Poly(carbonate-amide)s Derived from Bio-Based Resources: Poly(ferulic acid-co-tyrosine)

Ferulic acid (FA), a bio-based resource found in fruits and vegetables, was coupled with a hydroxyl-amino acid to generate a new class of monomers to afford poly(carbonate-amide)s with potential to degrade into natural products. l-Serine was first selected as the hydroxyl-amino partner for FA, from which the activated p-nitrophenyl carbonate monomer was synthesized. Unfortunately, polymerizations were unsuccessful, and the elimination product was systematically obtained. To avoid elimination, we revised our strategy and used l-tyrosine ethyl ester, which lacks an acidic proton on the α position of the ethyl ester. Four new monomers were synthesized and converted into the corresponding poly(carbonate-amide)s with specific regioselectivities. The polymers were fully characterized through thermal and spectroscopic analyses. Preliminary fluorescent studies revealed interesting photophysical properties for the monomers and their corresponding poly(carbonate-amide)s, beyond the fluorescence characteristics of l-tyrosine and FA, making these materials potentially viable for sensing and/or imaging applications, in addition to their attractiveness as engineering materials derived from renewable resources.