Benzyl-PEG18-MS is a high-purity PROTAC linker belonging to the polyethylene glycol (PEG) class of compounds. Its molecular structure consists of a benzyl group, 18 ethylene glycol repeating units, and a methanesulfonate ester group, endowing it with excellent hydrophilicity and reactivity. The production process employs precisely controlled esterification reactions, using benzyl alcohol and methanesulfonyl chloride as raw materials.定向偶联 is carried out under low temperature and inert gas protection, followed by purification via molecular distillation to obtain a product with purity ≥99%. This compound is primarily used in PROTAC molecule design, serving as a critical bridge connecting E3 ubiquitin ligase ligands with target protein ligands. It shows broad application prospects in fields such as tumor-targeted therapy and neurodegenerative disease research.