Novel β-amino-7-membered carbonates: ring-opening polymerization and copolymers with l-lactide, ε-caprolactone and trimethylene carbonate

Novel seven-membered cyclic carbonates bearing β-amino-protecting groups (Cbz, Boc) were synthesized from aspartic acid. Their homopolymerization and copolymerization with l -lactide ( l -LA), ε-caprolactone (ε-CL), and trimethylene carbonate (TMC) were conducted using stannous octoate catalyst. Both monomers showed high reactivity, reaching complete conversion within 30 min in homopolymerization and producing polymers with controlled molecular weights and narrow dispersity ( Đ ≈ 1.4–1.5). Copolymerizations at different ratios yielded copolymers with M n up to ∼9,100 g/mol. The copolymer microstructure was comonomer-dependent: blocky with ε-CL but statistical with l -LA. All homopolymers and most copolymers were amorphous, with homopolymer glass transition temperatures from 9 °C to 24 °C. These β-amino-substituted seven-membered cyclic carbonates are highly reactive monomers for developing functionalizable, biodegradable polycarbonates with tunable thermal properties for biomedical applications.