AcS-PEG4-OH

AcS-PEG4-OH is a polyethylene glycol (PEG)-based linker designed to support targeted protein degradation workflows by providing a flexible, hydrophilic spacer between a ligand and an E3-recruiting or target-binding module. Its ether-rich backbone can improve solubility and help tune the effective distance and conformational freedom required for productive ternary complex formation. The linker is well suited for modular PROTAC assembly, and the points below describe its structure and practical reactivity considerations in detail.

Structure: AcS-PEG4-OH comprises a PEG chain terminating in a hydroxyl group, with an acyl thioether (AcS) functionality that can serve as a reactive handle. The molecule is dominated by ether linkages, offering flexibility and strong hydrogen-bonding capacity via the terminal alcohol.

Reactivity: For PROTAC construction, the terminal hydroxyl enables standard coupling strategies such as esterification or ether formation after conversion to an activated intermediate. The acyl thioether handle can be leveraged for chemoselective transformations under conditions compatible with PEG stability, typically using mild bases or coupling reagents in polar organic solvents. Reaction design should prioritize preservation of PEG integrity and maintain linker flexibility for downstream conjugation steps.