First regioselective enzymatic acylation of amino groups applied to pyrimidine 3',5'-diaminonucleoside derivatives. Improved synthesis of pyrimidine 3',5'-diamino-2',3',5'-trideoxynucleosides.

The chemistry of natural nucleosides and their analogues has been widely studied due to their potential as fungicidal, antitumor, and antiviral agents. 1 Consequently, extensive modifications have been made to both the heterocyclic base and the sugar moiety in order to avoid the drawbacks shown by nucleosides or analogues in certain applications. For organic chemists, enzymatic-catalyzed reactions have become standard procedures for nucleoside modification, since they avoid the time-consuming protection and deprotection steps required by the occurrence of various hydroxyl groups in the sugar skeleton of the natural nucleosides. 2