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Amination Reactions (amination + reaction)

Distribution by Scientific Domains

Chemistry	96%

Selected Abstracts

A Pronounced Anionic Effect in the Pd-Catalyzed Buchwald,Hartwig Amination Reaction Revealed in Phosphonium Salt Ionic Liquids

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 9 2007
James McNulty
Abstract The Pd-mediated Buchwald,Hartwig amination reaction of aryl halides in a phosphonium salt ionic liquid consisting of a trihexyl(tetradecyl)phosphonium cation with a range of anions has been investigated. A pronounced anionic effect was uncovered with the reaction proceeding readily with weakly nucleophilic diarylamines only in the presence of noncoordinating anions. A mechanism is postulated to explain these results and it involves a rate-limiting ligand exchange step that proceeds through a dissociative pathway.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]

ChemInform Abstract: Palladium-Catalyzed Tandem Amination Reaction for the Synthesis of 4-Quinolones.

CHEMINFORM, Issue 23 2010
Tiankun Zhao
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

ChemInform Abstract: A New Approach to 3-Substituted Indoles Through Palladium-Catalyzed C,H Activation Followed by Intramolecular Amination Reaction of Enamines.

CHEMINFORM, Issue 17 2009
Kiyofumi Inamoto
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

ChemInform Abstract: Efficient Synthesis of 1-Aryl-1H-indazole Derivatives via Copper(I)-Catalyzed Intramolecular Amination Reaction.

CHEMINFORM, Issue 26 2008
Rui Liu
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

ChemInform Abstract: One-Pot Synthesis of Carbazole via Tandem Suzuki,Miyaura and Amination Reaction.

CHEMINFORM, Issue 22 2008
Yuki Kitamura
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Modification of the Titanium(IV) Isopropoxide Reductive Amination Reaction: Application to Solid Phase Synthesis.

CHEMINFORM, Issue 48 2005
John C. DiCesare
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Diastereoselective Synthesis of Substituted 2,3,4,5-Tetrahydro-1H-1-benzazepine-5-carboxylic Esters by a Tandem Reduction-Reductive Amination Reaction.

CHEMINFORM, Issue 52 2004
Richard A. Bunce
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Palladium-Catalyzed Aryl Amination Reactions of 6-Bromo- and 6-Chloropurine Nucleosides

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2010

Abstract Palladium-catalyzed CN bond forming reactions of 6-bromo- as well as 6-chloropurine ribonucleosides and the 2,-deoxy analogues with arylamines are described. Efficient conversions were observed with palladium(II) acetate/Xantphos/cesium carbonate, in toluene at 100,°C. Reactions of the bromonucleoside derivatives could be conducted at a lowered catalytic loading [5,mol% Pd(OAc)2/7.5,mol% Xantphos], whereas good product yields were obtained with a higher catalyst load [10,mol% Pd(OAc)2/15,mol% Xantphos] when the chloro analogue was employed. Among the examples evaluated, silyl protection for the hydroxy groups appears better as compared to acetyl. The methodology has been evaluated via reactions with a variety of arylamines and by synthesis of biologically relevant deoxyadenosine and adenosine dimers. This is the first detailed analysis of aryl amination reactions of 6-chloropurine nucleosides, and comparison of the two halogenated nucleoside substrates. [source]

ChemInform Abstract: Preparation and Characterization of Cobalt-Containing P,N-Ligands and an Unusual Palladium Complex Ion Pair: Their Applications in Amination Reactions.

CHEMINFORM, Issue 7 2009
You-Chen Hsiao
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Triazole-Based Monophosphines for Suzuki,Miyaura Coupling and Amination Reactions of Aryl Chlorides.

CHEMINFORM, Issue 10 2006
Duan Liu
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

Recyclable Polymer-Supported Pd Catalysts for Aryl Amination Reactions.

CHEMINFORM, Issue 3 2006
Meritxell Guino
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Scope and Limitations of Pd2(dba)3/P (i-BuNCH2CH2)3N-Catalyzed Buchwald,Hartwig Amination Reactions of Aryl Chlorides.

CHEMINFORM, Issue 20 2005
Sameer Urgaonkar
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Solvent-Free Amination Reactions of Aryl Bromides at Room Temperature Catalyzed by a (,-Allyl)palladium Complex Bearing a Diphosphinidenecyclobutene Ligand.

CHEMINFORM, Issue 4 2005
Anil S. Gajare
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

ChemInform Abstract: Amination Reactions of Aryl Halides with Nitrogen-Containing Reagents Mediated by Palladium/Imidazolium Salt Systems.

CHEMINFORM, Issue 18 2002
Gabriela A. Grasa
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

A Pronounced Anionic Effect in the Pd-Catalyzed Buchwald,Hartwig Amination Reaction Revealed in Phosphonium Salt Ionic Liquids

Palladium-Catalysed Amination of Electron-Deficient or Relatively Electron-Rich Benzo[b]thienyl Bromides , Preliminary Studies of Antimicrobial Activity and SARs

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 17 2004
Maria-João R. P. Queiroz
Abstract Several diarylamines in the benzo[b]thiophene series were prepared in good to high yields by palladium-catalysed amination of ethyl 3-bromobenzo[b]thiophene-2-carboxylate with anilines and 5-aminoindole in the presence of Pd(OAc)2, BINAP and Cs2CO3 in toluene. The presence of the ester group at the 2-position of the benzo[b]thiophene moiety increases the yields and lowers the heating times relative to the reactions performed with 3-bromobenzo[b]thiophene. When aminopyridines were used instead of anilines, the ligand and the solvent need to be changed to XANTHPHOS and dioxane in the amination reaction. With 2-aminopyridine a one-pot C,N coupling and intramolecular cyclization involving the nitrogen atom of the pyridine ring occurred, with loss of ethanol, giving an interesting fluorescent tetracyclic heteroaromatic compound. The antimicrobial activity, the minimal inhibitory concentrations (MICs) and the structure-activity relationships (SARs) were evaluated. A selectivity with low MICs was observed against Bacillus Cereus, and good results were also obtained against Candida albicans. The acids obtained by hydrolysis of the ester group, as non-proteinogenic ,,,-unsaturated ,-amino acids, can be incorporated into peptide chains to induce conformational constraints. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]

Conversion of a glutamate dehydrogenase into methionine/norleucine dehydrogenase by site-directed mutagenesis

FEBS JOURNAL, Issue 22 2001
Xing-Guo Wang
In earlier attempts to shift the substrate specificity of glutamate dehydrogenase (GDH) in favour of monocarboxylic amino-acid substrates, the active-site residues K89 and S380 were replaced by leucine and valine, respectively, which occupy corresponding positions in leucine dehydrogenase. In the GDH framework, however, the mutation S380V caused a steric clash. To avoid this, S380 has been replaced with alanine instead. The single mutant S380A and the combined double mutant K89L/S380A were satisfactorily overexpressed in soluble form and folded correctly as hexameric enzymes. Both were purified successfully by Remazol Red dye chromatography as routinely used for wild-type GDH. The S380A mutant shows much lower activity than wild-type GDH with glutamate. Activities towards monocarboxylic substrates were only marginally altered, and the pH profile of substrate specificity was not markedly altered. In the double mutant K89L/S380A, activity towards glutamate was undetectable. Activity towards l -methionine, l -norleucine and l -norvaline, however, was measurable at pH 7.0, 8.0 and 9.0, as for wild-type GDH. Ala163 is one of the residues that lines the binding pocket for the side chain of the amino-acid substrate. To explore its importance, the three mutants A163G, K89L/A163G and K89L/S380A/A163G were constructed. All three were abundantly overexpressed and showed chromatographic behaviour identical with that of wild-type GDH. With A163G, glutamate activity was lower at pH 7.0 and 8.0, but by contrast higher at pH 9.0 than with wild-type GDH. Activities towards five aliphatic amino acids were remarkably higher than those for the wild-type enzyme at pH 8.0 and 9.0. In addition, the mutant A163G used l -aspartate and l -leucine as substrates, neither of which gave any detectable activity with wild-type GDH. Compared with wild-type GDH, the A163 mutant showed lower catalytic efficiencies and higher Km values for glutamate/2-oxoglutarate at pH 7.0, but a similar kcat/Km value and lower Km at pH 8.0, and a nearly 22-fold lower S0.5 (substrate concentration giving half-saturation under conditions where Michaelis,Menten kinetics does not apply) at pH 9.0. Coupling the A163G mutation with the K89L mutation markedly enhanced activity (100,1000-fold) over that of the single mutant K89L towards monocarboxylic amino acids, especially l -norleucine and l -methionine. The triple mutant K89L/S380A/A163G retained a level of activity towards monocarboxylic amino acids similar to that of the double mutant K89L/A163G, but could no longer use glutamate as substrate. In terms of natural amino-acid substrates, the triple mutant represents effective conversion of a glutamate dehydrogenase into a methionine dehydrogenase. Kinetic parameters for the reductive amination reaction are also reported. At pH 7 the triple mutant and K89L/A163G show 5 to 10-fold increased catalytic efficiency, compared with K89L, towards the novel substrates. In the oxidative deamination reaction, it is not possible to estimate kcat and Km separately, but for reductive amination the additional mutations have no significant effect on kcat at pH 7, and the increase in catalytic efficiency is entirely attributable to the measured decrease in Km. At pH 8 the enhancement of catalytic efficiency with the novel substrates was much more striking (e.g. for norleucine ,,2000-fold compared with wild-type or the K89L mutant), but it was not established whether this is also exclusively due to more favourable Michaelis constants. [source]

An Unusual Peroxide-Mediated Amination of Cycloalkanes with Nitroarenes

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 3 2009
Guojun Deng
Abstract A direct amination of simple cycloalkanes with nitroarenes mediated by peroxides has been discovered. Various secondary arylamines were obtained efficiently from cycloalkanes. The reaction tolerates a wide range of functionalities as well as aqueous conditions. No metal was required for this novel amination reaction. [source]

Synthesis and properties of nitrogen-linked poly(2,7-carbazole)s as hole-transport material for organic light emitting diodes

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2009
Tsuyoshi Michinobu
Abstract A novel class of carbazole polymers, nitrogen-linked poly(2,7-carbazole)s, was synthesized by polycondensation between two bifunctional monomers using the palladium-catalyzed amination reaction. The polymers were characterized by 1H NMR, Infrared, Gel permeation chromatography, and MALDI-TOF MS and it was revealed that the combination of the monomer structures is important for producing high molecular weight polymers. Thermal analysis indicated a good thermal stability with high glass transition temperatures, e.g., 138 °C for the higher molecular weight polymer P2. To pursue the application possibilities of these polymers, their optical properties and energy levels were investigated by UV-Vis absorption and fluorescence spectra as well as their electrochemical characteristics. Although the blue light emission was indeed observed for all polymers in solution, the quantum yields were very low and the solid films were not fluorescent. On the other hand, the HOMO levels of the polymers estimated from the onset potentials for the first oxidation in the solid thin films were relatively high in the range of ,5.12 to ,5.20 eV. Therefore, light emitting diodes employing these polymers as a hole-transport layer and iridium(III) complex as a triplet emitter were fabricated. The device of the nitrogen-linked poly(2,7-carbazole) P3 with p,p,-biphenyl spacer, which has a higher HOMO level and a higher molecular weight, showed a much better performance than the device of P2 with m -phenylene spacer. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3880,3891, 2009 [source]

Solvent-Enhanced Diastereo- and Regioselectivity in the PdII -Catalyzed Synthesis of Six- and Eight-Membered Heterocycles via cis -Aminopalladation

CHEMISTRY - A EUROPEAN JOURNAL, Issue 30 2009
Árpád Balázs
Abstract The PdII -catalyzed intramolecular oxidative cyclization of tosyl-protected cis- and trans - N -allyl-2-aminocyclohexanecarboxamides was examined, and efficient syntheses of cyclohexane-fused pyrimidin-4-ones and 1,5-diazocin-6-ones were developed. In the course of the research, a marked solvent effect was observed on both the regio- and diastereoselectivity. Additionally, a novel PdII -mediated domino oxidation, oxidative amination reaction was discovered. Our experimental and theoretical findings suggest that the reactions proceed via a cis -aminopalladation mechanism. [source]

Norbornene Bidentate Ligands: Coordination Chemistry and Enantioselective Catalytic Applications

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 5 2010
Fernando Fernández
Abstract N - and P-donor derivatives have been prepared by functionalization of a readily available norbornene precursor. Palladium catalytic systems containing these new ligands were applied in allylic substitution, and yielded high activities and excellent enantioselectivities for the allylic alkylation and amination reactions (ee up to 97,%). A full coordination analysis of the catalytic precursors including modelling studies was also carried out. [source]

Highly Efficient and Practical Pyrrolidine,Camphor-Derived Organocatalysts for the Direct ,-Amination of Aldehydes

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 29 2010
Pang-Min Liu
Abstract A series of pyrrolidine,camphor-derived organocatalysts (1,4) were designed and synthesised. These organocatalysts were used for direct ,-amination of aldehydes with dialkyl azodicarboxylates to give the desired ,-aminated products in high chemical yields (up to 92,%) and with high to excellent levels of stereoselectivity (up to >99,% ee). The reactions proceeded rapidly (within 5 min) with low catalyst loading (5 mol-%) at ambient temperature. Enantioselective aminations of asymmetric ,,,-disubstituted aldehydes in the catalytic system were studied, with reasonable to high stereoselectivities (up to 75,% ee) being obtained. The utility of this methodology was demonstrated with the synthesis of derivatives of ,-amino-,-butyrolactone and a tetrasubstitutedcyclohexane-derived amino alcohol with high stereoselectivities. Transition models were proposed for the asymmetric ,-amination reactions; they involve hydrogen-bond interactions between the nucleophilic enamine formed in situ and the nitrogen source. [source]

Aza-MIRC Reactions of Sulfonyl-Activated Hydroxycarbamates with ,,,-Difunctionalised Acrylates

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 23 2003
Stefania Fioravanti
Abstract Highly functionalised aziridines are readily obtained in high yields (up to 95%) under mild conditions from the reaction of trisubstituted olefins bearing different groups with nosyloxycarbamates in the presence of calcium oxide. We propose a possible explanation for the different reactivities observed between these olefins and the aminating agents. Reagent-controlled stereoselective amination reactions led to the expected products with high conversions and purities. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source]

Palladium-Catalyzed Aryl Amination Reactions of 6-Bromo- and 6-Chloropurine Nucleosides

Nine Times Fluoride can be Good for your Syntheses.

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 17 2009
Not just Cheaper: Nonafluorobutanesulfonates as Intermediates for Transition Metal-Catalyzed Reactions
Abstract How much fluoride is good for a strong electron-withdrawing effect? In this review we summarize recent results on the use of perfluoroalkanesulfonates, in particular of the cost effective nonafluorobutanesulfonates (nonaflates), in transition metal-catalyzed reactions and a few other typical transformations. During the last decade many advantages over the commonly used triflates have been discovered. The generation of alkenyl and (het)aryl nonaflates and their applications in metal-catalyzed processes such as Heck, Suzuki, Sonogashira, Stille, and Negishi couplings or amination reactions are described. Although far from a systematic investigation, all the presented results clearly demonstrate the many advantages of nonaflates and of similar higher fluorinated sulfonates in laboratory and industrial scale organic synthesis. [source]

A Coherent Mechanistic Rationale for Additive Effects and Autoinductive Behaviour in Proline-Mediated Reactions

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 17 2009
Natalia Zotova
Abstract Differences in the kinetic behaviour of aldol reactions compared to aminoxylation and amination reactions are rationalized by consideration of the rate-determining step in each case. Both autoinductive behaviour and the rate-enhancing effect of additives are attributed to an effect on the enamine formation step. [source]

Towards Continuous Flow, Highly Enantioselective Allylic Amination: Ligand Design, Optimization and Supporting

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2009
Dana Popa
Abstract A family of enantiopure diphenylphosphinooxazolines (PHOX) containing in their structures a sterically tunable alkoxymethyl group (-CH2OR) has been optimized for the palladium-catalyzed asymmetric allylic amination. The optimal catalyst (R=CH3), depicting very high catalytic activity and broad scope applicability, has been further modified to include an ,-alkynyloxy substituent of variable length for polymer supporting via click chemistry, and has been anchored onto slightly cross-linked azidomethyl poly(styrene). The length of a polymethylene chain connecting the PHOX unit with the 1,2,3-triazole linker has been optimized, and the first polymer-supported PHOX ligands for the highly enantioselective allylic amination have been prepared in this manner. Conditions for catalyst recovery and reuse in microwave-promoted amination reactions have been established, and the system has been finally adapted to continuous flow operation. [source]

Enzymatic Synthesis of Enantiopure ,- and ,-Amino Acids by Phenylalanine Aminomutase-Catalysed Amination of Cinnamic Acid Derivatives

CHEMBIOCHEM, Issue 2 2009
Bian Wu
Abstract The phenylalanine aminomutase (PAM) from Taxus chinensis catalyses the conversion of ,-phenylalanine to ,-phenylalanine, an important step in the biosynthesis of the N -benzoyl phenylisoserinoyl side-chain of the anticancer drug taxol. Mechanistic studies on PAM have suggested that (E)-cinnamic acid is an intermediate in the mutase reaction and that it can be released from the enzyme's active site. Here we describe a novel synthetic strategy that is based on the finding that ring-substituted (E)-cinnamic acids can serve as a substrate in PAM-catalysed ammonia addition reactions for the biocatalytic production of several important ,-amino acids. The enzyme has a broad substrate range and a high enantioselectivity with cinnamic acid derivatives; this allows the synthesis of several non-natural aromatic ,- and ,-amino acids in excellent enantiomeric excess (ee >99,%). The internal 5-methylene-3,5-dihydroimidazol-4-one (MIO) cofactor is essential for the PAM-catalysed amination reactions. The regioselectivity of amination reactions was influenced by the nature of the ring substituent. [source]

Enantioselective Synthesis of 3-Azabicyclo[4.1.0]heptenes and 3-Azabicyclo[3.2.0]heptenes by Ir-Catalyzed Asymmetric Allylic Amination of N -Tosyl Propynylamine and Pt-Catalyzed Cycloisomerization

CHEMISTRY - A EUROPEAN JOURNAL, Issue 22 2010
Ji-Bao Xia
Irresistible! Highly regio- and enantioselective Ir-catalyzed allylic amination reactions of N -tosyl propynylamines have been realized. The resulting N -tosyl allylpropynylamines were transformed into highly enantioenriched 3-azabicyclo[4.1.0]heptenes and 3-azabicyclo[3.2.0]heptenes, respectively, in the presence of PtCl2 (see scheme; Ts=tosyl, cod=1,5-cyclooctadiene, TBAF=tetrabutylammonium fluoride, TMS=trimethylsilyl). [source]