DNP-PEG4-acid

DNP-PEG4-acid is a polyethylene glycol-based PROTAC linker designed to connect a targeting ligand to an E3 ligase-recruiting moiety while providing controlled spacing and improved solubility. Its ether-rich PEG backbone can reduce steric constraints and help maintain productive ternary-complex formation. Researchers commonly use this linker in targeted protein degradation workflows, where the subsequent sections describe its structural features and practical synthetic considerations for assembling PROTAC constructs.

Structure: The linker contains a PEG chain with multiple ether linkages, terminated by a carboxylic acid functionality. This combination yields a flexible, hydrophilic scaffold capable of conformational adaptation. The presence of an acid group enables stable amide or ester formation, supporting modular PROTAC synthesis.

Reactivity: The terminal carboxylic acid is typically converted to an activated intermediate (for example, via carbodiimide coupling or acid-derivatization strategies) to enable coupling with amine-bearing partners. Amide bond formation is generally performed under mild base conditions using appropriate coupling reagents, with solvents such as DMF or DMSO commonly used to promote solubilization. The PEG ether backbone is generally compatible with standard coupling conditions, preserving linker integrity during PROTAC assembly.