Reactions of cobalt-bound organic ligands

Although many examples of reactions of cobalt-bound organic ligands exist, most of these have been carried out for synthetic purposes rather than as studies of mechanism or of the effect of the covalently bound cobalt moiety. Although many such transformations are quite simple, they frequently lead to organocobalt complexes which are difficult, or impossible, to obtain by direct alkylation. For example, Schrauzer and Windgassen [51] prepared carboxymethyl- and carboxyethyl-(pyri-dine)cobaloxime by hydrolysis of the corresponding methyl esters in concentrated sulfuric acid. Similarly, Brown and coworkers [58] prepared p- and w-carbo-xyphenyl(aquo)cobaloximes from their methyl esters by hydrolysis in 0.5 N KOH in aqueous methanol. 

Acetal hydrolysis has also been successfully used to affect such organic ligand modifications. Thus Silverman and Dolphin [111] obtained both formylmethylco-baloxime and formylmethylcobalamin by hydrolysis of both the 2,2-diethoxyethyl-and 1,3-dioxa-2-cyclopentylmethyl-cobalt complexes (Eqn. 65). 

Formylmethylcobalamin has also been obtained by periodate cleavage of 2,3-de-hydroxy-n-propylcobalamin in aqueous ammonia (Eqn. 66) [111]. 

Golding and coworkers [112] have also obtained a series of dihydroxyalkylcobalo-ximes by hydrolysis of the appropriate cyclic acetals in aqueous hydrochloric acid (Eqn. 67). 

As a final example, Golding and coworkers [92] obtained 2-acetoxyethyl- and 

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A few more detailed kinetic and thermodynamic studies of the reactions of cobalt-bound organic ligands have been carried out. For instance, Golding et al. [92]... 

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