DNP-PEG3-N3

DNP-PEG3-N3 is a polyethylene glycol-based PROTAC linker designed to connect a targeting ligand to an E3 ligase-recruiting moiety through a terminal azide handle. Its flexible PEG spacer can improve conjugation efficiency and modulate the effective distance and mobility of the assembled degrader, supporting efficient formation of productive ternary complexes. The structure and reactivity considerations for synthesizing PROTACs with this linker are described in detail below.

Structure: DNP-PEG3-N3 contains a PEG chain that provides hydrophilicity and conformational flexibility, terminating in an azide functional group. The linker features ether linkages within the PEG backbone and a terminal azide suitable for bioorthogonal conjugation chemistry, supporting stable, water-compatible PROTAC architectures.

Reactivity: The terminal azide enables copper-catalyzed azide–alkyne cycloaddition or strain-promoted azide–alkyne cycloaddition, allowing modular attachment to alkyne-functional partners under conditions compatible with many ligands. Typical approaches use inert atmosphere and standard organic solvents for CuAAC, while SPAAC can be performed without copper. Reaction progress is monitored by chromatographic methods, and purification is commonly achieved by preparative chromatography or precipitation, depending on the conjugate polarity.