- Novel securinine derivatives as topoisomerase I based antitumor agents
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DNA topoisomerase I (Topo I) has been validated as a target for anticancer agents. In this study, a series of novel securinine derivatives bearing β′-hydroxy-α,β-unsaturated ketone moiety were designed and synthesized via a Baylis-Hillman reaction for screening as Topo I inhibitors and antitumor agents. Their topoisomerase I inhibitory activity as well as their cytotoxicity against four human cancer cell lines (A549, HeLa, HepG2, SH-SY5Y) were evaluated, and two pairs of diastereomers 4a-1 and 4a-6 with significant Topo I inhibitory activity and potent anti-proliferative activity against cancer cell lines were identified. The diastereomers were separated, and absolute configurations of five pairs of diastereomers were identified based on X-ray crystallographic analysis and circular dichroism (CD) spectra analysis. Further mechanism studies of the most active compounds 4a-1-R and 4a-1-S indicated that this kind of securinine derivative exhibits a different inhibitory mechanism from that of camptothecin, an established Topo I inhibitor. Unlike camptothecin, compounds 4a-1-R and 4a-1-S specifically inhibits the combination of Topo I and DNA rather than forming the drug-enzyme-DNA covalent ternary complex. In addition, molecular docking and molecular dynamic studies revealed the binding patterns of these compounds with Topo I.
- Hou, Wen,Wang, Zhen-Ya,Peng, Cheng-Kang,Lin, Jing,Liu, Xin,Chang, Yi-Qun,Xu, Jun,Jiang, Ren-Wang,Lin, Hui,Sun, Ping-Hua,Chen, Wei-Min
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Read Online
- Method for oxidative cracking of compound containing unsaturated double bonds
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The invention relates to a method for oxidative cracking of a compound containing unsaturated double bonds. The method comprises the following steps: (A) providing a compound (I) containing unsaturated double bonds, a trifluoromethyl-containing reagent and a catalyst, wherein the catalyst is shown as a formula (II): M(O)mL1yL2z (II), M, L1, L2, m, y, z, R1, R2 and R3 being defined in the specification; and (B) mixing the compound containing the unsaturated double bonds and the trifluoromethyl-containing reagent, and performing an oxidative cracking reaction on the compound containing the unsaturated double bonds in the presence of air or oxygen by using the catalyst to obtain a compound represented by formula (III),.
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Paragraph 0108-0114; 0127-0132
(2021/07/09)
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- METHOD FOR OXIDATIVE CLEAVAGE OF COMPOUNDS WITH UNSATURATED DOUBLE BOND
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A method for oxidative cleavage of a compound with an unsaturated double bond is provided. The method includes the steps of: (A) providing a compound (I) with an unsaturated double bond, a trifluoromethyl-containing reagent, and a catalyst; wherein, the catalyst is represented by Formula (II): M(O)mL1yL2z??(II);wherein, M, L1, L2, m, y, z, R1, R2 and R3 are defined in the specification; and(B) mixing the compound with an unsaturated double bond and the trifluoromethyl-containing reagent to perform an oxidative cleavage of the compound with the unsaturated double bond by using the catalyst in air or under oxygen atmosphere condition to obtain a compound represented by Formula (III):
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Paragraph 0071; 0077
(2021/07/10)
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- A Magnetically Recyclable Palladium-Catalyzed Formylation of Aryl Iodides with Formic Acid as CO Source: A Practical Access to Aromatic Aldehydes
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A magnetically recyclable palladium-catalyzed formylation of aryl iodides under CO gas-free conditions has been developed by using a bidentate phosphine ligand-modified magnetic nanoparticles-anchored- palladium(II) complex [2P-Fe 3O 4@SiO 2-Pd(OAc) 2] as catalyst, yielding a wide variety of aromatic aldehydes in moderate to excellent yields. Here, formic acid was employed as both the CO source and the hydrogen donor with iodine and PPh 3as the activators. This immobilized palladium catalyst can be obtained via a simple preparative procedure and can be facilely recovered simply by using an external magnetic field, and reused at least 9 times without any apparent loss of catalytic activity.
- You, Shengyong,Zhang, Rongli,Cai, Mingzhong
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p. 1962 - 1970
(2021/01/25)
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- V2O5@TiO2 Catalyzed Green and Selective Oxidation of Alcohols, Alkylbenzenes and Styrenes to Carbonyls
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The versatile application of different functional groups such as alcohols (1° and 2°), alkyl arenes, and (aryl)olefins to construct carbon-oxygen bond via oxidation is an area of intense research. Here, we report a reusable heterogeneous V2O5@TiO2 catalyzed selective oxidation of various functionalities utilizing different mild and eco-compatible oxidants under greener reaction conditions. The method was successfully applied for the alcohol oxidation, oxidative scission of styrenes, and benzylic C?H oxidation to their corresponding aldehydes and ketones. The utilization of mild and eco-friendly oxidizing reagents such as K2S2O8, H2O2 (30 % aq.), TBHP (70 % aq.), broad substrate scope, gram-scale synthesis, and catalyst recyclability are notable features of the developed protocol.
- Upadhyay, Rahul,Kumar, Shashi,Maurya, Sushil K.
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p. 3594 - 3600
(2021/07/02)
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- Visible-Light-Driven Oxidative Cleavage of Alkenes Using Water-Soluble CdSe Quantum Dots
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The oxidative cleavage of C=C bonds is an important chemical reaction, which is a popular reaction in the photocatalytic field. However, high catalyst-loading and low turnover number (TON) are general shortcomings in reported visible-light-driven reactions. Herein, the direct oxidative cleavage of C=C bonds through water-soluble CdSe quantum dots (QDs) is described under visible-light irradiation at room temperature with high TON (up to 3.7×104). Under the same conditions, water-soluble CdSe QDs could also oxidize sulfides to sulfoxides with 51–84 % yields and TONs up to 3.4×104. The key features of this photocatalytic protocol include high TONs, wide substrates scope, low catalyst loadings, simple and mild reaction conditions, and molecular O2 as the oxidant.
- Li, Jianing,Zhao, Jingnan,Ma, Cunfei,Yu, Zongyi,Zhu, Hongfei,Yun, Lei,Meng, Qingwei
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p. 4985 - 4992
(2021/10/16)
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- PhIO-Mediated oxidative dethioacetalization/dethioketalization under water-free conditions
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Treatment of thioacetals and thioketals with iodosobenzene in anhydrous DCM conveniently afforded the corresponding carbonyl compounds in high yields under water-free conditions. The mechanistic studies indicate that this dethioacetalization/dethioketalization process does not need water and the oxygen of the carbonyl products comes from the hypervalent iodine reagent.
- Du, Yunfei,Ouyang, Yaxin,Wang, Xi,Wang, Xiaofan,Yu, Zhenyang,Zhao, Bingyue,Zhao, Kang
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- Mechanism of Iodine(III)-Promoted Oxidative Dearomatizing Hydroxylation of Phenols: Evidence for a Radical-Chain Pathway
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The oxidative dearomatization of phenols with the addition of nucleophiles to the aromatic ring induced by hypervalent iodine(III) reagents and catalysts has emerged as a highly useful synthetic approach. However, experimental mechanistic studies of this important process have been extremely scarce. In this report, we describe systematic investigations of the dearomatizing hydroxylation of phenols using an array of experimental techniques. Kinetics, EPR spectroscopy, and reactions with radical probes demonstrate that the transformation proceeds by a radical-chain mechanism, with a phenoxyl radical being the key chain-carrying intermediate. Moreover, UV and NMR spectroscopy, high-resolution mass spectrometry, and cyclic voltammetry show that before reacting with the phenoxyl radical, the water molecule becomes activated by the interaction with the iodine(III) center, causing the Umpolung of this formally nucleophilic substrate. The radical-chain mechanism allows the rationalization of all existing observations regarding the iodine(III)-promoted oxidative dearomatization of phenols.
- Kraszewski, Karol,Tomczyk, Ireneusz,Drabinska, Aneta,Bienkowski, Krzysztof,Solarska, Renata,Kalek, Marcin
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supporting information
p. 11584 - 11592
(2020/08/11)
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- Porphyrin-Based Probe for Simultaneous Detection of Interface Acidity and Polarity during Lipid-Phase Transition of Vesicles
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Biochemical activities at a membrane interface are affected by local pH/polarity related to membrane lipid properties including lipid dynamics. pH and polarity at the interface are two highly interdependent parameters, depending on various locations from the water-exposed outer surface to the less polar inner surface. The optical response of common pH or polarity probes is affected by both the local pH and polarity; therefore, estimation of these values using two separate probes localized at different interface depths can be erroneous. To estimate interface pH and polarity at an identical interface depth, we synthesized a glucose-pendant porphyrin (GPP) molecule for simultaneous pH and polarity detection by a single optical probe. pH-induced protonation equilibrium and polarity-dependent π-πstacking aggregation for GPP are exploited to measure pH and polarity changes at the 1,2-dimyristoyl-sn-glycero-3-phospho-(1′-rac-glycerol) (DMPG) membrane interface during DMPG phase transition. An NMR study confirmed that GPP is located at the interface Stern layer of DMPG large unilamellar vesicle (LUV). Using UV-vis absorption studies with an adapted analysis protocol, we estimated interface pH, or its deviation from the bulk phase value (ΔpH), and the interface polarity simultaneously using the same spectra for sodium dodecyl sulfate micelle and DMPG LUV. During temperature-dependent gel to liquid-crystalline phase transition of DMPG, there was ~0.5 unit increase in ΔpH from approximately -0.6 to -1.1, with a small increase in the interface dielectric constant from ~60 to 63. A series of spectroscopic data indicate the utility of GPP for evaluation of local pH/polarity change during lipid phase transition of vesicles.
- Majumder, Rini,Roy, Snigdha,Okamoto, Kentaro,Nagao, Satoshi,Matsuo, Takashi,Parui, Partha Pratim
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p. 426 - 434
(2020/01/09)
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- A metal-free heterogeneous photocatalyst for the selective oxidative cleavage of CC bonds in aryl olefins: via harvesting direct solar energy
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Selective cleavage of CC bonds is highly important for the synthesis of carbonyl containing fine chemicals and pharmaceuticals. Novel methodologies such as ozonolysis reactions, Lemieux-Johnson oxidation reaction etc. already exist. Parallel to these, catalytic methods using homogeneous catalysts also have been discovered. Considering the various advantages of heterogeneous catalysts such as recyclability and stability, couple of transition metal-based heterogeneous catalysts have been applied for this reaction. However, the pharmaceutical industries prefer to use metal-free catalysts (especially transition metal-free) to avoid further leaching in the final products. This is for sure a big challenge to an organic chemist and to the pharmaceutical industries. To make this feasible, a mild and efficient protocol has been developed using polymeric carbon nitrides (PCN) as metal-free heterogeneous photocatalysts to convert various olefins into the corresponding carbonyls. Later, this catalyst has been applied in the gram scale synthesis of pharmaceutical drugs using direct solar energy. Detailed mechanistic studies revealed the actual role of oxygen, the catalyst, and the light source.
- Das, Shoubhik,Hatami, Nareh,Jooss, Christian,Lange, Niklas Simon,Ronge, Emanuel,Schilling, Waldemar,Zhang, Yu
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supporting information
p. 4516 - 4522
(2020/08/10)
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- 1,1,1,3,3,3-Hexafluoroisopropanol as an efficient medium for the room temperature oxidation of styrenes to benzaldehydes
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A room temperature N-hydroxyphthalimide-catalyzed oxidation of styrene derivatives to the corresponding aldehydes has been developed. The use of 1,1,1,3,3,3-hexafluoroisopropanol as the solvent was determined as being key for efficient oxidation. The incorporated oxygen atom originates from molecular dioxygen.
- Zhang, Zhuyong,Chen, Weidong,Luo, Junfei
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supporting information
(2020/10/23)
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- Visible light photoredox catalyzed deprotection of 1,3-oxathiolanes
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An efficient visible light photoredox catalyzed aerobic deprotection of 1,3-oxathiolanes using organic dye Eosin Y as a photocatalyst is disclosed. The deprotection procedure features the use of a metal-free catalyst, mild conditions, a broad range of substrate scope, and good functional group tolerance. 35 examples were tested under the standard conditions and most of them afforded the deprotected products in modest to high yields.
- Yang, Mingyang,Xing, Zhimin,Fang, Bowen,Xie, Xingang,She, Xuegong
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supporting information
p. 288 - 291
(2020/01/13)
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- Design, synthesis, and biological evaluation of dual targeting inhibitors of histone deacetylase 6/8 and bromodomain BRPF1
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Histone modifying proteins, specifically histone deacetylases (HDACs) and bromodomains, have emerged as novel promising targets for anticancer therapy. In the current work, based on available crystal structures and docking studies, we designed dual inhibitors of both HDAC6/8 and the bromodomain and PHD finger containing protein 1 (BRPF1). Biochemical and biophysical tests showed that compounds 23a,b and 37 are nanomolar inhibitors of both target proteins. Detailed structure-activity relationships were deduced for the synthesized inhibitors which were supported by extensive docking and molecular dynamics studies. Cellular testing in acute myeloid leukemia (AML) cells showed only a weak effect, most probably because of the poor permeability of the inhibitors. We also aimed to analyse the target engagement and the cellular activity of the novel inhibitors by determining the protein acetylation levels in cells by western blotting (tubulin vs histone acetylation), and by assessing their effects on various cancer cell lines.
- Erdmann, Frank,Günther, Stefan,Ghazy, Ehab,Hügle, Martin,Herp, Daniel,Jung, Manfred,Morales, Elizabeth R.,Robaa, Dina,Romier, Christophe,Schmidt, Matthias,Schmidtkunz, Karin,Sippl, Wolfgang,Zeyen, Patrik
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supporting information
(2020/06/03)
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- 2.6-diarylbenzo[d]oxaoles as MAO-B inhibitors and pharmaceutical composition comprising the same as an active ingredient
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A 1-diarylbenzoxazole derivative for MAO-B which is represented by Structural Formula 2,6 - and a pharmaceutical composition for inhibiting MAO-B comprising the same as an active ingredient. Thus, the present invention is not limited thereto. 2,6 -diarylbenzoxazole derivatives for inhibiting MAO-B activity and a pharmaceutical composition for inhibiting MAO-B activity are provided to suppress MAO-B activity by selectively acting on MAO-B. Structural 1. (by machine translation)
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Paragraph 0183-0185
(2021/02/04)
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- The studies on chemoselective promiscuous activity of hydrolases on acylals transformations
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Chemoselective, mild and convenient protocol for the hydrolysis of the synthetically relevant acylals via promiscuous enzyme-catalyzed hydrolysis has been developed. It has been shown that promiscuous activity of the used hydrolases dominates their native activity related with carboxylic esters hydrolysis. The main advantage of the present methodology is that it can be conducted under neutral conditions at room temperature. Moreover, complete deprotection of acylals takes place within 10–20 min. Developed protocol can be used with compounds having a variety of hydrolytic labile groups since the cleavage is proceeded under neutral conditions and occurs exclusively on acylal moiety. Further this protocol was extended by the tandem Passerini multicomponent reaction leading to the α-acetoxy amides using acylals as the surrogates of the carbonyl components to P-MCR.
- Koszelewski, Dominik,Ostaszewski, Ryszard
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- Chemoselective Nucleophilic Functionalizations of Aromatic Aldehydes and Acetals via Pyridinium Salt Intermediates
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The development of a novel chemoselective functionalization can diversify the strategy for synthesizing the target molecules. The perfect chemoselectivity between aromatic and aliphatic aldehydes is difficult to achieve by the previous methods. The aromatic aldehyde-selective nucleophilic addition in the presence of aliphatic aldehydes was newly accomplished. Namely, the aromatic aldehyde-selective nucleophilic addition using arenes and allyl silanes proceeded in the presence of trialkylsilyl triflate and 2,2′-bipyridyl, while the aliphatic aldehydes completely remained unchanged. The reactive pyridinium-type salt intermediate derived from an aromatic aldehyde chemoselectively underwent the nucleophilic substitution. Moreover, the aromatic acetals as the protected aldehydes could be directly transformed into similar pyridinium salt intermediates, which reacted with various nucleophiles coexisting with the aliphatic aldehydes.
- Kawajiri, Takahiro,Kato, Maho,Nakata, Hiroki,Goto, Ryota,Aibara, Shin-Yo,Ohta, Reiya,Fujioka, Hiromichi,Sajiki, Hironao,Sawama, Yoshinari
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p. 3853 - 3870
(2019/03/07)
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- Semi-heterogeneous Dual Nickel/Photocatalysis using Carbon Nitrides: Esterification of Carboxylic Acids with Aryl Halides
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Cross-coupling reactions mediated by dual nickel/photocatalysis are synthetically attractive but rely mainly on expensive, non-recyclable noble-metal complexes as photocatalysts. Heterogeneous semiconductors, which are commonly used for artificial photosynthesis and wastewater treatment, are a sustainable alternative. Graphitic carbon nitrides, a class of metal-free polymers that can be easily prepared from bulk chemicals, are heterogeneous semiconductors with high potential for photocatalytic organic transformations. Here, we demonstrate that graphitic carbon nitrides in combination with nickel catalysis can induce selective C?O cross-couplings of carboxylic acids with aryl halides, yielding the respective aryl esters in excellent yield and selectivity. The heterogeneous organic photocatalyst exhibits a broad substrate scope, is able to harvest green light, and can be recycled multiple times. In situ FTIR was used to track the reaction progress to study this transformation at different irradiation wavelengths and reaction scales.
- Pieber, Bartholom?us,Malik, Jamal A.,Cavedon, Cristian,Gisbertz, Sebastian,Savateev, Aleksandr,Cruz, Daniel,Heil, Tobias,Zhang, Guigang,Seeberger, Peter H.
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supporting information
p. 9575 - 9580
(2019/06/25)
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- Synthesis method of pterostilbene
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The invention provides a synthesis method of pterostilbene. The synthesis method takes 4-hydroxybenzaldehyde as a raw material and comprises the following steps: carrying out acetylation reaction to generate 4-acetoxybenzaldehyde; then carrying out wittig reaction to generate 4-acetoxystyrene; carrying out hydrolysis reaction on 4-acetoxystyrene to generate 4-hydroxystyrene; carrying out Heck reaction on 4-hydroxystyrene to obtain a target product pterostilbene. The method provided by the invention has the advantages of easiness for obtaining the raw materials, high product selectivity, relatively high yield, moderate reaction conditions and simplicity in operation.
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Paragraph 0027; 0028; 0036; 0041
(2018/09/21)
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- Copper-Catalyzed Oxidative Difunctionalization of Terminal Unactivated Alkenes
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The copper(II)-promoted free-radical oxidative difunctionalization of terminal alkenes to access ketoazides by utilizing molecular oxygen has been reported. A series of styrene derivatives have been evaluated and were found to be compatible to give the desired difunctionalized products in moderate to good yields. The role of molecular oxygen both as an oxidant and oxygen atom source in this catalytic transformation has been unquestionably demonstrated by 18O-labeling studies and a radical mechanistic pathway involving the oxidative formation of azidyl radicals is also designed. This environment-friendly catalytic oxidative protocol can transform aldehyde to nitrile.
- Hussain, Muhammad Ijaz,Feng, Yangyang,Hu, Liangzhen,Deng, Qingfu,Zhang, Xiaohui,Xiong, Yan
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p. 7852 - 7859
(2018/05/30)
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- Aerobic Photooxidative Synthesis of β-Alkoxy Monohydroperoxides Using an Organo Photoredox Catalyst Controlled by a Base
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Transition-metal-free synthesis of β-alkoxy monohydroperoxides via aerobic photooxidation using an acridinium photocatalyst was developed. This method enables the synthesis of some novel hydroperoxides. The peroxide source is molecular oxygen, which is cost-effective and atomically efficient. Magnesium oxide plays an important role as a base in the catalytic system.
- Asano, Yuya,Nagasawa, Yoshitomo,Yamaguchi, Eiji,Itoh, Akichika
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supporting information
p. 409 - 412
(2018/02/21)
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- The synthesis and antistaphylococcal activity of 9, 13-disubstituted berberine derivatives
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A series of novel 9, 13-disubstituted berberine derivatives have been synthesized and evaluated for the antibacterial activities against Staphylococcus aureus, including Newman strain and multidrug-resistant strains (NRS-1, NRS-70, NRS-100, NRS-108, and NRS-271). Compound 20 shows the most potent activity against the growth of Newman strain, with a MIC value of 0.78?μg/mL, which is comparable with the positive control vancomycin. In addition, compound 20, 21, and 33 are highly antistaphylococcal active against five strains of multidrug-resistant S.?aureus, with MIC values of 0.78–1.56?μg/mL. Of note, theses antibacterial active compounds have no obvious toxicity to the viability of human fibroblast (HAF) cells at the MIC concentration.
- Wang, Jing,Yang, Teng,Chen, Huang,Xu, Yun-Nan,Yu, Li-Fang,Liu, Ting,Tang, Jie,Yi, Zhengfang,Yang, Cai-Guang,Xue, Wei,Yang, Fan
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p. 424 - 433
(2017/01/17)
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- Esterification mechanism of lignin with different catalysts based on lignin model compounds by mechanical activation-assisted solid-phase synthesis
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In order to learn about the esterification mechanism of lignin by mechanical activation-assisted solid-phase synthesis (MASPS) technology, lignin model compounds, p-hydroxy benzaldehyde (H), vanillin and vanillyl alcohol (G), and syringaldehyde (S), were used in the reaction with acetic anhydride, with 4-dimethyl amino pyridine (DMAP), sodium acetate, and sulfuric acid as catalysts. FTIR, NMR, and UV/vis analyses of the products showed that all of the catalysts could enhance the esterification. Both the phenolic hydroxyl and aliphatic hydroxyl participated in the esterification and the reactivity of the basic structural units of lignin had a descending order of H, G, and S. Oxidations could happen in the presence of unsaturated groups such as aldehyde in the lignin model compounds. The catalytic mechanism of the three kinds of catalyst was different, and the catalytic activity had a descending order of DMAP, sodium acetate, and sulfuric acid. The reactivity of phenolic hydroxyl was higher than that of aliphatic hydroxyl with DAMP as the catalyst, but the reactivity of aliphatic hydroxyl was higher than that of phenolic hydroxyl with sodium acetate or sulfuric acid as the catalyst. With sulfuric acid as the catalyst, some side reactions took place and resulted in the ring cleavage or cross-linking of the benzene ring. Consistency verification indicated that the use of lignin model compounds for studying the esterification mechanism of lignin was reasonable and feasible.
- Zhao, Xiaohong,Zhang, Yanjuan,Wei, Liping,Hu, Huayu,Huang, Zuqiang,Yang, Mei,Huang, Aimin,Wu, Juan,Feng, Zhenfei
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p. 52382 - 52390
(2017/11/27)
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- Selective Aerobic Oxidation of Methylarenes to Benzaldehydes Catalyzed by N-Hydroxyphthalimide and Cobalt(II) Acetate in Hexafluoropropan-2-ol
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Efficient and highly selective catalytic conditions for the aerobic autoxidation of methylarenes to benzaldehydes, based on N-hydroxyphthalimide (NHPI) and cobalt(II) acetate in 1,1,1,3,3,3-hexafluoropropan-2-ol (HFIP), were developed. The sustainable conditions enable a multigram scale preparation of benzaldehyde derivatives in high efficiency and with excellent chemoselectivity (up to 99 % conversion and 98 % selectivity).
- Gaster, Eden,Kozuch, Sebastian,Pappo, Doron
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supporting information
p. 5912 - 5915
(2017/05/12)
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- Luminogenic and fluorogenic compounds and methods to detect molecules or conditions
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A method to detect the presence or amount of at least one molecule in a sample which employs a derivative of luciferin or a derivative of a fluorophore is provided.
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Paragraph 0394; 0395; 0396
(2016/07/27)
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- A selective and mild glycosylation method of natural phenolic alcohols
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Several bioactive natural p-hydroxyphenylalkyl β-D-glucopyranosides, such as vanillyl β-D-glucopyranoside, salidroside and isoconiferin, and their glycosyl analogues were prepared by a simple reaction sequence. The highly efficient synthetic approach was achieved by utilizing acetylated glycosyl bromides as well as aromatic moieties and mild glycosylation promoters. The aglycones, p-O-acetylated arylalkyl alcohols, were prepared by the reduction of the corresponding acetylated aldehydes or acids. Various stereoselective 1,2-trans-O-glycosylation methods were studied, including the DDQ-iodine or ZnO-ZnCl2 catalyst combination. Among them, ZnO-iodine has been identified as a new glycosylation promoter and successfully applied to the stereoselective glycoside synthesis. The final products were obtained by conventional Zemplén deacetylation.
- Mastihubová, Mária,Poláková, Monika
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supporting information
p. 524 - 530
(2016/04/08)
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- One-Pot, Enantioselective Synthesis of 2,3-Dihydroazulen-6(1H)-one: A Concise Access to the Core Structure of Cephalotaxus Norditerpenes
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A one-pot enantioselective synthesis of cis-substituted 2,3-dihydroazulen-6(1H)-one is described. In this cascade reaction, an organocatalyzed asymmetric Michael reaction furnishes a highly optically pure nitrobutylphenol intermediate, which is converted into an annulated tropone species by sequential oxidative dearomatization, conjugate addition, electrocyclic ring opening and nitrous acid elimination in the same reaction vessel. Both aliphatic and aromatic nitroalkenes are good substrates for the one-pot reaction, and this protocol appears to be general for various phenylpropionaldehydes as well. In the case of asymmetrically substituted phenylpropionaldehydes, the regioselectivity is likely determined by both the steric and electronic properties of the substituents. This methodology is successfully applied to the synthesis of the tricyclic core structure of Cephalotaxus norditerpenes.
- Yongsheng, Zheng,Ghazvini Zadeh, Ebrahim H.,Yuan, Yu
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supporting information
p. 2115 - 2119
(2016/05/09)
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- Tf2O-TMDS combination for the direct reductive transformation of secondary amides to aldimines, aldehydes, and/or amines
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The direct partial reduction of highly stable secondary amides to more reactive aldimines and aldehydes is a challenging yet highly demanding transformation. In this context, only three methods have been reported. We report herein an improved version of the Charette’s method. Our protocol consists of activation of secondary amides with triflic anhydride/2-fluoropyridine, and partial reduction of the resulting intermediates with 1,1,3,3-tetramethyldisiloxane (TMDS), which delivered aldimines or aldehydes upon acidic hydrolysis. Aromatic amides were reduced to the corresponding aldimines in 85%–100% NMR yields, and yields (NMR) from aliphatic amides were 72%–86%. Acidic hydrolysis of the aldimine intermediates afforded, in one-pot, the corresponding aldehydes in 80%–96% yields. A simple protocol was established to isolate labile aldimines in pure form in 92%–96% yields. The improved method gave generally higher yields as compared to the known ones, and features the use of cheaper and more atom-economical TMDS as a chemoselective reducing agent. In addition, a convenient extraction protocol has been established to allow the isolation of amines, which constitutes a mild method for the N-deacylation of amides, another highly desirable transformation. The extended method retains the advantages of the original method of Charette in terms of mild conditions, good functional group tolerance, and excellent chemoselectivity.
- Lang, Qi-Wei,Hu, Xiu-Ning,Huang, Pei-Qiang
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p. 1638 - 1644
(2016/12/07)
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- Method of manufacturing calbonyl compd.
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PROBLEM TO BE SOLVED: To provide a method of manufacturing a carbonyl compound by smoothly performing a dehydrogenation reaction while preventing side reactions.SOLUTION: A method of manufacturing a carbonyl compound includes a process of converting alcohol to aldehyde or ketone by irradiating visible light to a reaction system containing a primary alcohol or a secondary alcohol, SrTiOcarrying a Ru atom and doped with Rh atom, and water.
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Paragraph 0051; 0052
(2018/06/30)
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- Dramatic Effect of Ancillary NHC Ligand in the Highly Selective Catalytic Oxidative Carbon-Carbon Multiple Bond Cleavage
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Selective and controlled oxidation of olefins to aldehydes is a commonly used important transformation in chemistry. However, chemists still use the dangerous and inconvenient ozonolysis method or the less selective, low-yielding Lemieux-Johnson protocol. In a program of developing effective catalysts for this important reaction, we disclose here that an ancillary ligand can play a dramatic role in the above catalytic phenomenon, depending on the design of the ligand precursor chosen. Proof-of-principle is demonstrated with the help of two newly designed [LnRuII-NHC] precatalysts (NHC = an imidazolydene-based NHC, Im-NHC, or a triazolydene-based NHC, Trz-NHC; Ln = para-cymene) for catalytic selective oxidation of olefins/alkynes to carbonyl compounds. With the electron-deficient Trz-NHC ligand, [(para-cymene)RuII(Im-Trz)]+ precatalyst was found to be an order of magnitude more efficient than the [(para-cymene)RuII(Im-NHC)]+ precatalyst.
- Gupta, Suraj K.,Sahoo, Sandeep K.,Choudhury, Joyanta
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supporting information
p. 2462 - 2466
(2016/08/16)
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- Rh-Catalyzed Synthesis of Coumarin Derivatives from Phenolic Acetates and Acrylates via C-H Bond Activation
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An efficient annulation strategy involving the reaction of phenolic acetates with acrylates in the presence of [Rh2(OAc)4] as catalyst and formic acid as reducing agent, leading to the high yield synthesis of coumarin derivatives, has been developed. The addition of NaOAc as a base increased the yield of the products. The reaction is quite successful for both electron-rich as well as electron-deficient phenolic acetates, affording coumarins with excellent regioselectivity, and proceeds via C-H bond activation proven by deuterium incorporation studies.
- Gadakh, Sunita K.,Dey, Soumen,Sudalai, Arumugam
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p. 11544 - 11550
(2015/12/04)
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- Chloride transport activities of trans- and cis-amide-linked bisureas
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Of the bisurea compounds linked through trans- and cis-benzanilide spacers, the cis-amide derivatives were found to be effective in chloride transport, using which a stimuli-responsive mobile carrier was devised. This journal is
- Park, Eun Bit,Jeong, Kyu-Sung
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supporting information
p. 9197 - 9200
(2015/06/02)
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- Hydroformylation of olefins and reductive carbonylation of aryl halides with syngas formed ex situ from dehydrogenative decarbonylation of hexane-1,6-diol
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A variety of primary alcohols have been investigated as convenient substrates for the ex situ delivery of carbon monoxide and molecular hydrogen in a two-chamber reactor. The gaseous mixture is liberated in one chamber by an iridium-catalysed dehydrogenative decarbonylation of the alcohol and then consumed in the other chamber in either a rhodium-catalysed hydroformylation of olefins or a palladium-catalysed reductive carbonylation of aryl halides. Hexane-1,6-diol was found to be the optimum alcohol for both reactions where moderate to excellent yields were obtained of the product aldehydes. A relatively low pressure of 1.5-2.4 bar was measured in the closed system during the two transformations.
- Christensen, Stig Holden,Olsen, Esben P. K.,Rosenbaum, Jascha,Madsen, Robert
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p. 938 - 945
(2015/02/19)
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- In situ activation of benzyl alcohols with XtalFluor-E: Formation of 1,1-diarylmethanes and 1,1,1-triarylmethanes through Friedel-Crafts benzylation
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The Friedel-Crafts benzylation of arenes using benzyl alcohols activated in situ with XtalFluor-E is described. A wide range of 1,1-diarylmethanes and 1,1,1-triarylmethanes were prepared under experimentally simple and mild conditions, without the need for a transition metal or a strong Lewis acid. Notably, the reactivity observed demonstrates the potential of XtalFluor-E to induce C-OH bond ionization and SN1 reactivity of benzylic alcohols. This journal is
- Desroches, Justine,Champagne, Pier Alexandre,Benhassine, Yasmine,Paquin, Jean-Franois
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supporting information
p. 2243 - 2246
(2015/03/04)
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- An effective strategy to develop active cinnamic acid-directed antioxidants based on elongating the conjugated chains
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To optimize antioxidant activity and lipophilicity of cinnamic acid derivatives (CAs) including ferulic acid, sinapic acid, 3,4-dimethoxycinnamic acid, and p-hydroxycinnamic acid, four analogs bearing an additional double bond between their aromatic ring and propenoic acid moiety were designed and synthesized based on the conjugated chain elongation strategy. The antioxidant performance of the CAs were investigated by 2,2′-diphenyl-1-picrylhydrazyl (DPPH)-scavenging, ferric reducing/antioxidant power, cyclic voltammetry, DNA strand breakage-inhibiting and anti-haemolysis activity assays. It was found that CAs with elongation of conjugated chains display increased DPPH --scavenging, DNA strand breakage-inhibiting and anti-haemolysis activities as compared to their parent molecules, due to their improved hydrogen atom-donating ability and lipophilicity. Overall, this work highlights an effective strategy to develop potential CA-directed antioxidants by elongating their conjugated chain.
- Li, Yan,Dai, Fang,Jin, Xiao-Ling,Ma, Meng-Meng,Wang, Yi-Hua,Ren, Xiao-Rong,Zhou, Bo
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- Facile esterification of alcohols with 2-Acyl-4,5-dichloropyridazin-3(2 H)-ones under Friedel-Crafts conditions
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This paper describes the esterification of aromatic and aliphatic alcohols by using 2-acyl-4,5-dichloropyridazin-3(2H)-ones as an acyl source under Friedel-Crafts conditions. Twelve alcohols were reacted with four 2-acyl-4,5-dichloropyridazin-3(2H)-ones in the presence of AlCl3 in tetrahydrofuran at room temperature to give the corresponding esters in moderate to excellent yields. Thus, 2-acylpyridazin-3(2H)-ones serve as good and atom-economic acyl sources for the esterification of aromatic alcohols under Friedel-Crafts conditions, representing a rapid, practical, and efficient method of esterification. Georg Thieme Verlag Stuttgart. New York.
- Kim, Bo Ram,Sung, Gi Hyeon,Ryu, Ki Eun,Yoon, Hyo Jae,Lee, Sang-Gyeong,Yoon, Yong-Jin
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p. 1909 - 1915
(2014/08/18)
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- AIBN-catalyzed oxidative cleavage of gem -disubstituted alkenes with O 2 as an oxidant
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A 2,2-azobis(isobutyronitrile) (AIBN) catalyzed oxidative cleavage of gem-disubstituted alkenes with molecular oxygen as the oxidant has been described. Carbonyl compounds were obtained as the desired products in high yield under mild conditions. Based on previous documents and current experimental results, a relatively reasonable mechanism is proposed.
- Wang, Guang-Zu,Li, Xing-Long,Dai, Jian-Jun,Xu, Hua-Jian
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p. 7220 - 7225
(2014/08/18)
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- Friedel-crafts reaction of benzyl fluorides: Selective activation of C-f bonds as enabled by hydrogen bonding
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A Friedel-Crafts benzylation of arenes with benzyl fluorides has been developed. The reaction produces 1,1-diaryl alkanes in good yield under mild conditions without the need for a transition metal or a strong Lewis acid. A mechanism involving activation of the C-F bond through hydrogen bonding is proposed. This mode of activation enables the selective reaction of benzylic C-F bonds in the presence of other benzylic leaving groups.
- Champagne, Pier Alexandre,Benhassine, Yasmine,Desroches, Justine,Paquin, Jean-Franois
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supporting information
p. 13835 - 13839
(2015/02/05)
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- Synthesis, structure, and SAR of tetrahydropyran-based LpxC inhibitors
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In the search for novel Gram-negative agents, we performed a comprehensive search of the AstraZeneca collection and identified a tetrahydropyran-based matrix metalloprotease (MMP) inhibitor that demonstrated nanomolar inhibition of UDP-3-O-(acyl)-N-acetylglucosamine deacetylase (LpxC). Crystallographic studies in Aquifex aeolicus LpxC indicated the tetrahydropyran engaged in the same hydrogen bonds and van der Waals interactions as other known inhibitors. Systematic optimization of three locales on the scaffold provided compounds with improved Gram-negative activity. However, the optimization of LpxC activity was not accompanied by reduced inhibition of MMPs. Comparison of the crystal structure of the native product, UDP-3-O-(acyl)-glucosamine, in Aquifex aeolicus to the structure of a tetrahydropyran-based inhibitor indicates pathways for future optimization.
- Murphy-Benenato, Kerry E.,Olivier, Nelson,Choy, Allison,Ross, Philip L.,Miller, Matthew D.,Thresher, Jason,Gao, Ning,Hale, Michael R.
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supporting information
p. A1213 - A1218
(2015/04/27)
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- Polystyrene-supported TiCl4 as a novel, efficient and reusable polymeric Lewis acid catalyst for the chemoselective synthesis and deprotection of 1,1-diacetates under eco-friendly conditions
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Copolymer beads of styrene and divinylbenzene (5-7%) were synthesized and combined with titanium tetrachloride in CS2 to form a stable complex. The PS/TiCl4 complex was used as a mild and efficient polymer-supported Lewis acid catalyst for the preparation of 1,1-diacetates from various types of aldehydes under heterogeneous conditions at room temperature. Deprotection of the resulting 1,1-diacetates has also been achieved using the same catalyst in methanol. This new protocol has the advantages of easy availability, stability, reusability of the eco-friendly catalyst, high to excellent yields, chemoselectivity, simple experimental and work-up procedure. Moreover, this polymeric catalyst could be recovered easily and reused several times without significant loss in activity.
- Rahmatpour, Ali,Mohammadian, Sara
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p. 912 - 919
(2013/10/22)
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- Copper-catalyzed domino route to natural nostoclides and analogues: A total synthesis of nostoclides i and II
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An original and convenient domino route to natural nostoclides I and II has been developed using a two-step sequence consisting of a copper-cat-alyzed tandem reaction associated with Suzuki cross-coupling. The methodology employed for this total synthesis appeared to be an interesting and suffi-ciently flexible tool to allow the synthesis of numer-ous analogues of these nostoclides.
- Ngi, Samuel Inack,Petrignet, Julien,Duwald, Romain,El Hilali, El Mostafa,Abarbri, Mohamed,Duchêne, Alain,Thibonnet, Jér?me
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supporting information
p. 2936 - 2941
(2014/03/21)
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- Synthesis of pterostilbene by julia olefination
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A simple, E-stereoselective route for the synthesis of the biologically active compounds trans-pterostilbene and tetramethoxy stilbene from the readily available starting materials 3,5-dimethoxy benzyl alcohol and 4-hydroxy benzaldehyde was developed using Julia olefination as a key reaction. Taylor & Francis Group, LLC.
- Peddikotla, Prabhakar,Chittiboyina, Amar G.,Khan, Ikhlas A.
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p. 3217 - 3223
(2014/01/06)
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- Redox-selective generation of aldehydes and H2 from alcohols under visible light
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Photosynthetic dehydrogenation: Potential usefulness of visible-light-induced dehydrogenation of alcohols in organic synthesis was demonstrated, in which aldehydes and H2 were afforded by using Ru/SrTiO3:Rh and water (see scheme). Water was essential for the reaction. High efficiency (TON: up to 15 400 based on Rh; H2 and aldehyde evenly generated) and high selectivity were achieved. Copyright
- Liu, Zijun,Caner, Joaquim,Kudo, Akihiko,Naka, Hiroshi,Saito, Susumu
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supporting information
p. 9452 - 9456
(2013/07/26)
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- Rapid and Ecofriendly Esterification of Alcohols with 2-Acylpyridazinones
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Atom-economical esterification is of great importance in green chemistry. In this work, we demonstrated the catalyst and additive free esterification of alcohols by their reaction with 2-acyl-4,5-dichloropyridazin-3(2H)- ones without solvent at 100 oC. Aliphatic and aromatic alcohols were converted into the corresponding esters in good to excellent yields. It is noteworthy that the reaction is solvent-free, atom-economic, easy-workup, and rapid and that the process is inexpensive.
- Kim, Bo Ram,Sung, Gi Hyeon,Ryu, Ki Eun,Kim, Jeum-Jong,Yoon, Yong-Jin
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p. 3410 - 3414
(2014/01/06)
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- Catalyst-free esterification of alcohols using 2-acyl-4,5- dichloropyridazinones under microwave conditions
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Efficient and green esterification is of great importance. In this work, we demonstrate the catalyst-free esterification of alcohols by their reaction with 2-acyl-4,5-dichloropyridazin-3(2H)-ones under microwave irradiation. Aliphatic and aromatic alcohols were converted into the corresponding esters in good to excellent yields under microwave irradiation in solvent or solvent-free conditions. It is noteworthy that the reaction is catalyst-free, atom-economic, and rapid and that the process is inexpensive.
- Kim, Bo Ram,Sung, Gi Hyeon,Lee, Sang-Gyeong,Yoon, Yong Jin
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supporting information
p. 3234 - 3237
(2013/04/24)
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- Scope and limitations of the Heck-Matsuda-coupling of phenol diazonium salts and styrenes: A protecting-group economic synthesis of phenolic stilbenes
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4-Phenol diazonium salts undergo Pd-catalyzed Heck reactions with various styrenes to 4′-hydroxy stilbenes. In almost all cases higher yields and fewer side products were observed, compared to the analogous 4-methoxy benzene diazonium salts. In contrast, the reaction fails completely with 2- and 3-phenol diazonium salts. For these substitution patterns the methoxy-substituted derivatives are superior. The Royal Society of Chemistry 2013.
- Schmidt, Bernd,Elizarov, Nelli,Berger, René,H?lter, Frank
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supporting information
p. 3674 - 3691
(2013/06/27)
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- Probing dense packed limits of a hyperbranched polymer through ligand binding and size selective catalysis
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In the area of dendritic chemistry (hyperbranched polymers and dendrimers) it is often generalized that dendrimers are the molecule of choice for smart, selective, or technical applications involving encapsulation or controlled/selective environments. This is despite the fact that hyperbranched polymers (HBP)s are generally easier and cheaper to synthesize, making them more amenable to large-scale applications. Dendrimers have been successful in these applications by virtue of a dense packed or dense shell limit. This paper describes the synthesis of a series of narrowly dispersed HBPs possessing binding and catalytic cores with a high and uniform loading. Subsequent binding experiments clearly demonstrated the existence of a dense packed limit with respect to polymer molecular weight and ligand size. A series of catalytic experiments were also performed in an attempt to exploit these molecules and their dense packed limit to the area of shape/size selective catalysis - an area where dendrimers have previously been used with celebrated success. However, although we were able to show the existence of a dense packed limit, we were initially unable to demonstrate any selectivity based on substrate size or shape. Nevertheless, further studies into core branching motif and multiplicity eventually enabled us to obtain a series of HBPs capable of perturbing the shape/size selectivity of a simple oxidation reaction involving two alkenes. Specifically, we were able to demonstrate a 3.5-fold shift in chemoselectivity toward a smaller alkene of lower reactivity. These results compare favorably with those obtained using dendrimers and allow us to conclude that, with careful thought regarding core design, HBPs are indeed capable of being applied to technical/smart applications involving controlled and selective environments.
- Ellis, Adam,Twyman, Lance J.
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p. 7055 - 7074
(2013/09/24)
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- Crystal structures of 4-(oxiran-2-ylmethoxy) benzoic acid and 4-acetoxybenzoic acid
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Compounds 4-(oxiran-2-ylmethoxy)benzoic acid (2) and 4-acetoxybenzoic acid (4) are synthesized by a new synthetic route and studied by X-ray crystallography. Compound 2 crystallizes in the monoclinic system, P21/n space group, a = 5.1209(2) A, b = 30.3429(16) A, c = 5.9153(3) A, β = 96.725(3)°, V = 912.81(8) A3, Z = 4. Compound 4 crystallizes in the triclinic system, P-1 space group, a = 7.3400(4) A, b = 8.0819(3) A, c = 15.6548(9) A, α = 85.754(3)°, β = 84.268(2)°, γ = 70.023(3)°, V = 867.63(8) A3, Z = 4. The crystal structure of 2 comprises two crystallographically independent molecules of the compound. In the crystal structures of 2 and 4, pairs of molecules form carboxyl dimers. Original Russian Text Copyright
- Obreza, A.,Perdih, F.
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p. 793 - 799,7
(2020/09/09)
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- Polystyrene-supported GaCl3: A new, highly efficient and recyclable heterogeneous Lewis acid catalyst for acetylation and benzoylation of alcohols and phenols
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A new, simple and highly chemoselective method for both acetylation and benzoylation of alcohols and phenols with acetic anhydride in the presence of polystyrene-supported gallium trichloride (PS/GaCl3) as a highly active and reusable heterogeneous Lewis acid catalyst is presented. In this catalytic system, primary, secondary and tertiary alcohols as well as phenols were converted to the corresponding acetates and benzoates with high yields. The heterogenized catalyst is of high reusability and stability in the acetylation reactions and was recovered several times with negligible loss in its activity or a negligible catalyst leaching, and also there is no need for regeneration. Remarkably, a selective mono-acetylation of symmetrical diols can be achieved chemoselectively by employing the same catalyst.
- Rahmatpour, Ali
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p. 1048 - 1054
(2013/02/22)
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- Metal free: A novel and efficient aerobic oxidation of toluene derivatives catalyzed by N′, N″, Nprime;, -trihydroxyisocyanuric acid and dimethylglyoxime in PEG-1000-based dicationic acidic ionic liquid
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A non-metal catalytic system containing of N′, N″, Nprime;, -trihydroxyisocyanuric acid (THICA) and dimethylglyoxime (DMG) is described for the selective oxidation of toluene derivatives with dioxygen in PEG-1000-based dicationic acidic ionic liquid (PEG1000-DAIL). Several toluene derivatives were efficiently oxidized to corresponding acids under mild conditions. The oxidation followed a radical pathway and a possible mechanism was proposed. Both the catalyst and PEG1000-DAIL could be reused at least eight times without significantly decreasing the catalytic activity.
- Lu, Tingting,Mao, Yang,Yao, Kai,Xu, Jian,Lu, Ming
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p. 124 - 128
(2012/10/29)
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