40469-85-0Relevant articles and documents
Resolution of α/β-amino acids by enantioselective penicillin G acylase from Achromobacter sp.
Grulich, Michal,Brezovsky, Jan,?těpánek, Václav,Palyzová, Andrea,Kyslíková, Eva,Kyslík, Pavel
, p. 240 - 247 (2015/10/28)
Penicillin G acylases (PGAs) are enantioselective enzymes catalyzing a hydrolysis of stable amide bond in a broad spectrum of substrates. Among them, derivatives of α- and β-amino acids represent a class of compounds with high application potential. PGAEc from Escherichia coli and PGAA from Achromobacter sp. CCM 4824 were used to catalyze enantioselective hydrolyses of seven selected N-phenylacetylated α/β-amino acid racemates. The PGAA showed higher stereoselectivity for enantiomers of N-PhAc-β-homoleucine, N-PhAc-α-tert-leucine and N-PhAc-β-leucine. To study the mechanism of enantiodiscrimination on molecular level, we have constructed a homology model of PGAA that was used in molecular docking experiments with the same substrates. In-silico experiments successfully reproduced the data from experimental enzymatic resolutions confirming validity of employed modeling protocol. We employed this protocol to evaluate enantiopreference of PGAA towards seven new substrates with application potential. For five of them, high enantioselectivity of PGAA was predicted.
METHOD FOR OBTAINING OPTICALLY PURE AMINO ACIDS
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Page/Page column 7, (2012/02/01)
This invention relates to a method for obtaining optically pure amino acids, including optical resolution and optical conversion. This method significantly shortens the time taken for optical transformation, and enables the repeated use of an organic solution containing a enantioselective receptor, to thereby obtain optically pure amino acids in a simple and remarkably efficient manner, and to enable the very economical mass production of optically pure amino acids.
METHOD FOR OBTAINING OPTICALLY PURE AMINO ACIDS
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Page/Page column 10-11, (2012/02/14)
This invention relates to a method for obtaining optically pure amino acids, including optical resolution and optical conversion. This method significantly shortens the time taken for optical transformation, and enables the repeated use of an organic solution containing a enantioselective receptor, to thereby obtain optically pure amino acids in a simple and remarkably efficient manner, and to enable the very economical mass production of optically pure amino acids.
Experimental and theoretical studies on Mannich-type reactions of chiral non-racemic N-(benzyloxyethyl) nitrones
Diez-Martinez, Alba,Tejero, Tomas,Merino, Pedro
experimental part, p. 2934 - 2943 (2011/03/19)
The nucleophilic addition of both silyl ketene acetals and lithium enolates derived from methyl acetate to chiral non-racemic N-(benzyloxyethyl)nitrones has been studied both experimentally and theoretically. Aromatic nitrones showed lower reactivity that
Kinetic and NMR spectroscopic studies of chiral mixed sodium/lithium amides used for the deprotonation of cyclohexene oxide
Sott, Richard,Granander, Johan,Williamson, Carl,Hilmersson, Goeran
, p. 4785 - 4792 (2007/10/03)
The mixed-metal complex formed from n-butylsodium, n-butyllithium, and a chiral amino ether has been studied by NMR spectroscopy. Three different mixed-metal amides were used as chiral bases for the deprotonation of cyclohexene oxide. The selectivity and initial rate of reaction were compared for sodium-amido ethers, lithium-amido ethers, and mixtures of sodium and lithiumamido ethers in diethyl ether and tetrahydrofuran, respectively. The mixed sodium/lithium amides are more reactive than the single sodium and lithium amides, whereas the stereoselectivities are higher when lithium amides are used. The alkali-metal/γ-amido ethers exhibit both higher initial reaction rates and stereoselectivities than their β-amido ether analogues. NMR spectroscopic studies of mixtures of n-butylsodium (nBuNa), n-butyllithium (nBuLi), and the γ-amino ethers in diethyl ether show the exclusive formation of dimeric mixed-metal amides. In diethyl ether, the lithium atom of the mixed-metal amide is internally coordinated and the sodium atom is exposed to solvent; however, in tetrahydrofuran, both metals are internally coordinated.
PROCESS FOR PRODUCING AMINO ACID DERIVATIVES
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Page 8-10, (2008/06/13)
Process for producing amino acid derivatives, in which (a) an organic amine, the amino functionality of which is protected, or an α-amino acid, the amino functionality of which is protected, is subjected to an electrochemical reaction so as to form an ami
Chemoenzymatic synthesis of 4-amino-2-hydroxy acids: A comparison of mutant and wild-type oxidoreductases
Sutherland, Andrew,Willis, Christine L.
, p. 7764 - 7769 (2007/10/03)
We describe a new chemoenzymatic synthesis of enantiopure 4-amino-2-hydroxy acids using two biotransformations in a single-pot process in aqueous medium. These compounds are valuable as γ-turn mimics for investigations into the secondary structure of peptides. The enzyme substrates are a series of carbobenzyloxy (CBZ)-protected 4-amino-2-keto esters, prepared efficiently from the L-amino acids, alanine, leucine, phenylalanine, and valine. First, the α-amino acids were converted to the corresponding β-amino acids in a simple five-step procedure. A further one-carbon homologation via ozonolysis of the corresponding β-keto cyanophosphoranes gave the required α-keto esters in good yield. The enzyme catalyzed hydrolyses of all the α-keto esters to the corresponding α-keto acids proceeded smoothly with the lipase from Candida rugosa. Using the same reaction pot, it was found that wild-type lactate dehydrogenases from either Bacillus stearothermophilus CBS-LDH) or Staphylococcus epidermidis (SE-LDH) could be used to specifically reduce the ketone of the alanine-derived α-keto acid 2, giving the (S)- and CR)-2-hydroxy acids, respectively, in good yields. However, the more bulky α-keto acids 3, 4, and 5 (derived from valine, leucine, and phenylalanine) were not substrates for these enzymes. In contrast, the genetically engineered H205Q mutant of D-hydroxyisocaproate dehydrogenase proved to be an ideal catalyst for the reduction of all the α-keto acids 2-5, giving excellent yields of the CBZ-protected (2R,4S)-4-amino2-hydroxy acids as single diastereomers. This genetically engineered oxidoreductase has great potential value in synthesis due to its broad substrate specificity and high catalytic activity. For example, reduction of 1 mmol of N-protected (S)-4-amino-2-oxopentanoic acid 2 took just 4 h with the H205Q mutant giving, after esterification, the CR)-2-alcohol 25 in 85% yield, whereas with SE-LDH the reaction required 4 days to give a 67% yield of 25.
Enantioselektive Synthese von β-Aminosaeuren - TMS-SAMP als chirales Ammoniak-Aequivalent in der azaanalogen Michael-Addition an α,β-ungesaettigte Ester
Enders, Dieter,Wahl, Heiner,Bettray, Wolfgang
, p. 527 - 529 (2007/10/02)
Stichworte: Aminosaeuren * Asymmetrische Synthesen * Chirale Hilfsstoffe * Michael-Additionen
Stereochemistry of the Leucine 2,3-Aminomutase from Tissue Cultures of Andrographis paniculata
Freer, Isabel,Pedrocchi-Fantoni, Giuseppe,Picken, Douglas J.,Overton, Karl H.
, p. 80 - 82 (2007/10/02)
A leucine 2,3-aminomutase from Andrographis tissue cultures mediates the equilibrium between (2S)-α- and (3R)-β-leucine; the activity does not apparently depend on coenzyme B12.