Methylamino-PEG3-azide

Methylamino-PEG3-azide is a polyethylene glycol (PEG)-based bifunctional linker designed for modular PROTAC synthesis, enabling efficient conjugation between a targeting ligand and an E3 ligase recruiter. Its PEG spacer supports favorable solubility and conformational flexibility, which can improve productive ternary complex formation. The azide handle provides a widely used chemical “click” site for bioconjugation, while the amine functionality supports complementary coupling strategies.

Structure: The linker contains a PEG chain with ether linkages, terminated by an azide group and a methylamino substituent. The azide is a stable azide functionality suitable for copper-catalyzed azide–alkyne cycloaddition, while the amine enables nucleophilic coupling. Overall, the PEG segment imparts hydrophilicity and chain flexibility.

Reactivity: The azide group participates in azide–alkyne cycloaddition under standard click chemistry conditions, typically using a copper catalyst system and an appropriate solvent compatible with both partners. For amine-mediated assembly, nucleophilic substitution or amide/urea-forming coupling can be performed using activated carboxylic acid derivatives under base and inert or controlled atmospheres. Reaction design should consider aqueous solubility, steric accessibility, and preservation of sensitive functional groups.