Nucleosides. III. Investigation of the Electrochemical Synthesis of N4, O5'-Diacetyl-2',3'-dideoxy-2',3'-didehydrocytidine

The influence of the reaction conditions on the yield of N4,O5′-diacetyl-2′,3′-dideoxy-2′,3′-didehydrocytidine (3), by electrochemical synthesis from N4,O2′,O5′-triacetyl-3′-bromo-3′-deoxycytidine (2), has been studied in order to evaluate the potential of this reaction for synthesis on a larger scale. We have characterized the half-wave potentials of the precursor (2) and the product (3) by polarography under various conditions, and found that reduction in the base moiety can easily take place giving by-products. Furthermore, this reduction consumes protons leading to rapid solvolysis in protic solvents. We have demonstrated for the first time that (3) can be formed near quantitatively in both protic and aprotic solvents. The success of the synthesis of (3) as well as of other 2′,3′-dideoxy 2′,3′-didehydro nucleosides also depends to a large extent on how uniform the current density across the working electrode surface can be maintained during electrolysis.