BOC-SAR-OSU, or N-(tert-Butoxycarbonyl)sarcosine N-hydroxysuccinimide ester, is a specialized reagent in peptide synthesis. It acts as an activated ester of Boc-protected sarcosine, enabling efficient and selective coupling of the sarcosine residue to the amino terminus of peptide chains. This compound is crucial in solid-phase peptide synthesis (SPPS), providing stability, high yield, and control to minimize side reactions. It is extensively used in the preparation of complex peptides and proteins for biochemical research, pharmaceutical development, and the synthesis of bioactive peptides with potential therapeutic applications.