2521-86-0Relevant articles and documents
Amine-boranes: Effective reducing agents for the deracemisation of DL-amino acids using L-amino acid oxidase from Proteus myxofaciens
Alexandre, Fran?ois-René,Pantaleone, David P.,Taylor, Paul P.,Fotheringham, Ian G.,Ager, David J.,Turner, Nicholas J.
, p. 707 - 710 (2007/10/03)
The deracemisation of DL-α-amino acids using L-amino acid oxidase from Proteus myxofaciens and amine-boranes as chemical reducing agents has been investigated. Amine-boranes were found to be of particular interest in terms of reactivity and chemoselectivity compared to sodium borohydride and cyanoborohydride. Starting from the racemate, a range of D-amino acids were obtained in yields of up to 90% and e.e. >99%.
New expedient route to both enantiomers of nonproteinogenic α-amino acid derivatives from the unsaturated 2-aza-bicyclo moiety
Alonso, Diego A.,Bertilsson, Sophie K.,Johnsson, Sandra Y.,Nordin, Sofia J. M.,Soedergren, Mikael J.,Andersson, Pher G.
, p. 2276 - 2280 (2007/10/03)
The influence of the reaction conditions on the catalytic hydrogenation of 2-aza-bicyclo hept-5-ene and oct-5-ene derivatives has been investigated. We found it possible to fully control the extent of allylic vs benzylic C-N hydrogenolysis by simple variations of H2 pressure and acidity of the reaction medium. The use of the reaction pathways was demonstrated by the selective preparation of four categories of optically active α-amino acid derivatives. The strategy was also extended to the synthesis of enantiopure α-amino ketones.
Synthesis of Racemic α-Amino Carboxamides via Lewis Acid-Mediated Reactions of α-Methoxyglycinamide Derivatives with Allylsilanes: Enzymatic Resolution to Optically Active α-Amino Acids
Roos, Eric C.,Mooiweer, Hendrik H.,Hiemstra, Henk,Speckamp, W. Nico,Kaptein, Bernard,et al.
, p. 6769 - 6778 (2007/10/02)
A short and expedient synthetic route to optically active, saturated and γ,δ-unsaturated α-amino acids is reported.The key step is a BF3*Et2O-mediated reaction of allylsilanes with N-(alkoxycarbonyl)-α-methoxyglycinamides 11-15, leading to the corresponding γ,δ-unsaturated α-aminocarboxamides.The genuine SN1-character of this process with iminium ion 6 as intermediate is proven in the case of the glycine ester 10.Thus, reaction of enzymatically resolved 10 with ?-nucleophiles leads to racemic products.The most useful iminium precursors are the N-methoxyamides 12-14 providing good yields of coupling products.The most convenient N-protective group is the allyloxycarbonyl group.Deprotection proceeds via a Pd(O)-catalyzed transprotection to the corresponding BOC-protected analogues.Four examples of the enzymatic resolution of α-amino carboxamides, by using an L-specific aminopeptidase from Pseudomonas putida, are described in detail.Most notably, secondary N-methoxyamides are good substrates for the enzyme to provide the desired α-amino acids in high optical purity.
