Pseudo-Wang Handle for the Preparation of Fully Protected Peptides. Synthesis of Liraglutide by Fragment Condensation

A handle for the protection of the C-terminus of peptides after cleaving with low concentration of trifluoroacetic acid (2–4%) is reported. The handle prevents polymerization reactions in the convergent condensation of peptidic fragments. Moreover, it is traceless, being removed during the final deprotection step of the peptide synthesis. This cheap and convenient handle is easily attached to the solid support, causing no disturbance to peptide elongation and thus proving to be useful in the convergent synthesis of long peptides.