Cobalt chelates as models for methyl donors and acceptors in vitamin B12-dependent transmethylation. Direct methylation of vitamin B12a

The dimethyl derivative of 1,3-bis(biacetylmonoximeimino) propanecobalt (III)[(CH3)2CO{(DOH)(DO)pn}], behaves as a methylating reagent toward electrophilic metal atoms and protons, thus allowing the preparation of several methyl-cobalt derivatives from the corresponding CoIII complexes by a reaction which involves the transfer of a methyl carbanion and is related to the catalytic action of the Vitamin B12a in transmethylases.