Ring-Opening Polymerization of γ-(4-Vinylbenzyl)-L-glutamate N-Carboxyanhydride for the Synthesis of Functional Polypeptides

The preparation of polypeptides with poly(L-glutamate) backbone and a variety of different side chains via controlled polymerization of VB-Glu-NCA followed by a variety of highly efficient post functionalization reactions is presented. VB-Glu-NCA was readily prepared and purified in multigram scale in crystalline form. The purified VB-Glu-NCA is very stable in moisture-free conditions and can be stored in the freezer of a glovebox at 30°C for more than 6 months without noticeable change of properties. The amount of NB had very limited effect on polymerization rates and theMWs of the resulting PVBLGs, suggesting that NB functions as a radical inhibitor and does not participate in chain propagation. Notably, the aldehyde functionalized PVBLG-b was very reactive and could be used for further grafting of various functional moieties with amines, hydrazides, and oxyamines through reductive amination.