This compound is widely used in peptide synthesis as an activated ester derivative. It serves as a protected form of glutamic acid, allowing for selective coupling reactions in the construction of peptides. The Boc (tert-butoxycarbonyl) group protects the amino group, while the OtBu (tert-butyl ester) group protects the carboxyl side chain. The ONp (para-nitrophenyl ester) group acts as an activating agent, facilitating efficient amide bond formation with other amino acids or peptide fragments. Its application is particularly valuable in solid-phase peptide synthesis, where controlled and stepwise assembly of peptides is required. The compound is also useful in the preparation of complex peptides and proteins, especially those involving glutamic acid residues, in both academic research and pharmaceutical development.