Synthesis of copoly(vinylamine-vinylalcohol) containing two kinds of asymmetric nucleic acid base derivatives as grafted pendants

Abstract

Preparation of new model polymers of polynucleotides with poly(vinylamine-vinylalcohol) [P(Vam-Val)] backbones and different kinds of nucleic acid base derivatives as grafted pendants is described. At first, the grafting of (−) and (±)-2-(thymin-1-yl)propionic acid [(−) and (±)TPA] onto linear P(Vam-Val) at the amino group via an amide bond was carried out in a mixed solvent of ethanol-dimethylformamide by selective N-acylation of the active ester of N -hydroxy-5-norbornene-2,3-dicarboximide (HONB) or N -hydroxysuccinimide (HOSu). This procedure gave the corresponding hydroxyl polymers P[Vam(−)T-Val] and P[Vam(±)T-Val]. In addition, direct, low temperature esterification was used to graft (−), (±)TPA, and (±)-2-(uracil-1-yl)propionic acid, [(±)UPA], onto the hydroxyl polymer at the hydroxyl group via an ester bond. This process gave the corresponding copoly(Vam-Val) with different or the same kinds of nucleic acid base derivatives. P[Vam(−)-Ve(−)T], P[Vam(±)T-Ve(±)T], P[Vam(−)T-Ve(±)U], and P[Vam(±)T-Ve(±)U] are representative examples. The related monomer and segmental model compounds were also prepared by this method; 3-aminopentane, 3-pentanol, 3-amino-1-propanol, and threo-2-amino-4-pentanol were employed in the syntheses. The segment models were separated and purified using HPLC techniques.