This compound, Boc-Glu(Osu)-OtBu, is a protected derivative of glutamic acid widely used in peptide synthesis. The N-Boc (tert-butoxycarbonyl) group protects the α-amino function, the tert-butyl ester (OtBu) protects the side chain carboxyl group, and the OSu (N-hydroxysuccinimide) ester activates the α-carboxyl group for efficient amide bond formation with amines of other amino acids. It prevents unwanted side reactions during peptide coupling. These groups provide stability and selective deprotection under mild conditions, making it essential for stepwise construction of complex peptides, especially in solid-phase peptide synthesis (SPPS) and pharmaceutical peptide preparation. It supports the development of peptide-based drugs and bioactive molecules with high purity and yield.