- Enantioselective Synthesis of β-Amino Acid Derivatives Enabled by Ligand-Controlled Reversal of Hydrocupration Regiochemistry
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A Cu-catalyzed enantioselective hydroamination of α,β-unsaturated carbonyl compounds for the synthesis of β-amino acid derivatives was achieved through ligand-controlled reversal of the hydrocupration regioselectivity. While the hydrocupration of α,β-unsaturated carbonyl compounds to form α-cuprated species has been extensively investigated, we report herein that, in the presence of an appropriate ancillary chiral ligand, the opposite regiochemistry can be observed for cinnamic acid derivatives, leading to the delivery of the copper to the β-position. This copper can react with an electrophilic aminating reagent, 1,2-benzisoxazole, to provide enantioenriched β-amino acid derivatives, which are important building blocks for the synthesis of natural products and bioactive small molecules.
- Buchwald, Stephen L.,Guo, Sheng,Zhu, Jiaqi
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supporting information
p. 20841 - 20845
(2020/09/16)
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- Β-phenylalanine ester synthesis from stable β-keto ester substrate using engineered ω-transaminases
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The successful synthesis of chiral amines from ketones using ω-transaminases has been shown in many cases in the last two decades. In contrast, the amination of β-keto acids is a special and relatively new challenge, as they decompose easily in aqueous solution. To avoid this, transamination of the more stable β-keto esters would be an interesting alternative. For this reason, ω-transaminases were tested in this study, which enabled the transamination of the β-keto ester substrate ethyl benzoylacetate. Therefore, a ω-transaminase library was screened using a coloring o-xylylenediamine assay. The ω-transaminase mutants 3FCR_4M and ATA117 11Rd show great potential for further engineering experiments aiming at the synthesis of chiral (S)- and (R)-β-phenylalanine esters. This alternative approach resulted in the conversion of 32% and 13% for the (S)- and (R)-enantiomer, respectively. Furthermore, the (S)-β-phenylalanine ethyl ester was isolated by performing a semi-preparative synthesis.
- BuΒ, Oliver,Voss, Moritz,Delavault, André,Gorenflo, Pascal,Syldatk, Christoph,Bornscheuer, Uwe,Rudat, Jens
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- Chiral Lewis Base-Catalyzed, Enantioselective Reduction of Unprotected β-Enamino Esters with Trichlorosilane
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Catalytic asymmetric reduction of N-unsubstituted β-enamino esters represents a major challenge for asymmetric catalysis. In this paper, the first organocatalytic system that could be used for the asymmetric hydrosilylation of N-unsubstituted β-enamino esters has been developed. Using N-tert-butylsulfinyl-L-proline-derived amides and L-pipecolinic acid-derived formamides as catalyst, a broad range of β-aryl- and β-alkyl-substituted free β-amino esters could be prepared with high yields and enantioselectivities. The practicality was illustrated by the gram-scale asymmetric synthesis of ethyl (R)-3-amino-3-phenylpropanoate and isopropyl (S)-3-amino-4-(2,3,5-trifluorophenyl)butanoate. The resulting product can be smoothly transformed to the FDA approved medicines dapoxetine and sitagliptin in a short synthetic route.
- Ye, Jianheng,Wang, Chao,Chen, Lin,Wu, Xinjun,Zhou, Li,Sun, Jian
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p. 1042 - 1047
(2016/04/19)
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- Development of a commercial process for (S)-β-phenylalanine (1)
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The development of a commercial manufacturing route for (S)-β-phenylalanine 8, a key pharmaceutical building block, is described. The different approaches which were investigated, based on catalytic asymmetric hydrogenation of enamide intermediates and on biocatalysis using acylase and lipase hydrolyses, are compared. The lipase resolution route was chosen for scale-up, and the final two-step process, based on readily available raw materials, is shown to be robust at full manufacturing scale
- Grayson, J. Ian,Roos, Juergen,Osswald, Steffen
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p. 1201 - 1206
(2011/12/16)
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- Scalable scny BRAnthesis of β-amino esters via reformatskcny BRA reaction with N-tert-butanesulfincny BRAl imines
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The Reformatskcny BRA reagents derived from ethcny BRAl bromoacetate and tert-butcny BRAl bromoacetate add cleanlcny BRA, in high cny BRAield, and with good diastereoselectivitcny BRA to N-tert-butanesulfincny BRAl aldimines and ketimines. Importantlcny BRA, this reaction scales well (>50 mmol), and affords products upwards of 70% cny BRAield over three steps, starting from commerciallcny BRA available N-tert-butanesulfinamide, aldehcny BRAdes, and ketones.
- Brinner, Kristin,Doughan, Brandon,Poon, Daniel J.
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experimental part
p. 991 - 993
(2009/10/10)
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- PROCESS FOR PRODUCING AMINO ACID DERIVATIVES
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The present invention relates to a process for producing amino acid derivatives such as optically active β-amino acid in short steps with good yield and high optical purity, which comprises reacting a keto acid of the formula (1): wherein R1 is hydrogen, an optionally substituted hydrocarbon, etc.; R2 is a spacer; and R3 is an optionally substituted alkoxy, etc., or a salt thereof, with ammonia or an amine or a salt thereof in the presence of a chiral catalyst and in the presence or absence of an acid and/or a fluorine-containing alcohol, to give an amino acid derivative of the formula (2): wherein Q is a group formed by removing one hydrogen atom from ammonia or an amine; X' is an acid and/or a fluorine-containing alcohol; and b is 0 or 1.
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Page/Page column 56
(2008/06/13)
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- Method for producing an optically active beta-amino acid
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To provide a producing method of an optically active β-amino acid useful as intermediate for the production of medicines, agricultural chemicals and physiologically active substances, by means of a catalytic and asymmetric synthesis method of high performance and a high enantiomeric excess, without requiring additional procedures such as introduction and removal of protecting group and so on. A producing method of an optically active β-amino acids which comprises subjecting an enamine to an asymmetric hydrogenation.
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- Non-peptide αvβ3 antagonists. Part 3: Identification of potent RGD mimetics incorporating novel β-amino acids as aspartic acid replacements
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Potent non-peptidic αvβ3 antagonists have been prepared incorporating various β-amino acids as aspartic acid mimetics. Modification of the β-alanine 3-substituents alters the potency and physicochemical properties of these receptor a
- Coleman, Paul J,Brashear, Karen M,Hunt, Cecilia A,Hoffman, William F,Hutchinson, John H,Breslin, Michael J,McVean, Carol A,Askew, Ben C,Hartman, George D,Rodan, Sevgi B,Rodan, Gideon A,Leu, Chih-Tai,Prueksaritanont, Thomayant,Fernandez-Metzler, Carmen,Ma, Bennett,Libby, Laura A,Merkle, Kara M,Stump, Gary L,Wallace, Audrey A,Lynch, Joseph J,Lynch, Robert,Duggan, Mark E
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- Discovery of an orally active non-peptide fibrinogen receptor antagonist based on the hydantoin scaffold
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Antagonists of the platelet fibrinogen receptor (GP IIb/IIIa receptor) are expected to be a promising new class of antithrombotic agents. The binding of fibrinogen to the fibrinogen receptor depends on an Arg-Gly-Asp-Ser (RGDS) tetrapeptide recognition motif. Structural modifications of the RGDS lead have led to the discovery of a non-peptide RGD mimetic GP IIb/IIIa antagonist 44 (S 1197). Compound 44 inhibited, in a dose dependent and reversible manner, human and dog platelet aggregation as well as 125I-fibrinogen binding to ADP-activated human gel filtered platelets and isolated GP IIb/IIIa with Ki values of 9 nM and 0.17 nM, respectively. A pharmacophore mapping procedure with QXP and a 3D-QSAR analysis applying the GRID/GOLPE methodology yielded a stable, rather predictive model and revealed structural features which are important for binding. Hydrophobic substitutions both at the hydantoin nucleus and at the C-terminus increase the affinity toward the fibrinogen receptor. The crystalline ethyl ester prodrug 48 (HMR 1794) is an orally active antithrombotic agent which is a promising drug candidate for the treatment of thrombotic diseases in humans.
- Stilz,Guba,Jablonka,Just,Klingler,K?nig,Wehner,Zoller
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p. 1158 - 1176
(2007/10/03)
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- Synthesis of enantiopure N-protected 4,5-disubstituted 3-pyrrolidinones and N-protected 2,5-disubstituted 3-pyrrolidinones via the Dieckmann reaction of dicarbonyl compounds derived from enantiopure β-amino esters
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Under the action of KHMDS in THF solvent the Dieckmann reaction of dicarbonyl compounds derived from enantiopure β-amino esters provides enantiopure N-protected 4,5-disubstituted 3-pyrrolidinones, whereas N-protected 2,5-disubstituted 3-pyrrolidinones formed in reactions mediated by tert-BuOK in DMF or toluene. Reduction of these pyrrolidinones afforded enantiopure polysubstituted pyrrolidines.
- Wang, Yue,Ma, Dawei
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p. 725 - 730
(2007/10/03)
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