Recyclability of Oxime Resin in Solid-Phase Peptide Synthesis

Greener approaches are essential to significantly reduce the environmental impact of solid phase peptide synthesis (SPPS). In this regard, we report a systematic study on the sustainable use of the Kaiser-DeGrado oxime resin. The reusability efficiency of this polystyrene-based resin was investigated through the synthesis of linear and cyclic model peptides with different structural features. We demonstrated that the oxime resin can be reused over multiple SPPS cycles without any special treatment, while still affording crude peptides in good purity and yield even after eight cycles. Furthermore, regeneration of the resin improved its efficiency approaching performances comparable to those of the freshly prepared resin. In addition, the same resin can be reused multiple times within a single reaction vessel using significantly fewer reagents and solvents, reducing material expenditures and waste while simplifying workflow.