Azido-PEG5-alcohol

Azido-PEG5-alcohol is a polyethylene glycol-based linker bearing a terminal azide and a hydroxyl group, designed for modular assembly of PROTAC constructs. Its flexible PEG scaffold supports favorable solubility and conformational adaptability, while the azide handle enables bioorthogonal conjugation to complementary partners used in targeted protein degradation workflows. The hydroxyl functionality further facilitates downstream derivatization. Detailed structural and reactivity considerations are provided below.

Structure: The linker consists of an ether-rich PEG chain terminating in an azide and an alcohol. It features multiple C–O ether linkages that confer flexibility, along with a terminal organic azide suitable for click-type coupling. The presence of a hydroxyl group provides an additional functional site for derivatization.

Reactivity: The terminal azide is compatible with copper-catalyzed azide–alkyne cycloaddition and related strain-promoted azide–alkyne reactions, enabling efficient formation of stable triazole linkages under mild, commonly used synthetic conditions. For PROTAC assembly, select the complementary alkyne-bearing warhead or E3 ligase ligand and perform conjugation in appropriate polar organic solvents with standard catalytic systems and oxygen-tolerant handling as required. The alcohol group can be functionalized for further coupling steps when needed.