Polymerization of nucleotide analogues I: reaction of nucleoside 5'-phosphorimidazolides with 2'-amino-2'-deoxyuridine.

2'-Amino-2'-deoxyuridine reacts efficiently with nucleoside 5'-phosphorimidazolides in aqueous solution. The dinucleoside monophosphate analogues were obtained in yields exceeding 80% under conditions in which little reaction occurs with the natural nucleosides. In a similar way, the 5'-phosphorimidazolide of 2'-amino-2'-deoxyuridine undergoes self-condensation in aqueous solution to give a complex mixture of oligomers. The phosphoramidate bond in the dinucleoside monophosphate analogues is stable for several days at room temperature and pH 7. The mechanisms of their hydrolysis under acidic and alkaline conditions are described.