THP-PEG3-alcohol

THP-PEG3-alcohol is a PEG-based PROTAC linker building block designed to provide a hydrophilic, flexible spacer between a target-binding ligand and an E3 ligase recruiter. Its ether-rich chain can improve solubility and help tune the effective distance and conformational freedom required for productive ternary complex formation. The following sections describe the linker’s structural features and practical considerations for assembling PROTACs using this scaffold in research workflows.

Structure: THP-PEG3-alcohol contains a tetrahydropyran (THP) protecting group attached to an oxygen-bearing linker, connected to a short polyethylene glycol segment terminated with a primary alcohol. The scaffold is dominated by ether linkages and a protected hydroxyl functionality, supporting favorable hydrophilicity and conformational flexibility.

Reactivity: The terminal primary alcohol enables derivatization through standard PROTAC linker coupling strategies, including formation of ester or carbonate linkages to connect to ligand carboxylates or activated intermediates. The THP group can be used as a protected handle, typically removed under mild acid conditions to reveal the alcohol for subsequent functionalization. Common coupling approaches rely on activated carboxylic acids (e.g., NHS/EDC-type chemistry) in polar organic solvents with base, followed by purification to obtain well-defined conjugates.