Preparation And Characterization Of N-substituted Poly(amidoacrylic) Acids Containing Thymine And Uracil Derivatives As Pendant Groups.

Abstract

New strategies for the preparation of high molecular weight water-soluble polymers containing nucleic acid bases as pendant groups were developed. Specifically, it was found that amidoacrylic acids substituted at the N-position with propionic acid derivatives of thymine and uracil will undergo polymerization in THF/NaCl (aq.) solution using a water-soluble azo initiator. The resulting polymers are of molecular weight 10$\sp5$ and are extremely water-soluble over a wide range of pH. The present study represents the first time that such polymers have been rigorously characterized in terms of molecular weight. In addition to molecular weight characterization, the dilute solution properties of these polymers were investigated. Electronic spectra showed the presence of large amounts of short-range base-stacking interactions in both polymers. Viscosity and photon correlation experiments were performed to assess the hydrodynamic dimensions of these polymers and it was found that the previously noted short-range interactions do result in a slight amount of chain stiffness above what would be expected for a completely random coil. The dimensions of the backbone are not large enough to permit a quantitative assessment of this stiffness. Interaction experiments were undertaken with the polymers and model compounds to provide a rationale for the biological activity of these materials. While the data point towards some interactions with native polynucleotides, these interactions are not strong and additional study is needed to draw any firm conclusions.