Synthesis and Irradiation of Vitamin‐B12‐Derived Complexes Incorporating Peripheral G⋅C Base Pairs

Abstract

The vitamin-B12 derivative 11, incorporating a peripheral N4-acetylcytosine moiety, was alkylated under reductive conditions with 2-(iodomethyl)-2-methylmonothiomalonate 8 bearing the complementary guanine moiety. The reaction yielded a mixture of vitamin-B12-derived complexes with variations in the cytosine moiety: products 16–18 with a cytosine, a N4-acetylated cytosine, and a N4-acetylated reduced cytosine moiety were formed (see Scheme 5). The complexes were photolyzed in CHCl3/MeCN to yield the dimethylmalonate derivative 22 (Scheme 6) but not the rearranged succinate, in contrast to the results obtained earlier with complexes incorporating the A⋅T base pair (see Scheme 1).