Degradable <i>N</i>-Vinyl Copolymers through Radical Ring-Opening Polymerization of Cyclic Thionocarbamates

A thiocarbonyl radical ring-opening polymerization approach was implemented with cyclic thionocarbamates to generate degradable copolymers with <i>N</i>-vinyl monomers. The rigid structures of cyclic <i>N</i>-substituted thionocarbamates have been revealed by X-ray crystallography and NMR spectroscopy. The corresponding copolymers show incorporation of the thiocarbamates within the carbon backbone of polyvinylpyrrolidone influenced by acyl substituents through radical ring-opening copolymerization. The phenyl-substituted cyclic thionocarbamate copolymerized with <i>N</i>-vinyl carbazole and <i>N</i>-vinyl caprolactam, while little to no incorporation occurred with ^<i>t</i>Bu acrylate and styrene, respectively. Further, these copolymers can undergo hydrolytic degradation under mild conditions. A new family of cyclic thionocarbamates capable of radical ring-opening copolymerization with <i>N</i>-vinyl monomers has been established.