- Method for Preparing Unnatural Amino Acids
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The present invention relates to a manufacturing method of unnatural amino acids and unnatural amino acids manufactured thereby. Specifically, the present invention relates to an asymmetric synthesis method which can manufacture unnatural amino acids having significantly high optical purity, and to the unnatural amino acids manufactured thereby. A manufacturing method of unnatural amino acids represented by chemical formula 6 or chemical formula 7 comprises the steps of: synthesizing a compound represented by chemical formula 4 or chemical formula 5; manufacturing a diol compound; and manufacturing a carboxylic acid compound.COPYRIGHT KIPO 2016
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Paragraph 0172; 0173; 0193; 0194
(2017/01/09)
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- Self-assembly of a tripeptide into a functional coating that resists fouling
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This communication describes the self-assembly of a tripeptide into a functional coating that resists biofouling. Using this peptide-based coating we were able to prevent protein adsorption and interrupt biofilm formation. This coating can be applied on numerous substrates and therefore can serve in applications related to health care, marine and water treatment.
- Maity, Sibaprasad,Nir, Sivan,Zada, Tal,Reches, Meital
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supporting information
p. 11154 - 11157
(2014/11/08)
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- Phenylalanine ammonia-lyase: The use of its broad substrate specificity for mechanistic investigations and biocatalysis - Synthesis of L-arylalanines
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Several fluoro-and chlorophenylalanines were found to be good substrates of phenylalanine ammonialyase (PAL/EC 4.3.1.5) from parsley. The enantiomerically pure L-amino acids were obtained in good yields by reaction of the corresponding cinnamic acids with 5M ammonia solution (buffered to pH 10) in the presence of PAL. The kinetic constants for nine different fluoro-and chlorophenylalanines do not provide a rigorous proof for but are consistent with the previously proposed mechanism comprising an electrophilic attack of the methylidene-imidazolone cofactor of PAL at the aromatic nucleus as a first chemical step. In the resulting Friedel-Crafts-type σ complex the β-protons are activated for abstraction and consequently the pro-S is abstracted by an enzymic base. Results from semi-empirical calculations combined with a proposed partial active site model showed a correlation between the experimental kinetic constants and the change in polarization of the pro-S Cβ-H bond and heat of formation of the σ complexes, thus making the electrophilic attack at the neutral aromatic ring plausible. Furthermore, while 5-pyrimidinylalanine was found to be a moderately good substrate of PAL, 2-pyrimidinylalanine was an inhibitor.
- Gloge, Andreas,Zon, Jerzy,Koevari, Agnes,Poppe, Laszlo,Retey, Janos
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p. 3386 - 3390
(2007/10/03)
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- HOMOCHIRAL HETEROORGANIC ANALOGS OF NATURAL COMPOUNDS. III. BIOCATALYTIC METHOD OF OBTAINING HOMOCHIRAL FLUORINE-CONTAINING (R)- AND (S)-PHENYLALANINES AND (S,R)- AND (R,S)-PHENYLSERINES
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A convenient biocatalytic method of obtaining homochiral (S)- and (R)-threo-β-(4-fluorophenyl)serine and -2-, -3-, and 4-fluoro- and -2,3,4,5,6-pentafluorophenylalanines by the enantioselective hydrolysis of their racemic N-phenylacetyl derivatives under the action of Escherichia coli penicillin acylase is proposed.
- Soloshonok, V. A.,Shvyadas, V. K.,Kukhar, V. P.,Galaev, I. Yu.,Kozlova, E. V.,Svistunova, N. Yu.
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p. 236 - 240
(2007/10/02)
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- Asymmetric synthesis of organoelement analogues of natural products; Part 12: General method for the asymmetric synthesis of fluorine-containing phenylalanines and α-methyl(phenyl)alanines via alkylation of the chiral nickel(II) Schiff's base complexes of
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Nickel(II) complexes of Schiff's bases derived from (S)-o-[(N-benzyl]prolyl)amino]benzophenone [N-(2-benzoylphenyl)-1-benzylpyrrolidine-2-carboxamide] (BBP) and glycine or alanine have been used for asymmetric synthesis of fluoro (S)-phenylalanines and (S
- Kukhar,Belokon,Soloshonok,Svistunova Yu.,Rozhenko,Kuz'mina
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p. 117 - 120
(2007/10/02)
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- RESOLUTION AND USE IN α-AMINO ACID SYNTHESIS OF IMIDAZOLIDINONE GLYCINE DERIVATIVES
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The imidazolidinones (rac.-1 and rac.-2) obtained from pivalaldehyde and glycine amides are resolved efficiently by crystallization of diastereomeric ammonium salts with chiral acids (mandelates and a gulonate respectively).The free bases are acylated under Schotten-Baumann conditions to give enantiomerically pure 1-Bz-, 1-BOC-, 1-Z- or 1-formyl-2-t-butyl-3-methyl- or -3-benzyl-4-imidazolidinones.Diastereoselective alkylation of the 3-methyl derivatives (BMI) with a variety of electrophiles (LDA/THF -70 to +25 degC) gives trans-disubstituted imidazolidinones exclusively (3-22).Some of these are hydrolyzed by a procedure employing excess acidic ion exchange resin to give enantiomerically pure (R)- or (S)-amino acids.The procedure is compared with other methods of generating chiral glycine enolates.
- Fitzi, Robert,Seebach, Dieter
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p. 5277 - 5292
(2007/10/02)
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- 19F and 1H NMR of Aldimines of Fluoroamino Acids with Pyridoxal-5'-phosphate
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1H and 19F NMR spectra were obtained for six Schiff bases (aldimines)formed by pyridoxal-5'-phosphate (PLP) with four fluorinated or their two parent non-fluorinated α-amino acids (phenylalanine and α-aminobutyric acid). pKA Values were derived from 1H and 19F titration curves.The imine nitrogen of the aldimines is very basic (ca. 13) and sensitive to the electron withdrawing effect of fluorine.The pyridine nitrogen is less basic in the aldimines (ca. 7) than in PLP (8.12) and is less sensitive to the electron withdrawing effect of the fluorine than is the imine nitrogen.The phosphate group has a pK in the same range (ca. 6) and the chemical shifts of some nuclei are sensitive to both pK values.Protonation of the aldimine causes the 1H signal to shift downfield at the methyl protons of the pyridine ring and at the aldehydic proton of the aldimine for the high pK value (except for the aldimines prepared from the β-fluorophenylalanine), but upfield at the aromatic proton and at the aldehydic proton of the aldimine for the low pK.Protonation of the aldimine causes the 19F signal of an aryl fluorine to shift downfield but gives an upfield shift at a β-fluorine.These data are related to the highly conjugated electronic structure of the Schiff bases.
- Beguin, Claude,Hamman, Sylvain
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p. 129 - 132
(2007/10/02)
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