Bromo-PEG7-alcohol

Bromo-PEG7-alcohol is a polyethylene glycol-based linker bearing a terminal bromo functional group and a hydroxyl handle, designed to support modular synthesis of PROTACs through controlled attachment to ligands. Its flexible PEG scaffold can enhance solubility and provide spacing between binding elements, which is beneficial for efficient ternary complex formation. The following sections describe the linker’s structural features and practical reactivity considerations for constructing PROTAC architectures in the laboratory.

Structure: The molecule consists of a PEG chain terminated by a primary alcohol and a bromo substituent, providing a flexible, ether-rich backbone. The key functional groups include an alkyl bromide suitable for substitution and an alcohol for derivatization. The structure contains ether linkages and a reactive carbon–bromine bond.

Reactivity: The terminal bromo group is typically used in nucleophilic substitution reactions to connect the linker to ligand-derived nucleophiles (such as amines or oxygen nucleophiles), proceeding via an SN-type displacement pathway depending on substrate and conditions. Common approaches employ polar aprotic solvents and controlled base systems to promote substitution while minimizing side reactions. The hydroxyl group can be converted to activated derivatives (for example, via standard esterification or carbonate formation) to enable further coupling to complementary functional groups.