- Base-free conversion of glycerol to methyl lactate using a multifunctional catalytic system consisting of Au-Pd nanoparticles on carbon nanotubes and Sn-MCM-41-XS
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Multifunctional catalytic systems consisting of physical mixtures of (i) bimetallic Au-Pd nanoparticles (average size of 3-5 nm) supported on functionalised carbon nanotubes (CNTs) and (ii) Sn-MCM-41 nanoparticles (50-120 nm), were synthesised and investigated for the base-free, selective conversion of glycerol to methyl lactate in a batch reactor. The catalysts were characterised by means of transmission electron microscopy, N2-physisorption, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and by Boehm titration. The catalyst based on bimetallic AuPd/CNTs showed much higher activity than the monometallic Au or Pd counterparts, thus indicating synergetic effects. Functionalisation of the CNTs by oxidative treatments had a positive effect on catalyst performance, which was correlated to the observed increase in surface acidity and hydrophilicity. The highest yield of methyl lactate achieved in this work was 85% at 96% glycerol conversion (140 °C, 10 h at 30 bar air), which is the highest yield ever reported in the literature so far. Insights in the reaction pathway were obtained by monitoring the conversion-time profiles for intermediates and their possible role as inhibitors. Batch recycling experiments demonstrated the excellent reusability of the catalyst.
- Tang, Zhenchen,Boer, Dina G.,Syariati, Ali,Enache, Mihaela,Rudolf, Petra,Heeres, Hero J.,Pescarmona, Paolo P.
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p. 4115 - 4126
(2019/08/12)
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- Concise Asymmetric Synthesis of Kweichowenol A
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An asymmetric 11-step synthesis of the polyoxygenated cyclohexene natural product kweichowenol A from the traditional Chinese medicinal herb Uvaria kweichowesis is reported. The oxygenation pattern was installed on a linear precursor by exploiting the acyclic stereocontrol of the Kiyooka aldol reaction, as well as Cram chelate-controlled Grignard reactions. Ring-closing metathesis and a selective benzoylation then gave the natural product.
- Konrad, David B.,Kicin, Bilal,Trauner, Dirk
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supporting information
p. 383 - 386
(2019/02/26)
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- Dihydroxylation of Olefins with Potassium Permanganate Catalyzed by Imidazolium Salt
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The development of an efficient and cost-effective cis -dihydroxylation reaction of acrylate derivatives was achieved. The reaction proceeded in acetone with an imidazolium salt as catalyst to furnish the dihydroxylation of olefins at 0-5 °C using KMnO 4 as the oxidant. This efficient and non-aqueous protocol was highly suitable for the large-scale preparation of cis -dihydroxylated compounds from the corresponding acrylate derivatives in high yields without overoxidation.
- Khan, Imran,Luo, Zhi-Bin,Valeru, Anil,Xu, Yin,Liu, Bin,Sangepu, Bhavanarushi,Xie, Ji-Min
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p. 1815 - 1819
(2018/02/19)
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- An Efficient and Practical Method for Olefin Dihydroxylation
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An efficient and economic procedure was developed for the dihydroxylation of various olefin derivatives with commercial KMnO4 as the oxidant in the presence of a quaternary ammonium salt. This practical procedure is suitable for large-scale production of cis-dihydroxy compounds, even those bearing primary and secondary alcohol groups, without overoxidation.
- Luo, Zhi-Bin,Zhao, Chen,Xie, Jimin,Lu, Hong-Fei
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p. 3696 - 3700
(2016/11/08)
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- NOVEL PYRAZOLO PYRIMIDINE DERIVATIVES AND THEIR USE AS MALT1 INHIBITORS
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The present invention describes new pyrazolo-pyrimidine derivatives of formula (I) or a pharmaceutically acceptable salt thereof; (I) wherein, R1 is halogen, cyano, or C1-C3alkyl optionally substituted by halogen; R2 is C1-C6alkyl optionally substituted one or more times by C1-C6alkyl, C2-C6alkenyl, hydroxyl, N,N-di-C1-C6alkyl amino, N-mono-C1-C6alkyl amino, O-Rg, Rg, phenyl, or by C1-C6alkoxy wherein said alkoxy again may optionally be substituted by C1-C6alkoxy, N,N-di-C1-C6alkyl amino, Rg or phenyl; C3-C6cycloalkyl optionally substituted by C1-C6alkyl, N,N-di-C1-C6alkyl amino or C1-C6alkoxy-C1-C6alkyl, and/or two of said optional substituents together with the atoms to which they are bound may form an annulated or spirocyclic 4 - 6 membered saturated heterocyclic ring comprising 1 - 2 O atoms; phenyl optionally substituted by C1-C6alkoxy; a 5 - 6 membered heteroaryl ring having 1 to 3 heteroatoms selected from N and O said ring being optionally substituted by C1-C6alkyl which may be optionally substituted by amino or hydroxy; Rg; or N,N-di-C1-C6alkyl amino carbonyl; and R is phenyl independently substituted two or more times by Ra, 2-pyridyl independently substituted one or more times by Rb, 3-pyridyl independently substituted one or more times by Rc, or 4-pyridyl independently substituted one or more times by Rd; which are generally interacting with MALT1 proteolytic and/or autoproteolytic activity, and in particular which may inhibit said activity. The present invention further describes the synthesis of said new pyrazolo-pyrimidine derivatives, their use as a medicament, especially by interacting with MALT1 proteolytic and/or autoproteolytic activity.
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Page/Page column 42; 43
(2015/12/31)
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- Chiral resolution through stereoselective transglycosylation by sucrose phosphorylase: Application to the synthesis of a new biomimetic compatible solute, (R)-2-O-α-d-glucopyranosyl glyceric acid amide
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Sucrose phosphorylase catalysed glycosylation of glyceric acid amide with complete regio- and diastereo-selectivity is studied. (R)-2-O-α-d- Glucopyranosyl glyceric acid amide was obtained in high yield from single-step transformation of racemic glyceric acid amide and sucrose. Non-productive binding of (S)-glyceric acid amide appeared to underlie strict enantiodiscrimination by the enzyme, thus supporting chiral resolutions based on stereoselective transglycosylation.
- Wildberger, Patricia,Brecker, Lothar,Nidetzky, Bernd
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supporting information
p. 436 - 438
(2014/01/06)
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- Kinetic resolution of racemic carboxylic acids by an L-histidine-derived sulfonamide-induced enantioselective esterification reaction
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(Chemical Equation Presented) The direct and catalytic kinetic resolution of racemic carboxylic acids bearing a Bronsted base such as O-protected α-hydroxy carboxylic acids and N-protected α-amino acids has been accomplished through an L-histidine-derived sulfonamide-induced enantioselective esterification reaction with tert-butyl alcohol for the first time. Highly asymmetric induction [S(kfast/kslow) = up to 56] has been achieved under the equilibrium between a chiral catalyst and two diastereomeric acylammonium salts through an intramolecular hydrogen-bonding interaction.
- Ishihara, Kazuaki,Kosugi, Yuji,Umemura, Shuhei,Sakakura, Akira
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supporting information; experimental part
p. 3191 - 3194
(2009/05/27)
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- Catalytic asymmetric dihydroxylation of olefins using polysulfone-based novel microencapsulated osmium tetroxide
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A polysulfone based novel polymer-supported osmium catalyst has been developed. The catalyst was prepared from commercially available polysulfone, based on a microencapsulation technique and was employed in the asymmetric dihydroxylation of various olefins using (DHQD)2PHAL as the chiral ligand and NMO as the co-oxidant in H2O-acetone-CH3CN (1:1:1). The catalyst was recovered by simple filtration and was reused to obtain excellent yields with good enantioselectivity up to five times.
- Malla Reddy,Srinivasulu,Venkat Reddy,Narasimhulu,Venkateswarlu
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p. 5285 - 5288
(2007/10/03)
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- Compositions and methods for enhancing phagocytosis or phagocyte activity
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The present invention provides a system for enhancing clearance or destruction of undesirable cells or noncellular molecular entities by tagging such cells or noncellular molecular entities with a marker that targets the cells or noncellular molecular entities for phagocytosis (phagocytic marker). The target cells can be, for example, endothelial cells, tumor cells, leukocytes, or virus-infected cells. In certain embodiments of the invention the tagging is accomplished by administering a composition comprising an antibody or ligand linked to the phagcytotic marker, wherein the antibody or ligand binds to a cell type specific marker present on or in the cell surface of a target cell. In preferred embodiments of the invention, the phagocytic marker comprises phosphatidylserine or a group derived from phosphatidylserine, thrombospondin-1, annexin I, or a derivative of any of these.
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Page/Page column sheet 15; 21
(2008/06/13)
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- Stereoselective synthesis of nucleoside analogues
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The invention is a process for stereoselectively producing a dioxolane nucleoside analogue from an anomeric mixture of β and α anomers represented by the following formula A or formula B: wherein R is selected from the group consisting of C1-6alkyl and C6-15aryl and Bz is benzoyl. The process comprises hydrolyzing said mixture with an enzyme selected from the group consisting of Protease N, Alcalase, Savinase, ChiroCLEC-BL, PS-30, and ChiroCLEC-PC to stereoselectively hydrolyze predominantly one anomer to form a product wherein R1is replaced with H. The process also includes the step of separating the product from unhydrolyzed starting material. Additionally, the functional group at the C4 position is stereoselectively replaced with a purinyl or pyrimidinyl or derivative thereof.
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- Synthesis of Alkyl (+/-)-2,3-Di-O-acylglycerates and Attempts Directed to their Conversion into Alkyl (R)-2,3-Di-O-acylglycerates by Enzyme-catalyzed Enantioselective Deacylation Reactions
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By screening several lipases and proteases as catalysts for an enantioselective partial deacylation of methyl (+/-)-2,3-di-O-acylglycerates, it was found that methyl (R)-2,3-di-butanoylglycerate can be obtained with an enantiomeric excess of >96percent and a yield of 20percent related to the racemic starting material.This was prepared from methyl acrylate through dihydroxylation with potassium permanganate at -30 deg C and a subsequent bisacylation.
- Schick, H.,Schroetter, E.,Szymanowski, M.,Knoll, A.
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p. 628 - 632
(2007/10/02)
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- Catalytic Conversion of Diethyl Tartrate into Pyruvate over Silica-Supported Potassium Disulfate
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Potassium hydrogensulfate (KHSO4), which melts at a lower temperature of 197 deg, was adapted for vapor-phase fixed-bed flow operations as a silica-supported potassium disulfate (K2S2O7/SiO2) to afford 60percent ethyl pyruvate continuously from the tartrate at 300 deg C.The catalyst was effective for the intramolecular dehydration of glycol moieties, much less active for hydrolysis of esters, and capable of converting enol- to keto-form for the intermediate oxalacetate in favor of pyruvate.A TGA analysis revealed that KHSO4 was converted to K2S2O7 at 300 deg C, this was in consistent with the XRD analysis.
- Sugiyama, Shigeru,Fukunaga, Sadao,Kawashiro, Katsuhiro,Hayashi, Hiromu
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p. 2083 - 2085
(2007/10/02)
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- Analogues of phospholipids: synthesis and biological evaluation of a series of 3-phosphocholine glyceric acid derivatives
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A series of phospholipid analogues derived from 3-phosphocholine glyceric acid (1a-e) have been prepared and tested as lysophosphatidylcholine or PAF analogues according to their structure.Of these compounds, hexadecyl 3-phosphocholine glycerate (1a), the
- Valcavi, U,Aveta, R,Brandt, A,Corsi, GB,Pascucci, G,Solinas, F
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p. 327 - 332
(2007/10/02)
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- (±)-Dioxolane-T ((±)-1-[(2β,4β)-2-(hydroxymethyl)-4-dioxolanyl]thymine). A new 2',3'-dideoxynucleoside prototype with in vitro activity against HIV
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A novel analogue of 3'-deoxythymidine, in which the 3'-carbon is replaced by oxygen, was synthesized in 5 steps from benzyloxyacetaldehyde dimethyl acetal and (±)-methyl glycerate. In ATH8 cells, this analogue showed significant inhibition of the infectiv
- Norbeck,Spanton,Broder,Mitsuya
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p. 6263 - 6266
(2007/10/02)
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- Synthesis and Determination of the Enantiomeric Pyrity of (R)- and (S)-2,3-Dihydroxy-3-methylbutyl p-Toluensulfonate
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(R)- and (S)-2,3-dihydroxy-3-methylbutyl p-toluenesulfonate, used as building blocks for vitamine D3 metabolites and carotenoids, respectively, were resynthesized since differing melting points and optical rotations are reported in the literature.The give
- Schoenecker, Bruno
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p. 705 - 712
(2007/10/02)
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