Synthesis of Vitamin-B12 Derivatives with Peripheral Tris(oxyethylene) Chains

Abstract

The new derivatives 7a-c, of vitamin B12, with a peripheral tris(oxyethylene) chain linked to the corrin ring by an amide or ester group, are prepared, and their ligand-exchange reactions are investigated. Upon reduction of the aqua-cyano complexes 8a-c with NaBH4, cleavage of the 'outer' ester and amide group is observed.