Aminooxy-PEG4-alcohol

This Aminooxy-PEG4-alcohol linker is designed for modular PROTAC synthesis, providing an aminooxy handle for chemoselective coupling and a PEG-based spacer to tune solubility and spatial presentation of ligands. Its ether-rich, flexible architecture helps reduce steric constraints at the target-binding interface, supporting efficient formation of productive ternary complexes. The following sections describe the linker’s structure and the practical reactivity considerations for constructing PROTACs.

Structure: The linker contains an aminooxy functional group and a polyethylene glycol alcohol segment, featuring ether linkages that impart flexibility and hydrophilicity. It is characterized by an O–N bond precursor suitable for oxime formation and a terminal hydroxyl that enables further derivatization. Overall, it behaves as a PEG-based spacer with polar, hydrogen-bonding capability.

Reactivity: The aminooxy group is well suited to oxime ligation with aldehyde-bearing partners under mildly acidic to neutral conditions, typically using an aldehyde and allowing water-tolerant condensation. The ether-linked PEG chain remains stable across common coupling workflows. The terminal alcohol can be activated for subsequent conjugation routes (for example, ester or ether formation) using standard activating reagents, with solvent systems chosen to maintain solubility of both PROTAC components.