2-arylcyclopropylmethanols as substitutes to homoallyl aryl alcohols and their reactions with aliphatic aldehydes in the presence of SnCl4 in CH2Cl2 leads to an efficient Prins cyclization to generate cis-2,6-disubstituted tetrahydropyrans in high yields. The reaction is free from 2-oxonia-Cope rearrangement. This protocol was used to synthesize (±)-centrolobine in an overall 84% yield over three steps. The protocol holds promise for scaffold generation for medicinal chemistry exploitation. This journal is
- Yadav, Veejendra K.,Verma, Ashish K.,Kumar, Piyush,Hulikal, Vijaykumar
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p. 15457 - 15460
(2015/02/19)
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- Core-shell AgNP@CeO2 nanocomposite catalyst for highly chemoselective reductions of unsaturated aldehydes
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Selective silver: A core-shell AgNP-CeO2 nanocomposite (AgNP@CeO2) acted as an effective catalyst for the chemoselective reductions of unsaturated aldehydes to unsaturated alcohols with H2 (see figure). Maximizing the AgNP-CeO2 interaction successfully induced the heterolytic cleavage of H2, resulting in highly chemoselective reductions. Furthermore, a highly dispersed AgNP@CeO2 system was also developed that exhibited a higher activity than the original AgNP@CeO2. Copyright
- Mitsudome, Takato,Matoba, Motoshi,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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supporting information
p. 5255 - 5258
(2013/05/22)
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- Remarkable effect of bases on core-shell AgNP@CeO2 nanocomposite-catalyzed highly chemoselective reduction of unsaturated aldehydes
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A highly dispersed coreshell silver nanoparticleceria nanocomposite catalyst (AgNP@CeO2-D) was prepared. The addition of bases was found to enhance the catalytic efficiency of AgNP@CeO2-D significantly in the chemoselective reduction of diverse unsaturated aldehydes to the corresponding unsaturated alcohols.
- Mitsudome, Takato,Matoba, Motoshi,Yamamoto, Masaaki,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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p. 660 - 662
(2013/07/05)
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- Sterically controlled alkylation of arenes through iridium-catalyzed C-H borylation
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Complementary chemistry: A one-pot method for the site-selective alkylation of arenes controlled by steric effects is reported. The process occurs through Ir-catalyzed C-H borylation, followed by Pd- or Ni-catalyzed coupling with alkyl electrophiles. This selectivity complements that of the typical Friedel-Crafts alkylation; meta-selective alkylation of a broad range of arenes with various electronic properties and functional groups occurs in good yield with high site selectivity. Copyright
- Robbins, Daniel W.,Hartwig, John F.
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supporting information
p. 933 - 937
(2013/02/25)
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- Improved synthesis of natural ester sintenin and its analogues via Wittig reaction
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The synthesis of a cytotoxic natural ester sintenin (7a) and twenty eight of its analogues including nitrogen-containing heterocyclic indole moiety (7b-7t), saturated (10a-10d) and unsaturated (10e-10h) amides were carried out by convenient route via one-pot Wittig reaction in aqueous medium with improved yield. A systematic structure activity relationship of sintenin ester was designed by chemically modified derivatives in order to get better cytotoxicity.
- Sharma, Mukul,Rajesh, U. Chinna,Rawat, Diwan S.
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p. 1853 - 1860
(2014/01/17)
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- Simple and efficient 1,3-isomerization of allylic alcohols using a supported monomeric vanadium-oxide catalyst
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Promotion by group high five: Silica-supported monomeric vanadium-oxide promoted the isomerization of various allylic alcohols, including under scaled-up and solvent-free reaction conditions. This catalyst also exhibited high reusability with no drop in activity.
- Mitsudome, Takato,Sueoka, Shoichiro,Ikeda, Satoshi,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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p. 2879 - 2882
(2013/10/21)
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- Finding more active antioxidants and cancer chemoprevention agents by elongating the conjugated links of resveratrol
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Resveratrol is the subject of intense research as a natural antioxidant and cancer chemopreventive agent. There has been a great deal of interest and excitement in understanding its action mechanism and developing analogs with antioxidant and cancer chemoprevention activities superior to that of the parent compound in the past decade. This work delineates that elongation of the conjugated links is an important strategy to improve the antioxidant activity of resveratrol analogs, including hydrogen atom- or electron-donating ability in homogeneous solutions and antihemolysis activity in heterogeneous media. More importantly, C3, a triene bearing 4,4′-dihydroxy groups, surfaced as an important lead compound displaying remarkably increased antioxidant, cytotoxic, and apoptosis-inducing activities compared with resveratrol.
- Tang, Jiang-Jiang,Fan, Gui-Juan,Dai, Fang,Ding, De-Jun,Wang, Qi,Lu, Dong-Liang,Li, Ran-Ran,Li, Xiu-Zhuang,Hu, Li-Mei,Jin, Xiao-Ling,Zhou, Bo
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scheme or table
p. 1447 - 1457
(2012/05/05)
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- Synthesis of some phenylpropanoid glycosides (PPGs) and their acetylcholinesterase/xanthine oxidase inhibitory activities
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In this research, three categories of phenylpropanoid glycosides (PPGs) were designed and synthesized with PPGs isolated from Rhodiola rosea L. as lead compounds. Their inhibitory abilities toward acetylcholinesterase (AChE) and xanthine oxidase (XOD) were also tested. Some of the synthetic PPGs exhibited excellent enzyme inhibitory abilities.
- Li, Xiao-Dong,Kang, Shuai-Tao,Li, Guo-Yu,Li, Xian,Wang, Jin-Hui
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p. 3580 - 3596
(2011/07/07)
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- Tetrahydropyrimidine derivatives as efficient organic reductants for transfer hydrogenation
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Two six-membered heterocyclic organic reductants, 1-acetyl-2,3-dimethyltetrahydropyrimidine (ADMP) and 1-tosyl-2,3-dimethyltetrahydro-pyrimidine (TDMP), were designed and synthesized for transfer hydrogenation. It was shown that both the two reductants could directly reduce a variety of aldehydes and imines to the corresponding saturated products in good yields.
- Zhang, Yongbin,Zhou, Guofu,Guo, Wei
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experimental part
p. 1541 - 1548
(2009/12/24)
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- Discovery of chiral cyclopropyl dihydro-alkylthio-benzyl-oxopyrimidine (5-DABO) derivatives as potent HIV-1 reverse transcriptase inhibitors with high activity against clinically relevant mutants
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The role played by stereochemistry in the C2-substituent (left part) on the S-DABO scaffold for anti-HIV-1 activity has been investigated for the first time. A series of S-DABO analogues, where the double bond in the C2-substituent is replaced by an enant
- Radi, Marco,Maga, Giovanni,Alongi, Maddalena,Angeli, Lucilla,Samuele, Alberta,Zanoli, Samantha,Bellucci, Luca,Tafi, Andrea,Casaluce, Gianni,Giorgi, Gianluca,Armand-Ugon, Mercedes,Gonzalez, Emmanuel,Este, José A.,Baltzinger, Mireille,Bec, Guillaume,Dumas, Philippe,Ennifar, Eric,Botta, Maurizio
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body text
p. 840 - 851
(2009/12/26)
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- Etherification of darylmethanols and 1-phenylalkan-1-ols over platinum on carbon
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In the presence of platinum on carbon (Pt/C), diarylmethanols and donor substituted 1-phenylalkan-1-ols undergo cross-etherification with primary and secondary alcohols.
- Thiemann, Thies
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experimental part
p. 515 - 525
(2010/04/23)
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- Regio- and stereoselective heck α-arylation of cinnamyl alcohols
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The Heck reaction of cinnamyl alcohols with aryl iodides has been investigated using n-Bu4NOAc as the base in toluene. Under these conditions, the reaction affords regio- and stereoselectively (Z)-2,3-diarylallylic alcohols in moderate to good yields. Experimental evidence suggests that the observed selectivity in formation of the vinylic substitution products is kinetic in origin under these conditions and that both the base and the solvent play a key role. Georg Thieme Verlag Stuttgart.
- Ambrogio, Ilaria,Cacchi, Sandro,Fabrizi, Giancarlo,Goggiamani, Antonella,Sgalla, Simona
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experimental part
p. 620 - 624
(2009/07/11)
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- Synthesis of oxadiazole-2-oxide analogues as potential antischistosomal agents
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The synthesis of several 1,2,5-oxadiazole-2-oxide (Furoxan) analogues is described herein. These compounds were prepared in an effort to probe the SAR around the phenyl substituent and oxadiazole core for our studies toward thioredoxin-glutathione reductase (TGR) inhibition and antischistosomal activity.
- Rai, Ganesha,Thomas, Craig J.,Leister, William,Maloney, David J.
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supporting information; experimental part
p. 1710 - 1713
(2009/07/05)
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- Structure mechanism insights and the role of nitric oxide donation guide the development of oxadiazole-2-oxides as therapeutic agents against schistosomiasis
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Schistosomiasis is a chronic parasitic disease affecting hundreds of millions of individuals worldwide. Current treatment depends on a single agent, praziquantel, raising concerns of emergence of resistant parasites. Here, we continue our explorations of an oxadiazole-2-oxide class of compounds we recently identified as inhibitors of thioredoxin glutathione reductase (TGR), a selenocysteine-containing flavoenzyme required by the parasite to maintain proper cellular redox balance. Through systematic evaluation of the core molecular structure of this chemotype, we define the essential pharmacophore, establish a link between the nitric oxide donation and TGR inhibition, determine the selectivity for this chemotype versus related reductase enzymes, and present evidence that these agents can be modified to possess appropriate drug metabolism and pharmacokinetic properties. The mechanistic link between exogenous NO donation and parasite injury is expanded and better defined. The results of these studies verify the utility of oxadiazole-2-oxides as novel inhibitors of TGR and as efficacious antischistosomal agents. 2009 American Chemical Society.
- Rai, Ganesha,Sayed, Ahmed A.,Lea, Wendy A.,Luecke, Hans F.,Chakrapani, Harinath,Prast-Nielsen, Stefanie,Jadhav, Ajit,Leister, William,Shen, Min,Inglese, James,Austin, Christopher P.,Keefer, Larry,Arnér, Elias S. J.,Simeonov, Anton,Maloney, David J.,Williams, David L.,Thomas, Craig J.
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supporting information; experimental part
p. 6474 - 6483
(2010/03/31)
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