- Olefins from biomass feedstocks: Catalytic ester decarbonylation and tandem Heck-type coupling
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With the goal of avoiding the need for anhydride additives, the catalytic decarbonylation of p-nitrophenylesters of aliphatic carboxylic acids to their corresponding olefins, including commodity monomers like styrene and acrylates, has been developed. The reaction is catalyzed by palladium complexes in the absence of added ligands and is promoted by alkali/alkaline-earth metal halides. Combination of catalytic decarbonylation and Heck-type coupling with aryl esters in a single pot process demonstrates the viability of employing a carboxylic acid as a "masked olefin" in synthetic processes. This journal is
- John, Alex,Hogan, Levi T.,Hillmyer, Marc A.,Tolman, William B.
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- Syntheses and characterisation of novel cyclodextrin vinyl derivatives from cyclodextrin-nitrophenol-derivatives
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In this study novel reactive α-, β- and γ-cyclodextrin-esters (acrylate, pent-4-enoate and undec-10-enoate) have been synthesised and characterised. The syntheses were carried out by using nitrophenol-esters with the ability to form inclusion complexes wi
- Nielsen, Anne L.,Steffensen, Kim,Wimmer, Reinhard,Worm-Leonhard, Martin,Larsen, Kim L.
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- Selective Decarbonylation of Fatty Acid Esters to Linear α-Olefins
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Selective decarbonylation of p-nitrophenol esters of fatty acids to the corresponding linear α-olefins (LAOs) was achieved using palladium catalysis. After extensive ligand screening, a mixed-ligand system exploiting the trans-spanning diphosphine XantPhos and an N-heterocyclic carbene (IPr) was identified as the most effective in yielding high α-selectivity and high conversions of the ester (>98% selectivity, >90% conversion using 2.5 mol % of PdCl2 and 5 mol % of the ligands, 190 °C, 2-2.5 h). On the basis of insights from modeling at the density functional level of theory, we propose that the mixed-ligand set achieves high α-selectivity by promoting olefin dissociation from the palladium center following β-hydride elimination, which is especially facilitated both by the combined steric bias of the mixed-ligand set and by the ability of the XantPhos ligand to coordinate in both mono- and bidentate fashions.
- John, Alex,Dereli, Büsra,Ortunìo, Manuel A.,Johnson, Hillis E.,Hillmyer, Marc A.,Cramer, Christopher J.,Tolman, William B.
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p. 2956 - 2964
(2017/08/21)
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- Silane compounds and use of same for functionalizing solid supports and immobilizing biological molecules on these supports
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The invention relates to novel silane compounds corresponding to the formula (I) below: [in-line-formulae]A-E-X?? (I)[/in-line-formulae] in which: X represents a silyl group capable of creating a covalent bond after reaction with the hydroxyl or hydride functional groups of a support;E represents an organic spacer group;A represents a group chosen from the groups of formulae below: in which: Z1 to Z5 independently represent a hydrogen atom or a halogen atom;Z6 and Z7 represent a group for protecting the phosphonic acid functional group, a hydrogen atom or a monovalent cation;Z8 to Z12 independently represent a group for protecting the carboxylic acid functional group, a hydrogen atom or a monovalent cation; andZ13 represents an imidazole, N-hydroxysuccinimide, nitrophenyl, pentafluorophenyl or acid anhydride group. Use of these silane compounds for functionalizing solid supports and for immobilizing biological molecules on these supports.
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Page/Page column 19
(2017/06/13)
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- C-GLYCOLIPIDS WITH ENHANCED TH-1 PROFILE
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The invention is directed to novel synthetic C-glycolipids that selectively induce a ThI -type immune response characterized by enhanced IL- 12 secretion and increased activation of dendritic cells. The compounds of the invention are thereby useful in treating infections, cancers, cell proliferative disorders, and autoimmune diseases, both directly and as adjuvants.
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Page/Page column 35
(2008/06/13)
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- Selective esterifications of alcohols and phenols through carbodiimide couplings
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Esterification of carboxylic acids capable of forming ketene intermediates upon treatment with carbodiimides permits the selective acylation of alcohols in the presence of phenols lacking strong electron-withdrawing groups. The selectivity of acylations involving highly acidic phenols could be reversed through the addition of catalytic amount of acid. Esterification of other carboxylic acids was found to proceed through the formation of symmetric anhydrides and provide the opposite chemoselectivity. In both cases the relative acylation rates of substituted phenols are consistent with a reaction mechanism involving an attack of phenolate anions on electrophilic intermediates such as ketenes and symmetric anhydrides, with the carbodiimides serving both as an activating reagent and as a basic catalyst.
- Shelkov, Rimma,Nahmany, Moshe,Melman, Artem
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p. 397 - 401
(2007/10/03)
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