Used in bioconjugation and pharmaceutical research to link molecules with improved solubility and stability. The PEG8 spacer enhances water solubility and reduces aggregation, making it ideal for constructing antibody-drug conjugates (ADCs) and targeted therapies. The azide group allows for click chemistry reactions, particularly copper-catalyzed azide-alkyne cycloaddition (CuAAC), enabling efficient and selective coupling with alkyne-containing compounds. The BOC (tert-butyloxycarbonyl) group protects the amine during synthesis and can be easily removed under mild acidic conditions to reveal the amine for further modification. Commonly used in the development of diagnostics, drug delivery systems, and functionalized biomolecules.