26-Hydroxy-3,6,9,12,15,18,21,24-octaoxahexacosyl 4-methylbenzenesulfonate

26-Hydroxy-3,6,9,12,15,18,21,24-octaoxahexacosyl 4-methylbenzenesulfonate, is designed to provide a flexible, poly(ethylene glycol)-like tether terminated with a sulfonate leaving group. Such linkers are widely used to connect ligands for targeted protein degradation, supporting controlled spatial presentation and improved solubility of conjugates. The following points describe its structure and practical reactivity considerations for PROTAC assembly in detail below.

Structure: The molecule contains a long, ether-rich chain with multiple oxygen atoms that confer conformational flexibility and hydrophilicity. It terminates in a sulfonate ester derived from 4-methylbenzenesulfonic acid, featuring a sulfonyl group linked to an oxygen leaving group. These features enable efficient ligand conjugation while maintaining aqueous compatibility.

Reactivity: The terminal arylsulfonate ester is suitable for nucleophilic substitution reactions with alcohol or amine nucleophiles under standard organic synthesis conditions. Conjugation is typically performed by activating the sulfonate toward displacement, using polar aprotic or mixed solvent systems and base to promote nucleophile formation. Reaction proceeds via a leaving-group displacement mechanism, and the sulfonate’s aryl sulfonyl group supports reliable transfer chemistry during PROTAC linker installation.