Boc-Glycine N-hydroxysuccinimide ester is a white to off-white crystalline powder with the molecular formula C11H16N2O6. It is a highly reactive active ester derivative of Boc-protected glycine, where the carboxylic acid group is activated by N-hydroxysuccinimide (NHS) to form an ester. This compound is a key reagent in peptide synthesis and bioconjugation chemistry. Its primary application is as a coupling reagent in solid-phase and solution-phase peptide synthesis. The NHS ester moiety readily reacts with primary amines (e.g., the N-terminus of a growing peptide chain or lysine side chains in proteins) under mild conditions to form stable amide bonds, while the Boc (tert-butoxycarbonyl) group serves as a temporary protecting group for the amino group of glycine. This makes it an essential building block for introducing a Boc-Glycine residue into peptides, proteins, or other amine-containing molecules. It is widely used in the synthesis of peptide drugs, diagnostic reagents, and for modifying biomolecules. The compound must be stored under anhydrous conditions at low temperatures (e.g., -20°C) due to its sensitivity to moisture, which can lead to hydrolysis and loss of reactivity. It is a standard, commercially available reagent in pharmaceutical research and development for constructing peptide backbones and creating conjugates.