mPEG5-azide

mPEG5-azide is a polyethylene glycol (mPEG) functionalized with an azide handle, designed to serve as a versatile PROTAC linker component for modular assembly. Its ether-rich PEG backbone promotes solubility and flexible spacing between binding elements, while the azide enables selective bioorthogonal conjugation strategies commonly used in targeted protein degradation workflows. The points below describe its structure and the practical reactivity considerations for constructing PROTAC architectures in the laboratory.

Structure: The linker comprises an mPEG chain terminated by a terminal azide group. It contains repeating ether linkages along the PEG backbone, providing conformational flexibility and hydrophilicity. The azide moiety is a stable, resonance-stabilized functional group suitable for click-type coupling chemistry.

Reactivity: The azide group is typically engaged in azide–alkyne cycloaddition reactions to connect PROTAC fragments bearing compatible alkyne partners. Copper(I)-catalyzed or copper-free strain-promoted variants are selected based on substrate compatibility and desired reaction conditions. Commonly used solvents include aqueous mixtures and polar organic media that maintain solubility of PEGylated intermediates, with reaction progress monitored by standard analytical methods.