I-PEG5-OH

I-PEG5-OH is a polyethylene glycol-based linker designed to support PROTAC assembly by providing a flexible, hydrophilic spacer between recognition and recruiting elements. Its ether-rich backbone can enhance solubility and help tune the effective distance and conformational freedom needed for productive ternary complex formation. Detailed structural and reactivity considerations for PROTAC synthesis are provided below.

Structure: I-PEG5-OH is a PEG chain terminating in a primary alcohol, featuring repeating ether linkages that impart flexibility and strong hydrogen-bonding capacity. The molecule is dominated by C–O ether bonds and C–C connectivity along the polymer backbone, yielding a hydrophilic, conformationally adaptable spacer suitable for bioconjugation chemistry.

Reactivity: The terminal hydroxyl enables linker functionalization via standard alcohol-to-derivative transformations commonly used in PROTAC synthesis. Suitable approaches include conversion to activated carbonate, ester, or leaving-group-bearing intermediates, followed by nucleophilic coupling to amine or other nucleophile-bearing partners under mild base or coupling conditions. Solvent systems such as polar aprotic media are typically employed, and reaction progress is monitored by chromatographic or spectroscopic methods to ensure clean linker incorporation.