From drug to adhesive: a new application of poly(dihydropyrimidin-2(1H)-one)s via the Biginelli polycondensation

Abstract

The reactions for polymer synthesis should be simple and efficient using easily available raw materials. A new difunctional monomer containing benzaldehyde and beta-keto ester groups (monomer AB) has been successfully prepared on a medium scale, and the corresponding poly(dihydropyrimidin-2(1H)-one)s (DP ∼84) can be synthesized via the Biginelli polycondensation in a short time (∼1 h). The in situ generated polycondensates could glue two metal sheets, demonstrating an interesting metal bonding property which cannot be observed in small molecules. The optimized multifunctional monomers (AB₂, A₂B₂ monomers) were subsequently used for the in situ polycondensation between metal sheets, and metal bonding strength could be improved to the similar level of commercial cyanoacrylate glue. Since the monomers could be easily prepared on a large scale and the polymerization could be simply performed, the Biginelli polycondensation might have potential as a new strategy to synthesize new functional polymers.