Partial synthesis of CoαCoβ-dicyano-176- norcobinamide

Abstract

Recent interest in norvitamin B12-derivatives, homologues of complete vitamin B12-derivatives, lacking the methyl group at carbon 176, stems from the identification of the corrinoid cofactor of the tetrachloroethene reductive dehalogenase of Sulfurospirillum multivorans as 176-nor-pseudovitamin B12. Here we report the partial synthesis of the corrinoid CoαCoβ-dicyano-176-norcobinamide by condensation of cobyric acid and 2-aminoethanol. In addition, the partial synthesis of crystalline Coα-aquo-Coβ- cyanocobyric acid by acid catalyzed hydrolysis of vitamin B12 is detailed, improving the method and the isolation procedure worked out earlier by Bernhauer et al. The solution structure of CoαCo β-dicyano-176-norcobinamide was studied by spectroscopy and was compared with that of the homologue CoαCoβ- dicyanocobinamide. The title compound, CoαCo β-dicyano-176-norcobinamide, represents the dicyano-form of a potential biosynthetic precursor of the 176-nor-B12-derivatives, such as 176-nor-pseudovitamin B12. © Springer-Verlag 2006.