SYNTHESIS AND REACTIVITY OF COORDINATED IMINES DERIVED FROM 2-KETO ACIDS

The synthesis of a series of [Co(NH3)5OCOCOR]2+ ions (R = H, CH3, C6H5, COOH, -CH2C6H5, C(CH3)3, CH2CH2CO2-) and a number of derivatives is described. In aqueous base most of these ions undergo cyclization to tetraammine iminocarboxylato chelates which undergo a variety of reactions; alkylation of the deprotonated imine N center, addition of nucleophiles at the imine C center, reduction of the imine to give an amino acid, and intramolecular condensations after the addition of the nucleophile. The compounds illustrate the potential of the metal ion to protect and activate organic molecules as well as to organize sucn intramolecular condensations. The kinetics of the imine cyclization are also discussed. © 1979, American Chemical Society. All rights reserved.