Amination: The creation of an amine. It can be produced by the addition of an amino group to an organic compound or reduction of a nitro group.Palladium: A chemical element having an atomic weight of 106.4, atomic number of 46, and the symbol Pd. It is a white, ductile metal resembling platinum, and following it in abundance and importance of applications. It is used in dentistry in the form of gold, silver, and copper alloys.Amines: A group of compounds derived from ammonia by substituting organic radicals for the hydrogens. (From Grant & Hackh's Chemical Dictionary, 5th ed)Rhodium: Rhodium. A hard and rare metal of the platinum group, atomic number 45, atomic weight 102.905, symbol Rh. (Dorland, 28th ed)Hydrocarbons, Acyclic: Organic compounds composed exclusively of carbon and hydrogen where no carbon atoms join to form a ring structure.Alkenes: Unsaturated hydrocarbons of the type Cn-H2n, indicated by the suffix -ene. (Grant & Hackh's Chemical Dictionary, 5th ed, p408)Molecular Structure: The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.Stereoisomerism: The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Catalysis: The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.Alanine Dehydrogenase: An NAD-dependent enzyme that catalyzes the reversible DEAMINATION of L-ALANINE to PYRUVATE and AMMONIA. The enzyme is needed for growth when ALANINE is the sole CARBON or NITROGEN source. It may also play a role in CELL WALL synthesis because L-ALANINE is an important constituent of the PEPTIDOGLYCAN layer.Lycopodium: A plant genus of the family LYCOPODIACEAE. Members contain ALKALOIDS. Lycopodium oil is obtained from L. clavatum.Physicochemical Processes: Physical reactions involved in the formation of or changes in the structure of atoms and molecules and their interactions.Hydrocarbons, HalogenatedGlutamate Dehydrogenase: An enzyme that catalyzes the conversion of L-glutamate and water to 2-oxoglutarate and NH3 in the presence of NAD+. (From Enzyme Nomenclature, 1992) EC 1.4.1.2.Iridium: A metallic element with the atomic symbol Ir, atomic number 77, and atomic weight 192.22.Phosphines: Inorganic or organic compounds derived from phosphine (PH3) by the replacement of H atoms. (From Grant & Hackh's Chemical Dictionary, 5th ed)Aziridines: Saturated azacyclopropane compounds. They include compounds with substitutions on CARBON or NITROGEN atoms.Green Chemistry Technology: Pollution prevention through the design of effective chemical products that have low or no toxicity and use of chemical processes that reduce or eliminate the use and generation of hazardous substances.Cyclization: Changing an open-chain hydrocarbon to a closed ring. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Amino Acid Oxidoreductases: A class of enzymes that catalyze oxidation-reduction reactions of amino acids.Allyl CompoundsBoron: A trace element with the atomic symbol B, atomic number 5, and atomic weight [10.806; 10.821]. Boron-10, an isotope of boron, is used as a neutron absorber in BORON NEUTRON CAPTURE THERAPY.Styrene: A colorless, toxic liquid with a strong aromatic odor. It is used to make rubbers, polymers and copolymers, and polystyrene plastics.Styrenes: Derivatives and polymers of styrene. They are used in the manufacturing of synthetic rubber, plastics, and resins. Some of the polymers form the skeletal structures for ion exchange resin beads.Boron Compounds: Inorganic or organic compounds that contain boron as an integral part of the molecule.Alkylation: The covalent bonding of an alkyl group to an organic compound. It can occur by a simple addition reaction or by substitution of another functional group.Liquid-Liquid Extraction: The removal of a soluble component from a liquid mixture by contact with a second liquid, immiscible with the carrier liquid, in which the component is preferentially soluble. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Borohydrides: A class of inorganic or organic compounds that contain the borohydride (BH4-) anion.Solubility: The ability of a substance to be dissolved, i.e. to form a solution with another substance. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)AcetophenonesPropiophenonesomega-Chloroacetophenone: A potent eye, throat, and skin irritant. One of its uses is as a riot control agent.Amidine-Lyases: These enzymes catalyze the elimination of ammonia from amidines with the formation of a double bond. EC 4.3.2.Amides: Organic compounds containing the -CO-NH2 radical. Amides are derived from acids by replacement of -OH by -NH2 or from ammonia by the replacement of H by an acyl group. (From Grant & Hackh's Chemical Dictionary, 5th ed)Formates: Derivatives of formic acids. Included under this heading are a broad variety of acid forms, salts, esters, and amides that are formed with a single carbon carboxy group.Encyclopedias as Topic: Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)Formate Dehydrogenases: Flavoproteins that catalyze reversibly the reduction of carbon dioxide to formate. Many compounds can act as acceptors, but the only physiologically active acceptor is NAD. The enzymes are active in the fermentation of sugars and other compounds to carbon dioxide and are the key enzymes in obtaining energy when bacteria are grown on formate as the main carbon source. They have been purified from bovine blood. EC 1.2.1.2.Chromatography, Liquid: Chromatographic techniques in which the mobile phase is a liquid.Solid Phase Extraction: An extraction method that separates analytes using a solid phase and a liquid phase. It is used for preparative sample cleanup before analysis by CHROMATOGRAPHY and other analytical methods.Ochrobactrum anthropi: A species of gram-negative, obligately aerobic rods. Motility occurs by peritrichous flagella. (From Bergey's Manual of Determinative Bacteriology, 9th ed)KetonesOchrobactrum: A genus of the family BRUCELLACEAE comprising obligately aerobic gram-negative rods with parallel sides and rounded ends.Ketone Bodies: The metabolic substances ACETONE; 3-HYDROXYBUTYRIC ACID; and acetoacetic acid (ACETOACETATES). They are produced in the liver and kidney during FATTY ACIDS oxidation and used as a source of energy by the heart, muscle and brain.Patents as Topic: Exclusive legal rights or privileges applied to inventions, plants, etc.Inventions: A novel composition, device, or process, independently conceived de novo or derived from a pre-existing model.Solvents: Liquids that dissolve other substances (solutes), generally solids, without any change in chemical composition, as, water containing sugar. (Grant & Hackh's Chemical Dictionary, 5th ed)Biotechnology: Body of knowledge related to the use of organisms, cells or cell-derived constituents for the purpose of developing products which are technically, scientifically and clinically useful. Alteration of biologic function at the molecular level (i.e., GENETIC ENGINEERING) is a central focus; laboratory methods used include TRANSFECTION and CLONING technologies, sequence and structure analysis algorithms, computer databases, and gene and protein structure function analysis and prediction.Ether: A mobile, very volatile, highly flammable liquid used as an inhalation anesthetic and as a solvent for waxes, fats, oils, perfumes, alkaloids, and gums. It is mildly irritating to skin and mucous membranes.EthersComputer Security: Protective measures against unauthorized access to or interference with computer operating systems, telecommunications, or data structures, especially the modification, deletion, destruction, or release of data in computers. It includes methods of forestalling interference by computer viruses or so-called computer hackers aiming to compromise stored data.Confidentiality: The privacy of information and its protection against unauthorized disclosure.Chemistry, Organic: The study of the structure, preparation, properties, and reactions of carbon compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Privacy: The state of being free from intrusion or disturbance in one's private life or affairs. (Random House Unabridged Dictionary, 2d ed, 1993)

Reaction specificity of native and nicked 3,4-dihydroxyphenylalanine decarboxylase. (1/218)

3,4-Dihydroxyphenylalanine (Dopa) decarboxylase is a stereospecific pyridoxal 5'-phosphate (PLP)-dependent alpha-decarboxylase that converts L-aromatic amino acids into their corresponding amines. We now report that reaction of the enzyme with D-5-hydroxytryptophan or D-Dopa results in a time-dependent inactivation and conversion of the PLP coenzyme to pyridoxamine 5'-phosphate and PLP-D-amino acid Pictet-Spengler adducts, which have been identified by high performance liquid chromatography. We also show that the reaction specificity of Dopa decarboxylase toward aromatic amines depends on the experimental conditions. Whereas oxidative deamination occurs under aerobic conditions (Bertoldi, M., Moore, P. S., Maras, B., Dominici, P., and Borri Voltattorni, C. (1996) J. Biol. Chem. 271, 23954-23959; Bertoldi, M., Dominici, P., Moore, P. S., Maras, B., and Borri Voltattorni, C. (1998) Biochemistry 37, 6552-6561), half-transamination and Pictet-Spengler reactions take place under anaerobic conditions. Moreover, we examined the reaction specificity of nicked Dopa decarboxylase, obtained by selective tryptic cleavage of the native enzyme between Lys334 and His335. Although this enzymatic species does not exhibit either decarboxylase or oxidative deamination activities, it retains a large percentage of the native transaminase activity toward D-aromatic amino acids and displays a slow transaminase activity toward aromatic amines. These transamination reactions occur concomitantly with the formation of cyclic coenzyme-substrate adducts. Together with additional data, we thus suggest that native Dopa decarboxylase can exist as an equilibrium among "open," "half-open," and "closed" forms.  (+info)

Effect of the ratio between essential and nonessential amino acids in the diet on utilization of nitrogen and amino acids by growing pigs. (2/218)

In 36 growing pigs (30 to 60 kg), N balance and amino acid (AA) composition of weight gain were measured to evaluate the interactive effect of the ratio between N from essential amino acids (EAA(N)) to nonessential amino acids (NEAA(N)) and total N level (T(N)) in the diet on N retention and utilization of N, EAA(N), NEAA(N), and AA. Nine diets composed from ordinary feedstuffs and supplemented with crystalline AA were used (three EAA(N):NEAA(N) ratios of 38:62, 50:50, and 62:38 at three T(N) levels of 18.8, 22.9, and 30.0 g/kg). Pigs were fed restrictedly, at a level of 2.8 x energy for maintenance. In all diets, EAA (including arginine) supply was according to or slightly above the recommended ratios to lysine. Measurements were done in four blocks of nine pigs each. In a concomitant slaughter experiment, the AA composition of deposited body protein was determined to estimate AA utilization. The effects of T(N) and EAA(N):NEAA(N) and their interaction for N retention and utilization were significant. Nitrogen retention increased with higher T(N) in the diet. Increasing EAA(N):NEAA(N) from 38:62 to 50:50 improved N retention only at the two lower T(N) levels. Increasing EAA(N): NEAA(N) above 50:50 failed to improve N retention significantly at any of the three T(N) levels. Lowering T(N) improved the utilization of total and digested N and of EAA(N) and NEAA(N). The increase in EAA(N): NEAA(N) consistently resulted in a lower utilization of EAA(N), but this was compensated by a higher utilization of NEAA(N). The utilization of T(N) was improved by increasing EAA(N):NEAA(N) from 38:62 to 50:50 at the two lower T(N) levels and was relatively unaffected by EAA(N):NEAA(N) at the highest T(N). However, a lower utilization of N was observed at a ratio of 62:38 at a T(N) level of 22.9 g/kg. The effects were similar for utilization of individual EAA and NEAA. Utilization of alanine, aspartic acid, and glycine was close to or >100% at the highest EAA(N):NEAA(N), which was expected because all of these AA are synthesized in pigs. Also, the utilization of arginine was >100% in most of the treatments, which confirms the semiessential character of this AA for maintenance. We concluded that the required ratio of EAA(N):NEAA(N) for optimal N retention and utilization is approximately 50:50. The EAA(N):NEAA(N) is more important at lower dietary protein levels. This study indicates that EAA(N): NEAA(N) can be increased up to 70:30 without lowering the utilization of N. Thus, deaminated EAA(N) was efficiently utilized for the synthesis of NEAA(N).  (+info)

Effects of branched-chain-enriched amino acids and insulin on forearm leucine kinetics. (3/218)

Although amino acid mixtures enriched in branched-chain amino acids (BCAA) and deficient in aromatic amino acids (AAA) are often used together with insulin and glucose in clinical nutrition, their physiological effects on muscle protein anabolism are not known. To this aim, we studied forearm leucine kinetics in post-absorptive volunteers, before and after the systemic infusion of BCAA-enriched, AAA-deficient amino acids along with insulin and the euglycaemic clamp. The results were compared with the effects of insulin infusion alone. A compartmental leucine forearm model was employed at steady state. Hyperaminoacidaemia with hyperinsulinaemia (to approximately 80-100 micro-units/ml) increased the leucine plasma concentration (+70%; P<0.001), inflow into the forearm cell (+150%; P<0.01), disposal into protein synthesis (+100%; P<0.01), net intracellular retention (P<0.01), net forearm balance (by approximately 6-fold; P<0.01) and net deamination to alpha-ketoisocaproate (4-methyl-2-oxopentanoate) (+9%; P<0.05). Leucine release from forearm proteolysis and outflow from the forearm cell were unchanged. In contrast, hyperinsulinaemia alone decreased plasma leucine concentrations (-35%; P<0.001) and leucine inflow (-20%; P<0.05) and outflow (-30%; P<0.01) into and out of forearm cell(s), it increased net intracellular leucine retention (P<0.03), and it did not change leucine release from forearm proteolysis (-20%; P=0.138), net leucine deamination to alpha-ketoisocaproate, leucine disposal into protein synthesis or net forearm protein balance. By considering all data together, leucine disposal into protein synthesis was directly correlated with leucine inflow into the cell (r=0.71; P<0.0001). These data indicate that the infusion of BCAA-enriched, AAA-deficient amino acids along with insulin is capable of stimulating forearm (i.e. muscle) protein anabolism in normal volunteers by enhancing intracellular leucine transport and protein synthesis. These effects are probably due to hyperaminoacidaemia and/or its interaction with hyperinsulinaemia, since they were not observed under conditions of hyperinsulinaemia alone.  (+info)

Fluorescent neoglycolipids. Improved probes for oligosaccharide ligand discovery. (4/218)

A second generation of lipid-linked oligosaccharide probes, fluorescent neoglycolipids, has been designed and synthesized for ligand discovery within highly complex mixtures of oligosaccharides. The aminolipid 1,2-dihexadecyl-sn-glycero-3-phosphoethanolamine (DHPE), which has been used extensively to generate neoglycolipids for biological and structural studies, has been modified to incorporate a fluorescent label, anthracene. This new lipid reagent, N-aminoacetyl-N-(9-anthracenylmethyl)-1, 2-dihexadecyl-sn-glycero-3-phosphoethanolamine (ADHP), synthesized from anthracenaldehyde and DHPE gives an intense fluorescence under UV light. Fluorescent neoglycolipids derived from a variety of neutral and acidic oligosaccharides by conjugation to ADHP, by reductive amination, can be detected and quantified by spectrophotometry and scanning densitometry, and resolved by TLC and HPLC with subpicomole detection. Antigenicities of the ADHP-neoglycolipids are well retained, and picomole levels can be detected using monoclonal carbohydrate sequence-specific antibodies. Among O-glycans from an ovarian cystadenoma mucin, isomeric oligosaccharide sequences, sialyl-Lea- and sialyl-Lex-active, could be resolved by HPLC as fluorescent neoglycolipids, and sequenced by liquid secondary-ion mass spectrometry. Thus the neoglycolipid technology now uniquely combines high sensitivity of immuno-detection with a comparable sensitivity of chemical detection. Principles are thus established for a streamlined technology whereby an oligosaccharide population is carried through ligand detection and ligand isolation steps, and sequence determination by mass spectrometry, enzymatic sequencing and other state-of-the-art technologies for carbohydrate analysis.  (+info)

Structure of the Bordetella pertussis 1414 endotoxin. (5/218)

The endotoxin (lipopolysaccharide) of Bordetella pertussis, the agent of whooping cough, consists of a lipid A linked to a highly branched dodecasaccharide containing several acid and amino sugars. The elucidation of the polysaccharide structure was accomplished by first analyzing the structures of fragments obtained by hydrolysis and nitrous deamination and then piecing the fragments together. The fine structure of the antigenic distal pentasaccharide, presented here, was determined by chemical analyses as well as by high-resolution nuclear magnetic resonance and mass spectrometry. The complete structure was reconstituted and confirmed by matrix-assisted laser desorption/ionization mass spectrometry. The following structure was derived from the combined experimental data:The detailed structure combined with previously reported serological data now allows the synthesis of its epitopes for potential vaccines.  (+info)

Electrospray mass spectrometry and fragmentation of N-linked carbohydrates derivatized at the reducing terminus. (6/218)

Derivatives were prepared from N-linked glycans by reductive amination from 2-aminobenzamide, 2-aminopyridine, 3-aminoquinoline, 2-aminoacridone, 4-amino-N-(2-diethylaminoethyl)benzamide, and the methyl, ethyl, and butyl esters of 4-aminobenzoic acid. Their electrospray and collision-induced dissociation (CID) fragmentation spectra were examined with a Q-TOF mass spectrometer. The strongest signals were obtained from the [M + Na]+ ions for all derivatives except sugars derivatized with 4-amino-N-(2-diethylaminoethyl)benzamide which gave very strong doubly charged [M + H + Na]2+ ions. The strongest [M + Na]+ ion signals were obtained from the butyl ester of 4-aminobenzoic acid and the weakest from 2-aminopyridine. The most informative spectra were recorded from the [M + Li]+ or [M + Na]+ ions. These spectra were dominated by ions produced by sequence-revealing glycosidic cleavages and "internal" fragments. Linkage-revealing cross-ring cleavage ions were reasonably abundant, particularly from high-mannose glycans. Although the nature of the derivative was found to have little effect upon the fragmentation pattern, 3-aminoquinoline derivatives gave marginally more abundant cross-ring fragments than the other derivatives. [M + H]+ ions formed only glycosidic fragments with few, if any, cross-ring cleavage ions. Doubly charged molecular ions gave less informative spectra; singly charged fragments were weak, and molecular ions containing hydrogen ([M + 2H]2+ and [M + H + Na]2+) fragmented as the [M + H]+ singly charged ions with no significant cross-ring cleavages.  (+info)

Bisulfite genomic sequencing: systematic investigation of critical experimental parameters. (7/218)

Bisulfite genomic sequencing is the method of choice for the generation of methylation maps with single-base resolution. The method is based on the selective deamination of cytosine to uracil by treatment with bisulfite and the sequencing of subsequently generated PCR products. In contrast to cytosine, 5-methylcytosine does not react with bisulfite and can therefore be distinguished. In order to investigate the potential for optimization of the method and to determine the critical experimental parameters, we determined the influence of incubation time and incubation temperature on the deamination efficiency and measured the degree of DNA degradation during the bisulfite treatment. We found that maximum conversion rates of cytosine occurred at 55 degrees C (4-18 h) and 95 degrees C (1 h). Under these conditions at least 84-96% of the DNA is degraded. To study the impact of primer selection, homologous DNA templates were constructed possessing cytosine-containing and cytosine-free primer binding sites, respectively. The recognition rates for cytosine (>/=97%) and 5-methylcytosine (>/=94%) were found to be identical for both templates.  (+info)

1-Oxo-2-hydroxy-1,2-dihydroacronycine: a useful synthon in the acronycine series for the introduction of amino substituents at 6-position and for the conversion into isopropylfuroacridones. (8/218)

Thermic aromatic nucleophilic displacement of the methoxy group at C-6 of (+/-)-1-oxo-2-hydroxy-1,2-dihydroacronycine (2) by an amine is a reaction that gives a facile entry to acronycine derivatives bearing an amino substituent at this position. The introduction of the amino substituents was confirmed with a long-range 1H-15N correlation NMR spectrum at natural abundance. Under basic conditions, compound 2 can also be rearranged to the corresponding isopropylfuroacridone 12, in 80% yield.  (+info)

TY - JOUR. T1 - Acid-base blend membranes based on Nafion®/aminated SPEEK for reducing methanol permeability. AU - Tsai, Jie Cheng. AU - Lin, Chien-Kung. PY - 2011/3/1. Y1 - 2011/3/1. N2 - Sulfonated poly(ether ether ketone)s (SPEEKs) were further substituted on the polymer main chain by amino groups to form an acid-basic polymer, and blended with acid polymeric Nafion® to create composite membranes. The acid-base blend membranes containing ionic crosslinking exhibited lower water uptake than recast Nafion®, and the methanol permeability was reduced significantly for various contents of aminated SPEEK, with a maximum proton conductivity of ~0.063Scm-1 at 30°C. The single-cell performance of the blend membranes with various contents of aminated SPEEK showed 20-26mWcm-2 for S45A47 at 80°C. Both the power density and open circuit voltage were higher than those of Nafion® 115 and recast Nafion®. The acid-base blend membranes satisfy the requirements for proton exchange membranes in the ...
TY - JOUR. T1 - Mechanism-Guided Engineering of ω-Transaminase to Accelerate Reductive Amination of Ketones. AU - Han, Sang Woo. AU - Park, Eul Soo. AU - Dong, Joo Young. AU - shin, jong shik. PY - 2015/5/1. Y1 - 2015/5/1. N2 - Asymmetric reductive amination of ketones using ω-transaminases (ω-TAs) offers a promising alternative to the chemocatalytic synthesis of chiral amines. One fundamental challenge to the biocatalytic strategy is the very low enzyme activities for most ketones compared with native substrates (i.e., ,1% relative to pyruvate). Here we have demonstrated that a single point mutation in the active site of the (S)-selective ω-TA from Ochrobactrum anthropi could induce a remarkable acceleration of the amination reaction without any loss in stereoselectivity and enzyme stability. Molecular modeling of quinonoid intermediates, alanine scanning mutagenesis and kinetic analysis revealed that the W58 residue acted as a steric barrier to binding and catalytic turnover of ketone ...
Allylic C-H functionalization has been an emerging field over the last decade due to the ability to convert inert C-H bonds into C-N, C-O, and C-C bonds. In the past two years the Blakey group has developed methodology for rhodium (III) catalyzed intermolecular allylic C-H amination and etherification of 1,2-disubstituted olefins. The allylic amination methodology was found to be regioselective however was not enantioselective. Therefore it was proposed that methodology for allylic C-H alkylation of 1,2-disubstiuted olefins could be developed. Optimization for this method was done using diphenylpropene as the substrate and dimethylmalonate as the nucleophile. This methodology was found to tolerate five nucleophiles with moderate to high yields. The nucleophiles that tolerated this system contained one nitro, ketone, ester, or two esters. The regioselectivity of the system was investigated using β-alkyl-styrenederivatives and a variety of the best nucleophiles from the reaction scope with ...
Lamani, M. and Prabhu, K. R. (2012), NIS-Catalyzed Reactions: Amidation of Acetophenones and Oxidative Amination of Propiophenones. Chem. Eur. J., 18: 14638-14642. doi: 10.1002/chem.201202703 ...
Reported herein is a chiral Brønsted acid-catalyzed asymmetric intramolecular allylic amination reaction, allowing facile access to a range of biologically interesting chiral 2-substituted hydroquinolines in up to 90% yield and with up to 93% ee. Furthermore, a significant effect of an N-protecting group was observ Synthetic methodology in OBC
Abstract. The bicyclic triaminophosphine P(i-BuNCH2CH2)3N serves as an effective ligand for the palladium-catalyzed amination of various aryl bromides and iodides. Other bicyclic or acyclic triaminophosphines, even those of similar basicity and/or bulk, were inferior.. ...
PROCESS FOR SEPARATING ONE OR MORE ALIPHATIC DIAMINES FROM REDUCTIVE AMINATION REACTION SOLVENTS AND IMPURITIES - The instant invention provides a process for separating one or more aliphatic diamines from reductive amination reaction solvents and impurities, and aliphatic diamines obtained via such a process. The process for separating one or more aliphatic diamines from reductive amination reaction solvents and impurities according to the instant invention comprises the steps of: (1) feeding one or more cycloaliphatic cyanoaldehydes, hydrogen, ammonia, and optionally one or more solvents into a continuous reductive amination reactor system; (2) contacting said one or more cycloaliphatic cyanoaldehydes, hydrogen, and ammonia with each other in the presence of one or more heterogeneous metal based catalyst systems at a temperature in the range of from 80° C. to about 160° C. and a pressure in the range of from 700 to 3500 psig; (3) thereby forming a product mixture comprising one or more ...
TY - JOUR. T1 - Enantioselective Hydroamination of Alkenes with Sulfonamides Enabled by Proton-Coupled Electron Transfer. AU - Roos, Casey B.. AU - Demaerel, Joachim. AU - Graff, David E.. AU - Knowles, Robert R.. PY - 2020/4/1. Y1 - 2020/4/1. N2 - An enantioselective, radical-based method for the intramolecular hydroamination of alkenes with sulfonamides is reported. These reactions are proposed to proceed via N-centered radicals formed by proton-coupled electron transfer (PCET) activation of sulfonamide N-H bonds. Noncovalent interactions between the neutral sulfonamidyl radical and a chiral phosphoric acid generated in the PCET event are hypothesized to serve as the basis for asymmetric induction in a subsequent C-N bond forming step, achieving selectivities of up to 98:2 er. These results offer further support for the ability of noncovalent interactions to enforce stereoselectivity in reactions of transient and highly reactive open-shell intermediates.. AB - An enantioselective, ...
Abstract. The use of aqueous ammonia is essential for a palladium-catalyzed allylic amination for the preparation of primary amines. It is noteworthy that ammonia gas did not react at all. The first catalytic asymmetric synthesis using aqueous ammonia as a nitrogen source has also been demonstrated.. ...
A new procedure has been developed for the direct intermolecular C-H amination of simple hydrocarbons using shelf-stable nonafluorobutanesulfonyl azide in the presence of a dirhodium(ii) tetracarboxylate catalyst under mild reaction conditions. Some mechanistic details are briefly discussed on the basis of control
In recent years great efforts have been taken for the development of highly active catalysts in the field of hydroamination- and cross-coupling-reactions. However, there is still a lack of generally applicable and user-friendly methodologies. In the present work, a sequential protocol for the synthesis of 2-aryl/alkenyl substituted indoles using low priced 2-chloro anilines and alkynes was developed. A Broensted-acid catalyzed intramolecular hydroamination of non-activated alkenes disclosed an atom-economical approach to functionalized pyrrolidine derivatives. Air-stable heteroatom substituted secondary phosphine oxide (HASPO) TADDOLP(O)H-ligand allowed for the use of aryl chlorides in palladium-catalyzed Kumada-Corriu couplings. Easily accessible air-stable HASPO-ligand PinP(O)H enabled palladium-catalyzed Kumada-Corriu cross-couplings of not only electron-rich and electron-poor tosylates but also heterocyclic tosylates. The use of a diaminophosphine chloride as preligand in palladium-catalyzed ...
0049] Possible homogeneous catalysts to be used in the process of the invention are all homogeneous catalysts known to those skilled in the art which are able to activate the CH bond of the carbon atom bearing the OH group to be aminated. Examples of such catalysts encompass alkali metal alkoxides, aluminum alkoxides and lanthanide alkoxides, inorganic compounds of noble metals (e.g. [RuCl3*nH2O], IrCl3), monometallic or multimetallic, mononuclear or multinuclear coordination compounds of one or more noble metals selected from among the elements ruthenium (e.g. [RuCl2(PPh3)3], [RuH2(PPh3)4], the Shvo catalyst ([(η4-C4Ph4CO)Ru(CO)3]2), [Ru(cod)(cot)], [(PPh3)2Ru(CH3CN)3Cl]BPh4, [Ru(p-cymene)Cl2]2, [Ru(p-cymene)Cl2]2/DPEphos, [Ru(PPh3)3(CO)H2], [Ru3(CO)12], [Ru3(CO)12]/N-phenyl-2-(PCl2)pyrrole, [RuCl2(dmso)4]), rhodium (e.g. the Wilkinson catalyst ([RhCl(PPh3)3]), [RhH(PPh3)3]), iridium (e.g. [IrCl3(dmso)3], [Cp*IrCl2]2, [Ir(cod)Cl]2/(dppp)/Cs2CO3, [IrCl2H(cod)]2, KOH-activated ...
Sodium triacetoxyborohydride has emerged as one of the reagents used most frequently for carrying out reductive amination of carbonyl compounds, a reaction that is also known as reductive alkylation of amines. A disadvantage of sodium triacetoxyborohydride is its poor solubility, and that product isolation requires an aqueous quench followed by liquid-liquid extraction and column chromatography.. Biotage® MP-Triacetoxyborohydride was developed to perform in a manner similar to that of sodium triacetoxyborohydride, while simplifying reagent handling and product purification. Moreover, for many of these reactions, a scavenger resin may be added for one-pot purification of the product.. ...
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The syntheses of azaMan-beta-(1--,6)-C-Glc (4), azaGlc-beta-(1--,6)-C-Glc (5), and azaGal-beta-(1--,6)-C-Glc (6) based upon double reductive amination of acetylenic carbohydrate-derived diketones is described. The required diketones are obtained by addition of the acetylenic sugar anion derived from dibromoolefin 7 to benzyl-protected mannopyranolactone, glucopyranolactone, or galactopyranolactone, followed by reduction of the ketose and oxidation of the resulting diol. Ensuing double reductive amination and hydrogenolysis affords the target compounds in reasonable to good yields. Enzyme inhibition tests show that neither of the three compounds 4, 5, and 6 inhibit beta-glycosidases, while moderate to good inhibitory activities were found on alpha-glycosidases, the most active being 6 (alpha-galactosidase: K-i = 0.092 mu M).. Keywords: carbohydrates ; aza sugars ; double reductive amination ; enzyme ; inhibitors ; glycosidase inhibitors ; Aza-c-disaccharides ; biological evaluation ; reductive ...
Organic compounds that contain nitrogen are very important intermediates in pharmaceutical and chemical industry. Hydroamination is the reaction that can form C-N bond with high atom economy. The research progress in metals catalyzed hydroamination of alkenes and alkynes from the perspective of reaction mechanism is categorized and summarized.
A series of bis(amidate)group 4-bis(amido) complexes have been prepared, characterized and have been shown to be highly tunable precatalysts for both the intra- and intermolecular hydroamination of alkynes.. ...
Tailor-made" single-cell biocatalysts co-expressing multiple enzymes enable efficient in vivo reaction cascades [28, 32]. Consequently, the design and application of such microbial cell factories has attracted attention in recent years, aiming for the production of a broad range of valuable chiral compounds. Since synthetic pathways commonly may involve cofactor-dependent redox reactions [51], various studies focused on the incorporation of reaction pathways in a host cell whereby the sequence itself enables a suitable cofactor regeneration resulting in redox self-sufficient single-cell catalysts [42, 52]. Alternatively, recycling of cofactors can be achieved by making use of the hosts inherent metabolic pathways, e.g. the catabolism of carbon sources like glucose [53]. In this study, we established a modular platform to construct E. coli single-cell biocatalysts tailored for the in vivo amination of ketoacids and prochiral ketones, exploiting both cell metabolism as well as additional ...
Eric Jacobsen and co-workers published in JACS on a hydroamination using a thiourea catalyst. Its refreshing to see a hydroamination without a transition metal. JACS paper
Lo Q, Sale D, Braddock D, Davies Ret al., 2019, New insights into the reaction capabilities of ionic organic bases in cu-catalysed amination, European Journal of Organic Chemistry, Vol: 2019, Pages: 1944-1951, ISSN: 1099-0690 The application of ionic organic bases in the copper‐catalyzed amination reaction (Ullmann reaction) has been studied at room temperature, with sub‐mol‐% catalyst loadings, and with more challenging amines at elevated temperatures. The cation present in the base has been shown to have little effect on the reaction at standard catalyst and ancillary ligand loadings, whereas the choice of anion is crucial for good reactivity. A substrate scope carried out at room temperature with the best performing bases, TBAM and TBPM, showed both bases to be highly effective under these mild reaction conditions. Moreover, under sub‐mol % catalyst loadings and room temperature conditions, TBPM gave good to excellent yields for a number of different amines and functionalized aryl ...
Although the Pd(II)-catalyzed alkene aminopalladation and allylic C-H activation have been much described in literature, the in-depth mechanism of such type of process is far from being a simple matter. This account focuses on the oxidative intramolecular Pd(II)-catalyzed amination of unsaturated N-sulfonyl carbamates and carboxamides, revealing that different mechanistic paths can be operative. In particular, after activation of the unsaturation by Pd(II) catalyst, aminopalladation can take place, affording the corresponding high-energy cyclic (5- or 6-membered) aminopalladated intermediate (AmPI). This latter can evolve along different pathways, such as: distocyclic β-H elimination, oxidation by a strong terminal oxidant, or carbopalladation. Otherwise, the cyclic AmPI can lay dormant, in equilibrium with the initial substrate. In this case, alternative reactivities may take place, such as allylic C-H activation of the olefinic substrate, [3,3]-sigmatropic rearrangement, or ...
The Chichibabin reaction (pronounced (chē)-chē-bā-bēn) is a method for producing 2-aminopyridine derivatives by the reaction of pyridine with sodium amide. It was reported by Aleksei Chichibabin in 1914. The following is the overall form of the general reaction: The direct amination of pyridine with sodium amide takes place in liquid ammonia. Following the addition elimination mechanism first a nucleophilic NH2− is added while a hydride (H−) is leaving. Ciganek describes an example of an intramolecular Chichibabin reaction in which a nitrile group on a fused ring is the source of nitrogen in amination. It is widely accepted that the Chichibabin reaction mechanism is an addition-elimination reaction that proceeds through an σ-adduct (Meisenheimer adduct) intermediate (the third structure). First, the nucleophilic NH2− group adds to the δ+ ring carbon pushing electrons onto the ring nitrogen and forming the anionic σ-adduct, which is stabilized by sodium. Electrons from the ...
Di-tert-butyl azodicarboxylate is a reagent used in the preparation of acyl hydrazinedicarboxylates. It is also used in the electrophilic amination of beta-keto esters catalyzed by an axially chiral guanidine. It serves as a precursor in an enantioselective synthesis of 3,6-dihyropyridazines employing organocatalysts such as L-proline or (S)-2-pyrrolidinyl tetrazole. It is also utilized in the asymmetric Friedel-Crafts amination through a chiral organocatalyst. Further, it acts as a reactant for preparation of hexapeptide key fragments through stereo selective selenocyclization/oxidative deselenylation reactions. In addition to this, it is employed as a starting material in the synthesis of pyrroloisoquinoline template through stereoselective N-acyliminium-mediated cyclization and enolate amination for preparation of peptidomimetic compounds and Barbier-type propargylation reactions ...
Scientists from RUDN University in collaboration with Russian and foreign colleagues have studied reductive amination reactions. The new reactions and catalytic systems on their basis will find a use in organic synthesis and also will boost the production of medicinal substances and agrochemicals in the future. The study was published in the Organic & Biomolecular Chemistry journal.
ISSN: 0253-2786 CN: 31-1321/06. Address: No.345 Lingling Road, Shanghai, PRC. Postcode: 200032. Tel: 021-54925244 Fax: +086-021-54925285. E-mail: [email protected] © 2019Shanghai Institute of Organic Chemistry 、Chinese Chemical Society. ...
Manipulating selectivity of covalently-bonded hyperbranched anion exchangers toward organic acids. part i: Influence of primary amine substituents in the internal part of the functional layer / A. S. Uzhel, A. V. Gorbovskaya, A. V. Zatirakha et al. // Journal of Chromatography A. - 2019. - Vol. 1589. - P. 65-72. Three covalently-bonded poly(styrene-divinylbenzene)-based (PS-DVB) hyperbranched anion exchangers prepared using primary amines with carboxylic, sulfonic or 2-hydroxyethyl substituents in the internal part of the functional layer were studied and compared for evaluating the effect of amines substituents on the chromatographic performance of the stationary phases. The hyperbranched coating was created on the surface of aminated PS-DVB substrate by repeating the modification cycles including alkylation with 1,4-butanediol diglycidyl ether (1,4-BDDGE) and amination with primary amine; glycine, taurine (2-aminoethanesulfonic acid) or ethanolamine were used in the first cycle, and 4 more ...
Nicholas R. Babij and Prof. John P. Wolfe Desymmetrization of meso-2,5-Diallylpyrrolidinyl Ureas through Asymmetric Palladium-Catalyzed Carboamination: Stereocontrolled Synthesis of Bicyclic Ureas Angewandte Chemie International Edition 52. Version of Record online: 3 JUL 2013 , DOI: 10.1002/anie.201302720 ...
Transition Metal-Catalyzed Hydroamination and Carboamination Reactions of Anthranyl Allenamides as a Route to 2-Vinyl- and 2-(α-Styryl)-quinazolin-4-one Derivatives ...
phdthesis{4b0cc7a0-c1e0-4225-a218-e36a1b47d5a5, abstract = {The centenarian Trögers base (TB) was envisaged as scaffold for the construction of tubular-shaped cleft molecules due to its the remarkable structural properties. This endeavor started with the synthesis of the three possible diastereomers of a linear symmetrically fused tris-TB analogue, the anti-anti, the syn-syn, and the syn-anti. All three diastereomers showed unprecedented stability to acid isomerization. The desymmetrization protocol presented, established the foundations for the synthesis of higher generations of fused analogues of TB.,br/,,br, Following this, new methodologies for the functionalization of both the aromatic and the methanodiazocine ring of TB were introduced. The development of a palladium-catalyzed amination conditions converted 2,8-dihalo analogues of TB to their corresponding mono- and diamino analogues. Regarding the diazocine ring, the benzylic methylenes of TB were oxidized to give the first example of a ...
Process chemistry is the arm of pharmaceutical chemistry concerned with the development and optimization of a synthetic scheme and pilot plant procedure to manufacture compounds for the drug development phase. Process chemistry is distinguished from medicinal chemistry, which is the arm of pharmaceutical chemistry tasked with designing and synthesizing molecules on small scale in the early drug discovery phase. Medicinal chemists are largely concerned with synthesizing a large number of compounds as quickly as possible from easily tunable chemical building blocks (usually for SAR studies). In general, the repertoire of reactions utilized in discovery chemistry is somewhat narrow (for example, the Buchwald-Hartwig amination, Suzuki coupling and reductive amination are commonplace reactions). In contrast, process chemists are tasked with identifying a chemical process that is safe, cost and labor efficient, "green," and reproducible, among other considerations. Oftentimes, in searching for the ...
ACS Amination and Hydrazine located into a single placement Water-preparation, but them are implemented into different cabinets CC1 and CC2, accordingly. Into each of the cabinets placed an individual controller, and the controller of ACS Hydrazine connected to local network through second interface of the controller of ACS Amination, where both of the interfaces connected to a Bridge. Main aim of the ACS Amination and Hydrazine is dosing transfer of ammonia and hydrazine-hydrate to the supply water, which performs by pumps connected through Frequency Converters (FC). Control by the FC performs from the PLC by the link interface RS-485 and the protocol ModBus/RTU.. ACS Phosphating divided to two parts. First part is presented by cabinet CC4 (placement of Central Heat Board) and into it installed PLC, and second part is presented by cabinet CC3 (placement of nonoperative contour of boiler #8) with a tray of Object Adjustment Devices (OAD) and frequency converters of pumps of ...
Hoeksema, B. (2013). Fungia dentigera Leuckart, 1841. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=207347 on 2018-01- ...
Targeted molecular imaging with hyaluronic acid (HA) has been highlighted in the diagnosis and treatment of CD44-overexpressing cancer. CD44, a receptor for HA, is closely related to the growth of cancer including proliferation, metastasis, invasion, and angiogenesis. For the efficient detection of CD44, we fabricated a few kinds of HA-modified MnFe2O4 nanocrystals (MNCs) to serve as specific magnetic resonance (MR) contrast agents (HA-MRCAs) and compared physicochemical properties, biocompatibility, and the CD44 targeting efficiency. Hydrophobic MNCs were efficiently phase-transferred using aminated polysorbate 80 (P80) synthesized by introducing spermine molecules on the hydroxyl groups of P80. Subsequently, a few kinds of HA-MRCAs were fabricated, conjugating different ratios of HA on the equal amount of phase-transferred MNCs. The optimized conjugation ratio of HA against magnetic content was identified to exhibit not only effective CD44 finding ability but also high cell viability through in vitro
SOLID-PHASE MODIFICATION WITH SUCCINIC POLYETHYLENEGLYCOL OF AMINATED LIPASE B FROM Candida antarctica: Effect of the immobilization protocol on enzyme catalytic properties ...
Magnetic Iron Oxide Nanocrystals in water coated with Dextran Available in following forms: Plain, Aminated (NH2), Carboxylated (-COOH), Avidin, Stretpavidin, Biotin, Protin A Size: 20 nm, 50 nm, 100 nm, 130 nm, 250 nm coated with Dextran: 20 nm, 50 nm, 100 nm, 130 nm, 250 nm online from Mknano.com.
The premise of reactions as sequential motions of electrons is a little too restrictive, at least how the authors interpret it. In the USPTO dataset that has been used previously by us [https://arxiv.org/abs/1709.04555] and Schwaller et al. [https://arxiv.org/abs/1711.04810], 27% of the reactions do not fit that premise. Its not obvious (without digging through the data set in greater detail) what exactly is lost in the 27% of these USPTO reactions. We pulled the first five test reactions that arenot in their subset and found a reductive amination, a total deprotection of a tertiary amine to a primary amine, a thioether oxidation to a sulfoxide, thiourea addition to an alkyl iodide, and an alkene ozonolysis to an aldehyde. So maybe not reactions you use every day, but these are certainly reactions one would want these systems to be able to predict. Still - if one is content to work under this premise, then the problem becomes much more structured. One can structure the models ability to make ...
Converted from rat to human using ortholog information, originally from KEGG. Originally edited by Sebastien Burel. This pathway describes the degradation of alanine and aspartate. Alanine is broken down by oxidative deamination, the inverse reaction of the reductive amination biosynthesis, catalyzed by the same enzymes. Proteins on this pathway have targeted assays available via the CPTAC Assay Portal ...
With regards to conjugation to KLH, Globo-H, MUC1-32mer, GM2, Lewis Y, Tn(c), STn(c), and TF(c) were covalently attached to KLH directly by reductive amination (GM2), using the 4-(4-maleimidomethyl) cyclohexane-1-carboxyl hydrazide heterobifunctional linker group (Globo-H and Lewis Y) and using the m-malemidobenzoyl-N-hydroxysuccinimide ester heterobifunctional linker group [MUC1, Tn(c), STn (c), and TF (c)] as described previously (18, 20-25, 29). The structures of these seven conjugates are summarized in Fig. 1. Antigen and adjuvant doses were selected based on previous phase 1 monovalent vaccine trials as follows: 3 μg Tn-MUC1-32mer (24), 10 μg Globo-H (15, 22), 10 μg GM2 (30), 10 μg Lewis Y (20), 3 μg Tn(c) (23), 3 μg STn(c), 3 μg TF(c) (18), and 100 μg QS21 (15, 30). These seven conjugates and QS21 were vialed together in 1 mL PBS. Vialed samples underwent testing for toxicity and immunogenicity in mice, as well as for sterility and endotoxin. Vaccines were given s.c. on weeks 1, 2, ...
A conjugate of polyL-lysine (PLL) with unsulfated dextran produced by reductive amination was found to have remarkable anti-HIV-1 activity against both the macrophage-tropic R5 virus Ba-L and T-cell line tropic X4 virus IIIB strains, although neither PLL nor dextran has such activity. The conjugate is a pseudoproteoglycan (pseudoPG) that simulates the structure of a proteoglycan. Conjugation with dextran was found to produce an antiviral effect in three kinds of assay systems including a human CD4(+) T-cell line, and the pseudoPG synthesized using 10 kDa PLL and 10 kDa dextran showed EC(50) 4-40 times lower than that of sulfated dextran or heparin against Ba-L and EC(50) equal to that against IIIB, indicating that PLL-dextran (PLL-Dex) was more effective against R5 virus than sulfated polysaccharides ...
Fluorescein isothiocyante (FITC) is frequently utilized as a fluorescent dye label for scientific research. This high affinity anti-FITC antibody is developed using FITC conjugated to KLH and affinity-purified with FITC-linked agarose. The affinity-purified anti-FITC is linked to HRP via reductive amination and is useful for detection of FITC-labeled molecules, such as proteins, peptides, or nucleic acids. ...
Affinity purified rabbit polyclonal anti-acetylated lysine antibody (anti-AcK) was developed using a unique technique that utilizes acetylated KLH as the immunogen. The purified antibody was conjugated to horseradish peroxidase (HRP) via reductive amination. Direct labelling of the primary antibody will avoid the use of secondary antibodies therefore eliminating the interference of the secondary antibody-conjugates ...
今日は昼休み中にRDKitのMMPAスクリプトをいじってました。 kzfmさんのブログを拝見させていただいたのがきっかけです。 RDKit_2013_03_2/Contrib/mmpa配下のrfag.pyの切断ルールをRECAP風にアレンジしてみました。 209行目以降 を とします。 これでエーテル、アミド、環状アミン、エステル、芳香環−芳香環、芳香族n−芳香環、スルフォンアミド、芳香環−N−芳香環(buchwald_amination)のボンドのサーチをかけてマッチした部分の結合に関わるアトムインデックスをゲッツします。 エーテルは飽和炭素ー酸素ー飽和炭素のインデックスをとるのでインデックスは前のペアと 後ろのペアを返すようにしました。 同様に芳香環−N−芳香環も同じです。 アミドやエステルはC(=O)N, C(=O
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Mechanistic pathways for the thermal decompn. of the solid-state energetic oxidizers ammonium dinitramide (ADN) and potassium dinitramide (KDN) are deciphered by carefully considering previously performed exptl. studies and using state of the art quantum chem. modeling of mol. clusters. Decompn. is governed by surface chem. processes, involving polarized (twisted) dinitramide anions of reduced stability. Under atm. and low-pressure conditions, the rate-detg. step for the decompn. of these dinitramide salts is the dissocn. into NO2 and NNO2- radicals. The activation barriers for these steps are estd. to be 30 and 36 kcal/mol for ADN and KDN, resp. The known stabilizing effect of water is explained by its hydrogen bonding ability, which counteracts polarization of surface dinitramides. The reactivity of ADN toward various chem. environments is likely explained through metastable decompn. radical intermediates. Donation of hydrogen bonds, antioxidant character, and basicity are properties believed to
The goal of the project is to identify and characterize populations at risk for developing pulmonary arterial hypertension (PAH). The project will establish a PAH subphenotype core cohort (CORE) to evaluate mechanistic pathways and test novel therapeutic agents. This core cohort serves as a resource for the Translational Program Project grant, Vascular Subphenotypes of Lung Disease (Mark Gladwin, PI). In order to construct the CORE, we have chosen to recruit COPD and HIV patients, two populations with advanced lung and systemic diseases that are enriched for PAH. We have selected these as prototypic conditions because: A) both COPD patients and HIV-infected patients develop PAH at a rate significantly greater than the general population, B) morbidity and mortality are greatly increased in dually-affected persons, C) mechanisms responsible for development of the PAH subphenotype are not well-understood, D) clinical and genetic characteristics of the subgroup with PAH are not known, and E) ...
The goal of the project is to identify and characterize populations at risk for developing pulmonary arterial hypertension (PAH). The project will establish a PAH subphenotype core cohort (CORE) to evaluate mechanistic pathways and test novel therapeutic agents. This core cohort serves as a resource for the Translational Program Project grant, Vascular Subphenotypes of Lung Disease (Mark Gladwin, PI). In order to construct the CORE, we have chosen to recruit COPD and HIV patients, two populations with advanced lung and systemic diseases that are enriched for PAH. We have selected these as prototypic conditions because: A) both COPD patients and HIV-infected patients develop PAH at a rate significantly greater than the general population, B) morbidity and mortality are greatly increased in dually-affected persons, C) mechanisms responsible for development of the PAH subphenotype are not well-understood, D) clinical and genetic characteristics of the subgroup with PAH are not known, and E) ...
30. Dengyou Zhang, Deju Ye, Enguang Feng, Jinfang Wang, Jianmei Shi, Hualiang Jiang, and Hong Liu. Highly alpha-Selective Synthesis of Sialyl Spirohydantoins by Regiospecific Domino Condensation/O®N Acyl Migration/N-Sialylation of Carbodiimides with Peracetylated Sialic Acid. J. Org. Chem. 2010, 75, 3552-3557.. 29. Lei Zhang, Deju Ye, Yu Zhou, Guannan Liu, Enguang Feng, Hualiang Jiang, and Hong Liu. Regioselective Synthesis of 3-Benzazepinones and Unexpected 5-Bromo-3-benzazepinones. J. Org. Chem. 2010, 75, 3671-3677.. 28. Xu Zhang, Yu Zhou, Hengshuai Wang, Diliang Guo, Deju Ye, Yungen Xu, Hualiang, Jiang, and Hong Liu. Silver-catalyzed intramolecular hydroamination of alkynes in aqueous media: efficient and regioselective synthesis for fused benzimidazoles. Green Chem. 2011, 13, 397-405.. 27. Deju Ye, Jinfang Wang, Dengyou Deng, Enguang Feng, Hualiang Jiang, and Hong Liu. Advances in O-Sialylation. Progress in Chemistry 2010, 22, 91-100.. 26. Xu Zhang, Yu Zhou, Hengshuai Wang, Diliang Guo, ...
Nowadays, biodiesel has become more attractive in the quest for a novel fuel source due to its environmental benefits and the biodegradable properties. Transesterification of Helianthus annuus (sunflower) seeds oil is one of methodsacci for producing biodiesel fuel. However, during this process, the impurities are frequently found in the synthesized biodiesel which degrades the quality of biodiesel. Therefore, a proper catalyst is required to obtain the high-quality biodiesel. In this study, a series of aminated polyethersulfone (PES- $$\mathrm{NH}_2$$ ) membranes was prepared as solid support for immobilized Mucor miehei lipase. Glutaraldehyde was used as a cross-linker agent in immobilization process to investigate the effect of spacer toward biodiesel production. Based on elemental analysis, lipase was successfully attached onto PES-
Functionalized nitrogen and oxygen heterocycles are an abundant class of compounds found throughout nature and the chemical industry. Their frequent use in biologically active molecules and as ligands for the metals involved in asymmetric catalysis has made these compounds attractive synthetic targets. The research that follows describes my contributions to alkene and allene difunctionalization catalyzed by copper(II) in the preparation of functionalized pyrrolidines and tetrahydrofurans. In chapter 1 a brief review of the current carboaminaiton literature is given before a new copper(II)-catalyzed carboamination reaction that gives 6-Azabicyclo[3.2.1]octanes is discussed. These bridged bicyclic products are formed in a single step from N-sulfonyl-2-aryl-4-pentenamines. Over a range of sulfonyl protecting groups and aryl substituents, the resulting heterocycles were generally formed in good yields with good to excellent enantiomeric excess (ee). Both substrate desymmeterization and reaction ...
Catalytic Hydroamination of Alkynes and Alkenes. Zhi-Yong,Han 14.Nov.,2009. Introduction Mechanistic Aspects Selected Reactions Involving Hydroamination. 1. Introduction. Problems:. slightly exothermic. but. a high reaction barrier. entropically negative. Amines: nucleophilic Slideshow 4750702 by idania
Amination[edit]. An important reaction is the conversion of hydroquinone to the mono- and diamino derivatives. ...
Reductive amination[edit]. Acetone can be transformed into isopropylamine as follows:[citation needed] ... Ammonium formate can be used for reductive amination of aldehydes and ketones (Leuckart reaction), by the following reaction:[3 ...
Deng, Guojun; Wenwen Chen; Chao-Jun Li (February 2009). "An Unusual Peroxide-Mediated Amination of Cycloalkanes with ...
Kumar A, Sharma S, Maurya RA (2010). "Single Nucleotide-Catalyzed Biomimetic Reductive Amination". Advanced Synthesis and ...
doi:10.1016/S0040-4039(00)83958-1. Erdik, E.; Ay, M. (1989). "Electrophilic amination of carbanions". Chemical Reviews. 89 (8 ... can behave as an electrophile at the nitrogen atom and react with a nucleophile as for example in the electrophilic amination ...
The rate of amination for three azoles proceeds quickest to slowest as follows: 1-methylbenzimidazole > 1-methylnaphth-[2,3-d] ... Amination Chichibabin, A. E.; Zeide, O. A. (1914). "[New Reaction for Compounds Containing the Pyridine Nucleus]". Zhur. Russ. ... The following is the overall form of the general reaction: The direct amination of pyridine with sodium amide takes place in ... For thermodynamically controlled additions, the rate of amination is related to the stability of the σ-adduct. Ease of hydride ...
Huber, Claudia; Günter Wächtershäuser (February 2003). "Primordial reductive amination revisited". Tetrahedron Letters. 44 (8 ...
Fernandez, E.; Maeda, K.; Hooper, M.W.; Brown, J.M. (2000). "Catalytic Asymmetric Hydroboration/Amination and Alkylamination ... "Catalytic asymmetric hydroboration-amination". Chemical Communications (2): 173. doi:10.1039/A606827H. ...
Amination of poly(styryl)lithium". Macromolecules. 19 (5): 1291-1294. Bibcode:1986MaMol..19.1291Q. doi:10.1021/ma00159a001. ...
Reductive amination Forster, Martin Onslow (1899). "XCI.-Influence of substitution on specific rotation in the bornylamine ...
Amination of Secondary C−H Bonds". Angewandte Chemie International Edition. 55 (34). doi:10.1002/anie.201604704/abstract. ISSN ... strategy that expands the scope of the Hofmann-Löffler-Freytag reaction via the Suárez modification to enable the amination of ...
Since then, this ligand has been utilized in multiple reactions including the amination of a wide range of aryl halides and ... XPhos was first used in 2003 for the general amination and amidation of arenesulfonates and aryl halides. XPhos has also been ... BrettPhos was originally reported in 2008 for the Pd-catalyzed amination of aryl mesylates and aryl halides. This ligand helps ... Charles, Mark D.; Schultz, Phillip; Buchwald, Stephen L. (1 September 2005). "Efficient Pd-Catalyzed Amination of Heteroaryl ...
Johnson, Jeffrey S.; Berman, Ashley M. (2005-07-01). "Nickel-Catalyzed Electrophilic Amination of Organozinc Halides". Synlett ... precatalysts also promote the amination of aryl chlorides, sulfamates, mesylates, and triflates. The nickel catalyst, (dppf)Ni( ... "Development of an Air-Stable Nickel Precatalyst for the Amination of Aryl Chlorides, Sulfamates, Mesylates, and Triflates". ...
... and α-amination… [reactions] of carbonyl compounds. In the literature, this reaction has been referred to by different names: [ ...
Klages, Claus-Peter; Alena Hinze; Peter Willich; Michael Thomas (2010). "Atmospheric-Pressure Plasma Amination of Polymer ...
Müller, T. E. Beller, M. (1998). "Metal-Initiated Amination of Alkenes and Alkynes". Chemical Reviews. 98 (2): 675-704. doi: ... doi:10.1016/s0957-4166(03)00429-4. Müller, Thomas E.; Beller, Matthias (1 April 1998). "Metal-Initiated Amination of Alkenes ... Koller, Jürgen; Bergman, Robert G. (22 November 2010). "Highly Efficient Aluminum-Catalyzed Hydro-amination/-hydrazination of ... catalytic amination of monoolefins". Journal of Molecular Catalysis. 49 (3): 235-259. doi:10.1016/0304-5102(89)85015-1. Johns, ...
Paradine, SM & White, MC (2012). "Iron-Catalyzed Intramolecular Allylic C-H Amination". Journal of the American Chemical ... most recent being the White catalyst's dehydrogenative Diels-Alder reaction and the iron-mediated intramolecular C-H amination ...
... electrophilic amination. Hassner's group pioneered in methodology for synthesis of small ring heterocycles such as aziridines, ...
Barrault, J.; Pouilloux, Y. (1997). "Catalytic Amination Reactions: Synthesis of fatty amines. Selectivity control in presence ...
Abdel-Magid, A. F.; Mehrman, S. J. (2006). "A Review on the Use of Sodium Triacetoxyborohydride in the Reductive Amination of ... Pandit, C. R.; Mani, N. S. (2009). "Expedient reductive amination of aldehyde bisulfite adducts". Synthesis (23): 4032-4036. ... Studies on Direct and Indirect Reductive Amination Procedures1". The Journal of Organic Chemistry. 61 (11): 3849-3862. doi: ... Sodium triacetoxyborohydride is especially suitable for reductive aminations of aldehydes and ketones. However, unlike sodium ...
Pyrimidine biosynthesis Lieberman I (1956). "Enzymatic amination of uridine triphosphate to cytidine triphosphate". The Journal ...
It is especially favored for reductive aminations, wherein aldehydes or ketones are treated with an amine in the presence of ... Selectivity is achieved at mildly basic solutions (pH 7-10). The reagent is ideal for reductive aminations ("Borch Reaction"). ... doi:10.1002/047084289X.rs059.pub2 Ellen W. Baxter, Allen B. Reitz Reductive Aminations of Carbonyl Compounds with Borohydride ... The commercial samples can be purified but the yields of the reductive aminations do not improve. Sodium triacetoxyborohydride ...
Kretovich VL, Stepanovich KM (1966). "[The enzyme catalyzing the reductive amination of oxypyruvate]". Izv. Akad. Nauk. SSSR. ...
In the N-amination of the unsubstituted tetrazole, a mixture of 1-amino- and 2-aminotetrazole is obtained. Also sulfur ... T.M. Klapötke; D.G. Piercey; J. Stierstorfer (2012). "Amination of energetic anions: high-performing energetic materials". ... N-amination of 1H-benzotriazole with hydroxylamine-O-sulfonic acid yields a mixture of 1-aminobenzotriazole (major product) and ...
Arylation, amination, and chlorination of benzylamines were also realized in March 2017. Wang, Xiao-Chen; Gong, Wei; Fang, Li- ... In October 2016, meta-C−H amination, alkynylation, as well as chlorination of aniline and phenol substrates were reported by Yu ... "Ligand-Promoted meta-C-H Amination and Alkynylation". Journal of the American Chemical Society. 138 (42): 14092-14099. doi: ...
Amination is the process by which an amine group is introduced into an organic molecule. This type of reaction is important ... Amination can occur in a number of ways including reaction with ammonia or another amine such as an alkylation, reductive ... In electrophilic amination, the amine as the nucleophile react with another the organic compound as the electrophile. This ... Many alkyl amines are produced industrially by the amination of alcohols using ammonia in the presence of acid catalysts. ...
Reductive amination (also known as reductive alkylation) is a form of amination that involves the conversion of a carbonyl ... ISBN 1-57259-153-6. Current methods for reductive amination Industrial Reductive amination at BASF. ... A step in the biosynthesis of many α-amino acids is the reductive amination of an α-ketoacid, usually by a transaminase enzyme ... This approach, known as direct reductive amination, employs reducing agents that are more reactive toward protonated imines ...
In particular, the processes provide for the reductive amination of 6-keto morphinans by cat ... Reductive amination of 6-keto normorphinans by catalytic hydrogen transfer. 2013-06-25. Grote et al.. 546/74. ... Remove Amination of 6-Keto Normorphinans by Catalytic Hydrogen Transfer. 2010-12-16. Grote et al.. ... The process involves the transformation of a 6-keto moiety of a morphinan to a 6-amino moiety by reductive amination in a ...
A rhodium-catalyzed amination reaction of aryl halides with amines takes place in the presence of a N-heterocyclic carbene ... The [RuCl2(p-cymene)]2/Ph2SiH2 catalytic system is very efficient for the reductive amination of aldehydes with anilines to ... Regioselective amination of unsymmetrical diaryl sulfoxides was also executed by means of steric bias.. Y. Yoshida, S. Otsuka, ... This amination tolerates a wide range of functional groups such as silyl, boryl, methylsulfanyl, and halogen moieties. ...
The selectivity of the amination of 2,6-dichloroquinoline was very low, substantially better results were obtained with 2,8- ... dichloroquinoline, and 4,8- and 4,7-dichloroquinolines provided the best yields of the amination products. Diamination of 4,8- ... Pd-catalyzed amination of isomeric 2,6-, 2,8-, 4,8- and 4,7-dichloroquinolines was studied using adamantane-containing amines ... Keywords: amines; adamantane; Pd catalysis; amination; quinoline amines; adamantane; Pd catalysis; amination; quinoline ...
Complex N-Heterocycle Synthesis via Iron-Catalyzed, Direct C-H Bond Amination ... Complex N-Heterocycle Synthesis via Iron-Catalyzed, Direct C-H Bond Amination ... Complex N-Heterocycle Synthesis via Iron-Catalyzed, Direct C-H Bond Amination ... Complex N-Heterocycle Synthesis via Iron-Catalyzed, Direct C-H Bond Amination ...
The DPEphos ligand is superior to DPPF in the case of palladium-catalyzed benzylic amination of benzylic esters.. R. Kuwano, Y ... A protocol for the dehydrative amination of alcohols in water using a water-soluble calix[4]resorcinarene sulfonic acid as a ... Nickel nanoparticles catalyse the reductive amination of aldehydes by transfer hydrogenation with isopropanol at 76 C.. F. ... Aromatic aldehydes can be converted to α-amino anion equivalents via amination with 2,2-diphenylglycine and subsequent ...
One of the most attractive strategies is the stereoselective installation of a chiral amine through C H amination, which is a ... Whole-​cell biocatalysts for stereoselective C-H amination reactions. Journal. Angewandte Chemie, International Edition. Volume ... benzylic aminations with ee values of 97.5 %. The cascade uses four heterologously expressed recombinant enzymes with cofactors ... cell biocatalyst for formal stereoselective C H amination. ...
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Ruthenium-catalyzed conversion of levulinic acid to pyrrolidines by reductive amination.. [Yao-Bing Huang, Jian-Jun Dai, Xiao- ...
... amination, hydrazination, hydroxyamination and related α-heteroatom functionalization of aldehydes, ketones and related active ... Organocatalytic asymmetric α-oxidation and amination reactions of carbonyl compounds are highly useful synthetic methodologies ... Organocatalyzed Asymmetric α-Oxidation, α-Aminoxylation and α-Amination of Carbonyl Compounds. Tirayut Vilaivan * and Worawan ... "Organocatalyzed Asymmetric α-Oxidation, α-Aminoxylation and α-Amination of Carbonyl Compounds." Molecules 15, no. 2: 917-958. ...
... more environmentally conservative solvents have been evaluated for use within the direct reductive amination reactions of ... reductive amination. processes Fiona I. McGonagle,a Donna S. MacMillan,a Jane Murray,b Helen F. Sneddon,c Craig Jamiesona and ... reductive amination. processes F. I. McGonagle, D. S. MacMillan, J. Murray, H. F. Sneddon, C. Jamieson and A. J. B. Watson, ... have been evaluated for use within the direct reductive amination reactions of aldehydes. using borane. -based reductants. The ...
This is known as direct reductive amination and is carried out with reducing agents that are more reactive toward protonated ... Reductive amination involves the conversion of a carbonyl group, most of the time a ketone or an aldehyde, to an amine via an ... Reductive amination involves the conversion of a carbonyl group, most of the time a ketone or an aldehyde, to an amine via an ... This is known as direct reductive amination and is carried out with reducing agents that are more reactive toward protonated ...
Formation and speciation of disinfection byproducts during chlor(am)ination of aquarium seawater.. [Haiting Zhang, Huiyu Dong, ...
A Seminal Supported Resin for Reductive Amination. 18 April 2016 Biotage® MP-Triacetoxyborohydride is a macroporous polystyrene ... The resin has primary applications in the reductive amination of aldehydes and ketones under neutral or mildly acidic reaction ... Sodium triacetoxyborohydride has emerged as one of the reagents used most frequently for carrying out reductive amination of ...
Lamani, M. and Prabhu, K. R. (2012), NIS-Catalyzed Reactions: Amidation of Acetophenones and Oxidative Amination of ...
... palladium-catalyzed allylic alkylation reactions and a method for visible light-mediated radical decarboxylative amination. ...
Among the best-performing homogeneous catalysts for the direct amination of activated secondary alcohols with electron-poor ... Direct Amination of Alcohols Catalyzed by Aluminum Triflate: An Experimental and Computational Study. ... Among the best-performing homogeneous catalysts for the direct amination of activated secondary alcohols with electron-poor ...
Amination at the β-position of 2-arylpropionitriles through catalytic dehydrogenation occurred by using [PdCl2(PMe3)2] catalyst ...
It is very useful in reductive amination and in the reduction of imines. Cyanide contamination of the product is a concern when ... Reductive Amination - Use Of SiliaBond® Cyanoborohydride. SiliaBond® Cyanoborohydride is the silica bound equivalent of sodium ... It is very useful in reductive amination and in the reduction of imines. Cyanide contamination of the product is a concern when ...
Angewandte Chemie Iron-Mediated Aminations Intramolecular Aromatic Amination through Iron-Mediated Nitrene Transfer** Michael P ... Intramolecular Aromatic Amination through Iron-Mediated Nitrene Transfer.. код для вставки. код для вставки на сайт или в блог ... Scheme 2. Common mechanism for observed NIH shifts in the hydroxylation and amination reactions; L is presumably CH3CN. Angew. ... and even aromatic amination, are clearly implied. Moreover, the apparent generation of an imidoiron(iv) species suggests the ...
Solvent-Free Amination of Heteroaromatic Chlorides. Author(s): Erwan Le Gall, Stephane Sengmany, Corinne Gosmini, Jacques ... Keywords:Amination, heteroaromatic chlorides, solvent-free reaction. Abstract: The coupling of 5-membered heterocyclic amines ... Erwan Le Gall, Stephane Sengmany, Corinne Gosmini, Jacques Perichon and Pascal Retailleau, " Solvent-Free Amination of ...
Reductive amination of butanal and methyl ethyl ketone (MEK) with ammonia (at ammonia/MEK molar ratios of ~ 14.5) and hydrogen ... Mass Transfer Rates During Three Phase Catalytic Reductive Amination over Supported Noble Metals. Domenii publicaţii > Chimie ... Rhodium and platinum based catalysts showed the highest activity in reductive amination of butanal and MEK. The rhodium ... Cuvinte cheie: Reductive amination, Butanal, Methyl ethyl ketone, Noble metal catalysts, Mass transfer ...
Catalytic amination of isopropanolamine and ammonia to 1,2-propanediamine over Raney Ni with potassium carbonate as the ... Li Y, Cheng H, Zhang C, Zhang B, Liu T, Wu Q, Su X, Lin W, Zhao F (2017) Reductive amination of 1,6-hexanediol with Ru/Al2O3 ... Zhang Y, Bai G, Yan X, Li Y, Zeng T, Wang J, Wang H, Xing J, Luan D, Tang X, Chen L (2007) Amination of ethanolamine over ... Wang W, Yu Q, Zhang Q, Mei S, Yuan J, Zhao F, Yang J, Lu J (2017) Reductive amination of 2-amino-2-methyl-1-propanol and ...
C-H amination transition metal catalysis organic chemistry. Abstract:. Nitrogen functionality is ubiquitous in biologically ... In seeking to expand the scope of this C-H amination methodology, we were struck by a clear divergence in the literature ... C(sp3)-H aminations under first row transition metal catalysis. Welcome to the IDEALS Repository. ... C-H amination represents a powerful alternative synthetic strategy. This approach involves the direct functionalization of ...
  • The first chapter of this dissertation describes the development of the first synthetically useful C-H amination method under iron catalysis. (illinois.edu)
  • for allylic C-H amination over a range of olefin classes and exhibiting site-selectivity trends that are orthogonal to those observed under rhodium catalysis. (illinois.edu)
  • Graphical abstract FeSO + CrCl 4 3 Oxidation-precipitation Cr-Fe O 3 4 NH NH + H O 3 2 2 Keywords C(sp )-H activation Radicals Cr-doped magnetite Catalytic amination Metals Heterogeneous catalysis Introduction bonds, which broadens the synthetic approach to organic synthesis. (deepdyve.com)
  • Moreover, the reactivity of such a cobalt catalysis could be diverted from C-H fluorination to amination by engineering substrates' conformational flexibility. (chem8.org)
  • The resin has primary applications in the reductive amination of aldehydes and ketones under neutral or mildly acidic reaction conditions. (biotage.com)
  • Ene reaction was accomplished via addition of PhTAD to the allylic position to react with syn and anti diastereomers for α-amination. (deepdyve.com)
  • The paradigm proposed herein for the exploitation of vinyl cations will also open up new vistas in the centuries-old aldol reaction and in amination chemistry. (thefreedictionary.com)
  • Two different reaction schemes are illustrated in Figure 2 and Figure 3 [14, where the common end-group forms of PEG-PLA derivatives include hydroformylation, propylene acylation, and amination . (thefreedictionary.com)
  • This reaction is exploited en route to popular antioxidants such as 2-tert-butyl-4-methoxyphenol ( "BHA" ). (wikipedia.org)
  • Reductive amination employing sodium triacetoxyborohydride instead of sodium cyanoborohydride was found to give shorter reaction times and much safer byproducts. (rit.edu)
  • Here we have demonstrated that a single point mutation in the active site of the (S)-selective ω-TA from Ochrobactrum anthropi could induce a remarkable acceleration of the amination reaction without any loss in stereoselectivity and enzyme stability. (elsevier.com)
  • Over the last two decades many different auxiliary ligand systems have been utilized in the copper-catalyzed Ullmann amination reaction. (imperial.ac.uk)
  • The Pd Catalyzed Amination Kits are ideal tools for the investigation of cross-coupling reaction conditions. (thomassci.com)
  • An efficient TA-catalyzed amination depends on the removal or recycling of the co-product to shift the reaction equilibrium towards the product side. (biomedcentral.com)
  • Amination-reduction reaction as simple protocol for potential boronic molecular receptors. (edu.pl)
  • The synthesis of the potential molecular receptors in the amination-reduction reaction has been investigated within the model system comprising (2-formylphenyl)boronic acid and morpholine. (edu.pl)
  • Both basic and acidic impurities were extracted separately and analysed by GC-MS. From this controlled study, two route specific impurities for the Leuckart method and one route specific impurity for the reductive amination method are reported. (strath.ac.uk)
  • A reductive amination method was developed for the tagging of sugars with the aim of it becoming part of a metabolomics work flow. (strath.ac.uk)
  • Fischer A, Maciejewski M, Burgi T, Mallat T, Baiker A (1999a) Cobalt-catalyzed amination of 1,3-propanediol: effects of catalyst promotion and use of supercritical ammonia as solvent and reactant. (springer.com)
  • Fischer A, Mallat T, Baiker A (1999d) Continuous amination of propanediols in supercritical ammonia. (springer.com)
  • Jenzer G, Mallat T, Baiker A (1999) Cobalt-catalyzed amination of 1,3-cyclohexanediol and 2,4-pentanediol in supercritical ammonia. (springer.com)
  • Main aim of the ACS 'Amination' and 'Hydrazine' is dosing transfer of ammonia and hydrazine-hydrate to the supply water, which performs by pumps connected through Frequency Converters (FC). (oscada.org)
  • Kos, NJ & van der Plas, HC 1980, ' Occurrence of the SN(ANRORC) Mechanism in the Amination of 2-Substituted Purines with Potassium Amide in Liquid Ammonia ', Journal of Organic Chemistry , vol. 45, pp. 2942-2945. (wur.nl)
  • One of the most attractive strategies is the stereoselective installation of a chiral amine through C H amination, which is a challenging chemical transformation. (uva.nl)
  • Erwan Le Gall, Stephane Sengmany, Corinne Gosmini, Jacques Perichon and Pascal Retailleau, " Solvent-Free Amination of Heteroaromatic Chlorides", Letters in Organic Chemistry (2008) 5: 120. (eurekaselect.com)
  • P. Stavropoulos, "Metal-Catalyzed and Metal-Free Intermolecular Amination of Light Alkanes and Benzenes," Comments on Inorganic Chemistry , vol. 37, no. 1, pp. 1-57, Taylor & Francis Inc., Jan 2017. (mst.edu)
  • Liu, PM, Magar, DR & Chen, K 2010, ' Highly efficient and practical pyrrolidine-camphor-derived organocatalysts for the direct α-amination of aldehydes ', European Journal of Organic Chemistry , no. 29, pp. 5705-5713. (ntnu.edu.tw)
  • We have developed an iron-dipyrrinato catalyst that leverages the reactivity of iron-borne metal-ligand multiple bonds to promote the direct amination of aliphatic C-H bonds. (sciencemag.org)
  • We sought to exploit the exquisite chemoselectivity of first row transition metals in order to develop a small molecule C-H amination catalyst that was truly general. (illinois.edu)
  • The second chapter of this dissertation describes the discovery and development of [Mn(tBuPc)], a novel manganese catalyst that for the first time is able to effectively functionalize all types of sp3 C-H bonds with preparative product yields (>50%) even for very strong 2° and 1° aliphatic C-H bonds, while maintaining excellent chemoselectivity for C-H amination (>20:1) in the presence of readily oxidizable π-bonds. (illinois.edu)
  • The authors here describe a direct reductive amination procedure using a oxo-rhenium catalyst and silanes as the hydride source. (blogspot.com)
  • Nitrene insertions to give aliphatic CH bond aminations have also been effected by metalloporphyrins or cytochrome P450. (docme.ru)
  • Such structures are frequently based on terpenoid or steroidal skeletons, though some relatively simple alkaloids also appear to be derived by similar late amination processes. (biocyclopedia.com)
  • This account focuses on the oxidative intramolecular Pd(II)-catalyzed amination of unsaturated N-sulfonyl carbamates and carboxamides, revealing that different mechanistic paths can be operative. (teknoscienze.com)
  • Palladium catalyzed oxidative aminations and oxylations: where are we? (degruyter.com)
  • The excitation of a RuII photosensitizer in the presence of ascorbic acid leads to the reduction of iminium ions to electron‐rich α‐aminoalkyl radical intermediates, which are rapidly converted into reductive amination products by thiol‐mediated hydrogen atom transfer (HAT). (unibas.ch)
  • A step in the biosynthesis of many α-amino acids is the reductive amination of an α-ketoacid, usually by a transaminase enzyme. (wikipedia.org)
  • With less sterically hindered a-amino acids, direct reductive amination generally yielded the bisalkylated product. (rit.edu)
  • In general, the amino groups can be divided into two types with the one is reductive amination and the other one is aminolysis. (science-marketplace.org)
  • The direct synthesis of N-substituted 3-amino-4-halopyridines is problematic, as reductive aminations and base-promoted alkylations are difficult in these systems. (syr.edu)
  • On the one hand the fermentative amination of α-ketoacids coupled both with metabolic and non-metabolic cofactor regeneration was studied, giving access to the corresponding α-amino acids in up to 96% conversion. (biomedcentral.com)
  • Copper-catalyzed α-amination of phosphonates and phosphine oxides: a direct approach to α-amino phosphonic acids and derivatives. (duke.edu)
  • Substoichiometric and unselective naphthalene amination by an uncharacterized adduct of iron(ii) chloride and chloramine-T has been reported, along with a handful of possibly analogous organometallic ligand transformations. (docme.ru)
  • Further research in this area is directed towards other methods for amination and diamination of carbon-carbon double and triple bonds, as well as the selective introduction of more complex nitrogen-containing functional groups, such as nitroso and nitro groups. (washington.edu)
  • However, they are poorly chemoselective in the presence of π-functionality such as olefins and alkynes, and direct addition to these π-bonds is often competitive with desired C-H amination reactivity. (illinois.edu)
  • The mechanism of direct amination of allyl alcohol by a palladium triphenylphosphite complex has been explored. (diva-portal.org)
  • Mannich, reductive amination) often rely on pre-existing functionality and require additional transformations such as oxidation state changes and/or protecting group maniuplations. (illinois.edu)