m-PEG5-Ms

This m-PEG5-Ms linker is designed to serve as a polyethylene glycol-based, mesylate-activated connector for building PROTACs via robust nucleophilic substitution. Its PEG character supports solubility and flexible spacing, while the mesylate leaving group enables efficient coupling to nucleophilic partners under standard organic synthesis conditions. The resulting linkers can be incorporated into targeted protein degradation constructs, where reliable bioconjugation chemistry is essential for assembling stable, well-defined PROTAC architectures. Detailed structure and reactivity considerations follow below.

Structure: m-PEG5-Ms is a PEG-linked mesylate featuring an aryl-substituted PEG segment terminated by a mesylate ester. The molecule contains ether linkages within the PEG chain and a sulfonate ester at the reactive terminus, providing a polar, flexible scaffold suitable for conjugation.

Reactivity: The mesylate group undergoes substitution with nucleophiles such as amines or thiols to form stable C–N or C–S bonds, typically under mild to moderate base conditions. Common solvents include polar aprotic media that support SN-type displacement. No special catalysts are required beyond standard coupling bases; reaction rates depend on nucleophile strength and leaving-group accessibility, enabling straightforward PROTAC assembly workflows.