Polymeric Sunscreen via the Biginelli Reaction and Sequential C-S Coupling Reaction for UV Protection.

Excessive ultraviolet (UV) radiation poses significant adverse health effects on humans, underscoring the critical need for novel sunscreen agents. Conventional small-molecule UV filters often suffer from drawbacks such as percutaneous absorption and environmental toxicity. In this work, we report the design and synthesis of novel monomers bearing both dihydropyrimidin-2(1H)-thione (DHPMT) and dihydrothiazole moieties through the integration of the Biginelli reaction and sequential C-S coupling reaction, followed by the copolymerization with poly(ethylene glycol) methyl ether methacrylate (PEGMA-950) to yield new functional polymers. The resulting polymers exhibited low cytotoxicity. Importantly, in vivo evaluation in a murine model demonstrated their effective protection against UV-induced skin damage. This work underscores the synthetic versatility of this two-step reaction in the development of UV-shielding polymeric materials and offers a promising strategy for engineering multifunctional polymers via multicomponent reaction platforms.