1006-64-0Relevant articles and documents
Chemoselective three-component synthesis of homoallylic azides using an FeCl3 catalyst
Pramanik, Suman,Ghorai, Prasanta
, p. 23157 - 23165 (2013)
A one-pot, three-component synthesis of homoallylic azides from corresponding aldehydes, TMS-allyl, and TMS-N3 has been developed for the first time using an FeCl3 catalyst. The aromatic and hetero-aromatic aldehydes provided the cor
Expanding the chemical diversity in artificial imine reductases based on the biotin-streptavidin technology
Quinto, Tommaso,Schwizer, Fabian,Zimbron, Jeremy M.,Morina, Albert,Koehler, Valentin,Ward, Thomas R.
, p. 1010 - 1014 (2014)
We report on the optimization of an artificial imine reductase based on the biotin-streptavidin technology. With the aim of rapidly generating chemical diversity, a novel strategy for the formation and evaluation of biotinylated complexes is disclosed. Tethering the biotin-anchor to the Cp* moiety leaves three free coordination sites on a d6 metal for the introduction of chemical diversity by coordination of a variety of ligands. To test the concept, 34 bidentate ligands were screened and a selection of the 6 best was tested in the presence of 21 streptavidin (Sav) isoforms for the asymmetric imine reduction by the resulting three legged piano stool complexes. Enantiopure α-amino amides were identified as promising bidentate ligands: up to 63 % ee and 190 turnovers were obtained in the formation of 1-phenyl-1,2,3,4-tetrahydroisoquinoline with [IrCp*biotin(L-ThrNH2)Cl]?SavWT as a catalyst. Biotinspired! A new strategy for the generation of chemical diversity in artificial transfer hydrogenases (ATHases) based on the biotin-streptavidin technology is disclosed. By combining a biotinylated MCp* fragment with 34 commercially available ligands in the presence of wild-type streptavidin, promising candidates for the asymmetric reduction of imines are identified. Selected ligands are screened against 21 streptavidin isoforms and the performance of the resulting constructs is evaluated.
Hybrid organic - Inorganic catalysts: A cooperative effect between support, and palladium and nickel salen complexes on catalytic hydrogenation of imines
Ayala,Corma,Iglesias,Rincon,Sanchez
, p. 170 - 177 (2004)
A method for immobilizing chiral salen palladium and nickel complexes (salen = (R,R)-N′,N′-bis-(3,5-di-tert-butylsalicylidene)-1,2- cyclohexanediamine) on ordered mesoporous silica supports (MCM-41), delaminated ITQ-2 and ITQ-6 zeolites, and amorphous silica has been developed. Hydrogenation of imines was studied with the homogeneous as well as with the heterogenized counterpart catalysts. The high accessibility introduced by the structure of the supports allows the preparation of highly efficient immobilized catalysts with TOFs of 200×103 h-1. A moderate acidity in the support increases the catalytic activity by stabilizing the charged transition state and can duplicate the activity of the homogeneous analogues. No deactivation of the catalysts was observed after repeated recycling.
Asymmetric reduction of cyclic imines catalyzed by a whole-cell biocatalyst containing an (S)-imine reductase
Leipold, Friedemann,Hussain, Shahed,Ghislieri, Diego,Turner, Nicholas J.
, p. 3505 - 3508 (2013)
Biocatalytic imine reduction: A whole-cell recombinant E. coli system, producing an (S)-selective imine reductase (IRED) from Streptomyces sp. GF3546, is developed. This biocatalyst is used for the enantioselective reduction of a broad range of substrates such as dihydroisoquinolines and dihydro-β- carbolines as well as iminium ions. Copyright
THE ZIRCONOCENE INDUCED COUPLING OF BENZYNE WITH NITRILES: SYNTHESIS, STRUCTURE AND REACTIONS OF NOVEL AZAMETALLACYCLOPENTENES
Buchwald, Stephen L.,Sayers, Ann,Watson, Brett T.,Dewan, John C.
, p. 3245 - 3248 (1987)
A series of novel azazirconacyclopentenes have been prepared by the thermolysis of diphenylzirconocene in the presence of one equivalent of a wide variety of nitriles.An X-ray crystal structure shows these metallacycles to be dimeric in the solid state.
Development of an R-selective amine oxidase with broad substrate specificity and high enantioselectivity
Heath, Rachel S.,Pontini, Marta,Bechi, Beatrice,Turner, Nicholas J.
, p. 996 - 1002 (2014)
Amine oxidases are useful bio-catalysts for the synthesis of enantiomerically pure 1°, 2° and 3° chiral amines. Enzymes in this class (e.g., MAO-N from Aspergillus niger) reported previously have been shown to be highly S selective. Herein we report the development of an enantiocomplementary R-selective amine oxidase based on 6-hydroxy-D-nicotine oxidase (6-HDNO) with broadened substrate scope and high enantioselectivity. The engineered 6-HDNO enzyme has been applied to the preparative deracemisation of a range of racemic amines to yield S-configured products, for example, (S)-nicotine, in high ee. Nicotine rush: An R-selective amine oxidase based on 6-hydroxy-D-nicotine oxidase (6-HDNO) with broadened substrate scope and high enantioselectivity has been developed. The engineered 6-HDNO enzyme is applied to the preparative deracemization of a range of racemic amines to yield S-configured products, for example, (S)-nicotine, in high ee.
Copper Cyanide-Catalyzed Palladium Coupling of N-tert-Butoxycarbonyl-Protected α-Lithio Amines with Aryl Iodides or Vinyl Iodides
Karl Dieter,Li, ShengJian
, p. 7726 - 7735 (1997)
Treatment of (α-aminoalkyl)lithium reagents with aryl iodides in the presence of catalytic amounts of CuCN and PdCl2(PPh3)2 or [(p-MeOC6H4)3P]4Pd affords 2-aryl substituted amines in modest to good yields. The yields can be improved by use of softer ligands such as AsPh3 and SbPh3 or by use of bis(diphenylphosphino)ferrocene (dppf). Coupled products are obtained with electron-rich aryl iodides (XArI, X = Me, OMe), and the reaction fails with electron-poor aryl iodides (XArI, X = NO2, CO2Li). Treatment of the (α-aminoalkyl)lithium reagents with vinyl iodides and Pd(0)/dppf/ CuCN afforded the coupling products in low to modest yields.
Sequence-Based In-silico Discovery, Characterisation, and Biocatalytic Application of a Set of Imine Reductases
Velikogne, Stefan,Resch, Verena,Dertnig, Carina,Schrittwieser, Joerg H.,Kroutil, Wolfgang
, p. 3236 - 3246 (2018)
Imine reductases (IREDs) have recently become a primary focus of research in biocatalysis, complementing other classes of amine-forming enzymes such as transaminases and amine dehydrogenases. Following in the footsteps of other research groups, we have established a set of IRED biocatalysts by sequence-based in silico enzyme discovery. In this study, we present basic characterisation data for these novel IREDs and explore their activity and stereoselectivity using a panel of structurally diverse cyclic imines as substrates. Specific activities of >1 U/mg and excellent stereoselectivities (ee>99 %) were observed in many cases, and the enzymes proved surprisingly tolerant towards elevated substrate loadings. Co-expression of the IREDs with an alcohol dehydrogenase for cofactor regeneration led to whole-cell biocatalysts capable of efficiently reducing imines at 100 mM initial concentration with no need for the addition of extracellular nicotinamide cofactor. Preparative biotransformations on gram scale using these ‘designer cells’ afforded chiral amines in good yield and excellent optical purity.
γ-Amino Butyric Acid (GABA) Synthesis Enabled by Copper-Catalyzed Carboamination of Alkenes
Zhu, Nengbo,Wang, Ting,Ge, Liang,Li, Yajun,Zhang, Xinhao,Bao, Hongli
, p. 4718 - 4721 (2017)
γ-Amino butyric acid (GABA) is the chief inhibitory neurotransmitter in the mammalian central nervous system. Many GABA derivatives are used clinically to prevent or treat neurodegenerative diseases. Copper-catalyzed carboamination of alkenes offers an efficient method to fashion the core structure of GABA derivatives from alkenes. In this reaction, acetonitrile serves as the source of the carbon and nitrogen functionalities used to difunctionalize alkenes. Experimental and density functional theory (DFT) studies were carried out to investigate the mechanism of the reaction, and a copper-catalyzed radical-polar crossover mechanism is proposed.
Design, synthesis and biological evaluation of N-hydroxy-aminobenzyloxyarylamide analogues as novel selective κ opioid receptor antagonists
He, Guangchao,Peng, Kewen,Song, Qiao,Wang, Junwei,Xu, Anhua,Xu, Yungen,Zhu, Qihua
, (2020)
Aminobenzyloxyarylamide derivatives 1a-i and 2a-t were designed and synthesized as novel selective κ opioid receptor (KOR) antagonists. The benzoyl amide moiety of LY2456302 was changed into N-hydroxybenzamide and benzisoxazole-3(2H)-one to investigate whether it could increase the binding affinity or selectivity for KOR. All target compounds were evaluated in radioligand binding assays for opioid receptor binding affinity. These efforts led to the identification of compound 1c (κ Ki = 179.9 nM), which exhibited high affinity for KOR. Moreover, the selectivity of KOR over MOR and DOR increased nearly 2-fold and 7-fold, respectively, compared with (±)LY2456302.
