Thiol-PEG5-alcohol

Thiol-PEG5-alcohol is a polyethylene glycol-based bifunctional linker designed for modular PROTAC assembly, enabling efficient conjugation to thiol-reactive warheads and subsequent coupling to other PROTAC components. Its flexible PEG scaffold supports favorable solubility and conformational adaptability, which can improve effective engagement of target proteins in targeted degradation workflows. The structure and reactivity considerations for using this linker in PROTAC synthesis are described in detail below.

Structure: The linker comprises a PEG-derived ether backbone terminating in an alcohol and a thiol functionality. It contains repeating ethylene glycol units providing hydrophilicity and conformational flexibility, with C–O ether linkages and terminal functional groups suitable for controlled bioconjugation chemistry.

Reactivity: Thiol-PEG5-alcohol is typically used in thiol-selective conjugation strategies, including alkylation or maleimide-type thioether formation, depending on the complementary PROTAC handle. For reliable coupling, maintain conditions that preserve thiol integrity, use inert atmospheres when appropriate, and select solvents compatible with both partners. Mild bases or buffering systems are commonly employed to promote nucleophilic thiol reactivity without degrading sensitive ligands.