- Synthesis of enantiopure free and N-benzyloxycarbonyl-protected 3-substituted homotaurines from naturally occurring amino acids
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Enantiopure N-benzyloxycarbonyl-protected and free 3-substituted homotaurines were synthesized from naturally occurring amino acids via N-benzyloxycarbonyl protection, Arndt-Eistert homologation, reduction, esterification with thioacetic acid, and oxidation with performic acid. The current method is a convenient, practical, and salt-free method for the synthesis of enantiopure 3-substituted homotaurine with moderate to good yields.
- Zheng, Yongpeng,Xu, Jiaxi
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p. 5197 - 5206
(2014/12/10)
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- Continuous flow synthesis of β-amino acids from α-amino acids via Arndt-Eistert homologation
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A fully continuous four step process for the preparation of β-amino acids from their corresponding α-amino acids utilizing the Arndt-Eistert homologation approach is described. the Partner Organisations 2014.
- Pinho, Vagner D.,Gutmann, Bernhard,Kappe, C. Oliver
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p. 37419 - 37422
(2014/12/09)
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- Synthesis of enantiopure free and N-benzyloxycarbonyl-protected 3-substituted homotaurines from naturally occurring amino acids
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Enantiopure N-benzyloxycarbonyl-protected and free 3-substituted homotaurines were synthesized from naturally occurring amino acids via N-benzyloxycarbonyl protection, Arndt-Eistert homologation, reduction, esterification with thioacetic acid, and oxidation with performic acid. The current method is a convenient, practical, and salt-free method for the synthesis of enantiopure 3-substituted homotaurine with moderate to good yields.
- Zheng, Yongpeng,Xu, Jiaxi
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p. 5197 - 5206
(2014/07/08)
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- MODULATORS OF HISTONE METHYLTRANSFERASE, AND METHODS OF USE THEREOF
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Disclosed are compounds, pharmaceutical compositions containing the compounds, and the uses of the compounds and compositions as modulators of histone methyltransferases, and for treating diseases influenced by modulation of histone methyltransferase activity.
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- Synthesis of novel N-protected β3-amino nitriles: study of their hydrolysis involving a nitrilase-catalyzed step
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Several commercially available nitrilases were investigated with regard to their potential to hydrolyze N-protected β3-amino nitriles into their corresponding N-protected β3-amino acids. The biotransformations were obtained in different proportions depending on the nitrilase involved. The best hydrolysis results were achieved for the N-Cbz-β3-amino nitrile from l-alanine using the NIT-107, in a phosphate buffer at 0.05 M. However, no biotransformation into the corresponding acids was observed for the N-sulfonylamide β3-amino nitriles. Two simple and efficient procedures to prepare the β3-amino nitriles from their analogous α-amino acids are described. Thirty four new substances were synthesized and characterized over the course of this work.
- Veitia, Maite Sylla-Iyarreta,Brun, Pierre Louis,Jorda, Pierre,Falguieres, Annie,Ferroud, Clotilde
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experimental part
p. 2077 - 2089
(2010/03/04)
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- Effective methods for the synthesis of N-methyl β-amino acids from all twenty common α-amino acids using 1,3-oxazolidin-5-ones and 1,3-oxazinan-6-ones
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N-Methyl β-amino acids are generally required for application in the synthesis of potentially bioactive modified peptides and other oligomers. Previous work highlighted the reductive cleavage of 1,3-oxazolidin-5-ones to synthesise N-methyl α-amino acids. Starting from α-amino acids, two approaches were used to prepare the corresponding N-methyl β-amino acids. First, α-amino acids were converted to N-methyl α-amino acids by the so-called '1,3-oxazolidin-5-one strategy', and these were then homologated by the Arndt-Eistert procedure to afford N-protected N-methyl β-amino acids derived from the 20 common α-amino acids. These compounds were prepared in yields of 23-57% (relative to N-methyl α-amino acid). In a second approach, twelve N-protected α-amino acids could be directly homologated by the Arndt-Eistert procedure, and the resulting β-amino acids were converted to the 1,3-oxazinan-6-ones in 30-45% yield. Finally, reductive cleavage afforded the desired N-methyl β-amino acids in 41-63% yield. One sterically congested β-amino acid, 3-methyl-3-aminobutanoic acid, did give a high yield (95%) of the 1,3-oxazinan-6-one (65), and subsequent reductive cleavage gave the corresponding AIBN-derived N-methyl β-amino acid 61 in 71% yield (Scheme 2). Thus, our protocols allow the ready preparation of all N-methyl β-amino acids derived from the 20 proteinogenic α-amino acids.
- Hughes, Andrew B.,Sleebs, Brad E.
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p. 2611 - 2637
(2007/10/03)
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- Exceptionally simple homologation of protected α- to β-amino acids in the presence of silica gel
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The Wolff rearrangement of α-amino acid-derived diazoketones is simply achieved by gentle warming in a ethyl acetate/silica gel slurry containing catalytic amounts of silver trifluoroacetate. Without workup (not counting filtration and evaporation) the pr
- Koch, Karen,Podlech, Joachim
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p. 2789 - 2794
(2007/10/03)
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- Wolff rearrangement of Nα-Boc-/Z-protected aminodiazoketones to the corresponding β-amino acids under microwave irradiation
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The Wolff rearrangement of Nα-Boc-/Z-protected aminodiazoketones in the presence of silver benzoate under microwave irradiation is described. The reaction is found to be rapid, efficient and complete. It results in the isolation of Boc-/Z- prot
- Kantharaju,Patil, Basanagoud S.,Suresh Babu, Vommina V.
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p. 2611 - 2613
(2007/10/03)
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- Synthesis of new β-amino acids via 5-oxazolidinones and the arndt-eistert procedure
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N-Methyl β-amino acids are potentially useful amino acid derivatives for incorporation in lead peptide therapeutics. The syntheses of five such compounds are presented. Their synthesis via 6-oxazinanones was low yielding. Alternatively, reductive cleavage of a 5-oxazolidinone gave the N-methyl β-amino acid, which was then homologated via an Arndt-Eistert procedure in high yield to give the N-methyl α-amino acid. CSIRO 2005.
- Hughes, Andrew B.,Sleebs, Brad E.
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p. 778 - 784
(2007/10/03)
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- Peptidic aldehydes based on α- and β-amino acids: Synthesis, inhibition of m-Calpain, and anti-cataract properties
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We present a new synthesis of SJA6017 (a potent m-calpain inhibitor) and its adaptation in order to prepare analogues in which the constituent Leu and Val residues are systematically replaced with their corresponding β-amino acids and/or the N-terminal fl
- Payne, Richard J.,Brown, Karina M.,Coxon, James M.,Morton, James D.,Lee, Hannah Yun-Young,Abell, Andrew D.
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p. 877 - 884
(2007/10/03)
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- α-Oxymethyl ketone enolates for the asymmetric Mannich reaction. From acetylene and N-alkoxycarbonylimines to β-amino acids
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The insufficient diastereoselectivity and generality, which are the main problems of the 'acetate' aza - aldol reaction, can now be addressed through the reaction of the lithium enolate of endo-O-trimethylsilyl acetyl isoborneol with various N[(p-tolylsul
- Palomo, Claudio,Oiarbide, Mikel,Gonzalez-Rego, M. Concepcion,Sharma, Arun K.,Garcia, Jesus M.,Gonzalez, Alberto,Landa, Cristina,Linden, Anthony
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p. 1063 - 1066
(2007/10/03)
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- Convenient in situ synthesis of nonracemic N-protected β-amino aldehydes from β-amino acids. Applications in Wittig reactions and heterocycle synthesis
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N-Z-γ-amino alcohols derived from nonracemic β-amino acids are smoothly oxidised by manganese dioxide in acetonitrile to afford aldehydes which can be trapped in situ in Wittig reactions with carbonyl-substituted phosphoranes. The application of this methodology to the synthesis of the alkaloids (S)-(+)-N-BOC-coniine, (S)-(-)-coniceine and a pipecoline precursor is described.
- Davies, Simon B.,McKervey, M. Anthony
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p. 1229 - 1232
(2007/10/03)
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- Chemoenzymatic synthesis of 4-amino-2-hydroxy acids: A comparison of mutant and wild-type oxidoreductases
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We describe a new chemoenzymatic synthesis of enantiopure 4-amino-2-hydroxy acids using two biotransformations in a single-pot process in aqueous medium. These compounds are valuable as γ-turn mimics for investigations into the secondary structure of peptides. The enzyme substrates are a series of carbobenzyloxy (CBZ)-protected 4-amino-2-keto esters, prepared efficiently from the L-amino acids, alanine, leucine, phenylalanine, and valine. First, the α-amino acids were converted to the corresponding β-amino acids in a simple five-step procedure. A further one-carbon homologation via ozonolysis of the corresponding β-keto cyanophosphoranes gave the required α-keto esters in good yield. The enzyme catalyzed hydrolyses of all the α-keto esters to the corresponding α-keto acids proceeded smoothly with the lipase from Candida rugosa. Using the same reaction pot, it was found that wild-type lactate dehydrogenases from either Bacillus stearothermophilus CBS-LDH) or Staphylococcus epidermidis (SE-LDH) could be used to specifically reduce the ketone of the alanine-derived α-keto acid 2, giving the (S)- and CR)-2-hydroxy acids, respectively, in good yields. However, the more bulky α-keto acids 3, 4, and 5 (derived from valine, leucine, and phenylalanine) were not substrates for these enzymes. In contrast, the genetically engineered H205Q mutant of D-hydroxyisocaproate dehydrogenase proved to be an ideal catalyst for the reduction of all the α-keto acids 2-5, giving excellent yields of the CBZ-protected (2R,4S)-4-amino2-hydroxy acids as single diastereomers. This genetically engineered oxidoreductase has great potential value in synthesis due to its broad substrate specificity and high catalytic activity. For example, reduction of 1 mmol of N-protected (S)-4-amino-2-oxopentanoic acid 2 took just 4 h with the H205Q mutant giving, after esterification, the CR)-2-alcohol 25 in 85% yield, whereas with SE-LDH the reaction required 4 days to give a 67% yield of 25.
- Sutherland, Andrew,Willis, Christine L.
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p. 7764 - 7769
(2007/10/03)
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