MS-PEG4-THP

This MS-PEG4-THP linker is designed for modular PROTAC assembly, providing a flexible polyethylene glycol spacer that can improve effective intramolecular reach and maintain productive geometry between the target-binding ligand and the E3 ligase-recruiting moiety. Its ether-rich, hydrophilic architecture supports solubility and can reduce nonspecific aggregation in aqueous formulations. The detailed structural and synthetic considerations are provided below to support robust linker incorporation into targeted protein degradation constructs.

Structure: The linker comprises a PEG-based polyether chain terminated with a tetrahydropyran (THP) functional handle suitable for further derivatization. It contains ether linkages that confer conformational flexibility, along with heteroatom-rich connectivity that enhances polarity and hydrogen-bonding capacity, supporting improved aqueous compatibility.

Reactivity: THP-functionalized linker handles are commonly used in PROTAC synthesis as protected or activated intermediates that can be converted under established organic conditions to introduce the required attachment point to ligands. Typical workflows rely on selective deprotection or functional-group interconversion using standard acid- or base-mediated strategies, followed by coupling reactions to form stable amide, carbamate, or related linkages. Solvent systems are chosen to balance PEG solubility and coupling efficiency, often using polar aprotic media and temperature-controlled conditions to preserve sensitive ligand functionality.