Used primarily as a key reagent in bioconjugation chemistry, especially in click chemistry applications. The azido group enables efficient copper-catalyzed azide-alkyne cycloaddition (CuAAC) reactions, allowing selective attachment to alkynes for labeling biomolecules such as peptides, proteins, and nucleic acids. The polyether backbone enhances water solubility and reduces nonspecific binding, making it ideal for use in biological assays and diagnostic probes. Commonly employed in the synthesis of PEGylated compounds to improve pharmacokinetic properties of therapeutic molecules. Also utilized in the development of functionalized surfaces for biosensors and microarrays. Its tert-butyl ester group can be deprotected under mild acidic conditions, enabling further coupling reactions in multi-step syntheses.