A Multinuclear Coordination System of L-Cysteine and L-Penicillamine That Induce Opposite Chiralities at Metal Centers

摘要

Long-standing interest in the chemistry of sulfur-containing amino acids stems from their importance in living and physiological systems. Among sulfur-containing amino acids, cysteine and penicillamine bearing a thiol group are of particular interest and have been dealt with in numerous reports over the past decades. Despite the structural similarity between cysteine and penicillamine other than the absence or presence of two methyl groups on the β-carbon atom, their stereochemical configurations in nature are opposite to each other; the natural cysteine is in the l form as are other protein-forming amino acids, whereas the natural penicillamine exists in the d form. In parallel with this fact, d-penicillamine has been used as a drug for the treatment of metal metabolism, although its l form is highly toxic, even in a small quantity.