NH-bis(PEG3-azide)

This PROTAC linker is designed to enable efficient conjugation strategies by providing a PEG-based spacer terminating in azide functionality. Its flexible ether-rich backbone can support productive ternary complex formation by reducing steric constraints, while the azide handle offers a widely used chemical “click” entry point for attaching ligands to E3 ligase or target-binding modules. The following sections describe its structural features and practical reactivity considerations for PROTAC assembly in research workflows.

Structure: NH-bis(PEG3-azide) contains a central amine (NH) connected to two PEG chains, each capped with an azide group. The linker is dominated by ether linkages that impart conformational flexibility and hydrophilicity, while the terminal azides provide orthogonal reactivity for bioconjugation.

Reactivity: The azide termini are suitable for copper-catalyzed azide–alkyne cycloaddition with complementary alkyne-functional partners, enabling rapid formation of stable triazole linkages under standard click chemistry conditions. Alternatively, strain-promoted azide–alkyne cycloaddition can be used when copper-free labeling is preferred. Typical solvents include polar aprotic media compatible with both azide stability and alkyne reactivity, and catalyst systems are selected to balance reaction rate and protein/ligand integrity during PROTAC synthesis.