Ald-CH2-PEG3-azide

Ald-CH2-PEG3-azide is a bifunctional polyethylene glycol-based linker designed for modular PROTAC assembly, combining an aldehyde handle for formation of conjugates with a terminal azide for orthogonal click chemistry. Its flexible PEG scaffold can enhance solubility and provide spatial separation between binding elements, supporting efficient formation of productive ternary complexes. Detailed structural and synthetic considerations are provided below to guide linker incorporation into targeted protein degradation workflows.

Structure: The linker contains an aldehyde-bearing carbon chain connected to a short PEG segment terminating in an azide group. It features ether linkages within the PEG, a terminal azide functional group, and a carbonyl-containing aldehyde, enabling orthogonal functionalization under compatible chemistries.

Reactivity: The aldehyde can participate in carbonyl chemistry such as formation of oxime or hydrazone linkages with appropriate nucleophiles, while the azide is well-suited to copper-catalyzed or strain-promoted azide–alkyne cycloaddition to install the complementary partner. Linker conjugation is typically performed under mild, water-compatible conditions, using standard coupling reagents or click catalysts compatible with PROTAC building blocks to preserve sensitive functional groups.