- Syntheses of (6S)-6-fluoro- and (6R)-6-hydroxyshikimic acids
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(6S)-6-Fluoroshikimic acid 2 and (6R)-6-hydroxyshikimic acid 3 have been synthesised via an OsO4-catalysed dihydroxylation of diene 6, which was derived from (-)-shikimic acid 1.
- Song, Chuanjun,Jiang, Shende,Singh, Gurdial
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- Rearrangement of 1,4,5,6-tetrahalo-7,7-dimethoxybicyclo[2.2.1]-hept-5-en-2-ones to phenolic derivatives
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A simple Diels-Alder route leading to methyl 2,3,4-trihalo-5-hydroxybenzoates via thermal Grob-type rearrangement of easily accessible 1,4,5,6-tetrahalo-7,7-dimethoxybicyclo[2.2.1]hept-5-en-2-one with concomitant methyl halide elimination is described.
- Khan, Faiz Ahmed,Dash, Jyotirmayee,Jain, Dheeraj,Prabhudas
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- A scalable and safe continuous flow procedure for in-line generation of diazomethane and its precursor MNU
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Diazomethane is a valuable C1-building block for organic synthesis. Due to its intrinsic reactivity and instability, handling of this reagent is associated with serious safety hazards. Herein we present a simple and robust continuous flow process, allowing a safe and on-demand generation of diazomethane with a productivity of 95-117 mmol h-1. The developed two-step process starts from non-hazardous N-methylurea, and generates and consumes N-methyl-N-nitrosourea (MNU) and diazomethane, thus enabling a safe and convenient scale-up to a multi-gram scale in a conventional synthesis laboratory.
- Lehmann
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- STD NMR and molecular modelling insights into interaction of novel mannose-based ligands with DC-SIGN
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Study of interaction of mannose-based ligands with receptor DC-SIGN using high resolution NMR in combination with molecular modelling showed that four α-d-mannoside ligands interact with the binding site predominantly through the mannose moiety. The other two aromatic groups that are bound to α-d-mannose through a glycerol linker demonstrate interaction that can be related to their substitution pattern. Ligand with naphthyl and meta-substituted phenyl ring exhibited the most favourable binding characteristics. In addition to the predicted hydrophobic interactions of aromatic moieties our results propose new contacts of substituted phenyl moiety in the more polar area of the flat binding site of DC-SIGN and thus offer new possibilities in further designing of novel, more potent DC-SIGN antagonists.
- Kotar, Anita,Toma?i?, Tihomir,Lenar?i? ?ivkovi?, Martina,Jug, Gregor,Plavec, Janez,Anderluh, Marko
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- Dioxetane formation and chemiluminescent emission upon the combination of a vinylphenol derivative with naphthalene endoperoxide
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We designed a chemiluminescent system using nanoparticles. We prepared mesoporous nanoparticles bearing naphthalene endoperoxide as a singlet oxygen generator in the pore and vinyl phenol derivative as an emission unit. The combination of these functional molecules gave highly efficient and bright chemiluminescence through the formation of a 1,2-dioxetane intermediate.
- Umehara, Yui,Son, Aoi,Kondo, Teruyuki,Tanabe, Kazuhito
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- Design, synthesis, and biological evaluation of novel FXR agonists based on auraptene
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Farnesoid X receptor (FXR) has been considered as an attractive target for metabolic disorder and liver injury, while many current FXR agonists suffer from undesirable side effects, such as pruritus. Therefore, it is urgent to develop new structure types different from current FXR agonists. In this study, a series of structural optimizations were introduced to displace the unstable coumarin and geraniol scaffolds of auraptene (AUR), a novel and safe FXR agonist. All of these efforts led to the identification of compound 14, a potent FXR agonist with nearly fourfold higher activity than AUR. Molecular modeling study suggested that compound 14 fitted well with binding pocket, and formed the key ionic bond with His291 and Arg328. In acetaminophen-induced acute liver injury model, compound 14 exerts better therapeutic effect than that of AUR, which highlighting its pharmacological potential in the treatment of drug-induced liver injury.
- Qiu, Qianqian,Wang, Yanjuan,Gu, Guolong,Yu, Fan,Zhang, Shichao,Zhao, Yining,Ling, Bai
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- Carboxyl Methyltransferase Catalysed Formation of Mono- and Dimethyl Esters under Aqueous Conditions: Application in Cascade Biocatalysis
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Carboxyl methyltransferase (CMT) enzymes catalyse the biomethylation of carboxylic acids under aqueous conditions and have potential for use in synthetic enzyme cascades. Herein we report that the enzyme FtpM from Aspergillus fumigatus can methylate a broad range of aromatic mono- and dicarboxylic acids in good to excellent conversions. The enzyme shows high regioselectivity on its natural substrate fumaryl-l-tyrosine, trans, trans-muconic acid and a number of the dicarboxylic acids tested. Dicarboxylic acids are generally better substrates than monocarboxylic acids, although some substituents are able to compensate for the absence of a second acid group. For dicarboxylic acids, the second methylation shows strong pH dependency with an optimum at pH 5.5–6. Potential for application in industrial biotechnology was demonstrated in a cascade for the production of a bioplastics precursor (FDME) from bioderived 5-hydroxymethylfurfural (HMF).
- Ashbrook, Chloe,Carnell, Andrew J.,Goulding, Ellie,Hatton, Harry,Johnson, James R.,Kershaw, Neil M.,McCue, Hannah V.,Rigden, Daniel J.,Ward, Lucy C.
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supporting information
(2022/02/21)
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- Monoacylglycerol lipase (MAGL) inhibitors based on a diphenylsulfide-benzoylpiperidine scaffold
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Monoacylglycerol lipase (MAGL) is an enzyme belonging to the endocannabinoid system that mainly metabolizes the endocannabinoid 2-arachidonoylglycerol (2-AG). Numerous studies have shown the involvement of this enzyme in various pathological conditions such as pain, cancer progression, Parkinson's and Alzheimer's disease, thus encouraging the development of new MAGL modulators. In this context, we developed new diphenylsulfide-benzoylpiperidine derivatives characterized by a high enzymatic MAGL inhibition activity in the low nanomolar range, a reversible mechanism of action and selectivity. The three most active compounds (15–17) induced an appreciable inhibition of cell viability in a panel of nine cancer cell lines, with IC50 values ranging between 0.32 and 10 μM, thus highlighting their potential as novel anticancer agents.
- Barravecchia, Ivana,Bononi, Giulia,Caligiuri, Isabella,Demontis, Gian Carlo,Granchi, Carlotta,Macchia, Marco,Minutolo, Filippo,Poli, Giulio,Rizzolio, Flavio,Tonarini, Giacomo,Tuccinardi, Tiziano
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- Rhodium-Catalyzed Twofold Unsymmetrical C-H Alkenylation-Annulation/Thiolation Reaction to Access Thiobenzofurans
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A Rh(III)-catalyzed twofold unsymmetrical C-H alkenylation-annulation/thiolation reaction has been developed, enabling the straightforward and efficient synthesis of various thiobenzofurans in one step. This robust protocol proceeds with a broad substrate scope and good functional group tolerance under relatively mild reaction conditions.
- Lin, Jian,Hu, Liuyu,Chen, Chao,Feng, Huijin,Yu, Yang,Yang, Yaxi,Zhou, Bing
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supporting information
p. 1194 - 1198
(2021/02/20)
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- Synthesis and structure-activity relationship studies of hydrazide-hydrazones as inhibitors of laccase from trametes versicolor
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A series of hydrazide-hydrazones 1-3, the imine derivatives of hydrazides and aldehydes bearing benzene rings, were screened as inhibitors of laccase from Trametes versicolor. Laccase is a copper-containing enzyme which inhibition might prevent or reduce the activity of the plant pathogens that produce it in various biochemical processes. The kinetic and molecular modeling studies were performed and for selected compounds, the docking results were discussed. Seven 4-hydroxybenzhydrazide (4-HBAH) derivatives exhibited micromolar activity Ki = 24-674 μM with the predicted and desirable competitive type of inhibition. The structure-activity relationship (SAR) analysis revealed that a slim salicylic aldehyde framework had a pivotal role in stabilization of the molecules near the substrate docking site. Furthermore, the presence of phenyl and bulky tert-butyl substituents in position 3 in salicylic aldehyde fragment favored strong interaction with the substrate-binding pocket in laccase. Both 3- and 4-HBAH derivatives containing larger 3-tert-butyl-5-methyl- or 3,5-di-tert-butyl-2-hydroxy-benzylidene unit, did not bind to the active site of laccase and, interestingly, acted as non-competitive (Ki = 32.0 μM) or uncompetitive (Ki = 17.9 μM) inhibitors, respectively. From the easily available laccase inhibitors only sodium azide, harmful to environment and non-specific, was over 6 times more active than the above compounds.
- Giurg, Miros?aw,Maniak, Halina,Matyja, Konrad,Talma, Micha?,Trusek, Anna
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supporting information
(2020/03/23)
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- Design, synthesis, and in vitro evaluation of novel 1,3,4-oxadiazolecarbamothioate derivatives of Rivastigmine as selective inhibitors of BuChE
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Rivastigmine has been prescribed for the therapy of Alzheimer’s disease (AD) symptoms. This drug is classified in the carbamate derivative group that has dual activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). According to the structure of Rivastigmine and its performance, a new series of 5-aryl-1,3,4-oxadiazole-2-carbamothioate compounds I–XI was synthesized using structure-based drug discovery approaches. For this purpose a set of these compounds were designed with computational docking method and their interactions with amino acid residues in the active sites of AChE and BuChE checked out. The structures of synthesized compounds were established by physicochemical and spectroscopic methods. The carbamoyl moiety of Rivastigmine structure was modified to carbamothioate and the effects of 1,3,4-oxadiazole heterocycle as a pharmacophoric nucleus were investigated. The potential of the synthesized compounds I–XI was evaluated against two most known agents of AD (AChE and BuChE) to determine their IC50 values. The results of the docking showed the range of binding affinity for the best poses of ten individual conformers for any compounds (I–XI) was between ?7.81 (VI) and ?6.75 (II) kcal/mol. The results of biological experiments displayed that most synthetic compounds (I–VIII) showed moderate to excellent selective activity range against BuChE (0.51–69.44 μM). In vitro cytotoxicity evaluation of these compounds (I–XI) by MTT assay on human dermal fibroblast (HDF) cell line exhibited no activity against HDF. The compound VI [S-(5-(p-tolyl)-1,3,4-oxadiazol-2-yl) ethyl(methyl)carbamothioate] showed the most stable binding affinity (?7.81 kcal/mol) and the lowest IC50 value (0.51 μM) in comparison with Rivastigmine with 7.72 μM and Donepezil with 5.20 μM against BuChE.
- Fallah, Akram,Mohanazadeh, Farajollah,Safavi, Maliheh
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p. 341 - 355
(2019/12/30)
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- Palladium-Catalyzed Hydroxylation of Aryl Halides with Boric Acid
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Boric acid, B(OH)3, is proved to be an efficient hydroxide reagent in converting (hetero)aryl halides to the corresponding phenols with a Pd catalyst under mild conditions. Various phenol products were obtained in good to excellent yields. This transformation tolerates a broad range of functional groups and molecules, including base-sensitive substituents and complicated pharmaceutical (hetero)aryl halide molecules.
- Song, Zhi-Qiang,Wang, Dong-Hui
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supporting information
p. 8470 - 8474
(2020/11/18)
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- A Structure-Reactivity Relationship of the Tandem Asymmetric Dihydroxylation on a Biologically Relevant Diene: Influence of Remote Stereocenters on Diastereofacial Selectivity
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The Sharpless asymmetric dihydroxylation (AD) finds widespread use in natural product and drug molecule syntheses, in part, due to its efficiency and predictability. However, the tandem AD of dienes is much less studied, but important in complex molecular synthesis. Herein, a biologically relevant tandem AD is reported, and several anomalies are discovered with the accepted model. These include the formation of unpredicted diastereoisomers, with matched and mismatched stereocenters contradicting the Sharpless mnemonic device. From a structural analysis of the tandem AD, we present a strategy to improve asymmetric induction in sterically hindered alkenes using double diastereodifferentiation from a 9-bond distant stereocenter. A theoretical justification for the unpredicted stereoselectivity, accounting for the influence of steric hindrance and pre-installed chirality, is proposed.
- Gill, Daniel M.,Male, Louise,Jones, Alan M.
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supporting information
p. 7568 - 7577
(2019/12/11)
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- Hydrophobicity-oriented drug design (HODD) of new human 4-hydroxyphenylpyruvate dioxygenase inhibitors
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Involved in the tyrosine degradation pathway, 4-hydroxyphenylpyruvate dioxygenase (HPPD) is an important target for treating type I tyrosinemia. To discover novel HPPD inhibitors, we proposed a hydrophobicity-oriented drug design (HODD) strategy based on the interactions between HPPD and the commercial drug NTBC. Most of the new compounds showed improved activity, compound d23 being the most active candidate (IC50 = 0.047 μM) with about 2-fold more potent than NTBC (IC50 = 0.085 μM). Therefore, compound d23 is a potential drug candidate to treat type I tyrosinemia.
- Ndikuryayo, Ferdinand,Kang, Wei-Ming,Wu, Feng-Xu,Yang, Wen-Chao,Yang, Guang-Fu
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- Identification of new aryl hydrocarbon receptor (AhR) antagonists using a zebrafish model
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A new series of 1,3-diketone, heterocyclic and α,β-unsaturated derivatives were synthesized and evaluated for their AhR antagonist activity using zebrafish and mammalian cells. Compounds 1b, 2c, 3b and 5b showed significant AhR antagonist activity in a transgenic zebrafish model. Among them, compound 3b, and 5b were found to have excellent AhR antagonist activity with IC50 of 3.36 nM and 8.3 nM in a luciferase reporter gene assay. In stem cell proliferation assay, compound 5b elicited marked HSC expansion.
- Jeong, Jieun,Kim, Kun-Hee,Kim, Dong-Young,Chandrasekaran, Gopalakrishnan,Kim, Minhee,Pagire, Suvarna H.,Dighe, Mahesh,Choi, Eun Young,Bak, Su-Min,Kim, Eun-Young,Shin, Myung-Geun,Choi, Seok-Yong,Ahn, Jin Hee
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- Woody species: A new bio-based material for dual Ca/Mg catalysis with remarkable Lewis acidity properties
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Advances in green catalysis have promoted the development of ecocatalysis encountered in most of the main transformations of organic chemistry. Taking advantage of the remarkable capacity of certain plants to hyperaccumulate transition metals into shoots or roots, we have addressed the direct use of metals derived from contaminated plant wastes as supported Lewis acid catalysts, coupling agents, oxidative and reducing catalysts in green chemistry. This approach constituted the first example of chemical catalyst based on phytotechnologies. Herein, we show that the concept can be extended to common and abundant plant species that are surprisingly appropriated for chemical catalysis. We present that willow, birch, plane and linden trees can be used to produce bio-based and original Lewis acid catalysts. The catalytic potential of these species will be illustrated through two representative transformations, acetalisation and oxidative esterification. Thanks to their original polymetallic composition, ecocatalysts provided better results compared to classical metal chlorides such as MgCl2, CaCl2 or ZnCl2. This illustrates the interest of the ecocatalysis and is incorporated within the green and sustainable chemistry concept.
- Deyris, Pierre-Alexandre,Adler, Pauline,Petit, Eddy,Legrand, Yves-Marie,Grison, Claude
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p. 3133 - 3142
(2019/06/18)
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- Photoinduced Hydroxylation of Organic Halides under Mild Conditions
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Presented in this paper is photoinduced hydroxylation of organic halides, providing a mild access to a range of functionalized phenols and aliphatic alcohols. These reactions generally proceed under mild reaction conditions with no need for a photocatalyst or a strong base and show a wide substrate scope as well as excellent functional group tolerance. This work highlights the unique role of NaI that allows a challenging transformation to proceed under mild reaction conditions.
- Cai, Yue-Ming,Xu, Yu-Ting,Zhang, Xin,Gao, Wen-Xia,Huang, Xiao-Bo,Zhou, Yun-Bing,Liu, Miao-Chang,Wu, Hua-Yue
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supporting information
p. 8479 - 8484
(2019/10/16)
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- Efficient synthesis of esters through oxone-catalyzed dehydrogenation of carboxylic acids and alcohols
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Since esters are important organic synthesis intermediates, an environmentally friendly oxone catalyzed-esterification of carboxylic acids with alcohols has been developed. A series of carboxylic acid esters are obtained in high yield. This strategy requires mild reaction conditions, providing an attractive alternative for the construction of valuable carbonyl esters. Electron-rich and electron-deficient groups are compatible with the standard conditions and a variety of substrates are demonstrated. Moreover, the reaction could easily be adapted to typical prodrugs, drugs and gram-scale synthesis.
- Hou, Fei,Wang, Xi-Cun,Quan, Zheng-Jun
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supporting information
p. 9472 - 9476
(2019/01/03)
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- Sulfoximine-Assisted One-Pot Unsymmetrical Multiple Annulation of Arenes: A Combined Experimental and Computational Study
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Discussed herein is an unprecedented Ru-catalyzed one-pot unsymmetrical C-H difunctionalization of arenes comprising intramolecular hydroarylation of olefins and intermolecular annulation of alkynes. This unprecedented 2-fold C-H functionalization is validated on the basis of experimental and density functional theory (DFT) study. The transformation readily occurs with the assistance of methylphenyl sulfoximine (MPS) directing group in the presence of Ru catalyst forming two C-C and one C-N bonds in a single operation. The overall process is atom economical and step-efficient and provides unusual dihydrofuran-fused isoquinolone heterocycles. Further annulation of NH and the proximal o-C-H-arene of isoquinolone with alkynes build highly conjugated novel polycyclic compounds. Overall, three independent annulations in arene motifs are visualized and thoughtfully executed; finally, 5 ring-fused structural entities are constructed forming three C-C and two C-N bonds.
- Ghosh, Koushik,Shankar, Majji,Rit, Raja K.,Dubey, Gurudutt,Bharatam, Prasad V.,Sahoo, Akhila K.
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supporting information
p. 9667 - 9681
(2018/09/18)
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- MODIFIED COMPOUND OF ANDROGRAPHOLIDE
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The present disclosure discloses a modified compound of andrographolide, and particularly discloses a compound shown in formula (I) and (II) or a pharmaceutically acceptable salt thereof.
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Paragraph 0170-0172
(2019/01/04)
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- NOVEL INHIBITORS OF MAP4K1
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The invention relates to novel inhibitors of MAP4K1 (HPK1) useful for the treatment of diseases or disorders characterised by dysregulation of the signal transduction pathways associated with MAPK activation, including hyperproliferative diseases, diseases of immune system dysfunction, inflammatory disorders, neurological diseases, and cardiovascular diseases. The invention further relates to pharmaceutical compositions comprising the same and methods of treatment of said diseases and disorders. The inhibitors are of formula (I) wherein the definitions for A, D, E, F, R5, R6, R7, Z, ring Q, n, x and y are as given in the application.
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Page/Page column 63
(2018/12/13)
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- A biocatalytic method for the chemoselective aerobic oxidation of aldehydes to carboxylic acids
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Herein, we present a study on the oxidation of aldehydes to carboxylic acids using three recombinant aldehyde dehydrogenases (ALDHs). The ALDHs were used in purified form with a nicotinamide oxidase (NOx), which recycles the catalytic NAD+ at the expense of dioxygen (air at atmospheric pressure). The reaction was studied also with lyophilised whole cell as well as resting cell biocatalysts for more convenient practical application. The optimised biocatalytic oxidation runs in phosphate buffer at pH 8.5 and at 40 °C. From a set of sixty-one aliphatic, aryl-Aliphatic, benzylic, hetero-Aromatic and bicyclic aldehydes, fifty were converted with elevated yield (up to >99%). The exceptions were a few ortho-substituted benzaldehydes, bicyclic heteroaromatic aldehydes and 2-phenylpropanal. In all cases, the expected carboxylic acid was shown to be the only product (>99% chemoselectivity). Other oxidisable functionalities within the same molecule (e.g. hydroxyl, alkene, and heteroaromatic nitrogen or sulphur atoms) remained untouched. The reaction was scaled for the oxidation of 5-(hydroxymethyl)furfural (2 g), a bio-based starting material, to afford 5-(hydroxymethyl)furoic acid in 61% isolated yield. The new biocatalytic method avoids the use of toxic or unsafe oxidants, strong acids or bases, or undesired solvents. It shows applicability across a wide range of substrates, and retains perfect chemoselectivity. Alternative oxidisable groups were not converted, and other classical side-reactions (e.g. halogenation of unsaturated functionalities, Dakin-Type oxidation) did not occur. In comparison to other established enzymatic methods such as the use of oxidases (where the concomitant oxidation of alcohols and aldehydes is common), ALDHs offer greatly improved selectivity.
- Knaus, Tanja,Tseliou, Vasilis,Humphreys, Luke D.,Scrutton, Nigel S.,Mutti, Francesco G.
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p. 3931 - 3943
(2018/09/11)
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- Identification and Implementation of Biocatalytic Transformations in Route Discovery: Synthesis of Chiral 1,3-Substituted Cyclohexanone Building Blocks
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Several biocatalytic approaches for the preparation of optically pure methyl 3-oxocyclohexanecarboxylates (S)-, (R)-1 and 3-oxocyclohexanecarbonitriles (S)-, (R)-2 have been successfully demonstrated. Screening of reaction-focused enzyme collections was used to identify initial hits using three enzymatic strategies. Reaction optimization and scale-up enabled the production of chiral intermediates for route scouting efforts on scales of up to 100 g. The enzymes applied in these processes (lipases, enoate reductases, and nitrilases) have been shown to be robust catalysts for drug manufacturing and represent a green alternative to conventional methods to access these chiral cyclohexanone building blocks.
- Hadi, Timin,D?az-Rodr?guez, Alba,Khan, Diluar,Morrison, James P.,Kaplan, Justin M.,Gallagher, Kathleen T.,Schober, Markus,Webb, Michael R.,Brown, Kristin K.,Fuerst, Douglas,Snajdrova, Radka,Roiban, Gheorghe-Doru
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supporting information
p. 871 - 879
(2018/07/05)
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- Protection of COOH and OH groups in acid, base and salt free reactions
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We report an iron-catalyzed general functional group protection method with inexpensive reagents. This environmentally benign process does not use acids or bases, and does not produce waste products. Further purification beyond filtration and evaporation is, in most cases, unnecessary. Free COOH and OH groups can be protected in a one-pot reaction.
- Zhu, Xiaotao,Qian, Bo,Wei, Rongbiao,Huang, Jian-Dong,Bao, Hongli
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supporting information
p. 1444 - 1447
(2018/04/12)
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- Synthesis of Phenols: Organophotoredox/Nickel Dual Catalytic Hydroxylation of Aryl Halides with Water
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A highly effective hydroxylation reaction of aryl halides with water under synergistic organophotoredox and nickel catalysis is reported. The OH group of the resulting phenols originates from water, following deprotonation facilitated by an intramolecular base group on the ligand. Significantly, aryl bromides as well as less reactive aryl chlorides served as effective substrates to afford phenols with a wide range of functional groups. Without the need for a strong inorganic base or an expensive noble-metal catalyst, this process can be applied to the efficient preparation of diverse phenols and enables the hydroxylation of multifunctional pharmaceutically relevant aryl halides.
- Yang, Liu,Huang, Zhiyan,Li, Gang,Zhang, Wei,Cao, Rui,Wang, Chao,Xiao, Jianliang,Xue, Dong
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supporting information
p. 1968 - 1972
(2018/02/06)
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- Synergistic Photo-Copper-Catalyzed Hydroxylation of (Hetero)aryl Halides with Molecular Oxygen
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Photoredox-mediated copper-catalyzed hydroxylation of (hetero)aryl halides (including chlorides, bromides, and iodides) with O2 at room temperature has been developed. Preliminary mechanistic studies indicate no arylcopper intermediate and that aryl radicals are involved in this procedure. 18O-labeling experiments confirm the hydroxyl oxygen atom originated from molecular oxygen.
- Zhang, Xin,Wu, Ge,Gao, Wenxia,Ding, Jinchang,Huang, Xiaobo,Liu, Miaochang,Wu, Huayue
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supporting information
p. 708 - 711
(2018/02/09)
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- Visible-Light-Mediated Aerobic Oxidation of Organoboron Compounds Using in Situ Generated Hydrogen Peroxide
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A simple and general visible-light-mediated oxidation of organoboron compounds has been developed with rose bengal as the photocatalyst, substoichiometric Et3N as the electron donor, as well as air as the oxidant. This mild and metal-free protocol shows a broad substrate scope and provides a wide range of aliphatic alcohols and phenols in moderate to excellent yields. Notably, the robustness of this method is demonstrated on the stereospecific aerobic oxidation of organoboron compounds.
- Weng, Wei-Zhi,Liang, Hao,Zhang, Bo
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supporting information
p. 4979 - 4983
(2018/08/24)
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- Nhatrangin A: Total Syntheses of the Proposed Structure and Six of Its Diastereoisomers
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A total synthesis of the proposed structure of nhatrangin A is described. This strategy relies on two aldol reactions to install the chiral centers at C3/C4 and C3′/C4′, a lithium-mediated coupling between an advanced intermediate alkyne and a Weinreb amide to complete the C1-C13 alkyl scaffold, and a Yamaguchi esterification to set the side chain. Discrepancies in the spectroscopic data between synthetic and natural nhatrangins led us to synthesize six more diastereoisomers of the proposed structure of nhatrangin A.
- Dias, Luiz C.,Polo, Ellen C.
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p. 4072 - 4112
(2017/04/28)
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- Zirconocene-catalyzed direct (trans)esterification of acyl acids (esters) and alcohols in a strict 1:1 ratio under solvent-free conditions
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A highly efficient way for the direct (trans)esterification of acyl acids (esters) and alcohols in a strict 1:1 ratio using a zirconocene complex (1, 1 mol%), a strong Lewis acid of good water tolerance, as a catalyst under solvent-free conditions has been developed. A wide range of acid and alcohol (esters) substrates undergo (trans)esterification to produce carboxylic ester motifs in moderate to good or excellent yields with good functional tolerance, such as that towards C-Br as well as CC and CC bonds. And complex 1 can be recycled six times without showing a significant decline in catalytic efficiency. It was demonstrated that cyclandelate, which is used to treat high blood pressure as well as heart and blood-vessel diseases, can be directly synthesized on a gram scale with 81% yield (6.70 g) using complex 1.
- Tang, Zhi,Jiang, Qiutao,Peng, Lifen,Xu, Xinhua,Li, Jie,Qiu, Renhua,Au, Chak-Tong
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supporting information
p. 5396 - 5402
(2017/11/22)
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- Synthesis and antioxidant activity of 1,3,4-oxadiazoles and their diacylhydrazine precursors derived from phenolic acids
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Eight 1,3,4-oxadiazole derivatives containing phenolic acid moieties (7a-h) and eight of their diacylhydrazine precursors (6a-h) were synthesized, characterized using spectroscopic methods and examined by scavenging of stable DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals. The most potent phenolic 1,3,4-oxadiazoles showed better DPPH scavenging activity in comparison with their corresponding diacylhydrazine precursors as a result of participation of both aromatic rings and a 1,3,4-oxadiazole moiety in resonance stabilization of the formed phenoxyl radical. Four diacylhydrazines (6d, 6e, 6g, and 6h) and four 1,3,4-oxadiazoles (7d, 7e, 7g and 7h) with the best DPPH scavenging activity, were chosen for further evaluation of their antioxidant potential through various assays. The investigated compounds exerted pronounced ABTS radical scavenging capacity, moderate to good H2O2 scavenging properties and strong ferric ion reducing capacity. Further in vitro evaluation of the antioxidant properties of the most active compounds demonstrated their protective effects in normal lung fibroblasts MRC-5 against hydrogen peroxide induced oxidative stress. Diacylhydrazine 6h increased two times the activity of glutathione peroxidase in treated cells in comparison with a control sample and did not affect the superoxide dismutase activity.
- Mihailovi?, Nevena,Markovi?, Violeta,Mati?, Ivana Z.,Stanisavljevi?, Nemanja S.,Jovanovi?, ?ivko S.,Trifunovi?, Sne?ana,Joksovi?, Ljubinka
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p. 8550 - 8560
(2017/02/10)
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- Assembly and inhibitory activity of monovalent mannosides terminated with aromatic methyl esters: The effect of naphthyl groups
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A series of monovalent α-D-mannoside ligands terminated with aromatic methyl esters have been synthesized in excellent yields using the Cu(I) catalyzed azide-alkyne 1,3-dipolar cycloaddition (“click chemistry”). These mannosides were designed to have a unique aglycone moiety (tail) that combines a triazole ring attached to aromatic methyl esters via a six carbon alkyl chain. The mannose unit of these ligands was linked at the ortho, meta, and para positions of substituted methyl benzoates and 1-, 3-, and 6-substituted methyl 2-napthaoates. In hemagglutination assays, ligands (32A-38A) showed better inhibitory activities than the standard inhibitor, methyl α-D-mannopyranoside. Overall, the naphthyl-based mannoside ligand (37A) showed the best activity and therefore merits further development.
- Al-Mughaid, Hussein,Al-Zoubi, Raed M.,Khazaaleh, Maha,Grindley, T. Bruce
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- Photocatalytic benzene and benzene derivative direct hydroxylation or amination method
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The invention discloses a photocatalytic benzene and benzene derivative direct hydroxylation or amination method. The method is characterized by comprising the following steps: (1) adding a photo-sensitizer and a cobalt catalyst into a solvent to obtain a solution (A); (2) adding benzene (or benzene derivatives), water, ammonia gas, and amide derivatives (or sulfonamide derivatives) into the solution (A) to obtain a solution (B); and (3) in a N2 (or Ar) environment, radiating the solution (B) by a medium pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, or an LED lamp to obtain phenols or amines and H2. For the first time, a photo-sensitizer and a cobalt catalyst are combined and applied to photocatalytic hydroxylation and amination of benzene. The conditions of the method are mild, light is taken as the driving energy, no oxidant is added, the only byproduct is H2, and the whole process is green, concise, and efficient. High selective benzene one-step hydroxylation to generate phenol or high selective phenol/benzene one-step amination to generate aniline is realized, and the method can be applied to the production of phenol and aniline.
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Paragraph 0116-0117
(2017/11/29)
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- METHOD FOR PREPARING PHENOLICS USING A CATALYST
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The invention is directed to a method for preparing a phenolic compound comprising reacting a furanic compound with a dienophile in the presence of a catalyst comprising yttrium.
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Paragraph 12
(2017/07/14)
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- Ruthenium-Catalyzed Hydroarylation and One-Pot Twofold Unsymmetrical C?H Functionalization of Arenes
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A methyl phenyl sulfoximine (MPS) is used as a directing group in the ruthenium-catalyzed intramolecular hydroarylation of alkene-tethered benzoic acid derivatives to afford dihydrobenzofurans and indolines in good to excellent yields. A one-pot, unsymmetrical, twofold C?H functionalization involving intramolecular C?C and intermolecular C?C/C?N bond formations is successfully demonstrated by using a single set of catalytic reaction conditions, which is unprecedented thus far. A novel isoquinolone-bearing dihydrobenzofuran is constructed through an unsymmetrical twofold C?H functionalization.
- Ghosh, Koushik,Ramesh, E.,Rit, Raja K.,Sahoo, Akhila K.
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supporting information
p. 7821 - 7825
(2016/07/07)
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- Photocatalytic Hydrogen-Evolution Cross-Couplings: Benzene C-H Amination and Hydroxylation
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We present a blueprint for aromatic C-H functionalization via a combination of photocatalysis and cobalt catalysis and describe the utility of this strategy for benzene amination and hydroxylation. Without any sacrificial oxidant, we could use the dual catalyst system to produce aniline directly from benzene and ammonia, and phenol from benzene and water, both with evolution of hydrogen gas under unusually mild conditions in excellent yields and selectivities.
- Zheng, Yi-Wen,Chen, Bin,Ye, Pan,Feng, Ke,Wang, Wenguang,Meng, Qing-Yuan,Wu, Li-Zhu,Tung, Chen-Ho
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supporting information
p. 10080 - 10083
(2016/09/04)
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- A simple, one-pot oxidative esterification of aryl aldehydes through dialkyl acetal using hydrogen peroxide
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A simple and an efficient one-pot procedure has been developed to synthesize various aryl carboxylic esters directly from aryl aldehydes using hydrogen peroxide without any catalyst. The reaction proceeds smoothly at room temperature. A preliminary investigation suggests the formation of dialkyl acetal as an intermediate during the reaction sequence.
- Devarajan,Vijayakumar,Ramalingam,Vijayaraghavan
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p. 5849 - 5858
(2016/06/01)
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- Visible-Light Photoredox Borylation of Aryl Halides and Subsequent Aerobic Oxidative Hydroxylation
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Efficient and practical visible-light photoredox borylation of aryl halides and subsequent aerobic oxidative hydroxylation were developed. The protocols use readily available aryl halides and bis(pinacolato)diboron as the starting materials, fac-Ir(ppy)3 as the photocatalyst, and corresponding arylboronic esters and phenols were obtained in good yields. The methods show some advantages including simple equipment, mild conditions, easy operation, and wide substrate scope. Therefore, they should provide a valuable strategy for chemical transformations.
- Jiang, Min,Yang, Haijun,Fu, Hua
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p. 5248 - 5251
(2016/11/02)
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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 22; 23
(2016/08/10)
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- Laboratory-Scale Membrane Reactor for the Generation of Anhydrous Diazomethane
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A configurationally simple and robust semibatch apparatus for the in situ on-demand generation of anhydrous solutions of diazomethane (CH2N2) avoiding distillation methods is presented. Diazomethane is produced by base-mediated decomposition of commercially available Diazald within a semipermeable Teflon AF-2400 tubing and subsequently selectively separated from the tubing into a solvent- and substrate-filled flask (tube-in-flask reactor). Reactions with CH2N2 can therefore be performed directly in the flask without dangerous and labor-intensive purification operations or exposure of the operator to CH2N2. The reactor has been employed for the methylation of carboxylic acids, the synthesis of α-chloro ketones and pyrazoles, and palladium-catalyzed cyclopropanation reactions on laboratory scale. The implementation of in-line FTIR technology allowed monitoring of the CH2N2 generation and its consumption. In addition, larger scales (1.8 g diazomethane per hour) could be obtained via parallelization (numbering up) by simply wrapping several membrane tubings into the flask.
- Dallinger, Doris,Pinho, Vagner D.,Gutmann, Bernhard,Kappe, C. Oliver
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p. 5814 - 5823
(2016/07/26)
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- Zinc(II)-Assisted Aryl Finkelstein Reaction for the Synthesis of Aryl Iodides
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Aryl iodides play an important role in synthetic organic chemistry as they are frequently utilized in cross-coupling reactions and in oxidation processes using hypervalent iodine compounds. Their synthesis is, however, often cumbersome and may lead to unwanted side products. Here, we report on an improved protocol for the aryl Finkelstein reaction in which dehalogenation is prevented by addition of zinc iodide in lieu of copper(I). Generally, electron-poor ortho-bromo methyl benzoates, amides, and even unprotected phenols are well-suited for this method.
- Ueberschaar, Nico,Heine, Daniel,Hertweck, Christan
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p. 1794 - 1797
(2016/07/16)
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- QUINAZOLINE DERIVATIVES AS TAM FAMILY KINASE INHIBITORS
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Disclosed are compounds, compositions and methods for treating diseases, syndromes, conditions and disorders that are affected by the modulation of the activity of, e.g., the inhibition of, one or more members of the TAM family kinases.
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Paragraph 0180
(2015/06/08)
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- Ring Opening of Bicyclo[3.1.0]hexan-2-ones: A Versatile Synthetic Platform for the Construction of Substituted Benzoates
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Described is the development of a highly efficient 2πdisrotatory ring-opening aromatization sequence using bicyclo[3.1.0]hexan-2-ones. This unprecedented transformation efficiently proceeds under thermal conditions and allows facile construction of uniquely substituted and polyfunctionalized benzoates. In the presence of either amines or alcohols formation of substituted anilines or ethers, respectively, is achieved. Additionally, the utility of this method was demonstrated in a short synthesis of sekikaic acid methyl ester. Cracked open: A highly efficient thermal 2πdisrotatory ring-opening aromatization sequence of bicyclo[3.1.0]hexan-2-ones is described. The transformation proceeds in sulfolane to give uniquely substituted benzoates. In the presence of either amines or alcohols, formation of substituted anilines or ethers, respectively, is achieved.
- Feierfeil, Johannes,Grossmann, Adriana,Magauer, Thomas
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supporting information
p. 11835 - 11838
(2015/10/05)
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- Carbazolic porous organic framework as an efficient, metal-free visible-light photocatalyst for organic synthesis
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We report the visible-light-promoted photocatalytic activity of a highly porous carbazolic organic framework, Cz-POF-1, toward three prototypic organic transformations: net reductive dehalogenation of phenacyl bromide and its derivatives, net oxidative hydroxylation of arylboronic acids, and redox-neutral α-alkylation of aldehydes. We show that the extended π-conjugation in Cz-POF-1 enhances its visible light absorption, and the large porosity accelerates the reaction rate. For α-alkylation of aldehydes, Cz-POF-1 requires less strict reaction conditions and can be easily recovered and reused for up to 10 times. This work reveals a bright future for Cz-POFs as a new generation of metal-free photocatalysts for organic synthesis.
- Luo, Jian,Zhang, Xiang,Zhang, Jian
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p. 2250 - 2254
(2015/04/14)
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- Microwave-aided one-pot dehydration of the alcohol derived from (-)-shikimic acid for efficient synthesis of pericosines
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Dehydrating conditions of shikimate-derived alcohol 7, an early intermediate in the synthesis of the pericosine family of marine natural products, were examined. The triflate 8 was effectively converted to cyclohexadiene 9 with excess 4-N,N-dimethylaminopyridine (DMAP) at room temperature for 24 h. The reaction time was dramatically shortened by heating under microwave (MW) irradiation, preventing formation of the Diels-Alder type byproduct 14. Furthermore, the MW-aided one-pot dehydration of alcohol 7 with Tf2O and DMAP (2.4 eq.) to form diene 9 was realized.
- Mizuki, Koji,Yoneshige, Yusuke,Kawahata, Rikiya,Yoneyama, Hiroki,Harusawa, Shinya,Usami, Yoshihide
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p. 2161 - 2167
(2015/01/09)
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- Pd/C-catalyzed aerobic oxidative esterification of alcohols and aldehydes: A highly efficient microwave-assisted green protocol
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We herein describe an environmentally friendly microwave-assisted oxidative esterification of alcohols and aldehydes in the presence of molecular oxygen and a heterogeneous catalysis (Pd/C, 5 mol %). This efficient and ligandless conversion procedure does not require the addition of an organic hydrogen acceptor. The reaction rate is strongly enhanced by mild dielectric heating. Furthermore, it is a versatile green procedure which generally enables the isolation of esters to be carried out by simple filtration in almost quantitative yields.
- Caporaso, Marina,Cravotto, Giancarlo,Georgakopoulos, Spyros,Heropoulos, George,Martina, Katia,Tagliapietra, Silvia
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supporting information
p. 1454 - 1461
(2014/07/22)
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- The effect of indium(III) triflate in oxone-mediated oxidative methyl esterification of aldehydes
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An oxidative methyl esterification of aldehydes was effectively achieved. The trivalent indium reagent, indium(III) triflate, was revealed to accelerate the reactions in many cases. Aromatic aldehydes with various substituents were subjected to this method, and each produced the corresponding methyl esters in good to excellent yields within a relatively short reaction time.
- Mineno, Tomoko,Sakai, Mai,Ubukata, Akira,Nakahara, Kazuhide,Yoshimitsu, Hitoshi,Kansui, Hisao
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p. 870 - 872
(2013/09/12)
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- Controlled immobilization of Keggin-type heteropoly acids on the surface of silica encapsulated γ-Fe2O3 nanoparticles and investigation of catalytic activity in the oxidative esterification of arylaldehydes with methanol
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Preparation, leaching and solid acidity measurements of H 3PW12O40, H3PMo12O 40 and H4SiW12O40 supported on silica-encapsulated γ-Fe2O3 nanoparticles were performed. The impregnating solvent and calcination temperature were optimized using various techniques. Catalytic activity of samples was examined by carrying out oxidative esterification of benzaldehyde with methanol under the same conditions. The acidity of the catalysts that was determined by NH 3-temperature-programmed desorption technique and chemisorption of pyridine. The best catalyst was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy and laser particle size analyzer. Finally, a mild, simple and clean procedure was presented for the one-pot oxidative esterification of arylaldehydes with methanol using magnetically recoverable nanocatalyst and hydrogen peroxide as a green oxidant.
- Rafiee, Ezzat,Eavani, Sara
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- Aerobic oxidative heck/dehydrogenation reactions of cyclohexenones: Efficient access to meta-substituted phenols
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Jockeying for the (meta)position: A new dicationic palladium(II) catalyst, employing a 6,6′-dimethyl-2,2′-bipyridine ligand, promotes both the aerobic oxidative Heck coupling and dehydrogenation reactions of cyclohexenones. These reactions may be combined in a one-pot sequence to enable the straightforward synthesis of meta-substituted phenols (see scheme). Copyright
- Izawa, Yusuke,Zheng, Changwu,Stahl, Shannon S.
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supporting information
p. 3672 - 3675
(2013/04/23)
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- Study of a two-stage photobase generator for photolithography in microelectronics
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The investigation of the photochemistry of a two-stage photobase generator (PBG) is described. Absorption of a photon by a latent PBG (1) (first step) produces a PBG (2). Irradiation of 2 in the presence of water produces a base (second step). This two-photon sequence (1 + hν → 2 + hν → base) is an important component in the design of photoresists for pitch division technology, a method that doubles the resolution of projection photolithography for the production of microelectronic chips. In the present system, the excitation of 1 results in a Norrish type II intramolecular hydrogen abstraction to generate a 1,4-biradiacal that undergoes cleavage to form 2 and acetophenone (Φ ~ 0.04). In the second step, excitation of 2 causes cleavage of the oxime ester (Φ = 0.56) followed by base generation after reaction with water.
- Turro, Nicholas J.,Li, Yongjun,Jockusch, Steffen,Hagiwara, Yuji,Okazaki, Masahiro,Mesch, Ryan A.,Schuster, David I.,Willson, C. Grant
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supporting information
p. 1735 - 1741
(2013/03/29)
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- Microwave assisted synthesis of biologically active 4-hydroxy-N′- (phenylcarbonyl)-2H-1,2-benzothiazine-3-carbohydrazide 1,1-dioxide derivatives
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Microwave assisted synthesis of a series of 4-hydroxy-N′- (phenylcarbonyl)-2H-1,2-benzothiazine-3-carbohydrazide 1,1-dioxides from sodium saccharin is reported. Sodium o-benzosulfimide was N-alkylated with ethyl chloroacetate followed by base catalyzed ring expansion to six membered 1,2-benzothiazine through Gabriel-Coleman type rearrangement yielding ethyl 4-hydroxy-2H-1,2-benzothiazine-3-carboxylate 1,1-dioxide. It was later condensed with a series of benzohydrazides synthesized from various carboxylic acids to get the title compounds. All the synthesized compounds were subjected to preliminary evaluation for their biological activity against series of Gram positive, Gram negative bacteria and fungi. Some of the compounds showed marked activity against the selected microorganisms.
- Zaheer, Muhammad,Zia-Ur-Rehman, Muhammad,Rahman, Salma,Ahmed, Naveed,Chaudhary, Muhammad Nawaz
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p. 1492 - 1496
(2013/06/27)
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- Synthesis and antifungal properties of papulacandin derivatives
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Derivatives of an antifungal agent that targets the β-(1,3)-D-glucan synthase, papulacandin D, were synthesized and tested for activity. The papulacandin D structure contains a challenging benzannulated spiroketal unit, which is introduced in a palladiumcatalyzed cross-coupling reaction of a glycal silanolate and an aryl iodide followed by an oxidative spiroketalization. Four different variants were made, differing in the nature of the acyl side chain with respect to the length, and in the number and stereochemistry of the double bonds. Moderate biological activity was observed for the derivatives with a side chain based on palmitic acid and linoleic acid.
- Van Der Kaaden, Marjolein,Breukink, Eefjan,Pieters, Roland J.
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supporting information; experimental part
p. 732 - 737
(2012/07/14)
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- Synthesis of new tripodal hydroxybenzoic esters and their reaction with tris-(2-aminoethyl)amine under high pressure conditions
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The new simple method of synthesis of tripodal esters, building blocks for monomacrocyclic pendant macrocycles and bicyclic cryptands is reported. Six new tripodal esters, derivatives of hydroxybenzoic acids were prepared and characterized, and their reaction with tris(2-aminoethyl)amine carried under high pressure conditions was studied using Electrospray Ion Mass Spectrometry.
- Ceborska, Magdalena,Jurczak, Janusz
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body text
p. 114 - 117
(2012/07/28)
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