Cbz-N-amido-PEG8-acid

Cbz-N-amido-PEG8-acid, is designed to provide a flexible, water-compatible spacer that can connect a protein-binding ligand to an E3-recruiting moiety while supporting productive ternary complex formation. The linker’s PEG-based chain and amide functionality help tune distance and solubility, which are critical for targeted protein degradation workflows. The details below describe its structural features and practical considerations for PROTAC assembly.

Structure: The molecule contains a PEG ether backbone providing conformational flexibility and enhanced hydrophilicity, coupled to an amide linkage and a carboxylic acid handle. A benzyloxycarbonyl (Cbz) protecting group is present, enabling controlled functional-group transformations. Overall, it behaves as a polar, linker-type scaffold.

Reactivity: The carboxylic acid can be activated for amide-bond formation with amine-bearing ligands, commonly via carbodiimide-mediated coupling. The Cbz group is typically removed under hydrogenolysis conditions to expose the corresponding amine for subsequent conjugation steps. PEG linkers are generally compatible with standard organic synthesis solvents, but maintaining anhydrous conditions during activation steps can improve coupling efficiency.