Cobalt complex compounds with glycine

The compounds studied are the substituted triethylenetetra-aminecobalt(III) amino acid complexes depicted in Figure 1. Formally the A Bj chromophore will be the triethylenetetraamine-cobalt(III) glycinato moiety (compounds 1 and 7, identified in Figure 1) (with an associated configurational effect) and the optically active (Bj) chromophores will be represented by the various R2 substituents at the a-carbon of the chelated glycine... 

Little is known about the direct oxidation of amino acid derivatives. Although an a-acetoxy derivative can be prepared from hippuric acid by treatment with lead tetraacetate (99) this reaction is not applicable to N-phthaloyl- or N-benzyloxycarbonyl-glycine. Anodic oxidation of acetamidomalonic acid monoester in alcohol yielded the ot-alkoxy-a-acetamino acetic acid, while in acetic acid the corresponding oc-acetoxy compound was obtained (186). The oxidation of optically active N-salicylidene-alanine cobalt (III) complexes has been studied as a model reaction for enzymatic deamination of a-amino acids, and found to yield the corresponding diastereomeric a-hydroxy alanine complexes (118). 

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