Partial synthesis of CoCo-dicyano-176- norcobinamide

Recent interest in norvitamin B-derivatives, homologues of complete vitamin B-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 B. Here we report the partial synthesis of the corrinoid CoCo-dicyano-176-norcobinamide by condensation of cobyric acid and 2-aminoethanol. In addition, the partial synthesis of crystalline Co-aquo-Co- cyanocobyric acid by acid catalyzed hydrolysis of vitamin B is detailed, improving the method and the isolation procedure worked out earlier by Bernhauer et al. The solution structure of CoCo -dicyano-176-norcobinamide was studied by spectroscopy and was compared with that of the homologue CoCo- dicyanocobinamide. The title compound, CoCo -dicyano-176-norcobinamide, represents the dicyano-form of a potential biosynthetic precursor of the 176-nor-B-derivatives, such as 176-nor-pseudovitamin B. © Springer-Verlag 2006.