N-(Propargyl-PEG4-carbonyl)-N-bis(PEG1-methyl ester)

This PROTAC linker is designed to provide a stable, water-compatible polyethylene glycol scaffold that supports efficient conjugation between targeting ligands and E3-recruiting modules. Its PEG-rich architecture enhances solubility and can improve the effective reach and flexibility required for productive ternary complex formation. The linker’s functional handles enable modular assembly under standard bioconjugation workflows, facilitating systematic PROTAC optimization;

Structure: The molecule contains a carbonyl-linked PEG framework bearing propargyl functionality and bis(PEG1-methyl ester) termini. It features amide and ester linkages, ether-rich PEG segments, and a terminal alkyne suitable for chemoselective coupling. Overall, it is highly polar and typically exhibits good aqueous compatibility.

Reactivity: The propargyl group supports copper-catalyzed azide–alkyne cycloaddition or related alkyne-based conjugation strategies to connect PROTAC components bearing azide handles. Ester functionalities can participate in standard ester-to-amide transformations or be used as protected reactive sites depending on the chosen synthetic route. Typical preparations use inert atmospheres, polar organic solvents, and mild base or coupling conditions compatible with PEG stability, with catalysts selected according to the coupling chemistry employed.