Synthesis of optically active polynucleotide analogs with poly(vinyl alcohol)s as backbones and adenine and 5-bromouracil derivatives as pendants

Abstract

The optically active polynucleotide analogs were prepared by grafting nucleic acid base derivatives onto poly(vinyl alcohol). The ( R )-ethyl 2-(5-bromouracil-1-yl)propanoate was obtained either by reaction of 5-bromouracil sodium salt with ( S )-ethyl 2-[(methylsulfonyl)oxy]propanoate or reaction of 5-bromouracil with ( S )-ethyl lactate in the presence of triphenyl phosphine and diethyl azodicarboxylate. Subsequent hydrolysis of the ester is aqueous acid provided the optically pure ( R )-bromouracilypropanoic acid. The monomer model compounds were prepared by an esterification reaction of the pendant groups with 3-pentyl alcohol in the presence of dicyclohexylcarbodiimide and a catalytic amount of 4-pyrrolidinopyridine. Poly(vinyl alcohol) underwent reaction with the ( R )-bromouracilylpropanoic acid or the ( R )-adeninylpropanoic acid in the presence of dicyclohexylcarbodiimide and a catalytic amount of 4-pyrrolidinopyridine. The resulting polymers were optically active and percents grafting were almost quantitative.