- Improved enzymatic syntheses of valuable β-arylalkyl-β-amino acid enantiomers
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The enantioselective (E~ 200) Burkholderia cepacia-catalysed hydrolyses of β-amino esters with H2O (0.5 equiv.) in t-BuOMe or in i-Pr2O at 45 °C are described. The enantiomers of biologically relevant β-arylalkyl-substituted β-amino acids, and especially (R)-3-amino-3-(2,4,5-trifluorophenyl)butanoic acid, the intermediate of the new antidiabetic drug sitagliptine, were prepared with high enantiomeric excesses (ee≥96%) and in good yields (≥42%). The Royal Society of Chemistry 2010.
- Tasnadi, Gabor,Forro, Enik,Fueloep, Ferenc
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supporting information; experimental part
p. 793 - 799
(2010/06/20)
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- Lipase-involved strategy to the enantiomers of 4-benzyl-β-lactam as a key intermediate in the preparation of β-phenylalanine derivatives
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A simple chemoenzymatic method for the preparation of the enantiomers of 4-benzyl-β-lactam (4-benzylazetidin-2-one) from allylbenzene has been described. The enantiomers of this key intermediate have been used to produce the corresponding enantiomers of β-phenylalanine and N-Boc-protected β-phenylalanine amide through the simple cleavage of the lactam ring by acid-catalyzed hydrolysis and by ammonolysis, respectively. Burkholderia cepacia lipase-catalyzed kinetic double resolution techniques were responsible for achieving enantiopurity in the products. This was performed through the acylation of N-hydroxymethylated β-lactam followed by the butanolysis of the obtained (S)-ester. Direct lipase-catalyzed cleavage of the β-lactam ring has also been studied.
- Li, Xiang-Guo,Kanerva, Liisa T.
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p. 197 - 205
(2007/10/03)
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