- Green sustainable approach for carbon–carbon bond-forming reactions using FeNPs/DETA@rGO nano-catalyst
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We have fabricated eccentric highly persuasive bifunctional FeNPs/DETA@rGO (where DETA = diethylenetriamine) nano-catalyst with a dual activation mechanism by presenting aliphatic amine on the basal and/or edges sites offering a base characteristic and Fe
- Kane, Sanjeev R.,Modi, Chetan K.,Patel, Dikin,Srivastava, Himanshu,Trivedi, Komal A.
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- Cobalt-Catalyzed Asymmetric 1,4-Reduction of β,β-Dialkyl α,β-Unsaturated Esters with PMHS
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A cobalt-catalyzed asymmetric reduction of β,β-dialkyl α,β-unsaturated esters with polymethylhydrosiloxane (PMHS) was reported to deliver the corresponding esters containing a chiral trialkyl carbon center at β-position with up to 97 % yield and 98 % ee. The chiral tridentate ligand oxazoline iminopyridine (OIP) could perform well for the asymmetric reduction instead of chiral bidentate ligands. This operationally simple protocol shows a broad scope of substrates using one equivalent of readily available PMHS as a cheap and easy-to-handle reductive reagent.
- Lu, Dongpo,Lu, Peng,Lu, Zhan
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supporting information
p. 4861 - 4864
(2021/09/22)
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- 8-Hydroxyquinolin-2(1H)-one analogues as potential β2-agonists: Design, synthesis and activity study
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β2-Agonists that bind to plasmalemmal β2-adrenoceptors causing cAMP accumulation are widely used as bronchodilators in chronic respiratory diseases. Here, we designed and synthesized a group of 8-hydroxyquinolin-2(1H)-one analogues and studied their β2-agonistic activities with a cellular cAMP assay. Compounds B05 and C08 were identified as potent (EC50 2-agonists among the compounds tested. They behaved as partial β2-agonists in non-overexpressed HEK293 cells, and possessed rapid smooth muscle relaxant actions and long duration of action in isolated guinea pig tracheal strip preparations. In summary, B05 and C08 are β2-agonists with potential applicability in chronic respiratory diseases.
- Xing, Gang,Zhi, Zhengxing,Yi, Ce,Zou, Jitian,Jing, Xuefeng,Yiu-Ho Woo, Anthony,Lin, Bin,Pan, Li,Zhang, Yuyang,Cheng, Maosheng
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- Organocatalytic diastereo- And enantioselective oxa-hetero-Diels-Alder reactions of enones with aryl trifluoromethyl ketones for the synthesis of trifluoromethyl-substituted tetrahydropyrans
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Tetrahydropyran derivatives are found in bioactives, and introduction of the trifluoromethyl group into molecules often improves biofunctions. Here we report diastereo- and enantioselective oxa-hetero-Diels-Alder reactions catalyzed by amine-based catalyst systems that afford trifluoromethyl-substituted tetrahydropyranones. Catalyst systems and conditions suitable for the reactions to provide the desired diastereomer products with high enantioselectivities were identified, and various trifluoromethyl-substituted tetrahydropyranones were synthesized with high diastereo- and enantioselectivities. Mechanistic investigation suggested that the reactions involve a [4 + 2] cycloaddition pathway, in which the enamine of the enone acts as the diene and the ketone carbonyl group of the aryl trifluoromethyl ketone acts as the dienophile. In this study, tetrahydropyran derivatives with the desired stereochemistry that are difficult to synthesize by previously reported methods were concisely obtained, and the range of tetrahydropyran derivatives that can be synthesized was expanded. This journal is
- Pasha, Maira,Tanaka, Fujie
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supporting information
p. 9242 - 9250
(2021/11/16)
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- PQQ-dependent Dehydrogenase Enables One-pot Bi-enzymatic Enantio-convergent Biocatalytic Amination of Racemic sec-Allylic Alcohols
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The asymmetric amination of secondary racemic allylic alcohols bears several challenges like the reactivity of the bi-functional substrate/product as well as of the α,β-unsaturated ketone intermediate in an oxidation-reductive amination sequence. Heading for a biocatalytic amination cascade with a minimal number of enzymes, an oxidation step was implemented relying on a single PQQ-dependent dehydrogenase with low enantioselectivity. This enzyme allowed the oxidation of both enantiomers at the expense of iron(III) as oxidant. The stereoselective amination of the α,β-unsaturated ketone intermediate was achieved with transaminases using 1-phenylethylamine as formal reducing agent as well as nitrogen source. Choosing an appropriate transaminase, either the (R)- or (S)-enantiomer was obtained in optically pure form (>98 % ee). The enantio-convergent amination of the racemic allylic alcohols to one single allylic amine enantiomer was achieved in one pot in a sequential cascade.
- Gandomkar, Somayyeh,Rocha, Raquel,Sorgenfrei, Frieda A.,Montero, Lía Martínez,Fuchs, Michael,Kroutil, Wolfgang
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p. 1290 - 1293
(2020/12/23)
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- Inhibition of Autophagy by a Small Molecule through Covalent Modification of the LC3 Protein
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The autophagic ubiquitin-like protein LC3 functions through interactions with LC3-interaction regions (LIRs) of other autophagy proteins, including autophagy receptors, which stands out as a promising protein–protein interaction (PPI) target for the intervention of autophagy. Post-translational modifications like acetylation of Lys49 on the LIR-interacting surface could disrupt the interaction, offering an opportunity to design covalent small molecules interfering with the interface. Through screening covalent compounds, we discovered a small molecule modulator of LC3A/B that covalently modifies LC3A/B protein at Lys49. Activity-based protein profiling (ABPP) based evaluations reveal that a derivative molecule DC-LC3in-D5 exhibits a potent covalent reactivity and selectivity to LC3A/B in HeLa cells. DC-LC3in-D5 compromises LC3B lipidation in vitro and in HeLa cells, leading to deficiency in the formation of autophagic structures and autophagic substrate degradation. DC-LC3in-D5 could serve as a powerful tool for autophagy research as well as for therapeutic interventions.
- Chen, Kaixian,Chen, Zhifeng,Dang, Yongjun,Ding, Hong,Fan, Shijie,Hu, Junchi,Jiang, Hualiang,Li, Lianchun,Li, Quanfu,Lin, Tingting,Lu, Junyan,Luo, Cheng,Otomo, Chinatsu,Otomo, Takanori,Tan, Minjia,Tao, Hongru,Wan, Wei,Wen, Yi,Xie, Yuli,Xu, Pan,Yao, Zhiyi,Yue, Liyan,Zhang, Bidong,Zhang, Naixia,Zhang, Yuanyuan,Zhou, Bing,Zhu, Mingrui
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supporting information
p. 26105 - 26114
(2021/11/09)
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- Selective Cross-Dehydrogenative C(sp3)-H Arylation with Arenes
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Selective C(sp3)-C(sp2) bond construction is of central interest in chemical synthesis. Despite the success of classic cross-coupling reactions, the cross-dehydrogenative coupling between inert C(sp3)-H and C(sp2)-H bonds represents an attractive alternative toward new C(sp3)-C(sp2) bonds. Herein, we establish a selective inter-and intramolecular C(sp3)-H arylation of alcohols with nondirected arenes that thereby provides a general pathway to access a wide range of β-arylated alcohols, including tetrahydronaphthalen-2-ols and benzopyran-3-ols, with high to excellent chemo-and regioselectivity.
- Hao, Hong-Yan,Mao, Yang-Jie,Xu, Zhen-Yuan,Lou, Shao-Jie,Xu, Dan-Qian
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supporting information
p. 2396 - 2402
(2020/03/13)
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- Design, synthesis and biological evaluation of novel diaryl pyrazole derivatives as anticancer agents
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Cancer is one of the major causes of mortality all around the world. Globally, nearly 1 in 6 deaths is due to cancer. Researchers are trying to synthesize new anticancer agents. Previous studies demonstrated that some pyrazole derivatives could be considered as potential anticancer agents. Herein, ten novel derivatives of 1,5-diarylpyrazole were synthesized in four step reactions and cytotoxic activity was investigated by MTT cell viability assay. All of the compounds were characterized by1H NMR and13C NMR and their purity was confirmed by elemental analysis. The cytotoxicity was determined against three cancerous cell lines (HT-29, U87MG and MDA-MB 468) and AGO1522 as a normal cell line. Compound 5a showed the best cytotoxic activity on cancerous cell lines in comparison to paclitaxel. Annexin V/ PI staining assay also showed that compounds 5a and 5i would lead to significant apoptosis induction in MDA-MB 486 cell line.
- Nourmahammadi, Jalal,Moghadam, Ebrahim Saeedian,Shahsavari, Zahra,Amini, Mohsen
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p. 216 - 223
(2020/02/29)
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- Oxazole-linked triazole drug molecule for sterilization and disinfection, and preparation method and application thereof
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The invention discloses an oxazole-linked triazole drug molecule for sterilization and disinfection, and a preparation method and an application thereof, and belongs to the technical field of synthesis of antibacterial drugs. The oxazole-linked triazole d
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Paragraph 0023-0031
(2020/08/30)
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- A bioinspired microreactor with interfacial regulation for maximizing selectivity in a catalytic reaction
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We report a bioinspired emulsion microreactor composed of an electrical double layer to mimic the functions of cell membranes. This "artificial cell"can modulate the phase-oriented transport of reagents at the oil-liquid interface via the electrical double layer, affording a powerful tool to optimize the selectivity in a catalytic reaction. This journal is
- Han, Chenhui,Li, Xin-Hao,Waclawik, Eric R.,Xu, Haolan,Xu, Jingsan
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supporting information
p. 8059 - 8062
(2020/09/09)
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- Boosting multiple photo-assisted and temperature controlled reactions with a single redox-switchable catalyst: Solvents as internal substrates and reducing agent
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An alternative and economically viable process for the synthesis of β-aryl enals, enones and the aryl amines has been developed by partial oxidation of ethanol, isopropanol and N, N-dimethyl formamide (DMF). The formation of β-aryl enals, enones and the aryl amines was catalyzed by a mixed metal oxides layer of cobalt and chromium supported on halloysite nanotubes, designated as CoCr2O4-HNT. The C[sbnd]C and C[sbnd]N bond formation reactions were found to be influenced by temperature and the nature of base. The condensation of aldehyde with in situ generated acetaldehyde by ethanol oxidation forming β-aryl enals occurred selectively at 120 °C. The partial oxidation of isopropanol to acetone and its condensation with aldehydes forming β-aryl enones occurred at room temperature. Increase in temperature caused the liberation of hydrogen gas from isopropanol and allowed the reversible reduction of aldehydes to alcohols. Increase in temperature in isopropanol and increase in base concentration in ethanol causes the selective reduction of aldehydes to alcohols. Besides being active for the Claisen-Schmidt type of reactions and the aryl halides amination process, the synthesized catalyst was also found to be highly active for the photocatalytic oxidation of benzyl alcohols in absence of any external oxidizing agent. The positive holes (h+) generated at the Co(II) site as evident from EPR analysis was considered to be responsible for high photocatalytic activity of the material reducing the recombination rate of holes and electrons (e?). Density Functional Theory calculations were performed to understand the mechanism of ethanol oxidation to acetaldehyde.
- Bania, Kusum K.,Baruah, Manash J.,Bhattacharyya, Pradip K.,Das, Biraj,Karunakar, Galla V.,Roy, Subhasish,Saikia, Lakshi,Saikia, Pinku,Sharma, Mukesh
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p. 104 - 121
(2020/06/01)
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- Iodine/water-mediated deprotective oxidation of allylic ethers to access α,β-unsaturated ketones and aldehydes
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The first iodine/water-mediated deprotective oxidation of allylic ethers to access α,β-unsaturated ketones and aldehydes was achieved. The reaction tolerates a wide range of functionalities. Furthermore, this protocol was found to be applicable to the oxidative transformation of allylic acetates. The proposed mechanism involves an oxygen transfer from solvent water to the carbonyl products.
- Chen, Weifeng,Jiang, Kezhi,Xue, Yuntian,Yan, Yaolong,Yang, Lei
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p. 14720 - 14724
(2020/04/27)
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- NOVEL SMALL MOLECULES THAT BIND AND/OR MODULATE DIFFERENTFORMS OF TAU OLIGOMERS
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The present invention relates to novel small molecules of Formulas I, II, III, Ilia, Illb, and IV and pharmaceutically acceptable salts thereof, as well as the preparation and the use thereof.
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Page/Page column 34; 35
(2020/11/03)
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- Fe3O4?l-Proline/Pd nanocomposite for one-pot tandem catalytic synthesis of (±)-warfarin from benzyl alcohol: Synergistic action of organocatalyst and transition metal catalyst
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One-pot synthesis of (±)-warfarin, an anticoagulant, has been achieved from benzyl alcohol in a 'green way' by using a multicomponent catalyst. For the purpose, l-proline capped Fe3O4 nanoparticles (Fe3O4?l-proline NPs) were synthesized and metallic palladium was loaded on its surface (Fe3O4?l-proline/Pd NCs). The morphology, particle size and shape were studied by using FESEM and TEM analysis. The Pd present on the surface was responsible for oxidation of benzyl alcohol and its derivatives to the corresponding aldehyde in situ. This in turn, condensed with acetone to form the aldol condensation product, benzylideneacetone, at 70 °C due to the presence of the l-proline organocatalyst on the surface of Fe3O4 NPs. Later, 4-hydroxycoumarin was introduced to condense with in situ generated benzylideneacetone by a Michael addition to form the target product (±)-warfarin. It was established that benzyl alcohol can be converted into the final product, (±)-warfarin, with an overall 35% yield within 5 days in a single-pot process. This process requires a rise in temperature in stages to a maximum of 100 °C and 1 atm pressure of dioxygen gas. An important aspect of the developed process is the avoidance of loss of costly Pd by leaching and catalyst recovery by the use of a magnetic field. The use of a solvent like PEG-400 makes the process green in a true sense. The interaction of l-proline with Fe3O4 NPs and the presence of Pd on the surface were confirmed by the FTIR and XRD patterns, respectively. The present study hereby suggests a combined 3-step mechanism for the production of the target product warfarin. Pilot-scale one-pot production of (±)-warfarin was carried out and a flow diagram with various unit processes is presented.
- Tomer, Sanjiv O.,Soni, Hemant P.
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p. 6517 - 6531
(2019/11/20)
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- Construction of Multiple-Substituted Chiral Cyclohexanes through Hydrogenative Desymmetrization of 2,2,5-Trisubstituted 1,3-Cyclohexanediones
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The construction of chiral multiple-substituted cyclohexanes motifs is a challenging topic in organic synthesis. By the combination of desymmetrization and remote stereocontrol, a ruthenium-catalyzed transfer hydrogenative desymmetrization of 2,2,5-trisubstituted 1,3-cyclohexanediones has been successfully developed for the construction of chiral multiple-substituted cyclohexanes with high enantioselectivity and diastereoselectivity. When an ester group was introduced to the two-position, a hydrogenative desymmetrization/transesterification cascade occurred, affording the bicyclic lactones bearing three stereocenters, including two discrete stereocenters and one quaternary stereogenic center, with high enantioselectivity. The products are the multiple-substituted chiral cyclohexanes bearing the hydroxyl and carbonyl functional groups, which provide a new opportunity for further precise elaboration.
- Yu, Chang-Bin,Song, Bo,Chen, Mu-Wang,Shen, Hong-Qiang,Zhou, Yong-Gui
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supporting information
p. 9401 - 9404
(2019/11/28)
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- Encapsulating mesoporous metal nanoparticles: Towards a highly active and stable nanoreactor for oxidative coupling reactions in water
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We design and prepare a highly active and stable nanoreactor via encapsulating various mesoporous metal nanoparticles with an amphiphilic hollow shell, which presents excellent performance in oxidative coupling reactions in water for efficient production of α,β-unsaturated ketones.
- Zou, Houbing,Dai, Jinyu,Wang, Runwei
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supporting information
p. 5898 - 5901
(2019/05/27)
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- Ligand-free palladium-catalyzed tandem pathways for the synthesis of 4,4-diarylbutanones and 4,4-diaryl-3-butenones under microwave conditions
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Two efficient Pd-catalyzed tandem pathways for the synthesis of 4,4-diaryl-2-butanones and 4,4-diaryl-3-buten-2-ones were elaborated. The first step in both procedures was the Heck coupling of methyl vinyl ketone (MVK) and various aryl iodides leading to 4-aryl-3-buten-2-one with the yield of up to 92% in 1?hr. The second step performed with the same catalyst and a new portion of aryl iodide in the presence K2CO3 as a base produced 4,4-diaryl-3-buten-2-ones in high yield. Reaction selectivity changed completely to saturated 4,4-diaryl-2-butanones, reductive Heck products, when a tertiary amine was used instead of K2CO3. Due to the application of microwave irradiation (MW), the desired products were obtained in high yield in a short time (4?hr), using 0.5?mol% of the Pd (OAc)2 catalyst without additional ligands.
- Wirwis, Anna,Trzeciak, Anna M.
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- Boehmite - An efficient and recyclable acid-base bifunctional catalyst for aldol condensation reaction
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In this work boehmite was used as an acid-base bifunctional catalyst for aldol condensation reactions of aromatic aldehydes and ketones. The catalyst was prepared by simple sol-gel method using Al(NO3)3 · 9H2O and NH4OH as precursors. The catalyst has been characterized by X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM), UV-visible spectroscopy (DRS), BET surface area analyses. Boehmite is successfully applied as catalyst for the condensation reaction between 4-nitrobenzaldehyde and acetone as a model substrate giving α,β-unsaturated ketones without any side product. The scope of the reaction is extended for various substituted aldehydes. A probable mechanism has been suggested to explain the cooperative behavior of the acidic and basic sites. The catalyst is environmentally friendly and easily recovered from the reaction mixture. Also the catalyst is reusable up to 3 catalytic cycles.
- Reshma, P.C. Rajan,Vikneshvaran, Sekar,Velmathi, Sivan
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p. 4270 - 4275
(2018/01/11)
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- Evaluation of sulphonamide derivatives acting as inhibitors of human carbonic anhydrase isoforms I, II and Mycobacterium tuberculosis β-class enzyme Rv3273
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A series of novel sulphonamide derivatives was obtained from sulphanilamide which was N4-alkylated with ethyl bromoacetate followed by reaction with hydrazine hydrate. The hydrazide obtained was further reacted with various aromatic aldehydes. The novel sulphonamides were characterised by infrared, mass spectrometry, 1H- and 13C-NMR and purity was determined by high-performance liquid chromatography (HPLC). Human (h) carbonic anhydrase (CA, EC 4.2.1.1) isoforms hCA I and II and Mycobacterium tuberculosis β-CA encoded by the gene Rv3273 (mtCA 3) inhibition activity was investigated with the synthesised compounds which showed promising inhibition. The KIs were in the range of 54.6 nM–1.8 μM against hCA I, in the range of 32.1 nM–5.5 μM against hCA II and of 127 nM–2.12 μM against mtCA 3.
- Wani, Tanvi V.,Bua, Silvia,Khude, Pravin S.,Chowdhary, Abdul H.,Supuran, Claudiu T.,Toraskar, Mrunmayee P.
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p. 962 - 971
(2018/05/29)
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- Rh(III)-Catalyzed Enaminone-Directed Alkenyl C-H Activation for the Synthesis of Salicylaldehydes
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A Rh(III)-catalyzed enaminone-directed alkenyl C-H coupling with alkynes for the synthesis of salicylaldehyde derivatives is reported. This represents a unique example of benzene ring framework formation through a transition-metal-catalyzed, directed C-H activation strategy. The two incorporated reactive functionalities, aldehyde and hydroxy groups, provide convenient synthetic handles for further structural elaboration.
- Qi, Bing,Guo, Shan,Zhang, Wenjing,Yu, Xiaolong,Song, Chao,Zhu, Jin
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supporting information
p. 3996 - 3999
(2018/07/15)
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- Gram-scale preparation of dialkylideneacetones through Ca(OH)2-catalyzed Claisen-Schmidt condensation in dilute aqueous EtOH
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A synthetic method of dialkylideneacetones has been developed. Compared with known protocols, the method employed catalytic Ca(OH)2 as the cheap, mild base catalyst and dilute aqueous EtOH (20%, v/v) as the green and safe solvent. The procedure was easily operated: In most cases, the product could be isolated by a simple filtration, and purified by washing with water. This paper provided experimental details of the reactions, which could be applied in gram-scale synthesis and should be a very reliable and practical protocol to prepare these useful compounds in laboratory and at the industrial level.
- Zhang, Hao,Han, Mengting,Yang, Chenggen,Yu, Lei,Xu, Qing
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- Linear polystyrene-stabilized Rh(III) nanoparticles for oxidative coupling of arylboronic acids with alkenes in water
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Linear polystyrene-stabilized Rh(III) nanoparticles (PS-Rh(III)NPs) were obtained when an aqueous solution of RhCl3 was stirred at 90 °C in the presence of KOH, 4-methylphenylboronic acid, and linear polystyrene, as indicated by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). PS-Rh(III)NPs exhibited high catalytic activity for the oxidative coupling of arylboronic acids with alkenes. In contrast, PS-Rh(0)NPs prepared with NaBH4 had little activity for the same reaction.
- Ohtaka, Atsushi,Fukui, Shiho,Sakon, Akira,Hamasaka, Go,Uozumi, Yasuhiro,Shinagawa, Tsutomu,Shimomura, Osamu,Nomura, Ry?ki
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- Natural product-based pesticide discovery: Design, synthesis and bioactivity studies of N-amino-maleimide derivatives
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Natural products are an important source of pesticide discovery. A series of N-amino-maleimide derivatives containing hydrazone group were designed and synthesized based on the structure of linderone and methyllinderone which were isolated from Lindera erythrocarpa Makino. According to the bioassay results, compounds 2 and 3 showed 60% inhibition against mosquito (Culex pipiens pallens) at 0.25 μg·mL?1. Furthermore, the results of antifungal tests indicated that most compounds exhibited much better antifungal activities against fourteen phytopathogenic fungi than linderone and methyllinderone and some compounds exhibited better antifungal activities than commercial fungicides (carbendazim and chlorothalonil) at 50 μg·mL?1. In particular, compound 12 exhibited broad-spectrum fungicidal activity (>50% inhibitory activities against 11 phytopathogenic fungi) and compounds 12 and 14 displayed 60.6% and 47.9% inhibitory activity against Rhizoctonia cerealis at 12.5 μg·mL?1 respectively. Furthermore, compound 17 was synthesized, which lacks N-substituent at maleimide and its poor antifungal activity against Sclerotinia sclerotiorum and Rhizoctonia cerealis at 50 μg·mL?1 showed that the backbone structure of N-amino-maleimide derivatives containing hydrazone group was important to the antifungal activity.
- Song, Xiangmin,Liu, Chunjuan,Chen, Peiqi,Zhang, Hao,Sun, Ranfeng
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- Dehydrogenative Formation of Resorcinol Derivatives Using Pd/C-Ethylene Catalytic System
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The conversion of substituted 1,3-cyclohexanediones to the alkyl ethers of resorcinol using a Pd/C-ethylene system is reported. In these reactions, ethylene works as a hydrogen acceptor. The efficient synthesis of resveratrol was achieved using this protocol as a key step. In addition, the direct formation of substituted resorcinols was carried out by adding K2CO3 into the reaction media.
- El-Deeb, Ibrahim Yussif,Funakoshi, Tatsuya,Shimomoto, Yuya,Matsubara, Ryosuke,Hayashi, Masahiko
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p. 2630 - 2640
(2017/03/14)
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- Palladium-Catalyzed Cleavage of α-Allenylic Aryl Ether toward Pyrazolemethylene-Substituted Phosphinyl Allenes and Their Transformations via Alkenyl C-P(O) Cleavage
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A palladium-catalyzed two-component coupling of allenylphosphine oxides with conjugated N-tosylhydrazones is revealed. For the first time, the cleavage of α-allenylic aryl ether toward pyrazolemethylene-substituted phosphinyl allenes enabled facile synthesis of combined motifs with pyrazole and allene. Moreover, the obtained adducts could be easily transformed to potential bioactive multifunctionalized phosphinates via a novel alkenyl C-P(O) cleavage.
- Zhu, Jie,Mao, Mao,Ji, Huan-Jing,Xu, Jiang-Yan,Wu, Lei
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supporting information
p. 1946 - 1949
(2017/04/28)
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- Kinetic and Mechanistic Examination of Acid-Base Bifunctional Aminosilica Catalysts in Aldol and Nitroaldol Condensations
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The kinetic and mechanistic understanding of cooperatively catalyzed aldol and nitroaldol condensations is probed using a series of mesoporous silicas functionalized with aminosilanes to provide bifunctional acid-base character. Mechanistically, a Hammett analysis is performed to determine the effects of electron-donating and electron-withdrawing groups of para-substituted benzaldehyde derivatives on the catalytic activity of each condensation reaction. This information is also used to discuss the validity of previously proposed catalytic mechanisms and to propose a revised mechanism with plausible reaction intermediates. For both reactions, electron-withdrawing groups increase the observed rates of reaction, though resonance effects play an important, yet subtle, role in the nitroaldol condensation, in which a p-methoxy electron-donating group is also able to stabilize the proposed carbocation intermediate. Additionally, activation energies and pre-exponential factors are calculated via the Arrhenius analysis of two catalysts with similar amine loadings: one catalyst had silanols available for cooperative interactions (acid-base catalysis), while the other was treated with a silanol-capping reagent to prevent such cooperativity (base-only catalysis). The values obtained for activation energies and pre-exponential factors in each reaction are discussed in the context of the proposed mechanisms and the importance of cooperative interactions in each reaction. The catalytic activity decreases for all reactions when the silanols are capped with trimethylsilyl groups, and higher temperatures are required to make accurate rate measurements, emphasizing the vital role the weakly acidic silanols play in the catalytic cycles. The results indicate that loss of acid sites is more detrimental to the catalytic activity of the aldol condensation than the nitroaldol condensation, as evidenced by the significant decrease in the pre-exponential factor for the aldol condensation when silanols are unavailable for cooperative interactions. Cooperative catalysis is evidenced by significant changes in the pre-exponential factor, rather than the activation energy for the aldol condensation.
- Collier, Virginia E.,Ellebracht, Nathan C.,Lindy, George I.,Moschetta, Eric G.,Jones, Christopher W.
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p. 460 - 468
(2016/01/12)
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- Discovery of New Monocarbonyl Ligustrazine-Curcumin Hybrids for Intervention of Drug-Sensitive and Drug-Resistant Lung Cancer
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The elevation of oxidative stress preferentially in cancer cells by inhibiting thioredoxin reductase (TrxR) and/or enhancing reactive oxygen species (ROS) production has emerged as an effective strategy for selectively targeting cancer cells. In this study, we designed and synthesized 21 ligustrazine-curcumin hybrids (10a-u). Biological evaluation indicated that the most active compound 10d significantly inhibited the proliferation of drug-sensitive (A549, SPC-A-1, LTEP-G-2) and drug-resistant (A549/DDP) lung cancer cells but had little effect on nontumor lung epithelial-like cells (HBE). Furthermore, 10d suppressed the TrxR/Trx system and promoted intracellular ROS accumulation and cancer cell apoptosis. Additionally, 10d inhibited the NF-κB, AKT, and ERK signaling, P-gp-mediated efflux of rhodamine 123, P-gp ATPase activity, and P-gp expression in A549/DDP cells. Finally, 10d repressed the growth of implanted human drug-resistant lung cancer in mice. Together, 10d acts a novel TrxR inhibitor and may be a promising candidate for intervention of lung cancer.
- Ai, Yong,Zhu, Bin,Ren, Caiping,Kang, Fenghua,Li, Jinlong,Huang, Zhangjian,Lai, Yisheng,Peng, Sixun,Ding, Ke,Tian, Jide,Zhang, Yihua
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p. 1747 - 1760
(2016/03/25)
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- Enzyme-catalyzed domino reaction: Efficient construction of spirocyclic oxindole skeleton using porcine pepsin
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Pepsin from porcine gastric mucosa was used as a sustainable and environmentally friendly biocatalyst in the domino Knoevenagel/Michael/Michael reaction for the synthesis of spirooxindole derivatives in methanol. A wide range of isatins and α,β-unsaturated ketones reacting with malononitrile provided the corresponding products in yields of up to 99% with diastereoselectivities of up to >99:1 dr. This pepsin-catalyzed domino reaction provided a novel case of enzyme catalytic promiscuity.
- He, Yan-Hong,He, Tao,Guo, Jun-Tao,Li, Rui,Xiang, Yang,Yang, Da-Cheng,Guan, Zhi
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p. 2239 - 2248
(2016/04/26)
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- Synthesis and neuroprotective evaluation of (E)-3,4-dihydroxystyryl p-substituted-phenethyl ketone derivatives against inflammatory and oxidative injury
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(E)-3,4-dihydroxystyryl p-substituted-phenethyl ketones and their 3,4-diacetylated derivatives were synthesized and examined their neuroprotective activities to further study the effect of p-substituents on the aromatic ring. The results revealed that steric hindrance effect of p-substituents has impact on neuroprotective activities against inflammatory and oxidative injury. Introduction of the bulkier groups are more beneficial to improve the neuroprotective activities than smaller groups. Compounds (4–5h, 4–5i and 4–5e) with p-substituted trifluoromethyl, isopropyl and t-butyl groups exhibited the best effects among all the target compounds.
- Cheng, Can,Ning, Xianling,Luo, Yongming,Tian, Chao,Wang, Xiaowei,Guo, Ying,Liu, Junyi,Zhang, Zhili
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p. 1678 - 1685
(2016/07/30)
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- Method for preparing alpha and beta-unsaturated ketone
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The invention provides a method for preparing alpha and beta-unsaturated ketone. The method includes that L-proline is used as a catalyst, secondary amine is used as a cocatalyst, and the alpha and beta-unsaturated ketone can be directly synthesized in alcohol or ketone solution by means of aldol condensation under neutral conditions at one step. Compared with the traditional method, the method has the advantages that raw materials are easily available, the method is low in cost and is environmental friendly, reaction conditions are mild, solvents are clean and environmental friendly, equipment can be protected against corrosion under the neutral conditions, the catalyst is high in acid resistance, and the method is applicable to industrial production.
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Paragraph 0012; 0013; 0034; 0035; 0036; 0040; 0041
(2016/10/31)
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- A multicomponent pathway-inspired regioselective synthesis of 2,3,4-trisubstituted 1H-pyrroles via [3+2] cycloaddition reaction
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A copper catalyzed regioselective synthesis of 2,3,4-trisubstituted 1H-pyrroles using a novel three-component coupled domino reaction of aldehydes, ketones and alkyl isocyanoacetates is reported. This transformation proceeds through the formation of a chalcone followed by a [3+2] cycloaddition reaction to obtain α-cuprioisocyanide, a cyclic organocopper intermediate, which on copper-hydrogen exchange followed by oxidation exclusively offers 2,3,4-trisubstituted 1H-pyrrole.
- Kalmode, Hanuman P.,Vadagaonkar, Kamlesh S.,Murugan, Kaliyappan,Chaskar, Atul C.
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p. 4631 - 4639
(2015/06/16)
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- Synthesis of Polysubstituted Pyridines via a One-Pot Metal-Free Strategy
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An efficient strategy for the one-pot synthesis of polysubstituted pyridines via a cascade reaction from aldehydes, phosphorus ylides, and propargyl azide is reported. The reaction sequence involves a Wittig reaction, a Staudinger reaction, an aza-Wittig reaction, a 6π-3-azatriene electrocyclization, and a 1,3-H shift. This protocol provides quick access to the polysubstituted pyridines from readily available substrates in good to excellent yields.
- Wei, Hongbo,Li, Yun,Xiao, Ke,Cheng, Bin,Wang, Huifei,Hu, Lin,Zhai, Hongbin
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supporting information
p. 5974 - 5977
(2016/01/09)
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- Graphene based material as a base catalyst for solvent free Aldol condensation and Knoevenagel reaction at room temperature
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Graphene oxide (GO) acts as a highly active heterogeneous base catalyst for a wide variety of reactions. Here we have described the catalytic activities of GO in the condensation reaction of various substituted benzaldehydes with acetophenone (aldol condensation) and with active methylene compound malononitrile (Knoevenagel reaction) at room temperature under solvent free condition. GO is characterized by powder X-ray diffraction (XRD), UV-visible spectra, Fourier transform infrared spectroscopy (FT-IR) and AFM. The experimental results showed that the GO had higher catalytic activity and it can be recycled without significant loss of its activity.
- Islam, Sk Manirul,Roy, Anupam Singha,Dey, Ram Chandra,Paul, Sumantra
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- I2-mediated oxidative C-N bond formation for metal-free one-pot synthesis of di-, tri-, and tetrasubstituted pyrazoles from α,β-unsaturated aldehydes/ketones and hydrazines
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An I2-mediated metal-free oxidative C-N bond formation methodology has been established for the regioselective pyrazole synthesis. This practical and eco-friendly one-pot protocol requires no isolation of the less stable intermediates hydrazone
- Zhang, Xinting,Kang, Jinfeng,Niu, Pengfei,Wu, Jie,Yu, Wenquan,Chang, Junbiao
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p. 10170 - 10178
(2015/02/19)
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- Carbon quantum dots with photoenhanced hydrogen-bond catalytic activity in aldol condensations
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Carbon quantum dots (CQDs) were synthesized by an electrochemical etching method. The CQDs are well-dispersed with uniform size about 5 nm. FT-IR spectra suggest the presence of many hydroxyl groups on the surface of CQDs. Here, CQDs with diameter approximately 5 nm, directly used as effective heterogeneous nanocatalysts for H-bond catalysis in aldol condensations, show excellent photoenhanced catalytic ability (89% yields when 4-cyanobenzaldehyde is used). It demonstrated that aldol condensation between acetone and aromatic aldehydes resulted in higher yields with visible light irradiation than in the dark, confirming visible light is necessary for good conversion. The H-bond catalytic activities of CQDs can be significantly enhanced with visible light irradiation. The high catalytic activities of CQDs are due to highly efficient electron-accepting capabilities. Repeated catalytic experiments suggest that the CQD catalyst can be easily recycled as a heterogeneous catalyst with a long catalyst life.
- Han, Yuzhi,Huang, Hui,Zhang, Hengchao,Liu, Yang,Han, Xiao,Liu, Ruihua,Li, Haitao,Kang, Zhenhui
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p. 781 - 787
(2014/04/03)
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- Catalytic microwave-promoted direct aldol condensation using resin-bound secondary amine
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A series of polystyrene-supported imino group-bearing catalysts were prepared. A highly efficient combination of recyclable catalysts and microwave irradiation was developed as a green protocol for the direct aldol reaction. Notably, microwaves greatly shorten the reaction times to only 20 min and improve the yield significantly. Catalyst loading was reduced as well. Different aromatic aldehydes as aldol donors were subjected to our catalyst system and afforded the corresponding products in satisfactory yields. Additionally, the polymer-supported catalysts could be recovered by simple filtration and were reusable for at least four times without significant loss of reactivity. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications for the following free supplemental resource(s): Full experimental and spectral details.]
- Liao, Fu Xu,Wang, Yu Guang,Zhu, Qing
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supporting information
p. 161 - 169
(2013/12/04)
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- Wacker-type oxidation and dehydrogenation of terminal olefins using molecular oxygen as the sole oxidant without adding ligand
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An efficient and economical palladium-catalyzed oxidation system has been identified. The oxidation system, characterized by not adding ligand and using molecular oxygen as the sole oxidant, can realize the Tsuji-Wacker oxidation of terminal olefins and especially styrenes to methyl ketones; in addition, this system can achieve tandem Wacker oxidation-dehydrogenation of terminal olefins to α,β-unsaturated ketones.
- Wang, Yu-Fei,Gao, Ya-Ru,Mao, Shuai,Zhang, Yan-Lei,Guo, Dong-Dong,Yan, Zhao-Lei,Guo, Shi-Huan,Wang, Yong-Qiang
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supporting information
p. 1610 - 1613
(2014/04/17)
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- Enantioselective [4 + 2] cycloaddition of cyclic N-sulfimines and acyclic enones or ynones: A concise route to sulfamidate-fused 2,6-disubstituted piperidin-4-ones
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A concise route to valuable sulfamate-fused 2,6-disubstituted piperidin-4-ones or 2,3-dihydropyridin-4(1H)-ones in good yield with high diastereo- and enantioselectivity is presented. The combination of chiral primary amine and o-fluorobenzoic acid efficiently promoted an asymmetric [4 + 2] cycloaddition reaction of N-sulfonylimines and enones or ynones. The cycloaddition reaction between cyclic N-sulfonylimines and ynones is first reported.
- Liu, Yong,Kang, Tai-Ran,Liu, Quan-Zhong,Chen, Lian-Mei,Wang, Ya-Chuan,Liu, Jie,Xie, Yong-Mei,Yang, Jin-Liang,He, Long
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p. 6090 - 6093
(2014/01/06)
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- Synthesis of β-sulfanyl ketones via a tandem rearrangement-conjugate addition reaction catalyzed by a Re(V)-oxo complex
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A method for synthesizing β-sulfanyl ketones via a tandem rearrangement and conjugate addition reaction has been developed. This methodology provides access to a range of β-sulfanyl ketones through the rearrangement of propargyl alcohols to the corresponding enones followed by the conjugate addition of unactivated thiols. The one-pot, tandem transformation is catalyzed by ReOCl3(OPPh3)(S(CH3)2) affording aryl and alkyl β-sulfanyl ketones in good to excellent yield.
- Garst, Alyson E.,Badiceanu, Alexandra D.,Nolin, Kristine A.
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supporting information
p. 459 - 461
(2013/02/23)
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- FLAVONE DERIVATIVES AND THEIR PREPARATIVE METHOD AND MEDICAL USE
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Flavone derivatives, preparative method of the derivatives and use thereof as medicaments for treating diabetes. The structure of the derivatives is presented by formula 1: In the structure, R1 and R2, which are identical or not, represent hydrogen atom, halogen, cyano, hydroxyl, trifluoromethyl, thio-methyl, benzyloxy, C1-C8 linear chain or branch chain alkyl, C1-C8 linear chain or branch chain alkoxy. The pharmacological test indicates that the flavone derivatives can significantly increase the glucose consumption of Hep-G2 cell with insulin resistance activity, promote translocation of glucose transporter 4 of skeletal muscle cells (L6GLUT4myc) at different level, and significantly increase glucose intake and utilization by cells. The test proves the fact for the first time that the flavone derivatives can significantly promote translocation of glucose transporter 4 of skeletal muscle cells, and one of the mechanisms for treating diabetes is activating the cell AMPK phosphorylation and phosphorylating the downstream ACC.
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Paragraph 0028
(2013/09/12)
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- Cu(OAc)2/TFA-promoted formal [3 + 3] cycloaddition/oxidation of enamines and enones for synthesis of multisubstituted aromatic amines
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New strategies for the oxidative cycloaddition of enones with enamines are developed. These cycloaddition reactions directly afford substituted aromatic amines, which are important in organic chemistry, in moderate to good yield. Cu(OAc)2/TFA is shown to be essential to achieve high reaction efficiency.
- Li, Liang,Zhao, Mi-Na,Ren, Zhi-Hui,Li, Jian-Li,Guan, Zheng-Hui
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supporting information; experimental part
p. 3506 - 3509
(2012/08/08)
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- Sequential aldol Condensation-Transition metal-Catalyzed addition reactions of aldehydes, methyl ketones, and arylboronic acids
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Sequential aldol condensation of aldehydes with methyl ketones followed by transition metal-catalyzed addition reactions of arylboronic acids to form β-substituted ketones is described. By using the 1,1′;-spirobiindane- 7,7′;-diol (SPINOL)-based phosphite, an asymmetric version of this type of sequential reaction, with up to 92% ee, was also realized. Our study provided an efficient method to access β-substituted ketones and might lead to the development of other sequential/tandem reactions with transition metal-catalyzed addition reactions as the key step.
- Liao, Yuan-Xi,Xing, Chun-Hui,Israel, Matthew,Hu, Qiao-Sheng
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supporting information; experimental part
p. 2058 - 2061
(2011/06/19)
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- Synthesis and biological activity of novel tiliroside derivants
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A series of new tiliroside derivatives were synthesized and characterized by analytical 1H NMR, 13C NMR and mass spectrometry. All of the compounds were evaluated for anti-diabetic properties in vitro using HepG2 cells. Compounds 3c, 3d, and 3i-l caused significant enhancements in glucose consumption by insulin-resistant HepG2 cells compared with control cells and cells that were exposed to metformin (an anti-diabetic drug). Moreover, compound 3l significantly activated adenosine 5′-monophosphate-activated protein kinase activity and reduced acetyl-CoA carboxylase activity. Thus, the tiliroside derivative 3l offers potential to be developed as a new approach for treating type II diabetes.
- Qin, Nan,Li, Chun-Bao,Jin, Mei-Na,Shi, Li-Huan,Duan, Hong-Quan,Niu, Wen-Yan
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scheme or table
p. 5189 - 5195
(2011/11/14)
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- A simple and efficient synthesis of pyrazoles in water
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A simple, highly efficient, and environmentally friendly method for the synthesis of substituted 1H-pyrazoles by one-pot condensation reaction of α,β-unsaturated carbonyl compounds with tosyl hydrazide in water was developed. The reaction system exhibited tolerance with various functional groups, Aromatic moiety with both electron-rich and electron-deficient substituents could give desired products in good to excellent yields.
- Wen, Jun,Fu, Yun,Zhang, Ruo-Yi,Zhang, Ji,Chen, Shan-Yong,Yu, Xiao-Qi
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supporting information; experimental part
p. 9618 - 9621
(2011/12/14)
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- QUINAZOLIN-OXIME DERIVATIVES AS HSP90 INHIBITORS
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Compounds of general formula (I); or a stereoisomers, tautomers, pharmaceutically acceptable salts, or prodrugs thereof, wherein R1, R2, R3, R4, R5, R6, R8 and R9 are as defined herein, are useful for the treatment of diseases and conditions which are mediated by excessive or inappropriate Hsp90 activity such as cancers, viral infection and inflammatory diseases or conditions.
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Page/Page column 11
(2011/06/10)
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- An Environment-friendly and efficient method for aldol condensation catalyzed by L-Lysine in pure water
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This is a new example of a nonmetallic small-molecule catalyst for direct intermolecular aldol reactions. We found L-lysine is an effective catalyst for this condensation between unmodified acetone and a variety of aldehydes in the presence of pure water. This green catalyst system could be reused.
- Zhang, Yan,Wang, Man Gang,Liang, Jun,Shang, Zhi Cai
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scheme or table
p. 27 - 31
(2010/08/07)
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- [Hydroxy(tosyloxy)iodo]benzene: A tosyloxylating agent with selectivity for ketones in the reactions with benzalacetones
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The treatment of enolizable ketones containing a conjugated double bond, namely benzalacetones with [hydroxy(tosyloxy)iodo]benzene, leads to regioselective tosyloxylation, thereby giving new compounds (α- tosyloxybenzalacetones).
- Prakash, Om,Sharma, Nitya,Ranjan, Pooja
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experimental part
p. 2875 - 2879
(2010/11/04)
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- Aryl ketone synthesis via tandem orthoplatinated triarylphosphite-catalyzed addition reactions of arylboronic acids with aldehydes followed by oxidation
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Tandem orthoplatinated triaryl phosphite-catalyzed addition reactions of arylboronic acids with aldehydes followed by oxidation to yield aryl ketones is described. 3-Pentanone was identified as a suitable oxidant for the tandem aryl ketone formation reaction. By using microwave energy, aryl ketones were obtained in high yields with the catalyst loading as low as 0.01%.
- Liao, Yuan-Xi,Hu, Qiao-Sheng
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scheme or table
p. 6986 - 6989
(2010/11/17)
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- Lipase-catalysed decarboxylative aldol reaction and decarboxylative Knoevenagel reaction
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Acrylic resin immobilized Candida antarctica lipase B (CAL-B) is able to catalyse decarboxylative aldol reaction and decarboxylative Knoevenagel reaction with good to excellent yields.
- Feng, Xing-Wen,Li, Chao,Wang, Na,Li, Kun,Zhang, Wei-Wei,Wang, Zao,Yu, Xiao-Qi
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scheme or table
p. 1933 - 1936
(2010/06/15)
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- Lithium hydroxide as base in the Wittig reaction. A simple method for olefin synthesis
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A mild and practical procedure for the Wittig olefination, promoted by lithium hydroxide and triphenylbenzyl phosphonium bromide, has been set up for the synthesis of stilbenes and styrenes. The experimental conditions allow aromatic, heteroaromatic, unsaturated and saturated aliphatic aldehydes to give final products in good yields.
- Antonioletti,Bonadies,Ciammaichella,Viglianti
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p. 4644 - 4648
(2008/09/20)
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