Aminooxy-PEG2-alcohol

Aminooxy-PEG2-alcohol is a PEG-based bifunctional linker designed for building PROTACs that employ oxime-formation chemistries. Its aminooxy handle enables efficient conjugation to carbonyl-bearing ligands, while the terminal alcohol provides a versatile site for further derivatization. The flexible polyethylene glycol segment can improve solubility and spacing between targeting and recruiting modules, supporting robust linker engineering. Detailed structural and synthetic considerations are provided below.

Structure: The linker contains an aminooxy functional group connected to a short polyethylene glycol chain terminating in a primary alcohol. It features ether linkages along the PEG backbone and an oxime-forming aminooxy moiety, providing a flexible, polar scaffold suitable for bioconjugation and aqueous compatibility.

Reactivity: The aminooxy group typically reacts with aldehydes or ketones under mild conditions to form oxime linkages, often using acid catalysis to accelerate condensation while maintaining ligand integrity. Solvents such as aqueous buffers with compatible co-solvents are commonly used, and reaction progress is monitored by analytical methods. The terminal alcohol can be activated for subsequent coupling steps, enabling modular PROTAC assembly through sequential conjugation strategies.