- The kinetic resolution of oxazinones by alcoholysis: access to orthogonally protected β-amino acids
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The catalytic, alcoholytic kinetic resolution of oxazinones is reported. A novel, stereochemically dense cinchona alkaloid-based catalyst can facilitate the highly enantiodiscriminatory (Sup to 101) ring-opening of oxazinones equipped with electrophilic aryl units to generate orthogonally protected β-amino acids for the first time.
- Connon, Stephen J.,Cronin, Sarah A.
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supporting information
p. 7348 - 7352
(2021/09/07)
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- Base-induced Sommelet–Hauser rearrangement of N-(α-(2-oxyethyl)branched)benzylic glycine ester-derived ammonium salts via a chelated intermediate
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The base-induced Sommelet–Hauser (S–H) rearrangement of N-(α-branched)benzylic glycine ester-derived ammonium salts 1 was investigated. When the α-branched substituent was a simple alkyl, such as a methyl or butyl, desired S–H rearrangement product 2 was obtained in low yield with formation of the [1,2] Stevens rearranged 4 and Hofmann eliminated products 5 and 6. However, when the α-branched substituent had a 2-oxy moiety, such as 2-acetoxyethyl or 2-benzoyloxyethyl, the yields of 2 were improved. These results could be explained by formation of chelated intermediate C that stabilizes the carbanionic ylide, and the subsequent initial dearomative [2,3] sigmatropic rearrangement would be accelerated. The existence of C was supported by mechanistic experiments. This enhancement effect is not very strong or effective; however, it will expand the synthetic usefulness of ammonium ylide rearrangements.
- Baba, Souya,Hirano, Kazuki,Tayama, Eiji
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supporting information
(2020/03/13)
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- Synthesis, molecular docking and biological evaluation of novel phthaloyl derivatives of 3-amino-3-aryl propionic acids as inhibitors of Trypanosoma cruzi trans-sialidase
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In the last two decades, trans-sialidase of Trypanosoma cruzi (TcTS) has been an important pharmacological target for developing new anti-Chagas agents. In a continuous effort to discover new potential TcTS inhibitors, 3-amino-3-arylpropionic acid derivatives (series A) and novel phthaloyl derivatives (series B, C and D) were synthesized and molecular docking, TcTS enzyme inhibition and determination of trypanocidal activity were carried out. From four series obtained, compound D-11 had the highest binding affinity value (?11.1 kcal/mol) compared to reference DANA (?7.8 kcal/mol), a natural ligand for TS enzyme. Furthermore, the 3D and 2D interactions analysis of compound D-11 showed a hydrogen bond, π-π stacking, π-anion, hydrophobic and Van der Waals forces with all important amino acid residues (Arg35, Arg245, Arg314, Tyr119, Trp312, Tyr342, Glu230 and Asp59) on the active site of TcTS. Additionally, D-11 showed the highest TcTS enzyme inhibition (86.9% ± 5) by high-performance ion exchange chromatography (HPAEC). Finally, D-11 showed better trypanocidal activity than the reference drugs nifurtimox and benznidazole with an equal % lysis (63 ± 4 and 65 ± 2 at 10 μg/mL) and LC50 value (52.70 ± 2.70 μM and 46.19 ± 2.36 μM) on NINOA and INC-5 strains, respectively. Therefore, D-11 is a small-molecule with potent TcTS inhibition and a strong trypanocidal effect that could help in the development of new anti-Chagas agents.
- Kashif, Muhammad,Chacón-Vargas, Karla Fabiola,López-Cedillo, Julio Cesar,Nogueda-Torres, Benjamín,Paz-González, Alma D.,Ramírez-Moreno, Esther,Agusti, Rosalia,Uhrig, Maria Laura,Reyes-Arellano, Alicia,Peralta-Cruz, Javier,Ashfaq, Muhammad,Rivera, Gildardo
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p. 252 - 268
(2018/07/14)
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- Kinetic Resolution of Aromatic β-Amino Acids Using a Combination of Phenylalanine Ammonia Lyase and Aminomutase Biocatalysts
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An enzymatic strategy for the preparation of (R)-β-arylalanines employing phenylalanine aminomutase and ammonia lyase (PAM and PAL) enzymes has been demonstrated. Candidate PAMs with the desired (S)-selectivity from Streptomyces maritimus (EncP) and Bacillus sp. (PabH) were identified via sequence analysis using a well-studied template sequence. The newly discovered PabH could be linked to the first ever proposed biosynthesis of pyloricidin-like secondary metabolites and was shown to display better β-lyase activity in many cases. In spite of this, a method combining the higher conversion of EncP with a strict α-lyase from Anabaena variabilis (AvPAL) was found to be more amenable, allowing kinetic resolution of five racemic substrates and a preparative-scale reaction with >98% (R) enantiomeric excess. This work represents an improved and enantiocomplementary method to existing biocatalytic strategies, allowing simple product separation and modular telescopic combination with a preceding chemical step using an achiral aldehyde as starting material. (Figure presented.).
- Weise, Nicholas J.,Ahmed, Syed T.,Parmeggiani, Fabio,Turner, Nicholas J.
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supporting information
p. 1570 - 1576
(2017/05/05)
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- Stereoselective chemoenzymatic preparation of β-amino esters: Molecular modelling considerations in lipase-mediated processes and application to the synthesis of (S)-dapoxetine
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A wide range of optically active 3-amino-3-arylpropanoic acid derivatives have been prepared by means of a stereoselective chemoenzymatic route. The key step is the kinetic resolution of the corresponding β-amino esters. Although the enzymatic acylations of the amino group with ethyl methoxyacetate showed synthetically useful enantioselectivities, the hydrolyses of the ester group catalyzed by lipase from Pseudomonas cepacia have been identified as the optimal processes concerning both activity and enantioselectivity. The enantiopreference of this lipase in these reactions has been explained, at the molecular level, by using a fragment-based approach in which the most favoured binding site for a phenyl ring and the most stable conformation of the 3-aminopropanoate core nicely match the (S)-configuration of the major products. The conversion and enantioselectivity values of the enzymatic reactions have been compared in order to understand the influence of the different substitution patterns present in the phenyl ring. This chemoenzymatic route has been successfully applied to the preparation of a valuable intermediate in the synthesis of (S)-dapoxetine, which has been chemically synthesised in excellent optical purity.
- Rodriguez-Mata, Maria,Garcia-Urdiales, Eduardo,Gotor-Fernandez, Vicente,Gotor, Vicente
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supporting information; experimental part
p. 395 - 406
(2010/06/15)
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- Phenylalanine aminomutase-catalyzed addition of ammonia to substituted cinnamic acids: A route to enantiopure α- and β-amino acids
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(Chemical Equation Presented) An approach is described for the synthesis of aromatic α- and β-amino acids that uses phenylalanine aminomutase to catalyze a highly enantioselective addition of ammonia to substituted cinnamic acids. The reaction has a broad scope and yields substituted α- and β-phenylalanines with excellent enantiomeric excess. The regioselectivity of the conversion is determined by substituents present at the aromatic ring. A box model for the enzyme active site is proposed, derived from the influence of the hydrophobicity of substituents on the enzyme affinity toward various substrates.
- Szymanski, Wiktor,Wu, Bian,Weiner, Barbara,De Wildeman, Stefaan,Feringa, Ben L.,Janssen, Dick B.
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supporting information; experimental part
p. 9152 - 9157
(2010/03/01)
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- LYSOBACTIN AMIDES
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The invention relates to lysobactin amides and methods for their preparation, as well as their use for manufacturing medicaments for the treatment and/or prophylaxis of diseases, in particular bacterial infectious diseases.
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- 3-AMINO-3-ARYLPROPIONIC ACID n-ALKYL ESTERS, PROCESS FOR PRODUCTION THEREOF, AND PROCESS FOR PRODUCTION OF OPTICALLY ACTIVE 3-AMINO-3-ARYLPROPIONIC ACIDS AND ESTERS OF THE ANTIPODES THERETO
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The present invention is to provide an n-alkyl 3-amino-3-arylpropionate represented by the formula (I): wherein Ar1 represents an aryl group which may have a substituent(s), provided that a phenyl group and 4-methoxyphenyl group are excluded, R1 represents an n-propyl group or an n-butyl group, and a process for preparing the same, and its optically active compound and an optically active (S or R)-3-amino-3-arylpropionic acid represented by the formula (III-a): wherein Ar represents an aryl group which may have a substituent(s), and * represents an asymmetric carbon, and a process for preparing an optically active n-alkyl (R or S)-3-amino-3-arylpropionate represented by the formula (IV-a): wherein Ar and R1 have the same meanings as defined above, * represents an asymmetric carbon, provided that it has a reverse absolute configuration to the compound of the formula (III-a).
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Page/Page column 33
(2008/06/13)
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- A one-pot synthesis of 3-amino-3-arylpropionic acids
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3-Aminopropionic acids (β-amino acids) are biologically active compounds of interest in medicinal and pharmaceutical chemistry. Twenty-one 3-amino-3-arylpropionic acids were synthesized via a facile one-pot synthesis. In addition, a series of mechanistic studies have been performed to optimize the production of these β-amino acids. The reaction mechanism of this one-pot synthesis of β-amino acids, as well as the electronic effect of para-substitution and the influence of solvent polarity on the proposed reaction mechanism are discussed.
- Tan,Weaver
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p. 7449 - 7461
(2007/10/03)
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- Design and preparation of serine-threonine protein phosphatase inhibitors based upon the nodularin and microcystin toxin structures. Part 3
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Nodularin and microcystins are complex natural cyclic isopeptidic hepatotoxins that serve as subnanomolar inhibitors of the eukaryotic serine-threonine protein phosphatases PP1 and PP2A, enzymes that are intimately involved in controlling cellular metabolism. Previously we described a solution-phase synthesis of stripped-down nodularin analogues; cyclo[-β-Ala-(R)-Glu-α-OMe-γ-Sar-(R)-Asp-α-OMe- β-(S)-Phe-] 3 and cyclo[-(3R)-3-hydroxymethyl-β-Ala-(R)-Glu-α-OMe-γ-Sar-(R)- Asp-α-OMe-β-(S)-Phe-] 5. The synthetic strategy was designed to allow post-macrocyclisation elaboration. Here we examine alternative methods for introducing diversity and achieving macrolactamisation and compare the relative efficiency of solution- vs. solid-phase peptide syntheses of the macrocycles. Syntheses and the biological activities of the macrocycles cyclo{-[(2R)-α-4-benzylpiperidinylamido-Asp]-β-[(R)-Glu]-γ- Sar-[(R)-Asp]-β-(S)-Phe-} 29 and cyclo{-(2S)-Phe-[(2R)-α-4-benzylpiperidinylamido-Asp]-(R)-Glu-γ- (S)-Pro-β-(R)-Asp-} 65 are compared. Both compounds contain sufficient side-chain functionality to interact with a hydrophobic groove at the enzyme active site. The proline containing analogues 30, 31 (R3 = CH3) where sarcosine is replaced in macrocycles 3 and 4, were also synthesised in order to correlate conformational properties with biological activity. In accord with predictions macrocycles 29 and 65 were found to be weak inhibitors of PP1 with IC50 2.9 and 2.7 mM respectively.
- Webster,Maude,O'Donnell,Mehrotra,Gani
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p. 1673 - 1695
(2007/10/03)
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- Anti-epileptogenic agents
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Methods and compounds useful for the inhibition of convulsive disorders, including epilepsy, are disclosed. The methods and compounds of the invention inhibit or prevent ictogenesis and epileptogenesis. Methods for preparing the compounds of the invention
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