mPEG8-bromide

This mPEG8-bromide is a polyethylene glycol-based brominated linker designed to support the modular synthesis of PROTAC conjugates. Its ether-rich, flexible scaffold can improve solubility and bioconjugation handling while providing a reactive bromide handle for controlled attachment to targeting ligands. The following points describe the linker’s structure and the practical reactivity considerations for assembling PROTAC architectures in a research setting.

Structure: The molecule comprises a methoxy-terminated poly(ethylene glycol) chain bearing a terminal bromide. It features repeating ether linkages that confer conformational flexibility, low polarity, and favorable hydrophilicity. The terminal C–Br bond serves as a leaving group for substitution, while the ether oxygen atoms stabilize solvated intermediates.

Reactivity: The bromide enables nucleophilic substitution under standard alkylation conditions used for PEG-linker installation in bioconjugation workflows. Suitable nucleophiles include amines or thiolates derived from functionalized targeting ligands, typically generated under mildly basic conditions. Polar aprotic solvents such as DMF or DMSO are commonly employed to promote SN2 reactivity, with temperature and stoichiometry tuned to minimize side reactions like elimination.