mPEG4-bromide

This mPEG-based bromide linker is designed to enable efficient installation of PEG handles in PROTAC-related constructs, improving aqueous compatibility and tuning physicochemical behavior of conjugates. Its electrophilic bromide functionality supports straightforward coupling to nucleophilic partners under standard organic conditions. The subsequent points provide detailed descriptions of the linker’s structure and practical reactivity considerations for PROTAC assembly.

Structure: The linker consists of a methoxy-terminated polyethylene glycol chain bearing a terminal bromide, providing a flexible, ether-rich polyether backbone. It contains ether linkages and a reactive carbon–bromine bond at the terminus, with a polar, hydrophilic character that promotes solubility and conformational mobility.

Reactivity: The terminal bromide can participate in nucleophilic substitution reactions with suitable nucleophiles used in PROTAC synthesis workflows, such as amines or thiols, to form stable C–N or C–S linkages. Typical conditions involve polar aprotic solvents and controlled base/temperature to favor substitution while minimizing side reactions; no special catalysts are generally required beyond standard coupling reagents used for alkylation chemistry.