Atom Transfer Radical Polymerization of Adenine, Thymine, Cytosine, and Guanine Nucleobase Monomers

Methacrylate monomers functionalized with thymine, adenine, cytosine, and guanine were prepared by alkylation of the nucleobases with 3-bromopropyl methacrylate. Application of atom transfer radical polymerization in deuterated DMSO allowed controlled polymerization of the adenine-, thymine-, and for the first time, also of the cytosine- and guanine-modified monomers. The guanine and cytosine monomers appeared to form a complex with the copper catalyst, as could be observed with 1 H NMR spectroscopy. In the case of guanine, this did not cause any problems for the polymerization process, while in the case of cytosine, a stronger copper binding ligand, PMDETA, needed to be applied to gain control over polymerization.