Synthesis, cyclopolymerization and cyclo-copolymerization of 9-(2-diallylaminoethyl)adenine and its hydrochloride salt.

We report herein the synthesis and characterization of 9-(2-diallylaminoethyl) adenine. We evaluated two different synthetic routes starting with adenine where the optimal route was achieved through coupling of 9-(2-chloroethyl)adenine with diallylamine. The cyclopolymerization and cyclo-copolymerization of 9-(2-diallylaminoethyl)adenine hydrochloride salt resulted in low molecular weight oligomers in low yields. In contrast, 9-(2-diallylaminoethyl)adenine failed to cyclopolymerize, however, it formed a copolymer with SO₂ in relatively good yields. The molecular weights of the cyclopolymers were around 1,700-6,000 g/mol, as estimated by SEC. The cyclo-copolymer was stable up to 226 °C. To the best of our knowledge, this is the first example of a free-radical cyclo-copolymerization of a neutral alkyldiallylamine derivative with SO₂. These polymers represent a novel class of carbocyclic polynucleotides.