- Bi-enzymatic Conversion of Cinnamic Acids to 2-Arylethylamines
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The conversion of carboxylic acids, such as acrylic acids, to amines is a transformation that remains challenging in synthetic organic chemistry. Despite the ubiquity of similar moieties in natural metabolic pathways, biocatalytic routes seem to have been overlooked for this purpose. Herein we present the conception and optimisation of a two-enzyme system, allowing the synthesis of β-phenylethylamine derivatives from readily-available ring-substituted cinnamic acids. After characterisation of both parts of the reaction in a two-step approach, a set of conditions allowing the one-pot biotransformation was optimised. This combination of a reversible deaminating and irreversible decarboxylating enzyme, both specific for the amino acid intermediate in tandem, represents a general method by which new strategies for the conversion of carboxylic acids to amines could be designed.
- Weise, Nicholas J.,Thapa, Prasansa,Ahmed, Syed T.,Heath, Rachel S.,Parmeggiani, Fabio,Turner, Nicholas J.,Flitsch, Sabine L.
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p. 995 - 998
(2020/01/21)
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- Organocatalytic Enantioselective Addition of α-Aminoalkyl Radicals to Isoquinolines
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With a dual organocatalytic system involving a chiral phosphoric acid and a dicyanopyrazine-derived chromophore (DPZ) photosensitizer and under the irradiation with visible light, an enantioselective Minisci-type addition of α-amino acid-derived redox-active esters (RAEs) to isoquinolines has been developed. A variety of prochiral α-aminoalkyl radicals generated from RAEs were successfully introduced on isoquinolines, providing a range of valuable α-isoquinoline-substituted chiral secondary amines in high yields with good to excellent enantioselectivities.
- Liu, Xiangyuan,Liu, Yang,Chai, Guobi,Qiao, Baokun,Zhao, Xiaowei,Jiang, Zhiyong
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supporting information
p. 6298 - 6301
(2018/10/09)
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- PROCESS FOR THE RACEMIZATION OF ALPHA-AMINO ACIDS
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According to the present invention, a method is provided wherein a basic aqueous phase containing an optically active α-amino acid is brought into contact with an organic phase containing a racemisation catalyst in the form of a copper metal complex of copper ions and an α-amino acid and salicylaldehyde, in the presence of a phase transition catalyst, thereby subjecting the optically active α-amino acid to racemisation. In the α-amino acid racemisation method according to the present invention, the reaction conditions are mild and thus there is little α-amino acid breakdown and the yield is high, the racemisation catalyst can be reused, the α-amino acid resulting from the racemisation can easily be isolated and purified, and the racemisation method can be implemented in volume such that the invention is economic.
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Paragraph 0075-0076
(2016/08/29)
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- Phenylalanine ammonia lyase catalyzed synthesis of amino acids by an MIO-cofactor independent pathway
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Phenylalanine ammonia lyases (PALs) belong to a family of 4-methylideneimidazole-5-one (MIO) cofactor dependent enzymes which are responsible for the conversion of L-phenylalanine into trans-cinnamic acid in eukaryotic and prokaryotic organisms. Under conditions of high ammonia concentration, this deamination reaction is reversible and hence there is considerable interest in the development of PALs as biocatalysts for the enantioselective synthesis of non-natural amino acids. Herein the discovery of a previously unobserved competing MIO-independent reaction pathway, which proceeds in a non-stereoselective manner and results in the generation of both L- and D-phenylalanine derivatives, is described. The mechanism of the MIO-independent pathway is explored through isotopic-labeling studies and mutagenesis of key active-site residues. The results obtained are consistent with amino acid deamination occurring by a stepwise E1cB elimination mechanism. All manner of things: A competing MIO-independent (MIO=4-methylideneimidazole-5-one) reaction pathway has been identified for phenylalanine ammonia lyases (PALs), which proceeds in a non-stereoselective manner, resulting in the generation of D-phenylalanine derivatives. The mechanism of D-amino acid formation is explored through isotopic-labeling studies and mutagenesis of key active-site residues.
- Lovelock, Sarah L.,Lloyd, Richard C.,Turner, Nicholas J.
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supporting information
p. 4652 - 4656
(2014/05/20)
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- Immunomodulatory peptides
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The invention relates to peptides derivatized with a hydrophilic polymer which, in some embodiments, bind to human FcRn and inhibit binding of the Fc portion of an IgG to an FcRn, thereby modulating serum IgG levels. The disclosed compositions and methods may be used in some embodiments, for example, in treating autoimmune diseases and inflammatory disorders. The invention also relates, in further embodiments, to methods of using and methods of making the peptides of the invention.
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- Enhanced reduction of C-N multiple bonds using sodium borohydride and an amorphous nickel catalyst
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Amorphous nickel powder (Ni0) was utilised as a catalyst under mild, aqueous, basic conditions for enhancing the sodium borohydride-mediated reduction of C-N multiple bonds such as oximes, imines, hydrazones and nitriles to produce the corresponding amines in good to excellent yields.
- Liu, Shouxin,Yang, Yihua,Zhen, Xiaoli,Li, Junzhang,He, Huimin,Feng, Juan,Whiting, Andrew
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experimental part
p. 663 - 670
(2012/01/15)
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- Convenient method for reduction of C-N double bonds in oximes, imines, and hydrazones using sodium Borohydride-Raney ni system
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(Chemical Equation Presented) A practical method has been developed for reduction of C-N double bond in oximes, imines, and hydrazones with sodium borohydride catalyzed by Raney Ni. The reactions were carried out in basic aqueous solution, and the desired products were obtained in moderate yields after a simple procedure. This method can be applied to synthesize simpler aliphatic or aromatic amines and its analogs. Copyright Taylor & Francis Group, LLC.
- Yang, Yihua,Liu, Shouxin,Li, Junzhang,Tian, Xia,Zhen, Xiaoli,Han, Jianrong
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experimental part
p. 2540 - 2554
(2012/07/27)
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- Solid phase reduction of oxazolones using BER-Ni2B-A simple synthesis of N-benzoylphenylalanines
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Borohydride exchange resin (BER)-Ni2B is successfully used as a reagent for the solid phase reduction of the C-4 exocyclic double bond of oxazolones to give the N-benzoylphenylalanines and hence the corresponding amino acids.
- Sikdar, Atul P.,Chetri, Ajoy B.,Das, Pranab J.
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p. 2878 - 2881
(2007/10/03)
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- N1 modified glycopeptides
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Described herein are N′-acylated derivatives of desleucylA82846B. The compounds are useful as antibacterial agents.
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- METABOLISM OF D,L-CHLORO-PHENYLALANINES BY PHENYLALANINE AMINOTRANSFERASE ISOZYMES PURIFIED FROM BUSHBEAN SHOOTS
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Key Word Index - Phaseolus vulgaris; Leguminosae; bushbean; metabolism; phenylalanine decarboxylase; phenylalanine aminotransferase; purification; substituted amino acids; D,L-chloro-phenylalanines.A series of mono-, di- and trichloro-D,L-phenylalanines was tested as substrates for both phenylalanine aminotransferase and phenylalanine decarboxylase partially purified from bushbean (Phaseolus vulgaris L.) seedling extracts by ammonium sulphate fractionation and Sephacryl S-300 gel filtration.While most of the D,L-chlorophenylalanines were transaminated at rates of 35-100percent of that observed with D,L-phenylalanine, no chloro-phenylalanine decarboxylase activity was observed.A transamination reaction is therefore likely to be the initial step in the conversion of chloro-phenylalanines to their corresponding chloro-phenylacetic acids via a reaction pathway similar to the known route for the metabolism of L-phenylalanine to phenylacetic acid.The highest specific activity of phenylalanine aminotransferase was found in both root and shoot tissues of bushbean at the 10-day stage of seedling growth.Partially purified extracts of these tissues were able to transaminate most of the mono- and dichloro-phenylalanines at ca 20-40percent of the rate observed with D,L-phenylalanine, while the trichloro-phenylalanines (assayed at lower concentrations due to solubility) were transaminated at rates equal to those observed with D,L-phenylalanine.The 4-chloro derivative was the best substrate tested showing rates of transamination that were 25percent higher than those observed with D,L-phenylalanine.Further purification of shoot fractions by DEAE-Sephacel chromatography resolved the phenylalanine aminotransferase activity into two peaks (enzymes I and II) which on further purification, were found to behave differently during hydrophobic chromatography and PAGE.These results indicated the presence of two isozymic forms of phenylalanine aminotransferase in bushbean shoots and both were found to catalyse transamination of the monochloro-phenylalanines examined in this study.
- Taylor, David C.,Wightman, Frank
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p. 1279 - 1288
(2007/10/02)
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- SYNTHESIS OF AMINO ACIDS. ALKYLATION OF ALDIMINE AND KETIMINE DERIVATIVES OF GLYCINE ETHYL ESTER UNDER VARIOUS PHASE-TRANSFER CONDITIONS
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The Schiff base derived from glycine ethyl ester and p-chlorobenzaldehyde can be alkylated by the ion-pair extraction method as well as under catalytic liquid-liquid or solid-liquid phase-transfer conditions.This imine is compared with the corresponding benzophenone Schiff base.
- Ghosez, Leon,Antoine, Jean-Pierre,Deffense, Etienne,Navarro, Mirtha,Libert, Valery,et al.
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p. 4255 - 4258
(2007/10/02)
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