Azido-PEG10-Acid

Azido-PEG10-Acid is a PEG-based PROTAC linker building block designed to connect a ligand-bearing functional group to the E3-recruiting or target-binding module through a chemically addressable handle. Its azide functionality enables robust bioorthogonal conjugation strategies, while the terminal acid supports straightforward coupling to activated derivatives. The flexible, hydrophilic PEG segment helps reduce steric constraints and can improve solubility and effective linker presentation in targeted protein degradation workflows. Detailed structural and reactivity considerations are provided below.

Structure: Azido-PEG10-Acid comprises a polyethylene glycol chain terminated by an azide group and a carboxylic acid. It contains ether linkages along the PEG backbone, with an aliphatic azide substituent and a terminal carboxyl group capable of forming amide or ester derivatives. The linker is typically hydrophilic and conformationally flexible.

Reactivity: The azide group is commonly used for copper-free “click” conjugation (strain-promoted azide–alkyne cycloaddition) or, where appropriate, azide-compatible coupling chemistries under conditions that preserve sensitive biomolecules. The carboxylic acid is suitable for activation to form reactive intermediates (for example, acid chlorides or activated esters) for subsequent amide bond formation. Typical PROTAC assembly employs dry, polar organic solvents with controlled pH and temperature, using standard coupling reagents and bases to drive efficient conjugation while minimizing side reactions.