Used as a key intermediate in the synthesis of pharmaceutical compounds, particularly in the development of targeted drug delivery systems. Its aldehyde functional group allows for conjugation with biomolecules such as peptides or antibodies through reductive amination, enabling the creation of bioconjugates for diagnostic or therapeutic applications. The tert-butyl ester can be deprotected to a carboxylic acid for further conjugation or linker attachment. The polyether chain provides water solubility and flexibility, enhancing biocompatibility and improving pharmacokinetic properties in final drug formulations. Commonly employed in the preparation of prodrugs and linker systems in antibody-drug conjugates (ADCs), where controlled release and stability are critical.