- Asymmetric Synthesis of N-Substituted α-Amino Esters from α-Ketoesters via Imine Reductase-Catalyzed Reductive Amination
-
N-Substituted α-amino esters are widely used as chiral intermediates in a range of pharmaceuticals. Here we report the enantioselective biocatalyic synthesis of N-substituted α-amino esters through the direct reductive coupling of α-ketoesters and amines employing sequence diverse metagenomic imine reductases (IREDs). Both enantiomers of N-substituted α-amino esters were obtained with high conversion and excellent enantioselectivity under mild reaction conditions. In addition >20 different preparative scale transformations were performed highlighting the scalability of this system.
- Yao, Peiyuan,Marshall, James R.,Xu, Zefei,Lim, Jesmine,Charnock, Simon J.,Zhu, Dunming,Turner, Nicholas J.
-
supporting information
p. 8717 - 8721
(2021/03/16)
-
- Synthesis of unnatural α-amino esters using ethyl nitroacetate and condensation or cycloaddition reactions
-
We report here on the use of ethyl nitroacetate as a glycine template to produce α-amino esters. This started with a study of its condensation with various arylacetals to give ethyl 3-aryl-2-nitroacrylates followed by a reduction (NaBH4 and then zinc/HCl) into α-amino esters. The scope of this method was explored as well as an alternative with arylacylals instead. We also focused on various [2 + 3] cycloadditions, one leading to a spiroacetal, which led to the undesired ethyl 5-(benzamidomethyl)isoxazole-3-carboxylate. The addition of ethyl nitroacetate on a 5-methylene-4,5-dihydrooxazole using cerium(IV) ammonium nitrate was also explored and the synthesis of other oxazole-bearing α-amino esters was achieved using gold(I) chemistry.
- Gagnot, Glwadys,Hervin, Vincent,Coutant, Eloi P.,Desmons, Sarah,Baatallah, Racha,Monnot, Victor,Janin, Yves L.
-
p. 2846 - 2852
(2018/11/27)
-
- IMIDAZOPYRAZINE DERIVATIVES, PROCESS FOR PREPARATION THEREOF, AND THEIR USES AS LUCIFERINS
-
The present invention is in the field of bioluminescence in biology and/or medicine. In particular, the invention provides imidazopyrazine derivatives, processes for preparation thereof, and their uses as luciferins.
- -
-
Page/Page column 64
(2018/11/22)
-
- Site-Selective γ-C(sp3)?H and γ-C(sp2)?H Arylation of Free Amino Esters Promoted by a Catalytic Transient Directing Group
-
The first selective PdII-catalysed γ-C(sp3)?H and γ-C(sp2)?H arylation of free amino esters using a commercially available catalytic transient directing group. A variety of free amino esters, including α-amino esters and β-amino esters, amino monoesters and amino bis-esters, are shown to react with a diverse range of simple aryl and heteroaryl iodide reagents.
- Lin, Hua,Wang, Chao,Bannister, Thomas D.,Kamenecka, Theodore M.
-
supporting information
p. 9535 - 9541
(2018/07/14)
-
- Copper-Catalyzed Addition of Alkylboranes to Iminoacetates: Access to α-Alkyl Branched α-Amino Acids
-
A copper(I)-catalyzed addition of alkylborane reagents to α-iminoacetates has been developed to assemble both acyclic and cyclic α-branched α-amino carboxylic acid derivatives in good yields. A wide variety of unactivated alkenes are well tolerated in this transformation. (Figure presented.).
- Xiao, Xinsheng,Zhang, Wei,Lu, Xiaoxia,Deng, Yuanfu,Jiang, Huangfeng,Zeng, Wei
-
p. 2497 - 2509
(2016/08/16)
-
- Preparation of cross-linked enzyme aggregates of l-aminoacylase via co-aggregation with polyethyleneimine
-
l-Aminoacylase from Aspergillus melleus was co-aggregated with polyethyleneimine and subsequently cross-linked with glutaraldehyde to obtain aminoacylase-polyethyleneimine cross-linked enzyme aggregates (termed as AP-CLEA). Under the optimum conditions, AP-CLEA expressed 74.9% activity recovery and 81.2% aggregation yield. The said method of co-aggregation and cross-linking significantly improved the catalytic stability of l-aminoacylase with respect to temperature and storage. AP-CLEA were employed for enantioselective synthesis of three unnatural amino acids (namely: phenylglycine, homophenylalanine and 2-naphthylalanine) via chiral resolution of their ester-, amide- and N-acetyl derivatives. The enantioselectivity of AP-CLEA was the highest for hydrolysis of amino acid amides; was moderate for hydrolysis of N-acetyl amino acids and was the least for hydrolysis of amino acid esters. Furthermore, AP-CLEA were found to retain more than 92% of the initial activity after five consecutive batches of (RS)-homophenylalanine hydrolysis suggesting an adequate operational stability of the biocatalyst.
- Vaidya, Bhalchandra K.,Kuwar, Suyog S.,Golegaonkar, Sandeep B.,Nene, Sanjay N.
-
experimental part
p. 184 - 191
(2012/03/22)
-
- Resolution of N-protected amino acid esters using whole cells of Candida parapsilosis ATCC 7330
-
Whole cells of Candida parapsilosis ATCC 7330 were used for the resolution of N-acetyl amino acid esters. Excellent enantioselectivities (E = 40 to >500) were achieved for the resolution of N-protected protein and non-protein amino acid esters giving good yields (28-50%) and high enantiomeric excesses (up to >99%) for both enantiomers.
- Stella, Selvaraj,Chadha, Anju
-
experimental part
p. 457 - 460
(2010/06/21)
-
- SUBSTITUTED BETA-PHENYL-ALPHA-HYDROXY PROPANOIC ACID, SYNTHESIS METHOD AND USE THEREOF
-
The present invention relates to a compound of the formula (I), wherein R1, R2 and R3 are each independently selected from H, OH, F, Cl, Br, methoxy and ethoxy; or alternatively, R1 and R2 together form -OCH2O-, R3 is selected from H, OH, methoxy, ethoxy and halogens; R4 is OH or acyloxy; R5 is cycloalkoxyl, amino and substituted amino, and when R5 is selected from amino, at least one of R1, R2 and R3 is not H. The present invention further relates to a process for synthesizing a compound of the formula (I), and use of the compound of the formula (I) in the manufacture of a medicament for the prevention or treatment of cardiovascular or cerebrovascular diseases.
- -
-
Page/Page column 10
(2009/02/10)
-
- Asymmetric petasis reactions catalyzed by chiral biphenols
-
Chiral biphenols catalyze the enantioselective Petasis reaction of alkenyl boronates, secondary amines, and ethyl glyoxylate. The reaction requires the use of 15 mol % of (S)-VAPOL as the catalyst, alkenyl boronates as nucleophiles, ethyl glyoxylate as the aldehyde component, and 3 A molecular sieves as an additive. The chiral α-amino ester products are obtained in good yields (71-92%) and high enantiomeric ratios (89:11-98:2). Mechanistic investigations indicate single ligand exchange of acyclic boronate with VAPOL and tetracoordinate boronate intermediates. Copyright
- Lou, Sha,Schaus, Scott E.
-
p. 6922 - 6923
(2008/09/21)
-
- Method for transferring amino acid into ketone acid(ester)
-
A method for transferring amino acid into ketone acid (ester) may obtain ketone acid (ester) at low cost. The method uses sodium hypochlorous acid as oxidizing agent and proceeds oxidation reaction with amino acid or its derivatives so as to obtain ketone acid and its derivatives. The sodium hypochlorous acid is easily to get with low cost and the conditions of the reaction are mild so that the method meets the needs of the industry.
- -
-
Page/Page column 2
(2008/06/13)
-
- Synthesis of 4-carboethoxy-4-oxazolin-2-ones from 3-nosyloxy-2-ketoesters
-
3-Nosyloxy-2-ketoesters, available from 2-ketoesters, react efficiently with methyl carbamate and tosic acid in refluxing toluene to provide 4-carboalkoxy-4-oxazolin-2-ones in good yields (41-84%).
- Hoffman, Robert V.,Johnson, M. Catherine,Okonya, John F.
-
p. 1283 - 1286
(2007/10/03)
-
- Ethyl N-(diphenylmethylene)glycinate as anionic glycine equivalent. Monoalkylation, dialkylation and michael additions under solid-liquid phase-transfer catalysis
-
Ethyl N-(diphenylmethylene)glycinate, 1, undergoes monoalkylations, dialkylations and Michael additions to ethylenic and acetylenic acceptors under appropriate solid-liquid phase transfer catalysis conditions. Further transformations of the α-disubstituted ketimines lead to α-alkylated aspartic and glutamic acid derivatives 10, 15, 19 and 26, to bicyclic amino acids or derivatives featuring pyrazolone and isoxazolone moieties 30 and 33, and to α-substituted (E)-3,4-dehydroglutamic acids. Copyright
- Lopez, Anna,Moreno-Manas, Marcial,Pleixats, Roser,Roglans, Anna,Ezquerra, Jesus,Pedregal, Concepcion
-
p. 8365 - 8386
(2007/10/03)
-
- Compounds for treating hypertension
-
Compounds of the formula STR1 and their pharmaceutically acceptable salts, wherein the substituents are as defined herein, having antihypertensive activity.
- -
-
-
- COMPOUNDS FOR TREATING HYPERTENSION
-
Compounds of the formula STR1 and their pharmaceutically acceptable salts, wherein the substituents are as defined herein, having antihypertensive activity.
- -
-
-