Producing 2'-deoxynucleosides or 2'-deoxynucleoside precursors from a compound (I), or its salts or protected form, in a process comprising a decarboxylation step, is new. Producing 2'-deoxynucleosides or 2'-deoxynucleoside precursors from a compound of formula (I), or its salts or protected form, in a process comprising a decarboxylation step, is new. [Image] An independent claim is also included for the use of a polynucleotide, or gluconate dehydrase and/or glucosaminate deaminase encoded by the polynucleotide, in producing (I). ACTIVITY : Virucide; Cytostatic. No biological data given. MECHANISM OF ACTION : Antisense-Therapy.