- Molecular structure, conformational preferences and vibrational analysis of 2-hydroxystyrene: A computational and spectroscopic research
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The molecular structure of 2-hydroxy-styrene has been investigated at DFT (B3LYP, mPW1PW91) and MP2 levels with an assortment of Pople's and Dunning's basis sets within the isolated molecule approximation. The presence of intramolecular hydrogen bonds has
- García, Gregorio,Navarro, Amparo,Granadino-Roldán, José Manuel,Garzón, Andrés,Ruiz, Tomás Pe?a,Fernández-Liencres, Maria Paz,Melguizo, Manuel,Pe?as, Antonio,Pongor, Gábor,E?ri, János,Fernández-Gómez, Manuel
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- Synthesis method of hydroxyl-substituted styrene compound and synthesis method of photoresist resin monomer
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The present invention provides a synthesis method of a hydroxyl-substituted styrene compound and a synthesis method of photoresist resin monomer. The synthesis method of the hydroxyl-substituted styrene compound comprises the following steps: a) the compound of formula I-1 is reacted with the Wetting reagent to obtain a compound of formula I-2. The synthesis method of the photoresist resin monomer comprises the following steps: a) the synthesis method of the styrene compound substituted with the above hydroxyl group to obtain a compound of formula I-2; b) the compound of formula I-2 is reacted with an acylating reagent to obtain the photoresist resin monomer, the structural formula is referred to formula I-3. The synthesis method of hydroxyl-substituted styrene compounds and photoresist resin monomers of the present invention has high yield and high purity.
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Paragraph 0006; 0068-0070; 0073-0075; 0078-0080
(2022/01/12)
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- Gold(I)-Catalyzed Intramolecular Dehydrative Amination of Sulfamate Esters Tethered to Allylic Alcohols: A Strategy for the Synthesis of Cyclic Sulfamidates
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An efficient synthesis protocol for cyclic sulfamidates has been developed via catalytic intramolecular cyclizations of sulfamate esters tethered to allylic alcohols. The reactions proceed smoothly at room temperature in the presence of (IPr)AuCl (5 mol%) and AgBF4 (5 mol%). This protocol features good to excellent yields, high selectivity, broad substrate scope, and mild reaction conditions. This method is also applicable to the synthesis of a seven-membered sulfamidate. (Figure presented.).
- Park, Yunjeong,Lee, Ji Sun,Ryu, Jae-Sang
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supporting information
p. 2183 - 2188
(2021/03/15)
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- MODIFIED MONOMER, MODIFIED POLYMER COMPRISING THE SAME AND METHOD FOR PREPARING THEM
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A modified monomer useful for the polymer modification of formula 1. The present invention relates to a method for preparing a modified monomer, a modified polymer comprising a modified monomer-derived functional group, a rubber composition comprising the modified polymer, and a molded article produced from the rubber composition.
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Paragraph 0197-0200
(2021/05/18)
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- KRAS G12D INHIBITORS
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The present invention relates to compounds that inhibit KRas G12D. In particular, the present invention relates to compounds that inhibit the activity of KRas G12D, pharmaceutical compositions comprising the compounds and methods of use therefor.
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Paragraph 01058
(2021/03/05)
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- Method for preparing alcohol and phenol through aerobic hydroxylation reaction of boric acid derivative in absence of photocatalyst
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The invention discloses a method for preparing alcohol and phenol through aerobic hydroxylation reaction of a boric acid derivative in the absence of a photocatalyst, wherein the boric acid derivativeis aryl boronic acid or alkyl boronic acid, and the corresponding target compounds are respectively a phenol-based compound and an alcohol-based compound. According to the method, by using a boric acid derivative as a reaction substrate, an additive is added under a solvent condition, and a hydroxylation reaction is performed under aerobic and illumination conditions to obtain a corresponding target compound. According to the invention, the new strategy is provided for the synthesis of phenols through aerobic hydroxylation of aryl boronic acid without a photocatalyst; the catalyst-free aerobic hydroxylation method for photocatalysis of aryl boronic acid or alkyl boronic acid by using triethylamine as an additive is firstly disclosed; and the new method has advantages of photocatalyst-freecondition, wide substrate range and good functional group compatibility.
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Paragraph 0025-0028; 0030-0032
(2020/01/25)
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- NiH-Catalyzed Migratory Defluorinative Olefin Cross-Coupling: Trifluoromethyl-Substituted Alkenes as Acceptor Olefins to Form gem-Difluoroalkenes
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We report a NiH-catalyzed migratory defluorinative coupling between two electronically differentiated olefins. A broad range of unactivated donor olefins can be joined directly to acceptor olefins containing an electron-deficient trifluoromethyl substituent in both intra- and intermolecular fashion to form gem-difluoroalkenes. This migratory coupling shows both site- and chemoselectivity under mild conditions, with the formation of a tertiary or quaternary carbon center.
- Chen, Fenglin,He, Yuli,Huang, Genping,Xu, Xianfeng,Zhu, Shaolin
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supporting information
p. 5398 - 5402
(2020/02/28)
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- A wacker-type strategy for the synthesis of unsymmetrical POCsp3E-nickel pincer complexes
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ECE-type pincer complexes have evolved into a diverse family of compounds possessing interesting structural/ bonding features, reactivities, and practical applications. An important factor promoting the growth of pincer chemistry is the availability of versatile synthetic pathways that give access to ever-diverse pincer complexes. This report describes the synthesis of pincer-Ni complexes possessing the following features: a central Ni-Csp3 linkage, two different peripheral donor moieties, and two differently sized metallacycles. The synthetic methodology reported herein is based on the reactivity of a phosphinite derived from 2-vinylphenol. Stirring the substrate 2-CH2=CH-C6H4-OP(i-Pr)2, 1, with the NiII precursor {(i-PrCN)NiBr2}n and Et3N at room temperature gave the 6,5-POCsp3PO-type pincer complex {κO,κC,κP-2-[(i-Pr)2P(O)CH2CH]-C6H4-OP(i-Pr)2}NiBr, 2. Conducting this reaction in the presence of an excess of 1 hinders the formation of 2, giving instead the nickellacyclopropane complex {κC,κ,κP-2-[(2-CH2=CH-C6H4O)P(i-Pr)2CHCH]-C6H4-OP(i-Pr)2}NiBr, 3, whereas introducing a second, stronger nucleophile into the reaction mixture leads to the formation of pincer complexes featuring rare 4-membered metallacycles. For instance, using HNR(R′) as nucleophile gave the 6,4-POCsp3N-type pincer complexes {κN,κC,κP-2-[R(R′)NCH2CH]-C6H4-OP(iPr)2}NiBr (NR(R′) = N-morpholyl, 4; NPh(Et), 5; NH(i-Pr), 6; NH(Ph), 7; NH(Cy), 8; NH(t-Bu), 9), whereas using HPR2 as nucleophile led to the 6,4-POCsp3P-type pincer complexes {κP,κC,κP′-2-[R2PCH2CH]-C6H4-OP(i-Pr)2}NiBr (R = i-Pr, 10; iPh, 11). Single crystal diffraction studies have established the solid-state structures of complexes 2-11. All the pincer complexes reported here feature 6-membered metallacycles defined by the phosphinite moiety, while the phosphine-oxide moiety in 2 defines a 5-membered metallacycle and 4-membered metallacycles form by the coordination of the amine moieties in 4-9 and the phosphines in 10 and 11. Cyclic voltammetry measurements on complexes 2, 4-6, 10, and 11 have shown that these pincer-Ni complexes undergo facile one-electron oxidation.
- Mangin, Lo?c P.,Michaud, Guillaume,Zargarian, Davit
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supporting information
p. 4006 - 4018
(2020/11/30)
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- HFIP Solvent Enables Alcohols to Act as Alkylating Agents in Stereoselective Heterocyclization
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A new method for the stereoselective synthesis of highly functionalized oxygen heterocycles using allyl or benzyl alcohols as alkylating agents is presented. The process is efficient and atom economic, generating water as the only stoichiometric byproduct. Substoichiometric amounts of Ti(OiPr)4 in HFIP solvent are key to this reactivity, and the method tolerates a broad substitution pattern on both the alcohol initiator and homoallylic alcohol substrate. Preliminary mechanistic studies reveal in situ formation of a titanium complex with HFIP which may initiate the cyclization reaction. Further stereoselective functionalization of the products allows access to a diverse range of interesting heterocyclic structures.
- Zhu, Yuxiang,Colomer, Ignacio,Thompson, Amber L.,Donohoe, Timothy J.
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supporting information
p. 6489 - 6493
(2019/05/06)
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- Spiroketal-Based C2-Symmetric Scaffold For Asymmetric Catalysis
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Provided herein is a compound of formula (I): wherein each R is independently selected from the group consisting of C1-8 alkyl, C1-8 heteroalkyl having 1-4 heteroatoms independently selected from N, O, and S, C3-6 cycloalkyl, 3-10 membered heterocycloalkyl having 1-4 heteroatoms independently selected from N, O, and S, C6-10 aryl, and 5-10 membered heteroaryl having 1-4 heteroatoms independently selected from N, O, and S; each X is independently selected from OH, PAr2, P(O)Ar2, OPAr2, C3-6 cycloalkyl, 3-10 membered heterocycloalkyl having 1-4 heteroatoms independently selected from N, O, and S or each X together form O2PNR′2; Ar is C6-10aryl; and each R′ is independently selected from hydrogen and C1-8 alkyl. Also provided are methods of making and using the compound of formula (I).
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Paragraph 0139; 0140
(2019/04/08)
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- Practical, Large-Scale Preparation of Benzoxepines and Coumarins through Rhodium(III)-Catalyzed C-H Activation/Annulation Reactions
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Herein we disclose the assembly of benzoxepines and coumarins from 2-alkenylphenol precursors using [Cp*RhCl2]2 as the precatalyst and alkynes or carbon monoxide as reacting partners. The preparation of benzoxepines and coumarins can be scaled up to 33 mmol using low catalyst loadings.
- Gulías, Moisés,Marcos-Atanes, Daniel,Mascare?as, José L.,Font, Marc
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supporting information
p. 1669 - 1673
(2019/09/04)
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- Phenolic Bis-styrylbenzo[ c]-1,2,5-thiadiazoles as Probes for Fluorescence Microscopy Mapping of Aβ Plaque Heterogeneity
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A fluorescent bis-styryl-benzothiadiazole (BTD) with carboxylic acid functional groups (X-34/Congo red analogue) showed lower binding affinity toward Aβ1-42 and Aβ1-40 fibrils than its neutral analogue. Hence, variable patterns of neutral OH-substituted bis-styryl-BTDs were generated. All bis-styryl-BTDs showed higher binding affinity to Aβ1-42 fibrils than to Aβ1-40 fibrils. The para-OH on the phenyl rings was beneficial for binding affinity while a meta-OH decreased the affinity. Differential staining of transgenic mouse Aβ amyloid plaque cores compared to peripheral coronas using neutral compared to anionic bis-styryl ligands indicate differential recognition of amyloid polymorphs. Hyperspectral imaging of transgenic mouse Aβ plaque stained with uncharged para-hydroxyl substituted bis-styryl-BTD implicated differences in binding site polarity of polymorphic amyloid plaque. Most properties of the corresponding bis-styryl-BTD were retained with a rigid alkyne linker rendering a probe insensitive to cis-trans isomerization. These new BTD-based ligands are promising probes for spectral imaging of different Aβ fibril polymorphs.
- Zhang, Jun,Konsmo, Audun,Sandberg, Alexander,Wu, Xiongyu,Nystr?m, Sofie,Obermüller, Ulrike,Wegenast-Braun, Bettina M.,Konradsson, Peter,Lindgren, Mikael,Hammarstr?m, Per
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p. 2038 - 2048
(2019/02/26)
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- Photoinduced hydroxylation of arylboronic acids with molecular oxygen under photocatalyst-free conditions
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Photoinduced hydroxylation of boronic acids with molecular oxygen under photocatalyst-free conditions is reported, providing a green entry to a variety of phenols and aliphatic alcohols in a highly concise fashion. This new protocol features photocatalyst-free conditions, wide substrate scope and excellent functional group compatibility.
- Xu, Yu-Ting,Li, Chen-Yuan,Huang, Xiao-Bo,Gao, Wen-Xia,Zhou, Yun-Bing,Liu, Miao-Chang,Wu, Hua-Yue
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supporting information
p. 4971 - 4975
(2019/09/30)
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- Reductive C-O, C-N, and C-S Cleavage by a Zirconium Catalyzed Hydrometalation/β-Elimination Approach
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A zirconium catalyzed reductive cleavage of Csp3 and Csp2 carbon-heteroatom bonds is reported that makes use of a tethered alkene functionality as a traceless directing group. The reaction is successfully demonstrated on C-O, C-N, and C-S bonds and proposed to proceed via a hydrozirconation/β-heteroatom elimination sequence of an in situ formed zirconium hydride catalyst. The positional isomerization of the catalyst further enables the cleavage of homoallylic ethers and the removal of terminal allyl and propargyl groups.
- Matt, Christof,K?lblin, Frederic,Streuff, Jan
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supporting information
p. 6983 - 6988
(2019/09/09)
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- Macrocyclic Modulators of the Ghrelin Receptor
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The present invention provides novel conformationally-defined macrocyclic compounds that have been demonstrated to be selective modulators of the ghrelin receptor (growth hormone secretagogue receptor, GHS-R1a and subtypes, isoforms and variants thereof). Methods of synthesizing the novel compounds are also described herein. These compounds are useful as agonists of the ghrelin receptor and as medicaments for treatment and prevention of a range of medical conditions including, but not limited to, metabolic and/or endocrine disorders, gastrointestinal disorders, cardiovascular disorders, obesity and obesity-associated disorders, central nervous system disorders, genetic disorders, hyperproliferative disorders and inflammatory disorders.
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Paragraph 0423; 0424
(2018/05/03)
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- A chiral phosphorus alkene ligand, synthetic method and the application of the asymmetric reaction in (by machine translation)
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The invention relates to a chiral phosphorus alkene ligand, a synthesis method and application thereof in asymmetric reaction. Specifically, the invention discloses a chiral phosphorus alkene compound, which has a structural formula shown as formula I or formula II in the specification, wherein R, R, R, R, R, R, R, R and R are defined in the specification. The chiral phosphorus alkene compound can be prepared from chiral 2, 2'-binaphthol or its derivative as the starting material through two to four steps of reaction by means of four methods. The chiral phosphorus alkene compound can be used as a chiral ligand in asymmetric addition reaction of rhodium catalyzed boric acid and prochiral C=X (X=C, O, N) double bond, and can achieve good yield and enantioselectivity.
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Paragraph 0196-0198
(2018/05/24)
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- Synthesis of Benzofuranones via Palladium-Catalyzed Intramolecular Alkoxycarbonylation of Alkenylphenols
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Herein, a new catalytic system to synthesize benzofuranones is reported. A palladium-catalyzed intramolecular alkoxycarbonylation is employed to generate 3-substituted-benzofuran-2(3H)-ones from alkenylphenols under mild reaction conditions, linked to an ex situ formation of CO from N-formylsaccharin. The carefully chosen catalytic system enables an efficient reaction with a novel functional group tolerance, despite the high polymerization tendency of the starting material.
- Hirschbeck, Vera,Fleischer, Ivana
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supporting information
p. 2854 - 2857
(2018/02/06)
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- Design, Synthesis, and Application of Chiral C2-Symmetric Spiroketal-Containing Ligands in Transition-Metal Catalysis
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We present an expedient and economical route to a new spiroketal-based C2-symmetric chiral scaffold, termed SPIROL. Based on this spirocyclic scaffold, several chiral ligands were generated. These ligands were successfully employed in an array of stereoselective transformations, including in iridium-catalyzed hydroarylations (up to 95 % ee), palladium-catalyzed allylic alkylations (up to 97 % ee), intermolecular palladium-catalyzed Heck couplings (up to 94 % ee), and rhodium-catalyzed dehydroalanine hydrogenation (up to 93 % ee).
- Argüelles, Alonso J.,Sun, Siyuan,Budaitis, Brenna G.,Nagorny, Pavel
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supporting information
p. 5325 - 5329
(2018/03/27)
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- Catalytic Geminal Difluorination of Styrenes for the Construction of Fluorine-rich Bioisosteres
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A geminal difluorination of alkenes based on I(I)/I(III) catalysis is disclosed, which is compatible with a range of electronically and substitutionally diverse styrenes (27 examples, up to 89% yield). Employing inexpensive p-TolI as the organocatalyst, turnover is enabled by Selectfluor-mediated oxidation to generate the ArIF2 species in situ. Extension to include α-substituted styrenes bearing fluorine-containing groups is disclosed and provides an expansive platform for the generation of fluorine-rich architectures.
- Scheidt, Felix,Neufeld, Jessica,Sch?fer, Michael,Thiehoff, Christian,Gilmour, Ryan
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supporting information
p. 8073 - 8076
(2019/01/04)
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- Enantioselective, Catalytic Vicinal Difluorination of Alkenes
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The enantioselective, catalytic vicinal difluorination of alkenes is reported by II/IIII catalysis using a novel, C2-symmetric resorcinol derivative. Catalyst turnover via in situ generation of an ArIIIIF2 species is enabled by Selectfluor oxidation and addition of an inexpensive HF–amine complex. The HF:amine ratio employed in this process provides a handle for regioselective orthogonality as a function of Br?nsted acidity. Selectivity reversal from the 1,1-difluorination pathway (geminal) to the desired 1,2-difluorination (vicinal) is disclosed (>20:1 in both directions). Validation with electron deficient styrenes facilitates generation of chiral bioisosteres of the venerable CF3 unit that is pervasive in drug discovery (20 examples, up to 94:06 e.r.). An achiral variant of the reaction is also presented using p-TolI (up to >95 % yield).
- Scheidt, Felix,Sch?fer, Michael,Sarie, Jér?me C.,Daniliuc, Constantin G.,Molloy, John J.,Gilmour, Ryan
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supporting information
p. 16431 - 16435
(2018/11/23)
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- Copper-Catalyzed Ring Opening of Benzofurans and an Enantioselective Hydroamination Cascade
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A copper(II) acetate/(R)-DTBM-SEGPHOS-catalyzed ring opening of benzofurans and enantioselective hydroamination cascade with dimethoxymethylsilane (DMMS) and hydroxylamine esters is described. Starting from readily available substituted benzofurans, a series of chiral N,N-dibenzylaminophenols, which are of high interest in pharmaceutical chemistry, were obtained with excellent enantioselectivities (up to 66 % yield, 94 % ee).
- Xu-Xu, Qing-Feng,Liu, Qiang-Qiang,Zhang, Xiao,You, Shu-Li
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p. 15204 - 15208
(2018/10/24)
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- Bichromatic Photosynthesis of Coumarins by UV Filter-Enabled Olefin Metathesis
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Herein, we report on a two-step bichromatic synthesis of coumarins involving UV-A and UV-C light. The first step is a UV-A-photoinduced ruthenium-catalyzed cross-metathesis (CM) reaction of 2-nitrobenzyl-protected 2-hydroxystyrenes with acrylates, using an external solution of 1-pyrenecarboxaldehyde as a UV filter. Irradiation in the absence of the filter permanently inhibits the light-activated catalyst due to photocleavage of the photolabile protecting group (PPG) and ensuing phenolate chelation to the ruthenium. The simple removal of the external filter after CM allows further photochemical reactions with UV-C light to achieve more complex architectures, such as the coumarins presented in this work. (Figure presented.).
- Eivgi, Or,Sutar, Revannath L.,Reany, Ofer,Lemcoff, N. Gabriel
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supporting information
p. 2352 - 2357
(2017/07/22)
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- 3H-1,2-benzoxathiepine 2,2-dioxides: a new class of isoform-selective carbonic anhydrase inhibitors
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A new chemotype with carbonic anhydrase (CA, EC 4.2.1.1) inhibitory action has been discovered, the homo-sulfocoumarins (3H-1,2-benzoxathiepine 2,2-dioxides) which have been designed considering the (sulfo)coumarins as lead molecules. An original synthetic strategy of a panel of such derivatives led to compounds with a unique inhibitory profile and very high selectivity for the inhibition of the tumour associated (CA IX/XII) over the cytosolic (CA I/II) isoforms. Although the CA inhibition mechanism with these new compounds is unknown for the moment, we hypothesize that it may be similar to that of the sulfocoumarins, i.e. hydrolysis to the corresponding sulfonic acids which thereafter anchor to the zinc-coordinated water molecule within the enzyme active site.
- Pustenko, Aleksandrs,Stepanovs, Dmitrijs,?alubovskis, Raivis,Vullo, Daniela,Kazaks, Andris,Leitans, Janis,Tars, Kaspars,Supuran, Claudiu T.
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p. 767 - 775
(2017/06/07)
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- Lewis Acid Catalyzed Cyclization of Propargylic Alcohols with 2-Vinylphenol
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An unprecedented Lewis acid catalyzed, protection-free, and high-efficiency synthesis of valuable 3,4-dihydro-2H-2,4-methanochromans via cycloaddition of propargylic alkynols with 2-vinylphenol is described. This cycloaddition protocol, which tolerates a
- Han, Ya-Ping,Song, Xian-Rong,Qiu, Yi-Feng,Li, Xue-Song,Zhang, Heng-Rui,Zhu, Xin-Yu,Liu, Xue-Yuan,Liang, Yong-Min
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supporting information
p. 3866 - 3869
(2016/08/16)
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- Regioselective Thiocarbonylation of Vinyl Arenes
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A palladium-catalyzed thiocarbonylation of styrene derivatives is reported for the first time. The combination of thiols as nucleophiles and a bidentate ligand ensures a unique reaction outcome with high regioselectivity toward the more valuable branched isomer and new reactivity. The ambient reaction conditions (temperature, catalyst loading) and the use of a CO surrogate render this transformation a useful method for the synthesis of thioesters from available feedstock. Various functional groups on arene and thiol substituents are tolerated by the system. Notably, challenging ortho-substituted styrenes are converted with unprecedentedly high regioselectivity.
- Hirschbeck, Vera,Gehrtz, Paul H.,Fleischer, Ivana
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supporting information
p. 16794 - 16799
(2017/01/10)
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- METHOD TO PREPARE PHENOLICS FROM BIOMASS
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The present invention is directed to a method for preparing a final phenolic product from biomass comprising the steps of providing a furanic compound obtainable from biomass; reacting the furanic compound with a dienophile to obtain a phenolic compound; reacting the phenolic compound further to obtain the final phenolic product.
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Page/Page column 45; 46
(2016/08/10)
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- Low-Pressure Cobalt-Catalyzed Enantioselective Hydrovinylation of Vinylarenes
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An efficient and practical protocol for the enantioselective cobalt-catalyzed hydrovinylation of vinylarenes with ethylene at low (1.2 bar) pressure has been developed. As precatalysts, stable [L2CoCl2] complexes are employed that are activated in situ with Et2AlCl. A modular chiral TADDOL-derived phosphine-phosphite ligand was identified that allows the conversion of a broad spectrum of substrates, including heterocyclic vinylarenes and vinylferrocene, to smoothly afford the branched products with up to 99 % ee and virtually complete regioselectivity. Even polar functional groups, such as OH, NH2, CN, and CO2R, are tolerated.
- Movahhed, Sohajl,Westphal, Julia,Dindaro?lu, Mehmet,Falk, Anna,Schmalz, Hans-Günther
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supporting information
p. 7381 - 7384
(2016/05/24)
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- Vinylation of phenol by acetaldehyde: A new reaction for the synthesis of o-vinylphenol
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A new catalytic reaction for the single-step synthesis of o-vinylphenol from phenol and acetaldehyde in the gas phase is investigated in this work. A search for an efficient catalyst was made. The best results were obtained with a modified Cr2O3 catalyst supported on γ-Al2O3. The effect of content of Cr2O3 and potassium as a modifying additive was studied. It was shown that the catalyst containing 13% Cr2O3 and 1% K makes it possible to obtain o-vinylphenol with a selectivity of 100% referred to phenol and up to 87% referred to acetaldehyde. The influence of reaction conditions on the activity, selectivity and stability of catalyst operation was elucidated.
- Parfenov, Mikhail V.,Pirutko, Larisa V.,Soshnikov, Igor E.,Starokon, Eugeny V.,Kharitonov, Alexander S.,Panov, Gennady I.
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- Highly Ligand-Controlled Regioselective Pd-Catalyzed Aminocarbonylation of Styrenes with Aminophenols
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Achieving chemo- and regioselectivity simultaneously is challenging in organic synthesis. Transition metal-catalyzed reactions are effective in addressing this problem by the diverse ligand effect on the catalyst center. Ligand-controlled regioselective Pd-catalyzed carbonylation of styrenes with aminophenols was realized, chemoselectively affording amides. Using a combination of boronic acid and 5-chlorosalicylic acid as the additives, linear amides were obtained in high yields and selectivity using tris(4-methoxyphenyl)phosphine (L3) in acetonitrile, while branched amides were obtained in high yields and selectivity in butanone by changing the ligand to 1,3,5,7-tetramethyl-2,4,8-trioxa-6-phenyl-6-phosphaadamantane (L5). Further studies show that the nature of the ligand is key to the regioselectivity. Cone angle and Tolman electronic parameter (TEP) have been correlated to the reactivity and regioselectivity. Studies on the acid additives show that different acids act as the proton source and the corresponding counterion can help enhance the reactivity and selectivity.
- Xu, Tongyu,Sha, Feng,Alper, Howard
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supporting information
p. 6629 - 6635
(2016/06/09)
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- OH-directed alkynylation of 2-vinylphenols with ethynyl benziodoxolones: A fast access to terminal 1,3-enynes
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The first direct alkynylation of 2-vinylphenols was developed. The rationally optimized hypervalent iodine reagent TIPS-EBX in combination with [(CpRhCl2)2] as a C-H-activating transition metal catalyst enables the construction of a variety of highly substituted 1,3-enynes in high yields of up to 98 %. This novel C-H activation method shows excellent chemoselectivity and exclusive (Z)-stereoselectivity, and it is also remarkably mild and tolerates a variety of functional groups. Furthermore, synthetic modifications of the resulting 1,3-enynes were demonstrated. To our knowledge, this is the first example for an OH-directed C-H alkynylation with hypervalent iodine reagents.
- Finkbeiner, Peter,Kloeckner, Ulrich,Nachtsheim, Boris J.
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supporting information
p. 4949 - 4952
(2015/04/14)
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- Silylated organometals: A family of recyclable homogeneous catalysts
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A general strategy has been developed to synthesize a family of silylated organometals (M-PPh2-TS and DPEN-Ru-PPh2-Ts, M = Pd2+, Rh+, Pt2+, Ir+, or Ru2+, PPh2-Ts = PPh2CH2CH2Si(OEt)3), DPEN = (1R,2R)-1,2-diphenylethylenediamine). They can act as homogeneous catalysts with high efficiencies in various organic reactions using THF, CH2Cl2 or toluene as the reaction medium. After reaction, they could be thoroughly settled down by adding pentane and then used repeatedly owing to the complete catalyst recovery and good preservation of the catalyst structure. This is particularly important due to the increasing concerns regarding the cost, toxicity and limited availability of these nonrenewable transition metals.
- Huang, Jian-Lin,Wang, Jun-Zhong,Li, He-Xing,Guo, Haibing,O'Doherty, George A.
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p. 1473 - 1478
(2015/03/18)
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- Rh-catalyzed oxidizing group-directed ortho C-H vinylation of arenes by vinylstannanes
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An efficient method for the synthesis of functionalized vinyl arenes from the reaction of N-methoxybenzamides or N-phenoxyacetamides with vinylstannanes via rhodium(III)-catalyzed C-H activation is described. The application of the methodology for the synthesis of a natural product thalactamine and a 7-membered ring oxepine are also demonstrated.
- Prakash, Sekar,Muralirajan, Krishnamoorthy,Cheng, Chien-Hong
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supporting information
p. 13362 - 13364
(2015/08/24)
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- Aldehyde-Assisted Ruthenium(II)-Catalyzed C-H Oxygenations
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Versatile ruthenium(II) complexes allow for site-selective C-H oxygenations with weakly-coordinating aldehydes. The challenging C-H functionalizations proceed with high chemoselectivity by rate-determining C-H metalation. The new method features an ample substrate scope, which sets the stage for the step-economical preparation of various bioactive heterocycles.
- Yang, Fanzhi,Rauch, Karsten,Kettelhoit, Katharina,Ackermann, Lutz
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supporting information
p. 11285 - 11288
(2016/02/18)
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- Straightforward assembly of benzoxepines by means of a rhodium(III)- catalyzed C-H functionalization of o-vinylphenols
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Readily available o-vinylphenols undergo a formal (5 + 2) cycloaddition to alkynes when treated with catalytic amounts of [Cp*RhCl2] 2 and Cu(OAc)2. The reaction, which involves the cleavage of the terminal C-H bond of the alkenyl moiety, generates highly valuable benzoxepine skeletons in a practical, versatile, and atom-economical manner. Using carbon monoxide instead of an alkyne as reaction partner leads to coumarin products which formally result from a (5 + 1) cycloaddition.
- Seoane, Andres,Casanova, Noelia,Quinones, Noelia,Mascarenas, Jose L.,Gulias, Moises
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supporting information
p. 834 - 837
(2014/02/14)
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- Endo-selective pd-catalyzed silyl methyl heck reaction
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A palladium (Pd)-catalyzed endo-selective Heck reaction of iodomethylsilyl ethers of phenols and aliphatic alkenols has been developed. Mechanistic studies reveal that this silyl methyl Heck reaction operates via a hybrid Pd-radical process and that the silicon atom is crucial for the observed endo selectivity. The obtained allylic silyloxycycles were further oxidized into (Z)-alkenyldiols.
- Parasram, Marvin,Iaroshenko, Viktor O.,Gevorgyan, Vladimir
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supporting information
p. 17926 - 17929
(2015/03/04)
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- Copper/silver-mediated cascade reactions for the construction of 2-sulfonylbenzo[b]furans from trans-2-hydroxycinnamic acids and sodium sulfinates
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Efficient construction of 2-sulfonylbenzo[b]furans is achieved from readily available trans-2-hydroxycinnamic acids and sodium sulfinates mediated by the CuCl2.2H2O/AgTFA system under mild conditions. This unprecedented synthetic protocol provides expedient access to a series of products in one step via a protodecarboxylation/C-S bond formation/C-O bond formation cascade.
- Li, Hong-Shuang,Liu, Gang
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p. 509 - 516
(2014/04/03)
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- Convenient transfer semihydrogenation methodology for alkynes using a PdII-NHC precatalyst
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A convenient and easy-to-use protocol for the Z-selective transfer semihydrogenation of alkynes was developed, using ammonium formate as the hydrogen source and the easily prepared and commercially available, highly stable complex PdCl(η3-C3H5)(IMes) (1) as the (pre)catalyst. Combined with triphenyl posphine as an additional ligand, this system provides a robust catalytic synthetic method that shows little to no over-reduction or isomerization after full substrate conversion. The system allows the direct use of solvents and reagents, as received from the supplier without drying or purification, thus providing a practical method for semihydrogenation of a broad range of alkynes. The mechanism behind these high and enhanced selectivities was determined through a set of kinetic experiments.
- Drost, Ruben M.,Bouwens, Tessel,Van Leest, Nicolaas P.,De Bruin, Bas,Elsevier, Cornelis J.
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p. 1349 - 1357
(2014/05/20)
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- Continuous-flow synthesis of functionalized phenols by aerobic oxidation of grignard reagents
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Phenols are important compounds in chemical industry. An economical and green approach to phenol preparation by the direct oxidation of aryl Grignard reagents using compressed air in continuous gas-liquid segmented flow systems is described. The process tolerates a broad range of functional groups, including oxidation-sensitive functionalities such as alkenes, amines, and thioethers. By integrating a benzyne-mediated in-line generation of arylmagnesium intermediates with the aerobic oxidation, a facile three-step, one-flow process, capable of preparing 2-functionalized phenols in a modular fashion, is established. Putting on airs: Aerobic oxidation of (hetero)aryl Grignard reagents using compressed air proceeds with a gas-liquid continuous-flow system, thus enabling preparation of fucntionalized phenols. By integrating an in-line generation of ArMgBr intermediates with the aerobic oxidation, ortho-functionalized phenols can be assembled. The method demonstrates good functional-group (FG) compatibility, mild reaction conditions, and short reaction times.
- He, Zhi,Jamison, Timothy F.
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supporting information
p. 3353 - 3357
(2014/04/03)
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- Palladium(II)-catalyzed direct carboxylation of alkenyl C-H bonds with CO2
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Pd-catalyzed direct carboxylation of alkenyl C-H bonds with carbon dioxide was realized for the first time. Treatment of 2-hydroxystyrenes and a catalytic amount of Pd(OAc)2 with Cs2CO3 under atmospheric pressure of CO2 afforded corresponding coumarins in good yield. Furthermore, isolation of the key alkenylpalladium intermediate via C-H bond cleavage was achieved. The reaction was proposed to undergo reversible nucleophilic addition of the alkenylpalladium intermediate to CO2.
- Sasano, Kota,Takaya, Jun,Iwasawa, Nobuharu
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supporting information
p. 10954 - 10957
(2013/08/23)
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- Palladium-catalyzed asymmetric intermolecular cyclization
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Domino cyclization: Alkylpalladium intermediates in an asymmetric Heck reaction were intercepted by a second alkene to give tricyclic products with high enantioselectivity (see scheme; Boc=tert-butoxycarbonyl). The method was applied to the asymmetric syn
- Hu, Jian,Hirao, Hajime,Li, Yongxin,Zhou, Jianrong
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supporting information
p. 8676 - 8680
(2013/09/12)
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- Catalytic asymmetric synthesis of cyclic ethers containing an α-tetrasubstituted stereocenter
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'Ether' furan or pyran: The exo-selective cyclization of enantioenriched allenols is accomplished with high chirality transfer using as little as 0.02 mol % of a gold catalyst. The new method is effective in the synthesis of a wide range of enantioenriche
- Cox, Nick,Uehling, Mycah R.,Haelsig, Karl T.,Lalic, Gojko
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supporting information
p. 4878 - 4882
(2013/06/05)
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- Resveratrol derived butyrylcholinesterase inhibitors
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Novel polyhydroxylated (E)-stilbenes were synthesized by Mizoroki-Heck reactions and tested for their ability to inhibit the enzymes acetyl- and butyrylcholinesterase. Several of them are good inhibitors of butyrylcholinesterase; one of them carrying an extra fluorine substituent is a 94-fold stronger inhibitor of butyrylcholinesterase than of acetylcholinesterase. Novel polyhydroxylated (E)-stilbenes synthesized by Mizoroki-Heck reactions were tested for their ability to inhibit the enzymes acetyl- and butyrylcholinesterase. Several of them were found to be good inhibitors of butyrylcholinesterase. One of them carrying an extra fluorine substituent is a 94-fold stronger inhibitor of butyrylcholinesterase than of acetylcholinesterase.
- Csuk, Rene,Albert, Sabrina,Kluge, Ralph,Stroehl, Dieter
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p. 499 - 503
(2013/07/26)
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- Synthesis and radical scavenging activities of resveratrol analogs
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Highly substituted polyhydroxylated (E)-stilbenes were synthesized by Mizoroki-Heck reactions and tested for their ability to act as radical scavenger. One of the 56 stilbenes included in this study and investigated in DPPH assays gave an SC50 value of 11.0 μM, hence exhibiting an about 9.3 times higher activity than resveratrol. As shown in a photometric SRB assay using mouse NiH 3T3 fibroblasts, this compound is not cytotoxic up to concentrations of 30 μM. Highly substituted polyhydroxylated (E)-stilbenes synthesized by Mizoroki-Heck reactions were tested for their ability to act as radical scavengers. One of the 56 stilbenes included exhibited about 9.3 times higher activity than resveratrol. At concentrations 30 μM, this compound was not cytotoxic.
- Csuk, Rene,Albert, Sabrina,Siewert, Bianka
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p. 504 - 510
(2013/07/26)
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- Highly practical iron-catalyzed C-O cleavage reactions
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Facile iron-catalyzed cleavage of various allyl, cinnamyl and benzyl C-O linkages has been effected in the presence of ethylmagnesium chloride. The protocol is operationally simple (xylene-THF, r.t., 1 h), requires low catalyst loading (1 mol% FeCl2) and tolerates halides, esters, amines, ethers and olefins. The allyl moiety is converted to volatile hydrocarbons which renders laborious product separation unnecessary.
- Gaertner, Dominik,Konnerth, Hannelore,Von Wangelin, Axel Jacobi
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p. 2541 - 2545
(2013/09/24)
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- Remarkable improvement achieved by imidazole derivatives in ruthenium-catalyzed hydroesterification of alkenes using formates
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Imidazole derivatives are revealed to be effective ligands in the Ru-catalyzed hydroesterification of alkenes using formates, affording one-carbonelongated esters in high yields. Further, intramolecular hydroesterification was successfully performed to give lactones for the first time. Imidazole derivatives can contribute to promote the reaction as well as to suppress the undesired decarbonylation of formate. Toxic CO gas, a directing group, and large excess alkenes are not required.
- Konishi, Hideyuki,Muto, Takashi,Manabe, Kei,Ueda, Tsuyoshi
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supporting information
p. 4722 - 4725,4
(2012/12/12)
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- Synthesis of coumarins via Pd-catalyzed oxidative cyclocarbonylation of 2-vinylphenols
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Palladium-catalyzed oxidative cyclocarbonylation of 2-vinylphenols constitutes a simple, direct method for the synthesis of coumarins. The reaction conditions, employing low pressures of CO, and air or 1,4- benzoquinone as the oxidant, are attractive in terms of environmental considerations and operational simplicity. Coumarins with a variety of functional groups were prepared in yields up to 85%.
- Ferguson, Jamie,Zeng, Fanlong,Alper, Howard
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supporting information
p. 5602 - 5605,4
(2012/12/12)
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- Palladium-catalyzed hydrofunctionalization of vinyl phenol derivatives with heteroaromatics
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A hydroheteroarylation reaction of vinyl phenols using an alkyl chloride as the sacrificial hydride source is reported. The method tolerates a wide range of heterocycles as the exogenous nucleophile including indoles and pyrroles. The resulting products are easily processed to biologically relevant scaffolds.
- Pathak, Tejas P.,Sigman, Matthew S.
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supporting information; experimental part
p. 2774 - 2777
(2011/06/25)
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- Synthesis and antimicrobial activity of (E) stilbene derivatives
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Plants use multiple defence mechanisms comprising both constitutive and inducible barriers to prevent entering of phytopathogenic micro-organisms. In many plant species one of the most efficient responses to combat attacking microbes is the rapid synthesis of antimicrobial low molecular weight phytoalexins, for example, resveratrol, 3,5,4′-trihydroxystilbene (1). Resveratrol and its natural derivatives, however, display only moderate antimicrobial effects. Nevertheless, resveratrol may be a useful lead structure for the chemical synthesis of antimicrobials. In this study, several series of stilbenes have been synthesized, starting from the aldehydes using Wittig reactions to access the corresponding styrenes that were subjected to Mizoroki-Heck reactions to yield the stilbenes in good yields. The stilbenes were tested in an agar diffusion assay against several bacteria and fungi. For some of these compounds the inhibiting zones for bacteria and fungi were comparable with those of the antibiotics tetracycline, streptomycin, ampicillin, or kanamycin, directed against prokaryotes, and nourseothricin or hygromycin controlling fungi, respectively.
- Albert, Sabrina,Horbach, Ralf,Deising, Holger B.,Siewert, Bianka,Csuk, René
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supporting information; experimental part
p. 5155 - 5166
(2011/10/04)
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- New urinary metabolites formed from ring-oxidized metabolic intermediates of styrene
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The urine from mice exposed to styrene vapors (600 and 1200 mg/m 3, 6 h) was analyzed for ring-oxidized metabolites of styrene. To facilitate the identification of metabolites in urine, the following potential metabolites were prepared: 2-, 3-, and 4-vinylphenol (2-, 3-, and 4-VP), 4-vinylpyrocatechol, and 2-, 3-, and 4-vinylphenylmercapturic acid (2-, 3-, and 4-VPMA). For the analysis of vinylphenols β-glucuronidase-treated urine was extracted and derivatized with acetanhydride/triethylamine before injection into GC/MS. Three isomers, 2-, 3-, and 4-VP, were found in the exposed urine using authentic standards. Additionally, three novel minor urinary metabolites, arylmercapturic acids 2-, 3-, and 4-VPMA, were identified by LC-ESI-MS 2 by comparison with authentic standards. Excretion of the most abundant isomer, 4-VPMA, amounted to 535 ± 47 nmol/kg and 984 ± 78 nmol/kg, representing approximately 0.047 and 0.043% of the absorbed dose for the exposure levels of 600 and 1200 mg/m3, respectively. The ratio of 2-VPMA, 3-VPMA, and 4-VPMA was approximately 2:1:6. In model reactions of styrene 3,4-oxide (3,4-STO) with N-acetylcysteine in aqueous solutions and of its methyl ester in methanol, 4-vinylphenol was always the main product, while 3-vinylphenol has never been detected. No mercapturic acid was found in the reaction of 3,4-STO with N-acetylcysteine in aqueous solution at pH 7.4 or 9.7, but a small amount of 4-VPMA methyl ester was detected by LC-ESI-MS after the reaction of 3,4-STO with N-acetylcysteine methyl ester. In contrast, no mercapturic acid was found in the reaction of 3,4-STO with N-acetylcysteine in aqueous solution at pH 7.4 or 9.7. These findings indicate a capability of 3,4-STO to react with cellular thiol groups despite its rapid isomerization to vinylphenol in an aqueous environment. Moreover, the in vivo formation of 2- and 3-isomers of both VP and VPMA, neither of which was formed from 3,4-STO in vitro, strongly suggests that another arene oxide, styrene 2,3-oxide, might be a minor metabolic intermediate of styrene.
- Linhart, Igor,Mraz, Jaroslav,Scharff, Jan,Krouzelka, Jan,Duskova, Sarka,Nohova, Hana,Vodickova, L'udmila
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body text
p. 251 - 257
(2011/02/16)
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