- Dynamic Kinetic Resolution for Asymmetric Synthesis of L-Noncanonical Amino Acids from D-Ser Using Tryptophan Synthase and Alanine Racemase
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L-Ser is often used to synthesize some significant l-noncanonical α-amino acids(l-ncAAs), which are the prevalent intermediates and precursors for functional synthetic compounds. In this study, threonine aldolase from Escherichia coli k-12 MG1655 has been used to synthesize l-Ser. In contrast to the maximum catalytic capacity (20 g/L) for l-threonine aldolase(LTA), d-Ser was synthesized with high yield (240 g/L) from cheap Gly and paraformaldehyde using d-threonine aldolase (DTA) from Arthrobacter sp ATCC. In order to fully utilize d-Ser and expand the resource of l-Ser, a dynamic kinetic resolution system was constructed to convert d/dl-Ser to l-Ser through combining alanine racemase (Alr) from Bacillus subtilis with l-tryptophan synthase (TrpS) from Escherichia coli k-12 MG1655, and l-ncAAs including l-Trp and l-Cys derivatives were synthesized with excellent enantioselectivity and in high yields. The results indicated l-ncAAs could be efficiently synthesized from d-Ser using this original and green dynamic kinetic resolution system, and the reliable l-Ser resource has been established from simple and achiral substrates.
- Yu, Jinhai,Li, Jing,Gao, Xia,Zeng, Shuiyun,Zhang, Hongjuan,Liu, Junzhong,Jiao, Qingcai
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p. 6618 - 6625
(2019/11/03)
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- Subtype-Specific Agonists for NMDA Receptor Glycine Binding Sites
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A series of analogues based on serine as lead structure were designed, and their agonist activities were evaluated at recombinant NMDA receptor subtypes (GluN1/2A-D) using two-electrode voltage-clamp (TEVC) electrophysiology. Pronounced variation in subunit-selectivity, potency, and agonist efficacy was observed in a manner that was dependent on the GluN2 subunit in the NMDA receptor. In particular, compounds 15a and 16a are potent GluN2C-specific superagonists at the GluN1 subunit with agonist efficacies of 398% and 308% compared to glycine. This study demonstrates that subunit-selectivity among glycine site NMDA receptor agonists can be achieved and suggests that glycine-site agonists can be developed as pharmacological tool compounds to study GluN2C-specific effects in NMDA receptor-mediated neurotransmission.
- Maolanon, Alex R.,Risgaard, Rune,Wang, Shuang-Yan,Snoep, Yoran,Papangelis, Athanasios,Yi, Feng,Holley, David,Barslund, Anne F.,Svenstrup, Niels,Hansen, Kasper B.,Clausen, Rasmus P.
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p. 1681 - 1687
(2017/08/21)
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- PROCESS FOR PRODUCING SULFUR-CONTAINING AMINO ACIDS
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The present invention relates to a process for producing a sulfur-containing amino acid, comprising a step of oxidizing a 2-aminoethanol compound having, at position 2, a sulfur-containing hydrocarbon group having 1 to 24 carbon atoms in the presence of copper and water.
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Page/Page column 17-18
(2011/10/31)
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- N-Salicylideneamino acidato complexes of oxovanadium(IV). the cysteine and penicillamine complexes
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Oxovanadium(iv) complexes with ligands derived from the reaction of salicylaldehyde with L-cysteine and with D- and D,L-penicillamine are prepared. The compounds are characterised by elemental analysis, spectroscopy (UV-VIS, CD, EPR), TG, DSC and magnetic susceptibility measurements (9-295 K). We discuss several aspects related to the structure of these complexes in the solid state and in solution; in particular, the possibility of forming thiazolidine complexes, and their comparison with the characterised complexes is studied by molecular mechanics and density functional theory calculations. The solution structures depend on pH and solvent, and while with L-Cys the spectroscopic results show trends similar to those of the L-Ala and L-Ser systems up to ca. pH 8-9, where thiolate coordination starts being detected, the penicillamine system is quite distinct, namely thiolate coordination occurs for pH > 6.5. In the presence of salicylaldehyde and VIVO the desulfydration of cysteine proceeds rapidly, but no similar reaction occurs with penicillamine, although its decomposition is also activated. The DFT calculations do not indicate any energetic basis for this distinct reactivity, which possibly results from different complexes present in the Cys and Pen systems. In the cysteine system, the N-salicylidene dehydroalanine-VIVO complex V is believed to form in an intermediate stage of the desulfydration. Further, addition of several nucleophiles to the cysteine reaction mixtures produce amino acid derivatives by a Michael-type base-catalysed addition, a result compatible with the formation of V. The products of these reactions were analysed by TLC and HPLC, and in some cases isolated.
- Pessoa, Joao Costa,Calhorda, Maria J.,Cavaco, Isabel,Costa, Paulo J.,Correia, Isabel,Costa, Dina,Vilas-Boas, Luis F.,Felix, Vitor,Gillard, Robert D.,Henriques, Rui T.,Wiggins, Robert
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p. 2855 - 2866
(2007/10/03)
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- Versatile Synthesis of Stereospecifically Labelled D-Amino Acids via Labelled Aziridines - Preparation of (2R,3S)-- and (2R,3R)--Serine; (2S,2'S,3S,3'S)-- and (2S,2'S,3R,3'R)--Cystine; and (2S,3S)- and (2S,3R)--β-Chloroalanine
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Stereospecifically β-labelled protected 2-carboxyaziridines 2, with the stereochemistry of a D-amino acid at C-2, have been prepared by a chemicoenzymic synthesis.Preparation of the labelled malates 5, by hydration of fumaric acid using the enzyme fumarase or by amination with aspartase followed by nitrosation, was followed by conversion into the isoserines 3, by a process involving Curtius rearrangement with retention of stereochemistry at the chirally labelled primary centre.Protection and ring closure gave the aziridines 2, which, on ring opening with the appropriate nucleophiles and deprotection, gave stereospecifically labelled samples of D-serine 16, D-cystine 20 and β-chloro-D-alanine 22.
- Axelsson, B. Svante,O'Toole, Kevin J.,Spencer, Philip A.,Young, Douglas W.
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p. 807 - 816
(2007/10/02)
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- ASYMMERTIC SYNTHESIS OF Β-SUBSTITUTED α-AMINO ACIDS VIA A CHIRAL Ni(II) COMPLEX OF DEHYDROALANINE
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An efficient approach to the asymmetric synthesis of β-substituted (S)-alanines is describen.The chiral Ni(II) complex of a Schiff base derived from (S)-o-N-(N-benzylpropyl)aminobenzophenone (BBP) and glycine was treated with formaldehyde and sodium methoxide to give a corresponding (R)-serine complex which, in turn, was converted to the chiral Ni(II) dehydroalanine complex.Michael type base catalyzed addition of nucleophiles (including MeOH, Me2NH, PhCH2NH2, imidazole, PhSH, PhCH2SH,, malonic ester and benzylmagnesium chloride) produced a mixture of diastereoisomeric complexes with a 70-90percent excess of S,S (or L,L) isomers over the S,R (or L,D) ones.The cleavage of pure diastereoisomers with aqueous HCl gave, in good yields, β-substituted (S) (or L)-alanines and regenerated the chiral auxiliary (BBP).
- Belokon, , Yuri N.,Sagyan, Ashot S.,Djamgaryan, Silva M.,Bakhmutov, Vladimir I.,Belikov, Vasili M.
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p. 5507 - 5514
(2007/10/02)
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- Amino Acids, 12. - Syntheses of DL-Cysteines from Acrylic Acid Derivatives
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The addition of sulfenyl chlorides 1 to 2-alkenoic acid esters 2 gives mixtures of 2(3)-chloro-3(2)-thioalkenoic acid esters 3/4, whereas the addition of thiols 7 to methyl 2-chloro-2-propenoate (6) results in the formation of methyl 2-chloro-3-thiopropanoates 3 only.The dependence of the isomerization of 3 to 4 on the reaction conditions was investigated; at higher temperatures the formation of 4 is especially favored.At temperatures below 55 deg C the 2-azido compounds 8 are obtained without isomerization from 3 by reaction with sodium azide in the presence of a PT catalyst.Cysteine derivatives 9 or 10, resp., are obtained by hydrogenation of 8 with H2S/pyridine/H2O or with H2/Re2S; the overall yields of 9 or 10, resp., starting from 6 are as high as 70percent.DL-Cysteine is obtained in good overall yields as hydrochloride hydrate 16 by HCl-catalyzed hydrolysis of the 2-thiazolines 15a*HCl and 15e, which are prepared by HCl-catalyzed addition of thioacetamide (11a) to α-chloroacrylic acid (12) or the amide 13 and consecutive ring closure.
- Effenberger, Franz,Beisswenger, Thomas,Dannenhauer, Fritz
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p. 2209 - 2224
(2007/10/02)
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- S-substituted 2-azido-3-mercapto-propionic acid ester and process for its production and use
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The subject matter of the invention are S-substituted 2-azido-3-mercapto-propionic acid esters of the general formula STR1 in which R1 is a methyl or ethyl group and R2 is an unsubstituted or substituted alkyl group, a cycloalkyl group, an unsubstituted or substituted aromatic or heteroaromatic group or a benzyl group, and a process for their production by reaction of a methyl or ethyl ester of 2-chloroacrylic acid with a corresponding thiol to form an S-substituted 2-chloro-3-mercapto-propionic acid ester and subsequently exchanging the chlorine atom with an azido group as well as use of the compounds of formula (I) as intermediate products in the production of D,L-cysteine or derivatives of D,L-cysteine.
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