NUCLEOSIDES .3. 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 O5'-diacetyl- 2',3'-dideoxy-2',3'-didehydrocytidine (3), by electrochemical synthesi s from N4,O2',O5'-triacetyl-3'-bromo-3'-deoxycytidine (2), has been st udied in order to evaluate the potential of this reaction for synthesi s on a larger scale. We have characterized the half-wave potentials of the precursor (2) and the product (3) by polarography under various c onditions, and found that reduction in the base moiety can easily take place giving by-products. Furthermore, this reduction consumes proton s 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 w ell as of other 2',3'-dideoxy 2',3'-didehydro nucleosides also depends to a large extent on how uniform the current density across the worki ng electrode surface can be maintained during electrolysis.