Hydroxy-Amino-bis(PEG2-propargyl)

Hydroxy-Amino-bis(PEG2-propargyl) is a PEG-based bifunctional linker designed for modular PROTAC assembly, enabling efficient conjugation between a ligand-bearing warhead and an E3-recruiting moiety. Its propargyl termini support orthogonal click chemistry, while the hydroxy and amino functionality provides additional handles for controlled derivatization and tuning of physicochemical properties. The molecule is commonly used to build degraders where linker length, polarity, and attachment geometry influence ternary complex formation and degradation performance;

Structure: The linker contains a PEG-derived ether chain backbone with terminal propargyl groups, providing flexible, hydrophilic spacing. It also includes a hydroxy group and an amino functionality, enabling hydrogen-bonding and potential salt formation. Multiple heteroatoms and carbon–carbon triple bonds define its connectivity and reactivity profile.

Reactivity: The primary synthetic utility arises from alkyne participation in copper-catalyzed azide–alkyne cycloaddition, typically requiring a Cu(I) source, an appropriate ligand, and an aqueous or mixed solvent system compatible with sensitive biomolecule conjugates. For PROTAC construction, the propargyl groups can be reacted with azide-functional partners to form stable triazole linkages. Reaction efficiency depends on solvent composition, oxygen control, and base/ligand selection to maintain catalytic Cu(I) speciation.