• The use of low loadings of a silver NHC catalysts enables a mild, selective oxidation of alcohols to aldehydes or carboxylic acids in the presence of BnMe 3 NOH or KOH under dry air in excellent yield. (organic-chemistry.org)
  • The hydrolysis rates measured in buffer solutions, of the twelve acetals studied were found to be dependent on the concentration of undissociated acid and shown to be authentic examples of general acid catalysis, with reference to current opinions that such observations might be manifestations of solvent, electrolyte or buffer effects. (gla.ac.uk)
  • The acid catalyst itself (AH) only contributes to the rate acceleration by shifting the chemical equilibrium between solvent S and AH in favor of the SH+ species. (wikipedia.org)
  • General acid-base catalysis, solvent deuterium isotope effects, and transition state characterization. (fastwash.de)
  • In these reactions, the conjugate acid of the carbonyl group is a better electrophile than the neutral carbonyl group itself. (wikipedia.org)
  • Acid catalysis is mainly used for organic chemical reactions. (wikipedia.org)
  • Reactions in which proton transfer is rate-determining exhibit general acid catalysis, for example diazonium coupling reactions. (wikipedia.org)
  • When reactions are conducted in nonpolar media, this kind of catalysis is important because the acid is often not ionized. (wikipedia.org)
  • Enzymes catalyze reactions using general-acid and general-base catalysis. (wikipedia.org)
  • We established a rational methodology for designing high-performance unimolecular or supramolecular catalysts based on the chemistry of acid- base combined catalysis for numerous types of organic reactions. (catalysiscongress.com)
  • Structure and bonding of organic compounds and their acid-base properties, stereochemistry, introduction to reactions and reaction mechanisms of carbon compounds and the relationship of reactivity and structure. (hamilton.edu)
  • Types of chemical steps in enzymatic reactions (nucleophilic attack, acid/base catalysis, ect). (uit.no)
  • Main focus will be on understanding how certain types of amino acids and their placement can promote chemical reactions. (uit.no)
  • His research with undergraduates at Central focuses on introducing students to catalysis and developing new organometallic catalysts for transfer hydrogenation reactions. (ionicviper.org)
  • As a validating case study, we combined published enantioselectivity datasets that employ 1,1′-bi-2-naphthol (BINOL)-derived chiral phosphoric acids for a range of nucleophilic addition reactions to imines and developed statistical models. (nature.com)
  • Copper (II) complexes of the macrocyclic ligands and of cis, ciscyclohexane-1,3,5-triamine have been prepared and their dissociation reactions with acid have been studied. (wgtn.ac.nz)
  • acid catalysis of, the dissociation reactions is observed. (wgtn.ac.nz)
  • The reactions are compared with those of copper and nickel complexes of linear polyamines and nickel-triazamacrocycle complexes, and the results obtained in this work are discussed in terms of a general mechanism, originally proposed by Margerum(105), for the dissociation of metal-polyamine complexes. (wgtn.ac.nz)
  • The aim of the course is that the students should achieve advanced knowledge and understanding of chemical reactions in the cell with focusing on the structure and function of proteins, enzyme catalysis and the total metabolism of the cell. (lu.se)
  • The structure of the cell, the structure and function of nucleic acids, the structure and function of proteins and membranes, enzyme catalysis, the metabolism of the cell and its regulation, bioinformatics and proteomics, and cell biology related methods. (lu.se)
  • Thus acids are used to convert alcohols into other classes of compounds, such as thiols and amines. (wikipedia.org)
  • Tris(2,2,2-trifluoroethyl)borate [B(OCH 2 CF 3 ) 3 ] is a mild and general reagent for condensation of amides or amines with carbonyl compounds providing N -Sulfinyl, N -toluenesulfonyl, N -(dimethylamino)sulfamoyl, N -diphenylphosphinoyl, N -(α-methylbenzyl), and N -(4-methoxyphenyl) aldimines at room temperature. (organic-chemistry.org)
  • This mild, operationally simple protocol transforms a wide variety of naturally abundant α-amino acids and readily available aryl halides into valuable chiral benzylic amines in high enantiomeric excess, thereby producing motifs found in pharmacologically active agents. (docksci.com)
  • In view of the appealing attributes of (i) enantioconvergent nickel-catalyzed cross-coupling and (ii) metallaphotoredox-mediated decarboxylative arylation, we recently decided to pursue the possibility that the two technologies could be merged to enable the enantioselective synthesis of benzylic amines from readily available α-amino acid starting materials. (docksci.com)
  • Busca, Guido "Acid Catalysts in Industrial Hydrocarbon Chemistry" Chemical Reviews 2007, volume 107, 5366-5410. (wikipedia.org)
  • We classified acid-base combined catalysts into two types: ion pair-type (A) and amphoteric molecule-type (B). Furthermore, type A can be subclassified into acidic ion pair-type (A1), neutral ion pair-type (A2), and basic ion pair-type (A3). (catalysiscongress.com)
  • We developed various high-performance catalysts based on acid-base combination chemistry. (catalysiscongress.com)
  • I will talk about some recent topics on highperformance acid-base catalysts. (catalysiscongress.com)
  • Knowles, R. R. & Jacobsen, E. N. Attractive noncovalent interactions in asymmetric catalysis: links between enzymes and small molecule catalysts. (nature.com)
  • The main difference between ribozymes and enzymes is that RNA catalysts are composed of nucleotides, whereas enzymes are composed of amino acids. (wikipedia.org)
  • Cooperative catalysis is emerging as a powerful strategy in asymmetric synthesis by providing new modes of activating molecules.1,2 The combination of Lewis base and Lewis acid activation of substrates can lead to new reactivity and selectivity patterns through the preorganization of starting materials. (datapdf.com)
  • Lam, M.K., Lee, K.T. and Mohamed, A.R. (2010) Homogeneous, Heterogeneous and Enzymatic Catalysis for Transesterification of High Free Fatty Acid Oil (Waste Cooking Oil) to Biodiesel: A Review. (scirp.org)
  • The kinetics of the hydrolysis of benzaldehyde substituted (X) - phenyl methyl acetals and substituted (Y)-benzaldehyde phenyl methyl acetals were measured in pivalate , acetate, d1-deutero-acetate, beta-chloropropionate, formate and chloroacetate buffers, and in hydrochloric and deutero-chloric acids. (gla.ac.uk)
  • The results obtained were all indicative of an A-SE2 mechanism in the general acid catalysed hydrolysis of aromatic aryl methyl acetals, with concerted proton transfer to phenolic oxygen and carbon-phenolic oxygen bond fission in the rate limiting step and where incipient carbonium ion stability and leaving group ability, rather than a high relative degree of proton transfer in the transition state, were commensurate to faster hydrolysis rates. (gla.ac.uk)
  • of general acid catalysis in acetal hydrolysis, although relief of steric strain through carbonium ion formation is also relevant. (gla.ac.uk)
  • The hydrolysis of benzaldehyde methyl acetyl acylal, the possible intermediate of acetate anion nucleophilic attack on benzaldehyde phenyl methyl acetal, was found to be general acid catalysed, and is believed to be the first reported example of buffer catalysis in acylal hydrolysis. (gla.ac.uk)
  • The hydrolysis of p-methylbenzaldehyde methyl S-phenyl thioacetal was carried out in weak acid buffers, and the results suggested, although not conclusively, that this substrate might also be catalysed by undissociated acid. (gla.ac.uk)
  • Strong acids catalyze the hydrolysis and transesterification of esters, e.g. for processing fats into biodiesel. (wikipedia.org)
  • As the hydrolysis reaction may be acid or base catalysed, the rate of reaction is expected to be slowest at around pH 7 and increase as the pH is raised or lowered. (europa.eu)
  • General acid-base catalysis, substrate destabilization and global and local conformational changes have all been proposed to contribute to the ribozyme catalytic mechanism. (rcsb.org)
  • Such cases exist: for example, a mutase such as phosphoglucomutase catalyses the transfer of a phospho group from one position to another, and isomerase is a more general term for an enzyme that catalyses any one-substrate one-product reaction, such as triosephosphate isomerase . (wikipedia.org)
  • CH 3 -H 4 folate complex 1 has revealed three active-site amino acid residues - Glu 28, Asp 120, and Phe 223 - with potential roles in folate substrate binding and catalysis in the oxidative half-reaction. (carleton.edu)
  • Pyrrolidine as an organocatalyst enables a general and efficient biomimetic method for the synthesis of aldimines from aldehydes and compounds bearing an amino group. (organic-chemistry.org)
  • As a recipient of an NIH Ruth L. Kirschstein postdoctoral fellowship, Matt spent several years at the University of Minnesota - Twin Cities studying nonheme iron systems with Professor Lawrence Que, Jr. His research interests include the design and synthesis of bio-mimetic/inspired inorganic compounds for catalysis. (ionicviper.org)
  • One type of RNA acts as a messenger between DNA and the protein synthesis complexes known as ribosomes , others form vital portions of the structure of ribosomes, act as essential carrier molecules for amino acids to be used in protein synthesis, or change which genes are active. (wikidoc.org)
  • ACC is required for the catalysis of the first step in fatty acid synthesis. (medscape.com)
  • The ionizable amino acid side chains of proteins are usually located at the surface. (lu.se)
  • RNA plays several important roles in the processes of translating genetic information from deoxyribonucleic acid ( DNA ) into proteins . (wikidoc.org)
  • These models reveal the general interactions that impart asymmetric induction and allow the quantitative transfer of this information to new reaction components. (nature.com)
  • Abstract An asymmetric decarboxylative Csp3-Csp2 cross-coupling has been achieved via the synergistic merger of photoredox and nickel catalysis. (docksci.com)
  • His research program investigates aspects of light-induced reactivity of metal-ligand multiple bonds, cooperative ligand designs that include proton coupled electron transfer relays, and main group element reactivity in catalysis. (ionicviper.org)
  • These applications fields are possible due to the unique properties of nanomaterials, such as high surface area, high reactivity and considerable porosity and morphological, electrical, magnetic and/or optical properties, which turn them into useful materials in catalysis, adsorption, sensing and optic-electronic applications [ 2 ]. (intechopen.com)
  • A constant rate is evidence for a specific acid catalyst. (wikipedia.org)
  • The highest yield of the desired product, 2-pentylidene-cyclopentanone, finding applications as fragrances, flavours and pharmaceuticals, was 66% obtained over FeO-MgO catalyst exhibiting both acid and basic sites. (springer.com)
  • We hypothesized that Glu28, located next to a structural water molecule near N10 of the folate, could serve as the general acid catalyst to aid 5-iminium cation formation. (carleton.edu)
  • Ribonucleic acid or RNA is a nucleic acid , consisting of many nucleotides that form a polymer . (wikidoc.org)
  • Further, the simple spin topologies (e.g. isolated 1 H- 13 C spin pairs) facilitates the application of relaxation dispersion techniques that give insights into nucleic acid dynamics underlying their function in ligand binding or catalysis. (uibk.ac.at)
  • In detail, we want to introduce the methyl TROSY technique in combination with deuteration to nucleic acid NMR spectroscopy to expand the addressable molecular weight of RNA protein complexes. (uibk.ac.at)
  • We further want to simplify the application of PRE NMR in nucleic acid protein complexes. (uibk.ac.at)
  • A key limitation of thioglycolic acid and its derivatives is susceptibility to oxidation by mechanisms such as air, high temperatures and trace metal-ions. (cosmeticsandtoiletries.com)
  • A process involving direct oxidation of 1,3-butadiene to crotonaldehyde with palladium catalysis has also been reported. (cdc.gov)
  • It was found that the relative concentration and spatial arrangement of cooperative functional groups were very important factors in the synergistic catalysis. (edu.sa)
  • There will be a computational part where students will use a (free) software to look at the active sites of selected enzymes and see how the catalytic residues are placed in 3D, illustrating how placement is important for efficient catalysis. (uit.no)
  • and even the role of particular amino acid residues in the mechanism. (wikipedia.org)
  • To examine the role of water penetration, we have measured the 17O and 2H magnetic relaxation dis- persions (MRD) for the V66E and V66K mutants of staphylococcal nuclease, where glutamic acid and lysine residues are buried in predominantly apolar environments. (lu.se)
  • To investigate these residues, we have prepared mutant enzymes containing amino acid changes at the site of interest and then measured the kinetic properties of the mutants compared to those of the wild-type enzyme. (carleton.edu)
  • In this communication, we report an enantioselective cooperative system that successfully integrates Lewis acid catalysis and carbene catalysis simultaneously, thus providing direct access to previously unobtainable substituted cyclopentenes with excellent levels of enantio- and diastereoselection. (datapdf.com)
  • Enantioselective Decarboxylative Arylation of α-Amino Acids via the Merger of Photoredox and Nickel Catalysis. (docksci.com)
  • for example, in the acid catalysed aldol reaction. (wikipedia.org)
  • Glutathione S-transferase (GST) is a search Centre (NRC), Cairo, Egypt from detoxification enzyme that catalyses the 2001 to 2004, in accordance with the ethical addition of glutathione to various xeno- principles of the NRC, in collaboration with biotics [ 4 ]. (who.int)
  • The result is that our olive oil has extraordinarily high values of polyphenols, acidity, linol acid as well as a general fatty acid structure that catalyses rapid intake of the facial oil and its beneficial molecules. (natrue.org)
  • Formulators creating a hair depilation product typically are cautioned not to use fatty acid esters due to their instability at high pH levels. (cosmeticsandtoiletries.com)
  • This observation supports its proposed role as a general base in the reaction mechanism. (rcsb.org)
  • For an acid-base catalysed reaction in buffered solution, the measured rate constant is a linear combination of terms describing contributions from the uncatalysed reaction as well as catalysis by hydronium, hydroxide, and general acids or bases. (europa.eu)
  • The most widely used category of alkaline bases are mercaptans, known as thioglycolic acid (and salts). (cosmeticsandtoiletries.com)
  • This course satisfies the second semester of a one-year General Chemistry requirement for post-graduate Health Professions programs, however, this course might not also satisfy a Health Profession program's requirement for a course in Biochemistry. (hamilton.edu)
  • David Benson currently teaches general chemistry, inorganic chemistry, instrumental analysis, and biochemistry at Calvin University in Grand Rapids, MI. (ionicviper.org)
  • Surface acid-base properties of the samples were determined by infrared spectroscopy using carbon dioxide and pyridine as probe molecules. (tue.nl)
  • This scenario might provide an environment in which a Lewis acid and Lewis base operate and activate starting materials simultaneously. (datapdf.com)
  • To solve the lack of generality and efficiency to access cis cyclopentenes using carbene catalysis, we chose this reaction as an initial platform to investigate the integration of Lewis acid and carbene catalysis. (datapdf.com)
  • Infrared characterization showed that zeolite CsY contains Lewis acid (Cs+)-base (O2-) pairs capable of adsorbing bidentate carbonates but does not exhibit Brönsted acidity. (tue.nl)
  • distinguish between general and specific acid or base catalysis and use the Bronsted linear free energy relationship. (dur.ac.uk)
  • Herein, we present a broad strategy in which dynamically assembled ternary complexes are converted into valuable azabicyclic scaffolds based on the concept of inverse hydride shuttle catalysis. (nature.com)
  • Fig. 1: Harnessing dynamically formed ternary complexes through inverse hydride shuttle catalysis. (nature.com)
  • In this research field we focus on the development of robust chemical tools that can be used in integrative structural biology approaches that target ribonucleoprotein (RNP) particles or RNA protein complexes with high molecular weight in general. (uibk.ac.at)
  • Depending on the chemical species that act as the acid or base, catalytic mechanisms can be classified as either specific catalysis and general catalysis. (wikipedia.org)
  • This course will focus on enzymatic mechanisms and the chemistry involved: typical amino acids in enzymatic mechanisms and the type of chemistry they catalyze. (uit.no)
  • Has the ability to read and understand in general terms, research papers where enzymatic mechanisms are discussed. (uit.no)
  • Of these three mechanisms, trace metal-ion catalysis is the most detrimental to hair depilatory formulations. (cosmeticsandtoiletries.com)
  • Selective acid-base poisoning of the alkylation of toluene with methanol was studied over alkali and alkaline-earth exchanged Y zeolites. (tue.nl)
  • In acid catalysis and base catalysis, a chemical reaction is catalyzed by an acid or a base. (wikipedia.org)
  • By Brønsted-Lowry acid-base theory, the acid is the proton (hydrogen ion, H+) donor and the base is the proton acceptor. (wikipedia.org)
  • In this study, a bifunctional graphene oxide material (GO-AEP-UDP) with a general acid, the ureidopropyl (UDP) group, and a general base, the 3-[2-(2-aminoethylamino)ethylamino]-propyl (AEP) group, was synthesized by silylanization of graphene oxide (GO) with organoalkoxysilane precursors. (edu.sa)
  • Capturing the Catalytic Proton of Dihydrofolate Reductase: Implications for General Acid-Base Catalysis. (expasy.org)
  • An intermolecular reductive Schiff base formation from nitroarenes and benzaldehydes to yield diarylimines is carried out in the presence of iron powder and dilute acid. (organic-chemistry.org)
  • In addition the following knowledge is recommended: Students should have a basic knowledge about protein structure and composition (amino acid types) and a basic knowledge in organic chemistry (fundamental concepts such as acid, base, covalent bond), alongside basic ability to read chemical structures (single/double bonds, etc). (uit.no)
  • In contrast, zeolite CsY formed mainly styrene and ethylbenzene, and was strongly deactivated by the addition of either acid or base compounds. (tue.nl)
  • Thus, selective poisoning results and sample characterization showed that bimolecular side-chain alkylation reaction on CsY requires a specific surface acid-base pairs configuration not only for activating toluene and methanol, but also for promoting the rate-limiting step. (tue.nl)
  • Many alkylamines are prepared by amination of alcohols, catalyzed by solid acids. (wikipedia.org)
  • The d1-acetic acid catalysed d4-methanolysis of benz-aldehyde phenyl methyl acetal was followed in a high resolution N. M. R. spectrometer and the initial bond fission found to occur between carbon and the phenolic oxygen. (gla.ac.uk)
  • The alliance focuses and catalyses efforts to achieve international goals on preventing children's exposure to lead from leaded paints and minimizing occupational exposures to such paint. (who.int)
  • A molar conversion (Br(-) to BrO3(-)) of 22.1% was observed under CuO catalysis, compared with little conversion in the absence of CuO. (who.int)
  • We also focus on how naturally occurring RNA modifications, such as simple methylations but also more complex side chains like the 5-oxyacetic acid modification influence the folding landscape of RNA. (uibk.ac.at)
  • Consistent with this role, mutant enzymes Glu28Gln and Glu28Asp are able to bind folate, but are completely inactive in catalysis. (carleton.edu)