Facile chemical dehydrogenation of α-amino acids chelated to a ruthenium(II) ion: (α-iminoacidato)bis(1,10-phenanthroline)ruthenium(II) complexes

Article abstract of DOI:10.1246/bcsj.70.1069

(α-Amino acidato)ruthenium(II) complexes were dehydrogenated to give (α-imino acidato)ruthenium(II) complexes by chemical oxidation. (α-Imino acidato)ruthenium(II) complexes, [Ru^II{N(R ¹) = C(R²)CO₂} (phen₂]⁺ (R₁ =H, Me, or Bn, R²=H; R¹ =H or Me, R ²=Me; R¹, R² =-(CH₂)₃-) were obtained from the (α-amino acidato)ruthenium(II) complexes (glycinato, N-Me-glycinato, Af-Bn-glycinato, (S)-alaninato, Af-Me-(S)-alaninato, and (S)-prolinato complexes) by using diammonium cerium(IV) nitrate (CAN) as an oxidizing reagent. On the other hand, in the presence of hydrogen peroxide, the α-imino acidato complexes were converted to the corresponding α-imino acidato complexes, except for the glycinato and (S)-alaninato complexes. In particular, the iminoacetatoruthenium(II) complex, [Ru(NH=CHCO₂)(phen)₂]⁺, was synthesized for the first time by this method using CAN as an oxidizing reagent. Dehydrogenation with CAN is more facile and versatile than any other method that we have ever examined.