"High-load" polyethylene glycol-polystyrene (PEG-PS) graft supports for solid-phase synthesis.

The choice of a polymeric support is a key factor for the success of solid-phase methods for syntheses of organic compounds and biomolecules such as peptides and oligonucleotides. Classical Merrifield solid-phase peptide synthesis (SPPS), performed on low cross-linked hydrophobic polystyrene (PS) beads, sometimes suffers from sequence-dependent coupling difficulties. The concept of incorporating polyethylene glycol (PEG) into supports for solid-phase synthesis represents a successful approach to alleviating such problems. Previous reports from our laboratories have shown the advantages of "low-load" PEG-PS (0.15-0.25 mmol/g) for SPPS. Herein, we demonstrate that the beneficial aspects of the PEG-PS concept can be extended with resins that have higher loadings (0.3-0.5 mmol/g).