N-Mal-N-bis(PEG2-amine)

N-Mal-N-bis(PEG2-amine) is a polyethylene glycol (PEG)-based bifunctional linker designed for assembling PROTAC constructs through robust amide-forming or amine-coupling strategies. Its flexible hydrophilic PEG segments can help tune solubility and reduce nonspecific interactions, supporting efficient ternary complex formation. The bis-amine functionality enables systematic conjugation to targeting ligands and E3 ligase recruiters, facilitating modular synthesis.

Structure: The molecule contains a maleimide-derived core substituted with two PEG-terminated amine arms. It features amide/urea-compatible functional groups, ether linkages within the PEG chains, and a maleimide-type electrophilic motif. The presence of PEG segments confers pronounced hydrophilicity and conformational flexibility, supporting aqueous handling and bioconjugation workflows.

Reactivity: Suitable PROTAC assembly typically employs amine-reactive coupling of the PEG-amine termini to complementary activated carboxyl or activated ester groups on ligands, using standard peptide-coupling chemistries. Where maleimide reactivity is leveraged, nucleophilic addition to thiol-containing partners proceeds under mildly basic aqueous conditions, often without harsh oxidants. Common catalysts include carbodiimides and bases, with polar aprotic or aqueous buffers to maintain solubility and control side reactions.