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Showing 1 to 20 of 33 for “"aldol condensation"”.
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The study of aldol condensation of ketones using zoelites as catalysts
… H-Beta and H-USY were evaluated as catalysts for aldol condensation reactions of acetone and cyclohexanone and the results compared with those using H₂SO₄. Cross-aldol condensation reactions of acetone and benzaldehyde were also performed.
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Synthesis of aza-tryptophan derivatives.
… from 7-azaindole has been accomplished. The aldol condensation of 1-tert-butoxycarbonyl-3-formyl-7-azaindole with methyl hippurate installed the carbon framework necessary for the intended product. Subsequent deoxygenation and deprotection of the indole, ring, and the amino and acid …
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Chemoenzymatic Synthesis of ent-Neopinone
… JM109(pDTG601) and features a Heck reaction, aldol condensation and a 1,6-conjugate addition.
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Cooperative activation of biomass-derived oxygenates with Lewis acid zeolites
… acid zeolites are shown to catalyze the cross-aldol condensation of aromatic aldehydes with acetone under mild reaction conditions with near quantitative yields. NMR studies with isotopically labeled molecules confirm that acid-base pairs in the Si-O-M framework ensemble promote soft …
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Nichtwässrige Synthese und Bildungsmechanismus von Übergangsmetalloxid-Nanopartikeln = Nonaqueous synthesis of transition-metal oxide nanoparticles and their formation mechanism
… formation in ketones proceeds via a Ti-mediated aldol condensation of the solvent, involving formal elimination of water which induces formation of the oxide. These processes also occurred when reacting solely the titanium alkoxide with ketones or aldehydes, leading to highly crystalline anatase …
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ESTUDOS VISANDO A SÍNTESE DE DIAMINAS DERIVADAS DE PINENOS COM POTENCIAIS ATIVIDADES NOS RECEPTORES NICOTÍNICOS DO SISTEMA NERVOSO CENTRAL
… in a synthetic sequence starting the aldol condensation reaction with aldehydes 6 and 7, followed by a stereoselective reduction to the corresponding ketones 1a,b. Later some unfruitful attempts of reductive amination had been carried through. So it had been produced the oximes 4a,b …
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A Concise, Stereocontrolled Total Synthesis of Rippertenol
… ketone and a demanding intramolecular aldol condensation, are described. An uncommon Lewis Acid-promoted inverse electron demand Diels-Alder reaction and a challenging ring expansion lead to the first laboratory total synthesis of rippertenol. The synthesis was completed in 19 total …
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An investigation of the chemistry of lithiotriphenylphosphineacetylmethylene
… by alkylation produced γ,γ-disubstituted ylides. Condensation of the ylide anion with various aldehydes and ketones afforded δ-hydroxy-β-keto ylides in reasonable yields, uncontaminated by normal Wittig products. Reaction of the ylide anion with o-phthalaldehyde resulted in terminal aldol …
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Applications of 2,3-Diketoesters in Organic Synthesis and Stereoselective Transformations
… prepared by zinc triflate catalyzed Mukaiyama-aldol condensation of methyl diazoacetoacetates with aldehydes, occurred in quantitative yield to form dihydrofuranols that undergo acid catalyzed dehydration under mild conditions to generate 3-methoxyfuran-2-carboxylates in good yield. Oxidation …
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Towards incorporation of catalytic function into small folded peptide scaffolds
… environment and is able to modestly enhance aldol condensation and retro-aldol reactions. Finally, a new trimeric Apa oligomer structure is evaluated as a functional peptide scaffold. Initially, the structural requirements of the motif are explored through a series of sequence modifications. …
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Mechanistic characterization of acetic acid resistance enzymes of Acetobacer aceti
… to the thioester moiety to catalyze a Claisen/aldol condensation reaction that forms a new carbon-carbon bond. Class I CoA-transferases such as AarC produce acylglutamyl anhydride intermediates that undergo attack by the CoA thiolate on one of its two carbonyl carbon atoms, forming distinct …
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NH-Isoxazolidines as Organocatalysts
… reaction, the Michael addition reaction and the Aldol condensation reaction is discussed. It has been demonstrated that the NH-isoxazolidines are effective in iminium ion catalysis and act as enantioselective organocatalysts for Diels-Alder reactions. The aldol reaction between acetone and …
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Investigation of artificial malonyl group carriers and multifunctional cyclic scaffolds towards the mimicry of PKS
… artificial malonyl carriers in decarboxylative aldol-type condensations. In the second part of the thesis, the first example of a base and metal -free decarboxylative aldol condensation is described. Three different catalytic systems have been successfully employed to carry out mild …
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Design of heterogeneous bifunctional catalyst for upgrading bioethanol through the Guerbet reaction
… were found to selectively catalyze acetaldehyde aldol condensation and exhibit high stability under humid conditions. To overcome the low dehydrogenation activity of titania, addition of a metallic function was proposed. Among several metals tested, copper was found to be the most selective …
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Production of Bio-based Lactone Monomers for Intrinsically Recyclable Plastics
… oxides supported on silica as catalysts for an aldol condensation reaction. CaO and BaO showed 90% and 83% selectivity, respectively, to α-methylene-δ-valerolactone at 60% DVL conversion. Following this, MVL was functionalized with 1,3-butadiene in a Diels-Alder addition to form the unsaturated …
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Preparation of azidobrevianamide A and synthetic and biological studies of tetrazomine
… was achieved via a stereoselective aldol condensation with a chiral glycine template and 4-pentenal. Following reductive ozonolysis the amino acid was generated by a novel one pot transformation in which a protecting group was cleaved, reductive amination realized and the chiral …
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Evolution of Enzymatic Activities in the OMPDC Suprafamily: Discovery, Design and Evolution of 3-Keto-L-Gulonate 6-Phosphate Decarboxylase
… anion intermediate in the context of OMPDC), aldol-condensation (through divalent metal-ion stabilization of an enediolate intermediate in the context of HPS), and metal-independent epimerization (through active site stabilization of an enediolate intermediate in the context of RPE). The …
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A dynamic knowledge graph approach to self-driving chemical laboratories
… a collaborative closed-loop optimisation for an aldol condensation reaction in real time. The two robots effectively produced a Pareto front for the cost-yield optimisation problem over the course of three days of operation. The dynamic knowledge graph approach is also applied to optimise two …
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Base catalysis by alkali modified zeolites
… majority of the reacted acetone appears to form aldol condensation products.
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