Abstract
For the synthesis of peptide containing glutamic acid residue (s) by solid phase peptide synthesis, γ-phenacyl or γ-nitrobenzyl ester group, which is stable to anhydrous hydrogen fluoride (HF), was used as γ-carboxyl protecting group of glutamic acid to minimize the side reactions. The protected peptide resins were treated with HF-anisole mixture followed by deprotection of the γ-carboxyl protecting group under mild conditions. This strategy gave a satisfactory result without detectable side reactions in the preparations of two model dipeptides, H-Ala-Glu-OH and H-Asn-Glu-OH, by solid phase peptide synthesis.
