Evaluation of greener solvents for solid-phase peptide synthesis

Polar aprotic solvents such as N,N-Dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP), N,N'-dimethylacetamide (DMAc) and chlorinated solvent such dichloromethane (DCM) are the most widely used solvents for Fmoc solid-phase peptide synthesis (SPPS). These solvents are considered hazardous chemicals but are normally used in large amounts for washing, deprotection, and coupling steps during SPPS. DMF, DMAc and NMP are classified as toxic for reproduction in accordance with Article 57(c) of REACH (Registration, Evaluation Authorization and Restriction of CHemicals) and were identified as SVHC (Substance Very High Concern). The aim of this study was to find a greener solvent alternative which could replace DMF in SPPS manufacturing processes at Ipsen. Greener solvents which demonstrated efficient resin swelling and solubility were selected as candidates for SPPS trials for the small-scale synthesis of commercial and developmental peptides.