1-(2-(2-(2-azidoethoxy)ethoxy)ethoxy)-6-chlorohexane

This PROTAC linker provides a flexible, ether-rich scaffold incorporating an azide handle that enables modular assembly of targeted protein degraders. Its design supports efficient conjugation to ligands via bioorthogonal azide chemistry, facilitating the construction of PROTACs with tunable linker length and conformational adaptability. The azide functionality is particularly useful for late-stage functionalization, and the following sections describe its structural attributes and practical reactivity considerations in PROTAC synthesis.

Structure: The molecule contains a chlorohexane backbone bearing a terminal azidoethoxy-ethoxy-ethoxy chain. Multiple ether linkages provide conformational flexibility, while the azide group serves as a reactive functional handle. The presence of a chloro substituent contributes to distinct chemical reactivity compared with purely ether-based linkers.

Reactivity: The azide group is suited for copper-catalyzed azide–alkyne cycloaddition or strain-promoted azide–alkyne cycloaddition, enabling reliable attachment to alkyne-functional PROTAC fragments under standard click-chemistry conditions. Typical approaches use compatible polar organic solvents and, where applicable, copper catalysts with appropriate ligands to minimize side reactions. Reaction design should consider solvent compatibility and stability of the azide and partner functional groups during coupling.