Synthesis of optically active polynucleotide analogs with polytrimethylenimine backbones and thymine moieties

Polynucleotide analogs with polytrimethylenimine backbones and optically active 2‐(thymin‐1‐yl)propionic acids as pendants were prepared. Linear polytrimethylenimines were obtained by ring‐opening polymerization of 2‐phenyl‐5,6‐dyhydro‐4H‐1,3‐oxazine and subsequent hydrolysis of the resulting polymers. 2‐(Thymin‐1‐yl)propionic acids were reacted with N‐hydroxy succinimide to form active esters. Optical purities of active esters were determined by NMR with chiral chemical shift reagents. The polynucloetide analogs and related monomer and dimer model compounds were prepared by grafting reactions using active esters.