Abstract
Treatment of vitamin B12a 1 (hydroxycobalamin
hydrochloride, aquocobalamin) with NaBH4 and ZnCl2 leads
to the selective cleavage of the nucleotide loop and gives dicyanocobinamide 2a in good yield. Methylcobinamide 4 was prepared from 2 via aquocyanocobinamide 3 . The glutathione-mediated methylation
of 3 in a pH 3.5 buffer solution proceeded
with MeI, but not with MeOTs.
Key words
vitamin - phosphorus ester - hydrolysis - alkylations - ligands
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