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Amination
Kinds of Amination Terms modified by Amination Selected AbstractsA Polymer-Bound Oxidovanadium(IV) Complex Prepared from an L -Cysteine-Derived Ligand for the Oxidative Amination of StyreneEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 4 2008Mannar R. Maurya Abstract The ligand H2sal-cys (I) derived from salicylaldehyde and L -cysteine has been covalently bonded to chloromethylated polystyrene cross-linked with 5,% divinylbenzene. Upon treatment with [VO(acac)2] in dimethylformamide (DMF) the polystyrene-bound ligand PS-H2sal-cys (II) gave the oxidovanadium(IV) complex, PS-[VO(sal-cys)·DMF] (1). The corresponding neat complex, [VO(sal-eta)]2 (2), has also been prepared similarly in methanol. These complexes have been characterised by IR, electronic, EPR spectroscopic studies, magnetic susceptibility measurements and thermal as well as scanning electron micrographs studies. Complex [VO(sal-eta)]2 exhibits a medium intensity band at 980 cm,1 in the IR spectrum due to ,(V=O) stretch. Broad features of the EPR spectrum for the neat complex along with magnetic susceptibility studies suggest the presence of antiferromagnetic exchange interaction between two vanadium centers in close proximity. Both complexes catalyze the oxidative amination of styrene, in mild basic conditions, with secondary amines (diethylamine, imidazole, and benzimidazole) and gave a mixture of two aminated products in good yields. Amongst the two aminated products, the anti-Markovnikov product is favored over the Markovnikov one due to the steric hindrance posed by the secondary amines. The polymer-anchored heterogeneous catalyst is free from leaching during catalytic action and recyclable.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Highly Efficient and Practical Pyrrolidine,Camphor-Derived Organocatalysts for the Direct ,-Amination of AldehydesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 29 2010Pang-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] Allylic Amination of Internal Alkynes with Aromatic and Aliphatic Amines Using Polymer-Supported Triphenylphosphane,Palladium Complex as a Heterogeneous and Recyclable CatalystEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 26 2010Yogesh S. Wagh Abstract A facile and novel protocol for the allylic amination of internal alkynes with amines by using a polymer-supported triphenylphosphane,palladium complex [PS,TPP,Pd] as a highly active heterogeneous reusable catalyst was developed. The catalyst exhibited remarkable activity and is reusable over five consecutive cycles. The protocol was applicable for a variety of hindered and functionalized aromatic/aliphatic amines and afforded the desired allylic products in good to excellent yield. [source] Efficient and Selective Method for the Synthesis of Dihydrodipyridopyrazines Based on the Pd-Catalysed Amination of HalopyridinesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 22 2009Oana-Irina Patriciu Abstract A novel methodology for the efficient and selective synthesis of isomers A and B of N -substituted dihydrodipyridopyrazines was developed. The key step is the intermolecular coupling of aminopyridines and halonitropyridines/dihalopyridines in the presence of a catalyst system composed of Pd(OAc)2/Xantphos. This system displays good functional group compatibility and the desired C,N bond-forming process proceeds in good yields. Cyclization of suitable nitro-substituted N,N, -dipyridinylamines produces monosubstituted dihydrodipyridopyrazines, which can easily be alkylated to give a large variety of unsymmetrical 5,10-dialkyl-5,10-dihydrodipyrido[2,3- b:2,,3,- e]pyrazines (isomers A) and 5,10-dialkyl-5,10-dihydrodipyrido[2,3- b:3,,2,- e]pyrazines (isomers B). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Palladium-Catalysed Amination of Electron-Deficient or Relatively Electron-Rich Benzo[b]thienyl Bromides , Preliminary Studies of Antimicrobial Activity and SARsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 17 2004Maria-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] Direct Amination of meso -Tetraarylporphyrin Derivatives , Easy Route to A3B-, A2BC-, and A2B2 -Type Porphyrins Bearing Two Nitrogen-Containing Substituents at the meso -Positioned Phenyl GroupsHELVETICA CHIMICA ACTA, Issue 10 2007Stanis, aw Ostrowski Abstract meso -Tetraarylporphyrinato complexes 1a,g (ZnII, CuII, and NiII) bearing one or two nitro-substituted aryl moieties react with 1,1,1-trimethylhydrazinium iodide in the presence of tBuOK in THF at 0,5° or in the presence of KOH in DMSO at 60,70° according to a nucleophilic substitution of an H-atom, thus affording porphyrins 2a,g and 3f,g with amino-functionalized meso -positioned aryl substituents in yields up to 73% (Scheme,1 and Table). The products obtained are attractive intermediates for further derivatization of porphyrins and may be of potential use as sensitizers in photodynamic cancer therapy. [source] Palladium-Catalyzed Amination of 3,5-Dihalopyridines , a Convenient Route to New PolyazamacrocyclesHELVETICA CHIMICA ACTA, Issue 7 2005Alexei Pd-Catalyzed amination of 3,5-dibromo- and 3,5-dichloropyridine (1a and 1b, resp.) with linear polyamines 2 leads to the formation of a new family of pyridine-containing macrocycles 3 with an ,exo'-oriented pyridine N-atom (Schemes,1 and 2). The dependence of the macrocycle yield on the nature of the halogen atom, the length of the polyamine chain and C/N atom ratio, and the composition of the catalytic system is studied. The synthesis of mono- and bis(5-halopyridin-3-yl)-substituted polyamines 4, 5, 8, 9, and of 3,5-bis(polyamino)-substituted pyridines 6 is described (Schemes,3 and 4), and the use of these compounds as intermediates on the way to the macrocycles 7, 16, and 18 with larger cavity (,cyclodimers' and ,cyclotrimers') is demonstrated (Schemes,5,10). [source] Efficient and Highly Chemoselective Direct Reductive Amination of Aldehydes using the System Silane/Oxorhenium ComplexesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 13 2010Sara C. A. Sousa Abstract This work reports a novel method for direct reductive amination of aldehydes with silanes catalyzed by several high-valent oxorhenium(V) and oxorhenium(VII) complexes. The catalytic system PhSiH3/ReIO2(PPh3)2 (2.5,mol%) was very efficient for the synthesis of secondary amines and highly chemoselective, tolerating a wide range of functional groups such as NO2, CF3, SO2R, CO2R, F, Cl, Br, I, CN, OH, OCH3, SCH3, NCOR, and double bonds. This novel method was also employed in the synthesis of tertiary amines with moderate yields. [source] Single Nucleotide-Catalyzed Biomimetic Reductive AminationADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 13 2010Atul Kumar Abstract We have successfully developed a single nucleotide (adenosine 5,-diphosphate)-catalyzed enantioselective direct reductive amination of aldehydes and ketones using a Hantzsch ester as reducing agent. The process is a simple, efficient and a real mimic of the NADH reduction approach for the synthesis of structurally diverse amines. This reaction is the first report demonstrating the ability of a single nucleotide as catalyst and one of the most genuine biomimetic reactions of organic chemistry. [source] One-Step Synthesis of Chiral Azamacrocycles via Palladium-Catalyzed Enantioselective Amination of 1,5-Dichloroanthraquinone and 1,5-DichloroanthraceneADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 13 2010Elena R. Ranyuk Abstract Asymmetric amination of 1,5-dichloroanthraquinone and 1,5-dichloroanthracene with di- and trioxadiamines catalyzed by palladium complexes with various chiral phosphine ligands gave chiral macrocycles with ee values of up to 60%. The dependence of the chemical yields and enantiomeric excess on the nature of the starting compounds and the phosphine ligands employed was demonstrated. An unexpected spontaneous resolution upon crystallization of the macrocycle comprising anthraquinone and dioxadiamine moieties was observed while in the case of the macrocycle with a trioxadiamine linker racemic monocrystals were obtained. Crystallization of the enantiomerically enriched mixtures afforded chiral macrocycles with 88,99% ee. [source] Chiral Amine Synthesis , Recent Developments and Trends for Enamide Reduction, Reductive Amination, and Imine ReductionADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 5 2010Thomas Abstract The review examines the chiral amine literature from 2000,2009 (May) concerning enantioselective and diastereoselective methods for N -acylenamide and enamine reduction, reductive amination, and imine reduction. The reaction steps for each strategy, from ketone to primary chiral amine, are clearly defined, with best methods and yields for starting material preparation and final deprotection noted. Categories of chiral amines have been defined in Section 1 to allow the reader to quickly understand whether their specific target amine falls within a difficult to synthesize, or not, structural class. Amino acids are not considered in this work. [source] Enantioselective Electrophilic Amination of ,-Cyanothioacetates with Azodicarboxylates Catalyzed by an Axially Chiral Guanidine BaseADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 17 2009Masahiro Terada Abstract An enantioselective electrophilic amination of ,-substituted cyanothioacetates with azodicarboxylate is demonstrated using an axially chiral guanidine as a chiral Brønsted base catalyst. The corresponding product, having a quaternary stereogenic center at the ,-carbon atom, is formed in excellent enantioselectivity. [source] An Efficient Copper-Catalyzed Amination of Aryl Halides by Aqueous AmmoniaADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009Deping Wang Abstract The copper(I) bromide/1-(5,6,7,8-tetrahydroquinolin-8-yl)-2-methylpropan-1-one (CuBr- L3) combination catalyzed the cross-coupling reactions between aryl or heteroaryl halides and aqueous ammonia with high yields to produce primary aromatic or heteroaromatic amines at room temperature or under mild conditions. [source] Towards Continuous Flow, Highly Enantioselective Allylic Amination: Ligand Design, Optimization and SupportingADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2009Dana 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] Origin of Enantioselectivity in the Organocatalytic Reductive Amination of ,-Branched AldehydesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2009Tommaso Marcelli Abstract The reason for enantioselectivity in the reductive amination of ,-branched aldehydes was investigated. The relative energies of all the diastereomeric transition states for hydride transfer of a suitable computational model were calculated at the B3LYP/6-311+G(2d,2p) level of theory. Our calculations successfully reproduce and rationalize the experimentally observed stereochemical outcome of the reaction. [source] An Unusual Peroxide-Mediated Amination of Cycloalkanes with NitroarenesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 3 2009Guojun 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] Mechanistic Inferences Derived from Competitive Catalytic Reactions: Pd(binap)-Catalyzed Amination of Aryl HalidesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7-8 2008Antonio Abstract Healthy competition: The Pd(binap)-catalyzed amination of aryl halides demonstrates how the results from competitive reactions can be strikingly different from those obtained from study of the separate reactions. We show how the competitive network provides mechanistic information not accessible from study of the reactions separately. [source] Diphosphines of dppf-Type Incorporating Electron-Withdrawing Furyl Moieties Substantially Improve the Palladium-Catalysed Amination of Allyl AcetatesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2005Aziz Fihri Abstract Highly active Pd/diphosphine catalytic systems incorporating new, air-stable ferrocenyl-furylphosphines allow nucleophilic allylic amination at room temperature with unprecedented turnover frequencies. For instance, in the presence of 0.01,mol,% catalyst the coupling of aniline to allyl acetate occurs at a TOF of more than 10,000,h,1; even the addition of the less nucleophile morpholine to allyl acetate is observed with a TOF of 4250,h,1. The amination of the sterically demanding geranyl acetate, a monoterpene derivative of interest in the flavour industry, at low catalyst loadings demonstrates the scope of this methodology, which provides in addition noticeable advantages in terms of economical (resource- and energy-saving) and sustainable chemistry (high selectivity, no additive, low metal content, and thus easier purification). [source] A Versatile Catalyst for Reductive Amination by Transfer Hydrogenation,ANGEWANDTE CHEMIE, Issue 41 2010Chao Wang Ein Iridiumkatalysator ermöglicht die reduktive Aminierung von Carbonylgruppen mit beispielloser Substratbreite, Selektivität und Aktivität in Gegenwart von Ameisensäure als Wasserstoffquelle (siehe Schema). Das Katalysatorsystem ist wesentlich besser als die verbreitet eingesetzten Borhydride. [source] Catalytic Asymmetric Reductive Amination of ,-Branched Ketones,ANGEWANDTE CHEMIE, Issue 27 2010Vijay Maßgebliche Substituenten: Die Titelreaktion nutzt die dynamische kinetische Racematspaltung und liefert so cis -2-substituierte Cyclohexylamine mit hohen Diastereo- und Enantioselektivitäten. [source] Silver-Mediated Direct Amination of Benzoxazoles: Tuning the Amino Group Source from Formamides to Parent Amines,ANGEWANDTE CHEMIE, Issue 48 2009Hwan Cho, Seung An die Quelle gegangen: Formamide oder die Stammamine wurden als Aminogruppenquelle bei der silbervermittelten Aminierung von Benzoxazolen eingesetzt. Während die Reaktionen der Formamide hohe Temperaturen erfordern, gelingt die direkte Aminierung mit Aminen bei sehr viel milderen Bedingungen (siehe Schema). Optisch aktive Aminogruppen konnten ohne Racemisierung eingesetzt werden. [source] Enzymatic Synthesis of Enantiopure ,- and ,-Amino Acids by Phenylalanine Aminomutase-Catalysed Amination of Cinnamic Acid DerivativesCHEMBIOCHEM, Issue 2 2009Bian 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] ChemInform Abstract: Enantioselective Synthesis of syn/anti-1,3-Amino Alcohols via Proline-Catalyzed Sequential ,-Aminoxylation/,-Amination and Horner,Wadsworth,Emmons Olefination of Aldehydes.CHEMINFORM, Issue 42 2010Vishwajeet Jha Abstract The target compounds are prepared with anti- or syn-selectivity using D- or L-proline as a catalyst, respectively. [source] ChemInform Abstract: Copper-Catalyzed Direct Amination of ortho-Functionalized Haloarenes with Sodium Azides as the Amino Source.CHEMINFORM, Issue 40 2010Haibo Zhao Abstract The method provides a mild and convenient approach to 2-aminobenzoic acids, 2-aminobenzamides, and N-(2-aminophenyl)amides which can smoothly be converted into benzoxazinones, quinazolinones, and benzimidazoles. [source] ChemInform Abstract: One-Pot Reductive Amination of Carbonyl Compounds Using Sodium Borohydride,Amberlyst 15.CHEMINFORM, Issue 40 2010Heshmatollah Alinezhad Abstract The title reaction can also be carried out in THF at 25 °C with comparable yields. [source] ChemInform Abstract: Copper-Catalyzed Amination of Primary Benzylic C,H Bonds with Primary and Secondary Sulfonamides.CHEMINFORM, Issue 39 2010David A. Powell Abstract The amination of secondary benzylic C,H bonds is also possible. [source] ChemInform Abstract: An Efficient Palladium-Catalyzed Amination of Aryl Chlorides in Presence of 1,3-Bis-(2,6-diisopropylphenyl)imidazolinium Chloride.CHEMINFORM, Issue 36 2010Huafeng Shen No abstract is available for this article. [source] ChemInform Abstract: Highly Efficient Catalytic System for Electrophilic Amination of Arylzinc Reagents.CHEMINFORM, Issue 19 2010Tahir Daskapan 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: An Inexpensive Cyclodiphosphazane as an Efficient Ligand for the Palladium-Catalyzed Amination of Aryl Bromides and Chlorides.CHEMINFORM, Issue 7 2010R. Rama Suresh 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: Intramolecular Ir(I)-Catalyzed Benzylic C,H Bond Amination of ortho-Substituted Aryl Azides.CHEMINFORM, Issue 2 2010Ke Sun 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] | ||||||||||||||||||||||||||||