Sequential and Single-Step, One-Pot Strategies for the Transformation of Hydrolytically Degradable Polyesters into Multifunctional Systems

Because of the significant interest in synthetic polymer systems with increasing degrees of complexity, we have focused attention upon the development of chemistries for the conversion of polyester backbones into functional materials. Facile conjugation strategies involving the reactions of both aminooxy and sulfonyl hydrazide nucleophiles with poly(e-caprolactone-co-2-oxepane-1,5-dione) (P(CL-co-OPD)) are studied as general methodologies employing a sequential vs a single-step approach. Agreement between product and feed stoichiometries was achieved with both of the model hydroxylamines, O-dodecylhydroxylamine or O-benzylhydroxylamine. However, when sequential reactions were performed with either hydroxylamine together with dansyl hydrazide, considerable deviations in the product composition, relative to the reaction feed stoichiometries, were noted. For a sequential series of reactions, the successful use of aminooxy and sulfonyl hydrazide molecules required ketoxime ether formation prior to sulfonyl hy...