New chiral synthons of ~(13)C- or 15N-labelled a-amino acids

摘要

Ni(II) complexes of Schiff bases of (S)-N-benzylproline (2-benzoylphenyl)-amide (BPB) and a-amino acids were developed as artificial analogues of pyridoxal 5'-phosphate (PLP)-dependent enzymes.1 Their applications in the asymmetric synthesis of a-amino acids are being perfected by a number of groups worldwide.2 Chiral synthons of a-amino acids labelled with ~(13)C or 15N are useful tools in preparation of a-amino acids that are enantiomerically pure and selectively isotopically substituted for NMR and MS studies of biological systems. Based on previously described preparation of labelled nucleophilic and electrophilic glycine synthons,3'4 different approaches to labelled a-methyl a-amino acids were evaluated.