Synthesis of vitamin B12 derivatives incorporating peripheral cytosine and N-acetylcytosine

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“…The structure of 18 was confirmed by the isolation of the dicyano complex 21 after irradiation (see below), the latter having been previously prepared and fully characterized [20]. Subsequently, the two diastereoisomers of 16 could be separated by column chromatography to give 7% 16a and 12% 16b.…”

“…The nature of the cytosine moiety in the alkylated complexes 16 ± 18 was confirmed by the isolation, after irradiation, of the known complexes 19 ± 21 [20]. Preparation of complex 16 required a reactive iodomethyl derivative as the alkylating agent and fast conversion of Co II to Co I with NaBH 4 .…”

“…The syntheses of vitamin-B 12 -derived complexes incorporating a cytosine and N 4acetylcytosine moiety have already been reported [20]. Here we present the synthesis of the substrate containing a guanine moiety, namely the 2-(iodomethyl)-2-methylmonothiomalonate 8, the preparation of the corresponding alkylated vitamin-B 12derived complexes, and the results of their irradiation.…”

“…In the synthesis of vitamin-B 12 derivatives incorporating a cytosine and an N 4 -acetylcytosine moiety in the side chain of the corrin, reduction and deacetylation of the cytosine moiety in the presence of NaBH 4 were reported [20]. In the synthesis of vitamin-B 12 derivatives incorporating a cytosine and an N 4 -acetylcytosine moiety in the side chain of the corrin, reduction and deacetylation of the cytosine moiety in the presence of NaBH 4 were reported [20].…”

“…) The differences in the 1 H-NMR chemical shifts for HÀC(5) and HÀC(6) of cytosine and N 4 -acetylcytosine were determined for the vitamin-B 12 derivatives[20] and for N 4 -acetylcytidine and cytidine[29].…”