Template-directed oligomerization of 5'-deoxy-5'-nucleosideacetic acid derivatives

5'-Deoxy-5'-nucleosideacetic acids II-V are isostructural analogues of nucleotides with a carboxylate group in the place of the 5'-phosphate group. We have studied their oligomerization in aqueous solution using a water-soluble carbodiimide as the condensing agent in the presence or absence of an appropriate polynucleotide template. Condensation of adenylic acid analogues IIa, IIIa, and Va in the presence of polyuridylic acid were found to be the most efficient reactions. Cyclization of the activated monomers to lactones and the insolubility of the oligomers in aqueous solution were found to be obstacles to the efficient formation of long oligomers.