抄録
Polymerization of tri (adenylic acid) bearing a 2'-O-(o-nitrobenzyl) group and a 3'-phosphate group at the 3'-end (A-A-A-NBD) was attempted in the presence of poly (uridylic acid), poly (U), using water-soluble carbodiimide. The nitrobenzyl group can be removed photochemically under mild conditions. A reaction containing the trimer and poly (U) in 1 : 2 ration at 0°for 15 days gave polymerized products (up to the 9-mer) in 14% yield and was proved to be dependent on the template. Raising the reaction temperature to 15°accelerated the polymerization rate. Reaction with a doubled trimer concentration at 0°did not improve the polymerization yield. Although the newly formed phosphodiester linkage was exclusively 3'-5', some isomerization (7%) to 2'-5' linkages seems to occur at bonds adjacent to free 2'-hydroxyl groups. As a side product, cyclic tri-(adenylic acid), which was formed by intramolecular condensation, was obtained in these reactions and in control reactions without template.
