Synthesis of vitamin B 12 derivatives incorporating peripheral cytosine and N-acetylcytosine

Abstract

The synthesis and structural characterisation of vitamin B 12 derivatives incorporating a cytosine and a N 4-acetyl cytosine in the side chain of the corrin and having the cobalt in different oxidation states are described. NaBH 4 reduction led to reduction of Co(III) to Co(I) but also to reduction and deacetylation of the cytosine moiety. Reaction conditions were found where only Co reduction was achieved. Reduction of the new B 12 derivative 8 with NaBH 4 led to the Co( 1) derivative but also to reduction and deacetylation of the cytosine moiety. By controlling the conditions, only cobalt reduction could be achieved. [Display omitted]