Alternating copolymerization of cyclic imino ethers with aryl α,β‐unsaturated carboxylates: A new method for synthesis of poly(ethyleneimine‐co‐acrylic acid)

This paper describes an alternating copolymerization of cyclic imino ethers with aryl α,β-unsaturated carboxylates, which occurs without added catalyst. In the combinations of 2-methyl-2-oxazoline (1a) with phenyl acrylate derivatives (2a-c), 1:1 alternating copolymers were produced. In other systems examined, 1:1 copolymers were not produced except for the combination of 2-methyl-5,6-dihydro-4H-1,3-oxazine (1b) with p-cyanophenyl or p-nitrophenyl acrylate (2b or c). The copolymerization mechanism was explained by the zwitterion intermediates. The present copolymerization let to a new synthesis of poly(ethylenamine-co-acrylic acid), a poly(amino acid) derivative, via the alkaline hydrolysis of the copolymer.