Solid-Phase Supported Polymer Synthesis of Sequence-Defined, Multifunctional Poly(amidoamines)

A novel synthesis route toward multifunctional, sequence-defined polyamides is described. A fully automated, solid-phase supported polymer synthesis was developed and utilized to obtain linear poly(amidoamine) segments (PAAs) that exhibit the absence of molecular weight and chemical distribution. This was achieved by an alternating assembly of diacids and diamines, using a forced step-growth mechanism, and driving each coupling step to completion. Within the monodisperse PAA segment, functionalities can be precisely positioned along the polymer chain allowing local control of the chain properties. The versatility of the approach was demonstrated by the conjugation of the monodisperse PAA segment toward an oligopeptide, leading to a single component block copolymer as verified by mass spectrometry. Moreover, two different poly(ethylene oxide)-PAA conjugates were synthesized utilizing the direct, solid-phase supported route. By varying the PAA repeat unit, the cationic nature of the PAA segment was adjusted, demonstrating the potential of the approach. The products were characterized by means of 1H NMR and matrix-assisted laser desorption mass spectrometry (MALDI-TOF-MS) methods, which confirmed the chemical structures conclusively.