Benzyl-PEG4-amine

Benzyl-PEG4-amine is a polyethylene glycol–based linker building block designed to support PROTAC construction by providing a flexible, hydrophilic spacer between a ligand and an E3-recruiting or target-binding moiety. Its ether-rich PEG segment can improve solubility and help tune the effective distance and conformational freedom needed for productive ternary complex formation. The benzyl-amine functionality enables straightforward coupling strategies, and the

Structure: The linker contains a benzyl group attached to a primary amine, connected to a short PEG chain composed of repeating ether units. It features aromatic carbon–carbon bonds, benzylic C–N linkage, and multiple ether C–O bonds, yielding a flexible, polar scaffold with favorable aqueous compatibility.

Reactivity: The primary amine enables nucleophilic coupling to activated carboxylic acids or activated esters commonly used in PROTAC synthesis. Typical approaches include amide bond formation via carbodiimide-mediated activation or using acid chlorides under controlled conditions. Solvents such as polar aprotic media or compatible aqueous-organic mixtures are often employed, with base to promote amine reactivity and minimize side reactions.