135635-69-7Relevant academic research and scientific papers
Exploring the scope of an α/β-aminomutase for the amination of cinnamate epoxides to arylserines and arylisoserines
Shee, Prakash K.,Ratnayake, Nishanka Dilini,Walter, Tyler,Goethe, Olivia,Onyeozili, Edith Ndubuaku,Walker, Kevin D.
, p. 7418 - 7430 (2019/08/20)
Biocatalytic process-development continues to advance toward discovering alternative transformation reactions to synthesize fine chemicals. Here, a 5-methylidene-3,5-dihydro-4H-imidazol-4-one (MIO)-dependent phenylalanine aminomutase from Taxus canadensis (TcPAM) was repurposed to irreversibly biocatalyze an intermolecular amine transfer reaction that converted ring-substituted trans-cinnamate epoxide racemates to their corresponding arylserines. From among 12 substrates, the aminomutase ring-opened 3′-Cl-cinnamate epoxide to 3′-Cl-phenylserine 140 times faster than it opened the 4′-Cl-isomer, which was turned over slowest among all epoxides tested. GC/MS analysis of chiral auxiliary derivatives of the biocatalyzed phenylserine analogues showed that the TcPAM-transamination reaction opened the epoxides enantio- A nd diastereoselectively. Each product mixture contained (2S)+(2R)-anti (erythro) and (2S)+(2R)-syn (threo) pairs with the anti-isomers predominating (-90:10 dr). Integrating the vicinal proton signals in the 1H NMR spectrum of the enzyme-catalyzed phenylserines and calculating the chemical shift difference (?"?) between the anti and syn proton signals confirmed the diastereomeric ratios and relative stereochemistries. Application of a (2S)-threonine aldolase from E. coli further established the absolute stereochemistry of the chiral derivatives of the diastereomeric enzymatically derived products. The 2R:2S ratio for the biocatalyzed anti-isomers was highest (88:12) for 3′-NO2-phenylserine and lowest (66:34) for 4′-F-phenylserine. This showed that the stereospecificity of TcPAM is in part directed by the substituent-type on the cinnamate epoxide analogue. The catalyst also converted each cinnamate epoxide analogue to its corresponding isoserine, highlighting a biocatalytic route to arylisoserines, which play a key role in building the pharmacophore seen in anticancer and protease inhibitor drugs.
ENGINEERED POLYPEPTIDES AND THEIR APPLICATIONS IN SYNTHESIS OF BETA-HYDROXY-ALPHA-AMINO ACIDS
-
Page/Page column 26-32; 63; 64, (2019/01/04)
Provided are engineered polypeptides that are useful for the asymmetric synthesis of β-hydroxy-α-amino acids under industrial-relevant conditions. The engineered polypeptides disclosed are developed through directed evolution based on the ability of catalytic synthesis of (2S, 3R) -2-amino-3-hydroxy-3- (4-nitrophenyl) propanoic acid. Also provided are polynucleotides encoding the engineered polypeptides, host cells capable of expressing engineered polypeptides, and methods of producing β-hydroxy-α-amino acids using engineered polypeptides. Compared to other processes of preparation, the use of the engineered polypeptides for the preparation of β-hydroxy-α-amino acids results in high purity of the desired stereoisomers, mild reaction conditions, low pollution and low energy consumption. It has good industrial application prospects.
A new d-threonine aldolase as a promising biocatalyst for highly stereoselective preparation of chiral aromatic β-hydroxy-α-amino acids
Chen, Qijia,Chen, Xi,Cui, Yunfeng,Ren, Jie,Lu, Wei,Feng, Jinhui,Wu, Qiaqing,Zhu, Dunming
, p. 5964 - 5973 (2017/12/26)
d-Threonine aldolase is an enzyme belonging to the glycine-dependent aldolases, and it catalyzes the reversible aldol reaction of glycine and acetaldehyde to give d-threonine and/or d-allo-threonine. In this study, a putative d-threonine aldolase gene from Delftia sp. RIT313 was cloned and expressed in Escherichia coli BL21 (DE3). The purified enzyme (DrDTA, 47 KDa) exhibited 21.3 U mg-1 activity for the aldol addition of glycine and acetaldehyde in MES-NaOH buffer (pH 6.0) at 50 °C. Both pyridoxal 5′-phosphate and metal ions were needed for the reaction, and the existence of the metal ions enhanced the stability of the enzyme. It was found that the conversion and Cβ-stereoselectivity were dramatically influenced by the reaction temperature, co-solvent, amount of enzyme and reaction time, and it is possible to enable the reaction under kinetic control to retain suitable conversion and high stereoselectivity at the β-carbon, thus tackling the "Cβ-stereoselectivity problem". DrDTA showed high activity toward aromatic aldehydes with electron-withdrawing substituents. Under the optimized reaction conditions, phenylserines with a 2′-fluoro- or 3′-nitro-substituent were obtained with >90% conversion and >90% de. In addition, dl-threo-phenylserine and dl-threo-4-(methylsulfonyl)phenylserine were efficiently resolved with an excellent enantiomeric excess value (ee, >99%) using a whole cell biocatalyst in a two-phase system at 1.0 M and 0.3 M, respectively, the highest substrate concentration reported so far. These results suggested that DrDTA might be a promising biocatalyst for producing chiral aromatic β-hydroxy-α-amino acids.
Design and synthesis of novel chloramphenicol amine derivatives as potent aminopeptidase N (APN/CD13) inhibitors
Yang, Kanghui,Wang, Qiang,Su, Li,Fang, Hao,Wang, Xuejian,Gong, Jianzhi,Wang, Binghe,Xu, Wenfang
experimental part, p. 3810 - 3817 (2009/10/10)
Herein we report a series of novel chloramphenicol amine derivatives as aminopeptidase N (APN)/CD13 inhibitors. All compounds were synthesized starting from commercially available (1S,2S)-2-amino-1-(4-nitrophenyl) propane-1,3-diol. The preliminary biologi
Synthesis of β-hydroxy-α-amino acids with a reengineered alanine racemase
Fesko, Kateryna,Giger, Lars,Hilvert, Donald
supporting information; experimental part, p. 5987 - 5990 (2009/06/25)
The Y265A mutant of alanine racemase (alrY265A) was evaluated as a catalyst for the synthesis of β-hydroxy-α-amino acids. It promotes the PLP-dependent aldol condensation of glycine with a range of aromatic aldehydes. The desired products were obtained wi
Synthesis of all stereoisomers and some congeners of isocytoxazone
Hamer?ak, Zdenko,?epac, Dragan,?iher, Dinko,?unji?, Vitomir
, p. 375 - 382 (2007/10/03)
cis-Isocytoxazone 2a and trans-isocytoxazone 2b, structural isomers of the antiasthmatic agent cytoxazone (-)-1, and their 5-substituted congeners 23-28 have been prepared. Aldol reaction of para-substituted benzaldehydes with 7-chloro-1-methyl-5-phenyl-1,4-benzodiazepin-2-one, followed by separation of diastereomeric racemates afforded 3-10. Acid-catalyzed 1,4-benzodiazepine ring opening, and transformation of the methyl esters of β-aryl-β-hydroxy-α-amino acids (11-16) via 4-methoxycarbonyl derivatives of 1,3-oxazolidin-2-one (17-22) and their reduction afforded the target oxazolidin-2-one derivatives 23-28. Racemic isocytoxazones 2a and 2b were prepared by an independent route starting from 4-methoxystyrene epoxide. Pure enantiomers of these diastereomeric racemates were separated by HPLC chromatography on chiral stationary phases. Their CD spectra, along with those of previously prepared enantiomers of cis-cytoxazone 1a and trans-cytoxazone 1b are discussed.
Neighbouring group effects promote substitution reactions over elimination and provide a stereocontrolled route to chloramphenicol
Easton, Christopher J.,Hutton, Craig A.,Merrett, Martin C.,Tiekink, Edward R. T.
, p. 7025 - 7036 (2007/10/03)
In reactions of β-brominated valine and p-nitrophenylalanine derivatives to give β-hydroxy amino acid derivatives the carboxyl group, when protected as an amide, exerts a neighbouring group effect to facilitate the substitution process, and reduce competing elimination reactions. As a consequence of the effect, the (2R,3R)- and (2R,3S)-stereoisomers of 3-bromo-N-tert-butyl-N(α)-phthaloyl-p-nitrophenylalaninamide both react to give (2S,3R)-3-hydroxy-N-tert-butyl-N(α)-phthaloyl-p-nitrophenylalaninamid e, providing a stereoconvergent route to chloramphenicol.
Preparation of (2R,3S)-β-hydroxy-α-amino acids by use of novel Streptomyces aldolase as a resolving agent for racemic material
Herbert, Richard B.,Wilkinson, Barrie,Ellames, George J.
, p. 114 - 117 (2007/10/02)
A unique aldolase, which was isolated from Streptomyces amakusaensis, is used to catalyse a reverse aldol reaction on representative racemic β-hydroxy-α-amino acids (3-6) to give samples of the (2R,3S)-(D-threo)-enantiomers with excellent enantiomeric purity.
General Method for the Synthesis of Enantiomerically Pure β-Hydroxy-α-amino Acids, containing Fluorine Atoms in the Side Chains. Case of Stereochemical Distinction between Methyl and Trifluoromethyl Groups. X-Ray Crystal and Molecular Structure of the Nickel(II) Complex of ...
Soloshonok, Vadim A.,Kukhar, Valeri P.,Galushko, Sergei V.,Svistunova, Nataly Yu.,Avilov, Dimitri V.,et al.
, p. 3143 - 3156 (2007/10/02)
The chiral NiII complex 1 of a Schiff's base derived from (S)-o-benzophenone (BPB) and glycine was treated with fluoro-substituted aldehydes (aliphatic and aromatic) in MeOH or CHCl3.The addition proceeds with high diastereoselectivity to give, if catalysed by MeONa in MeOH, the corresponding complexes of syn-(2R)-3-fluorophenylserines (84-100percent) d.e.) and syn-(2S)-fluoroalkylserines (90percent d.e.), and, if catalysed by NEt3 or DABCO (MeOH or CHCl3), the corresponding complexes of syn-(2S)-, and anti-(2S)-3-fluorophenylserines and fluoroalkylserines.The second-order asymmetric transformation may be successfully employed to obtain diastereoisomerically pure complexes of anti-(2R)-3-fluorophenylserines.Condensation of trifluoroacetone with complex 1, catalysed by MeONa, gave predominantly (at least >95percent d.e.) the diastereoisomeric complex, containing (2S,3S)-β-(trifluoromethyl)threonine, as shown by an X-ray diffraction structural study.Diastereoisomerically and enantiomerically pure fluorine-containing 3-phenyl- and 3-alkyl-serines were obtained from the corresponding diastereomerically pure complexes, separated by chromatography or crystallization.The initial chiral auxiliary BPB was recovered (80-98percent).The influence of the reaction's conditions and the nature of the corresponding fluoro-substituted aldehydes on the diastereoselectivity of the reactions is discussed.
Benzyl (R)- and (S)-tert-Butyl-5-oxo-oxazolidine-3-carboxylate for Convenient Preparation of D- and L-Threonine Analogs from Aldehydes
Blaser, Denis,Seebach, Dieter
, p. 1067 - 1078 (2007/10/02)
Lithium enolates of (R)- or (S)-oxazolidinones 1 (specified in the title) are generated with lithium hexamethyldisilazanide (LHMDS) in THF at -75 deg C and added to aliphatic or aromatic aldehydes (products 2-18 of hydroxyalkylation, yields mostly over 80percent, diastereoselectivities usually over 98percent; Scheme 2).The adducts can be cleaved to give threonine analogs (19-32) under salt-free conditions (H2/Pd-C, then H2O and evaporation of the solvents, Scheme 3).In some cases, the primary adducts may cyclize with elimination of benzyl alcohol to give bicyclic carbamates 33 which, in turn, can be hydrolyzed to 5-substituted trans-2-oxo-1,3-oxazolidine-4-carboxylic acids 34 (Scheme 4). - The essentially complete threo selectivity of the coupling step is proved by NMR spectroscopy and by chemical correlations.The stereochemical course of the reaction is opposite to that observed with carbocyclic enolates; possible reasons for this behavior are discussed (Scheme 5). - The starting material rac-1, prepared from glycine, pivalaldehyde and benzyl chloroformate, is readily resolved by chromatography on preparative scale by using the stationary phase Chiraspher and a Prepbar system (Scheme 1); The undesired enantiomer may be recycled by thermal racemization (heating at reflux in CH3CN for 8 h). Key Words: D- or L-Threonines / Aldol additions / Diastereoselective coupling of trigonal centers / 1,3-Oxazolidin-5-ones / 1,3-Oxazolidin-2-ones, 5-substituted, 4-carboxylic acid
