Azido-PEG7-amine

Azido-PEG7-amine is a polyethylene glycol (PEG)-based bifunctional linker featuring a terminal azide and a primary amine, enabling modular assembly of PROTACs through widely used chemoselective conjugation strategies. Its flexible, hydrophilic PEG segment can improve solubility and reduce steric constraints during targeted protein degradation workflows. The azide handle supports bioorthogonal “click” coupling, while the amine provides an orthogonal attachment point for installing warheads or connecting to other PROTAC modules. Detailed structural and reactivity considerations are provided below.

Structure: The linker consists of a PEG chain terminated by an azide group and a primary amine. It contains ether linkages within the PEG backbone and an azide functionality suitable for selective cycloaddition chemistry. Overall, it is designed for aqueous compatibility and conformational flexibility in bioconjugates.

Reactivity: The azide group is typically used in copper-catalyzed azide–alkyne cycloaddition or strain-promoted azide–alkyne cycloaddition to form stable triazole linkages under mild conditions. The amine can participate in amide coupling after activation of carboxylic acids, or in carbamate/urea formation depending on the electrophile. Commonly, reactions are performed in aqueous or mixed solvents with appropriate bases, and copper-free variants are often selected to minimize metal effects on sensitive biomolecules.